From: Andrei Zmievski Date: Tue, 11 Apr 2000 17:36:06 +0000 (+0000) Subject: Added PCRE 3.01. X-Git-Tag: php-4.0RC2~413 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=e39d70fff6f3520e26358bb2e894f59fb9c95e25;p=php Added PCRE 3.01. --- diff --git a/ext/pcre/pcrelib/doc/Tech.Notes b/ext/pcre/pcrelib/doc/Tech.Notes new file mode 100644 index 0000000000..03904db3cc --- /dev/null +++ b/ext/pcre/pcrelib/doc/Tech.Notes @@ -0,0 +1,242 @@ +Technical Notes about PCRE +-------------------------- + +Many years ago I implemented some regular expression functions to an algorithm +suggested by Martin Richards. These were not Unix-like in form, and were quite +restricted in what they could do by comparison with Perl. The interesting part +about the algorithm was that the amount of space required to hold the compiled +form of an expression was known in advance. The code to apply an expression did +not operate by backtracking, as the Henry Spencer and Perl code does, but +instead checked all possibilities simultaneously by keeping a list of current +states and checking all of them as it advanced through the subject string. (In +the terminology of Jeffrey Friedl's book, it was a "DFA algorithm".) When the +pattern was all used up, all remaining states were possible matches, and the +one matching the longest subset of the subject string was chosen. This did not +necessarily maximize the individual wild portions of the pattern, as is +expected in Unix and Perl-style regular expressions. + +By contrast, the code originally written by Henry Spencer and subsequently +heavily modified for Perl actually compiles the expression twice: once in a +dummy mode in order to find out how much store will be needed, and then for +real. The execution function operates by backtracking and maximizing (or, +optionally, minimizing in Perl) the amount of the subject that matches +individual wild portions of the pattern. This is an "NFA algorithm" in Friedl's +terminology. + +For the set of functions that forms PCRE (which are unrelated to those +mentioned above), I tried at first to invent an algorithm that used an amount +of store bounded by a multiple of the number of characters in the pattern, to +save on compiling time. However, because of the greater complexity in Perl +regular expressions, I couldn't do this. In any case, a first pass through the +pattern is needed, in order to find internal flag settings like (?i) at top +level. So PCRE works by running a very degenerate first pass to calculate a +maximum store size, and then a second pass to do the real compile - which may +use a bit less than the predicted amount of store. The idea is that this is +going to turn out faster because the first pass is degenerate and the second +pass can just store stuff straight into the vector. It does make the compiling +functions bigger, of course, but they have got quite big anyway to handle all +the Perl stuff. + +The compiled form of a pattern is a vector of bytes, containing items of +variable length. The first byte in an item is an opcode, and the length of the +item is either implicit in the opcode or contained in the data bytes which +follow it. A list of all the opcodes follows: + +Opcodes with no following data +------------------------------ + +These items are all just one byte long + + OP_END end of pattern + OP_ANY match any character + OP_SOD match start of data: \A + OP_CIRC ^ (start of data, or after \n in multiline) + OP_NOT_WORD_BOUNDARY \W + OP_WORD_BOUNDARY \w + OP_NOT_DIGIT \D + OP_DIGIT \d + OP_NOT_WHITESPACE \S + OP_WHITESPACE \s + OP_NOT_WORDCHAR \W + OP_WORDCHAR \w + OP_EODN match end of data or \n at end: \Z + OP_EOD match end of data: \z + OP_DOLL $ (end of data, or before \n in multiline) + OP_RECURSE match the pattern recursively + + +Repeating single characters +--------------------------- + +The common repeats (*, +, ?) when applied to a single character appear as +two-byte items using the following opcodes: + + OP_STAR + OP_MINSTAR + OP_PLUS + OP_MINPLUS + OP_QUERY + OP_MINQUERY + +Those with "MIN" in their name are the minimizing versions. Each is followed by +the character that is to be repeated. Other repeats make use of + + OP_UPTO + OP_MINUPTO + OP_EXACT + +which are followed by a two-byte count (most significant first) and the +repeated character. OP_UPTO matches from 0 to the given number. A repeat with a +non-zero minimum and a fixed maximum is coded as an OP_EXACT followed by an +OP_UPTO (or OP_MINUPTO). + + +Repeating character types +------------------------- + +Repeats of things like \d are done exactly as for single characters, except +that instead of a character, the opcode for the type is stored in the data +byte. The opcodes are: + + OP_TYPESTAR + OP_TYPEMINSTAR + OP_TYPEPLUS + OP_TYPEMINPLUS + OP_TYPEQUERY + OP_TYPEMINQUERY + OP_TYPEUPTO + OP_TYPEMINUPTO + OP_TYPEEXACT + + +Matching a character string +--------------------------- + +The OP_CHARS opcode is followed by a one-byte count and then that number of +characters. If there are more than 255 characters in sequence, successive +instances of OP_CHARS are used. + + +Character classes +----------------- + +OP_CLASS is used for a character class, provided there are at least two +characters in the class. If there is only one character, OP_CHARS is used for a +positive class, and OP_NOT for a negative one (that is, for something like +[^a]). Another set of repeating opcodes (OP_NOTSTAR etc.) are used for a +repeated, negated, single-character class. The normal ones (OP_STAR etc.) are +used for a repeated positive single-character class. + +OP_CLASS is followed by a 32-byte bit map containing a 1 bit for every +character that is acceptable. The bits are counted from the least significant +end of each byte. + + +Back references +--------------- + +OP_REF is followed by a single byte containing the reference number. + + +Repeating character classes and back references +----------------------------------------------- + +Single-character classes are handled specially (see above). This applies to +OP_CLASS and OP_REF. In both cases, the repeat information follows the base +item. The matching code looks at the following opcode to see if it is one of + + OP_CRSTAR + OP_CRMINSTAR + OP_CRPLUS + OP_CRMINPLUS + OP_CRQUERY + OP_CRMINQUERY + OP_CRRANGE + OP_CRMINRANGE + +All but the last two are just single-byte items. The others are followed by +four bytes of data, comprising the minimum and maximum repeat counts. + + +Brackets and alternation +------------------------ + +A pair of non-capturing (round) brackets is wrapped round each expression at +compile time, so alternation always happens in the context of brackets. +Non-capturing brackets use the opcode OP_BRA, while capturing brackets use +OP_BRA+1, OP_BRA+2, etc. [Note for North Americans: "bracket" to some English +speakers, including myself, can be round, square, curly, or pointy. Hence this +usage.] + +A bracket opcode is followed by two bytes which give the offset to the next +alternative OP_ALT or, if there aren't any branches, to the matching KET +opcode. Each OP_ALT is followed by two bytes giving the offset to the next one, +or to the KET opcode. + +OP_KET is used for subpatterns that do not repeat indefinitely, while +OP_KETRMIN and OP_KETRMAX are used for indefinite repetitions, minimally or +maximally respectively. All three are followed by two bytes giving (as a +positive number) the offset back to the matching BRA opcode. + +If a subpattern is quantified such that it is permitted to match zero times, it +is preceded by one of OP_BRAZERO or OP_BRAMINZERO. These are single-byte +opcodes which tell the matcher that skipping this subpattern entirely is a +valid branch. + +A subpattern with an indefinite maximum repetition is replicated in the +compiled data its minimum number of times (or once with a BRAZERO if the +minimum is zero), with the final copy terminating with a KETRMIN or KETRMAX as +appropriate. + +A subpattern with a bounded maximum repetition is replicated in a nested +fashion up to the maximum number of times, with BRAZERO or BRAMINZERO before +each replication after the minimum, so that, for example, (abc){2,5} is +compiled as (abc)(abc)((abc)((abc)(abc)?)?)?. The 200-bracket limit does not +apply to these internally generated brackets. + + +Assertions +---------- + +Forward assertions are just like other subpatterns, but starting with one of +the opcodes OP_ASSERT or OP_ASSERT_NOT. Backward assertions use the opcodes +OP_ASSERTBACK and OP_ASSERTBACK_NOT, and the first opcode inside the assertion +is OP_REVERSE, followed by a two byte count of the number of characters to move +back the pointer in the subject string. A separate count is present in each +alternative of a lookbehind assertion, allowing them to have different fixed +lengths. + + +Once-only subpatterns +--------------------- + +These are also just like other subpatterns, but they start with the opcode +OP_ONCE. + + +Conditional subpatterns +----------------------- + +These are like other subpatterns, but they start with the opcode OP_COND. If +the condition is a back reference, this is stored at the start of the +subpattern using the opcode OP_CREF followed by one byte containing the +reference number. Otherwise, a conditional subpattern will always start with +one of the assertions. + + +Changing options +---------------- + +If any of the /i, /m, or /s options are changed within a parenthesized group, +an OP_OPT opcode is compiled, followed by one byte containing the new settings +of these flags. If there are several alternatives in a group, there is an +occurrence of OP_OPT at the start of all those following the first options +change, to set appropriate options for the start of the alternative. +Immediately after the end of the group there is another such item to reset the +flags to their previous values. Other changes of flag within the pattern can be +handled entirely at compile time, and so do not cause anything to be put into +the compiled data. + + +Philip Hazel +February 2000 diff --git a/ext/pcre/pcrelib/doc/pcre.3 b/ext/pcre/pcrelib/doc/pcre.3 new file mode 100644 index 0000000000..bd435e9ecd --- /dev/null +++ b/ext/pcre/pcrelib/doc/pcre.3 @@ -0,0 +1,1702 @@ +.TH PCRE 3 +.SH NAME +pcre - Perl-compatible regular expressions. +.SH SYNOPSIS +.B #include +.PP +.SM +.br +.B pcre *pcre_compile(const char *\fIpattern\fR, int \fIoptions\fR, +.ti +5n +.B const char **\fIerrptr\fR, int *\fIerroffset\fR, +.ti +5n +.B const unsigned char *\fItableptr\fR); +.PP +.br +.B pcre_extra *pcre_study(const pcre *\fIcode\fR, int \fIoptions\fR, +.ti +5n +.B const char **\fIerrptr\fR); +.PP +.br +.B int pcre_exec(const pcre *\fIcode\fR, "const pcre_extra *\fIextra\fR," +.ti +5n +.B "const char *\fIsubject\fR," int \fIlength\fR, int \fIstartoffset\fR, +.ti +5n +.B int \fIoptions\fR, int *\fIovector\fR, int \fIovecsize\fR); +.PP +.br +.B int pcre_copy_substring(const char *\fIsubject\fR, int *\fIovector\fR, +.ti +5n +.B int \fIstringcount\fR, int \fIstringnumber\fR, char *\fIbuffer\fR, +.ti +5n +.B int \fIbuffersize\fR); +.PP +.br +.B int pcre_get_substring(const char *\fIsubject\fR, int *\fIovector\fR, +.ti +5n +.B int \fIstringcount\fR, int \fIstringnumber\fR, +.ti +5n +.B const char **\fIstringptr\fR); +.PP +.br +.B int pcre_get_substring_list(const char *\fIsubject\fR, +.ti +5n +.B int *\fIovector\fR, int \fIstringcount\fR, "const char ***\fIlistptr\fR);" +.PP +.br +.B const unsigned char *pcre_maketables(void); +.PP +.br +.B int pcre_fullinfo(const pcre *\fIcode\fR, "const pcre_extra *\fIextra\fR," +.ti +5n +.B int \fIwhat\fR, void *\fIwhere\fR); +.PP +.br +.B int pcre_info(const pcre *\fIcode\fR, int *\fIoptptr\fR, int +.B *\fIfirstcharptr\fR); +.PP +.br +.B char *pcre_version(void); +.PP +.br +.B void *(*pcre_malloc)(size_t); +.PP +.br +.B void (*pcre_free)(void *); + + + +.SH DESCRIPTION +The PCRE library is a set of functions that implement regular expression +pattern matching using the same syntax and semantics as Perl 5, with just a few +differences (see below). The current implementation corresponds to Perl 5.005, +with some additional features from the Perl development release. + +PCRE has its own native API, which is described in this document. There is also +a set of wrapper functions that correspond to the POSIX regular expression API. +These are described in the \fBpcreposix\fR documentation. + +The native API function prototypes are defined in the header file \fBpcre.h\fR, +and on Unix systems the library itself is called \fBlibpcre.a\fR, so can be +accessed by adding \fB-lpcre\fR to the command for linking an application which +calls it. The header file defines the macros PCRE_MAJOR and PCRE_MINOR to +contain the major and minor release numbers for the library. Applications can +use these to include support for different releases. + +The functions \fBpcre_compile()\fR, \fBpcre_study()\fR, and \fBpcre_exec()\fR +are used for compiling and matching regular expressions, while +\fBpcre_copy_substring()\fR, \fBpcre_get_substring()\fR, and +\fBpcre_get_substring_list()\fR are convenience functions for extracting +captured substrings from a matched subject string. The function +\fBpcre_maketables()\fR is used (optionally) to build a set of character tables +in the current locale for passing to \fBpcre_compile()\fR. + +The function \fBpcre_fullinfo()\fR is used to find out information about a +compiled pattern; \fBpcre_info()\fR is an obsolete version which returns only +some of the available information, but is retained for backwards compatibility. +The function \fBpcre_version()\fR returns a pointer to a string containing the +version of PCRE and its date of release. + +The global variables \fBpcre_malloc\fR and \fBpcre_free\fR initially contain +the entry points of the standard \fBmalloc()\fR and \fBfree()\fR functions +respectively. PCRE calls the memory management functions via these variables, +so a calling program can replace them if it wishes to intercept the calls. This +should be done before calling any PCRE functions. + + +.SH MULTI-THREADING +The PCRE functions can be used in multi-threading applications, with the +proviso that the memory management functions pointed to by \fBpcre_malloc\fR +and \fBpcre_free\fR are shared by all threads. + +The compiled form of a regular expression is not altered during matching, so +the same compiled pattern can safely be used by several threads at once. + + +.SH COMPILING A PATTERN +The function \fBpcre_compile()\fR is called to compile a pattern into an +internal form. The pattern is a C string terminated by a binary zero, and +is passed in the argument \fIpattern\fR. A pointer to a single block of memory +that is obtained via \fBpcre_malloc\fR is returned. This contains the +compiled code and related data. The \fBpcre\fR type is defined for this for +convenience, but in fact \fBpcre\fR is just a typedef for \fBvoid\fR, since the +contents of the block are not externally defined. It is up to the caller to +free the memory when it is no longer required. +.PP +The size of a compiled pattern is roughly proportional to the length of the +pattern string, except that each character class (other than those containing +just a single character, negated or not) requires 33 bytes, and repeat +quantifiers with a minimum greater than one or a bounded maximum cause the +relevant portions of the compiled pattern to be replicated. +.PP +The \fIoptions\fR argument contains independent bits that affect the +compilation. It should be zero if no options are required. Some of the options, +in particular, those that are compatible with Perl, can also be set and unset +from within the pattern (see the detailed description of regular expressions +below). For these options, the contents of the \fIoptions\fR argument specifies +their initial settings at the start of compilation and execution. The +PCRE_ANCHORED option can be set at the time of matching as well as at compile +time. +.PP +If \fIerrptr\fR is NULL, \fBpcre_compile()\fR returns NULL immediately. +Otherwise, if compilation of a pattern fails, \fBpcre_compile()\fR returns +NULL, and sets the variable pointed to by \fIerrptr\fR to point to a textual +error message. The offset from the start of the pattern to the character where +the error was discovered is placed in the variable pointed to by +\fIerroffset\fR, which must not be NULL. If it is, an immediate error is given. +.PP +If the final argument, \fItableptr\fR, is NULL, PCRE uses a default set of +character tables which are built when it is compiled, using the default C +locale. Otherwise, \fItableptr\fR must be the result of a call to +\fBpcre_maketables()\fR. See the section on locale support below. +.PP +The following option bits are defined in the header file: + + PCRE_ANCHORED + +If this bit is set, the pattern is forced to be "anchored", that is, it is +constrained to match only at the start of the string which is being searched +(the "subject string"). This effect can also be achieved by appropriate +constructs in the pattern itself, which is the only way to do it in Perl. + + PCRE_CASELESS + +If this bit is set, letters in the pattern match both upper and lower case +letters. It is equivalent to Perl's /i option. + + PCRE_DOLLAR_ENDONLY + +If this bit is set, a dollar metacharacter in the pattern matches only at the +end of the subject string. Without this option, a dollar also matches +immediately before the final character if it is a newline (but not before any +other newlines). The PCRE_DOLLAR_ENDONLY option is ignored if PCRE_MULTILINE is +set. There is no equivalent to this option in Perl. + + PCRE_DOTALL + +If this bit is set, a dot metacharater in the pattern matches all characters, +including newlines. Without it, newlines are excluded. This option is +equivalent to Perl's /s option. A negative class such as [^a] always matches a +newline character, independent of the setting of this option. + + PCRE_EXTENDED + +If this bit is set, whitespace data characters in the pattern are totally +ignored except when escaped or inside a character class, and characters between +an unescaped # outside a character class and the next newline character, +inclusive, are also ignored. This is equivalent to Perl's /x option, and makes +it possible to include comments inside complicated patterns. Note, however, +that this applies only to data characters. Whitespace characters may never +appear within special character sequences in a pattern, for example within the +sequence (?( which introduces a conditional subpattern. + + PCRE_EXTRA + +This option was invented in order to turn on additional functionality of PCRE +that is incompatible with Perl, but it is currently of very little use. When +set, any backslash in a pattern that is followed by a letter that has no +special meaning causes an error, thus reserving these combinations for future +expansion. By default, as in Perl, a backslash followed by a letter with no +special meaning is treated as a literal. There are at present no other features +controlled by this option. It can also be set by a (?X) option setting within a +pattern. + + PCRE_MULTILINE + +By default, PCRE treats the subject string as consisting of a single "line" of +characters (even if it actually contains several newlines). The "start of line" +metacharacter (^) matches only at the start of the string, while the "end of +line" metacharacter ($) matches only at the end of the string, or before a +terminating newline (unless PCRE_DOLLAR_ENDONLY is set). This is the same as +Perl. + +When PCRE_MULTILINE it is set, the "start of line" and "end of line" constructs +match immediately following or immediately before any newline in the subject +string, respectively, as well as at the very start and end. This is equivalent +to Perl's /m option. If there are no "\\n" characters in a subject string, or +no occurrences of ^ or $ in a pattern, setting PCRE_MULTILINE has no +effect. + + PCRE_UNGREEDY + +This option inverts the "greediness" of the quantifiers so that they are not +greedy by default, but become greedy if followed by "?". It is not compatible +with Perl. It can also be set by a (?U) option setting within the pattern. + + +.SH STUDYING A PATTERN +When a pattern is going to be used several times, it is worth spending more +time analyzing it in order to speed up the time taken for matching. The +function \fBpcre_study()\fR takes a pointer to a compiled pattern as its first +argument, and returns a pointer to a \fBpcre_extra\fR block (another \fBvoid\fR +typedef) containing additional information about the pattern; this can be +passed to \fBpcre_exec()\fR. If no additional information is available, NULL +is returned. + +The second argument contains option bits. At present, no options are defined +for \fBpcre_study()\fR, and this argument should always be zero. + +The third argument for \fBpcre_study()\fR is a pointer to an error message. If +studying succeeds (even if no data is returned), the variable it points to is +set to NULL. Otherwise it points to a textual error message. + +At present, studying a pattern is useful only for non-anchored patterns that do +not have a single fixed starting character. A bitmap of possible starting +characters is created. + + +.SH LOCALE SUPPORT +PCRE handles caseless matching, and determines whether characters are letters, +digits, or whatever, by reference to a set of tables. The library contains a +default set of tables which is created in the default C locale when PCRE is +compiled. This is used when the final argument of \fBpcre_compile()\fR is NULL, +and is sufficient for many applications. + +An alternative set of tables can, however, be supplied. Such tables are built +by calling the \fBpcre_maketables()\fR function, which has no arguments, in the +relevant locale. The result can then be passed to \fBpcre_compile()\fR as often +as necessary. For example, to build and use tables that are appropriate for the +French locale (where accented characters with codes greater than 128 are +treated as letters), the following code could be used: + + setlocale(LC_CTYPE, "fr"); + tables = pcre_maketables(); + re = pcre_compile(..., tables); + +The tables are built in memory that is obtained via \fBpcre_malloc\fR. The +pointer that is passed to \fBpcre_compile\fR is saved with the compiled +pattern, and the same tables are used via this pointer by \fBpcre_study()\fR +and \fBpcre_exec()\fR. Thus for any single pattern, compilation, studying and +matching all happen in the same locale, but different patterns can be compiled +in different locales. It is the caller's responsibility to ensure that the +memory containing the tables remains available for as long as it is needed. + + +.SH INFORMATION ABOUT A PATTERN +The \fBpcre_fullinfo()\fR function returns information about a compiled +pattern. It replaces the obsolete \fBpcre_info()\fR function, which is +nevertheless retained for backwards compability (and is documented below). + +The first argument for \fBpcre_fullinfo()\fR is a pointer to the compiled +pattern. The second argument is the result of \fBpcre_study()\fR, or NULL if +the pattern was not studied. The third argument specifies which piece of +information is required, while the fourth argument is a pointer to a variable +to receive the data. The yield of the function is zero for success, or one of +the following negative numbers: + + PCRE_ERROR_NULL the argument \fIcode\fR was NULL + the argument \fIwhere\fR was NULL + PCRE_ERROR_BADMAGIC the "magic number" was not found + PCRE_ERROR_BADOPTION the value of \fIwhat\fR was invalid + +The possible values for the third argument are defined in \fBpcre.h\fR, and are +as follows: + + PCRE_INFO_OPTIONS + +Return a copy of the options with which the pattern was compiled. The fourth +argument should point to au \fBunsigned long int\fR variable. These option bits +are those specified in the call to \fBpcre_compile()\fR, modified by any +top-level option settings within the pattern itself, and with the PCRE_ANCHORED +bit forcibly set if the form of the pattern implies that it can match only at +the start of a subject string. + + PCRE_INFO_SIZE + +Return the size of the compiled pattern, that is, the value that was passed as +the argument to \fBpcre_malloc()\fR when PCRE was getting memory in which to +place the compiled data. The fourth argument should point to a \fBsize_t\fR +variable. + + PCRE_INFO_CAPTURECOUNT + +Return the number of capturing subpatterns in the pattern. The fourth argument +should point to an \fbint\fR variable. + + PCRE_INFO_BACKREFMAX + +Return the number of the highest back reference in the pattern. The fourth +argument should point to an \fBint\fR variable. Zero is returned if there are +no back references. + + PCRE_INFO_FIRSTCHAR + +Return information about the first character of any matched string, for a +non-anchored pattern. If there is a fixed first character, e.g. from a pattern +such as (cat|cow|coyote), then it is returned in the integer pointed to by +\fIwhere\fR. Otherwise, if either + +(a) the pattern was compiled with the PCRE_MULTILINE option, and every branch +starts with "^", or + +(b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not set +(if it were set, the pattern would be anchored), + +then -1 is returned, indicating that the pattern matches only at the +start of a subject string or after any "\\n" within the string. Otherwise -2 is +returned. For anchored patterns, -2 is returned. + + PCRE_INFO_FIRSTTABLE + +If the pattern was studied, and this resulted in the construction of a 256-bit +table indicating a fixed set of characters for the first character in any +matching string, a pointer to the table is returned. Otherwise NULL is +returned. The fourth argument should point to an \fBunsigned char *\fR +variable. + + PCRE_INFO_LASTLITERAL + +For a non-anchored pattern, return the value of the rightmost literal character +which must exist in any matched string, other than at its start. The fourth +argument should point to an \fBint\fR variable. If there is no such character, +or if the pattern is anchored, -1 is returned. For example, for the pattern +/a\\d+z\\d+/ the returned value is 'z'. + +The \fBpcre_info()\fR function is now obsolete because its interface is too +restrictive to return all the available data about a compiled pattern. New +programs should use \fBpcre_fullinfo()\fR instead. The yield of +\fBpcre_info()\fR is the number of capturing subpatterns, or one of the +following negative numbers: + + PCRE_ERROR_NULL the argument \fIcode\fR was NULL + PCRE_ERROR_BADMAGIC the "magic number" was not found + +If the \fIoptptr\fR argument is not NULL, a copy of the options with which the +pattern was compiled is placed in the integer it points to (see +PCRE_INFO_OPTIONS above). + +If the pattern is not anchored and the \fIfirstcharptr\fR argument is not NULL, +it is used to pass back information about the first character of any matched +string (see PCRE_INFO_FIRSTCHAR above). + + +.SH MATCHING A PATTERN +The function \fBpcre_exec()\fR is called to match a subject string against a +pre-compiled pattern, which is passed in the \fIcode\fR argument. If the +pattern has been studied, the result of the study should be passed in the +\fIextra\fR argument. Otherwise this must be NULL. + +The PCRE_ANCHORED option can be passed in the \fIoptions\fR argument, whose +unused bits must be zero. However, if a pattern was compiled with +PCRE_ANCHORED, or turned out to be anchored by virtue of its contents, it +cannot be made unachored at matching time. + +There are also three further options that can be set only at matching time: + + PCRE_NOTBOL + +The first character of the string is not the beginning of a line, so the +circumflex metacharacter should not match before it. Setting this without +PCRE_MULTILINE (at compile time) causes circumflex never to match. + + PCRE_NOTEOL + +The end of the string is not the end of a line, so the dollar metacharacter +should not match it nor (except in multiline mode) a newline immediately before +it. Setting this without PCRE_MULTILINE (at compile time) causes dollar never +to match. + + PCRE_NOTEMPTY + +An empty string is not considered to be a valid match if this option is set. If +there are alternatives in the pattern, they are tried. If all the alternatives +match the empty string, the entire match fails. For example, if the pattern + + a?b? + +is applied to a string not beginning with "a" or "b", it matches the empty +string at the start of the subject. With PCRE_NOTEMPTY set, this match is not +valid, so PCRE searches further into the string for occurrences of "a" or "b". + +Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a special case +of a pattern match of the empty string within its \fBsplit()\fR function, and +when using the /g modifier. It is possible to emulate Perl's behaviour after +matching a null string by first trying the match again at the same offset with +PCRE_NOTEMPTY set, and then if that fails by advancing the starting offset (see +below) and trying an ordinary match again. + +The subject string is passed as a pointer in \fIsubject\fR, a length in +\fIlength\fR, and a starting offset in \fIstartoffset\fR. Unlike the pattern +string, it may contain binary zero characters. When the starting offset is +zero, the search for a match starts at the beginning of the subject, and this +is by far the most common case. + +A non-zero starting offset is useful when searching for another match in the +same subject by calling \fBpcre_exec()\fR again after a previous success. +Setting \fIstartoffset\fR differs from just passing over a shortened string and +setting PCRE_NOTBOL in the case of a pattern that begins with any kind of +lookbehind. For example, consider the pattern + + \\Biss\\B + +which finds occurrences of "iss" in the middle of words. (\\B matches only if +the current position in the subject is not a word boundary.) When applied to +the string "Mississipi" the first call to \fBpcre_exec()\fR finds the first +occurrence. If \fBpcre_exec()\fR is called again with just the remainder of the +subject, namely "issipi", it does not match, because \\B is always false at the +start of the subject, which is deemed to be a word boundary. However, if +\fBpcre_exec()\fR is passed the entire string again, but with \fIstartoffset\fR +set to 4, it finds the second occurrence of "iss" because it is able to look +behind the starting point to discover that it is preceded by a letter. + +If a non-zero starting offset is passed when the pattern is anchored, one +attempt to match at the given offset is tried. This can only succeed if the +pattern does not require the match to be at the start of the subject. + +In general, a pattern matches a certain portion of the subject, and in +addition, further substrings from the subject may be picked out by parts of the +pattern. Following the usage in Jeffrey Friedl's book, this is called +"capturing" in what follows, and the phrase "capturing subpattern" is used for +a fragment of a pattern that picks out a substring. PCRE supports several other +kinds of parenthesized subpattern that do not cause substrings to be captured. + +Captured substrings are returned to the caller via a vector of integer offsets +whose address is passed in \fIovector\fR. The number of elements in the vector +is passed in \fIovecsize\fR. The first two-thirds of the vector is used to pass +back captured substrings, each substring using a pair of integers. The +remaining third of the vector is used as workspace by \fBpcre_exec()\fR while +matching capturing subpatterns, and is not available for passing back +information. The length passed in \fIovecsize\fR should always be a multiple of +three. If it is not, it is rounded down. + +When a match has been successful, information about captured substrings is +returned in pairs of integers, starting at the beginning of \fIovector\fR, and +continuing up to two-thirds of its length at the most. The first element of a +pair is set to the offset of the first character in a substring, and the second +is set to the offset of the first character after the end of a substring. The +first pair, \fIovector[0]\fR and \fIovector[1]\fR, identify the portion of the +subject string matched by the entire pattern. The next pair is used for the +first capturing subpattern, and so on. The value returned by \fBpcre_exec()\fR +is the number of pairs that have been set. If there are no capturing +subpatterns, the return value from a successful match is 1, indicating that +just the first pair of offsets has been set. + +Some convenience functions are provided for extracting the captured substrings +as separate strings. These are described in the following section. + +It is possible for an capturing subpattern number \fIn+1\fR to match some +part of the subject when subpattern \fIn\fR has not been used at all. For +example, if the string "abc" is matched against the pattern (a|(z))(bc) +subpatterns 1 and 3 are matched, but 2 is not. When this happens, both offset +values corresponding to the unused subpattern are set to -1. + +If a capturing subpattern is matched repeatedly, it is the last portion of the +string that it matched that gets returned. + +If the vector is too small to hold all the captured substrings, it is used as +far as possible (up to two-thirds of its length), and the function returns a +value of zero. In particular, if the substring offsets are not of interest, +\fBpcre_exec()\fR may be called with \fIovector\fR passed as NULL and +\fIovecsize\fR as zero. However, if the pattern contains back references and +the \fIovector\fR isn't big enough to remember the related substrings, PCRE has +to get additional memory for use during matching. Thus it is usually advisable +to supply an \fIovector\fR. + +Note that \fBpcre_info()\fR can be used to find out how many capturing +subpatterns there are in a compiled pattern. The smallest size for +\fIovector\fR that will allow for \fIn\fR captured substrings in addition to +the offsets of the substring matched by the whole pattern is (\fIn\fR+1)*3. + +If \fBpcre_exec()\fR fails, it returns a negative number. The following are +defined in the header file: + + PCRE_ERROR_NOMATCH (-1) + +The subject string did not match the pattern. + + PCRE_ERROR_NULL (-2) + +Either \fIcode\fR or \fIsubject\fR was passed as NULL, or \fIovector\fR was +NULL and \fIovecsize\fR was not zero. + + PCRE_ERROR_BADOPTION (-3) + +An unrecognized bit was set in the \fIoptions\fR argument. + + PCRE_ERROR_BADMAGIC (-4) + +PCRE stores a 4-byte "magic number" at the start of the compiled code, to catch +the case when it is passed a junk pointer. This is the error it gives when the +magic number isn't present. + + PCRE_ERROR_UNKNOWN_NODE (-5) + +While running the pattern match, an unknown item was encountered in the +compiled pattern. This error could be caused by a bug in PCRE or by overwriting +of the compiled pattern. + + PCRE_ERROR_NOMEMORY (-6) + +If a pattern contains back references, but the \fIovector\fR that is passed to +\fBpcre_exec()\fR is not big enough to remember the referenced substrings, PCRE +gets a block of memory at the start of matching to use for this purpose. If the +call via \fBpcre_malloc()\fR fails, this error is given. The memory is freed at +the end of matching. + + +.SH EXTRACTING CAPTURED SUBSTRINGS +Captured substrings can be accessed directly by using the offsets returned by +\fBpcre_exec()\fR in \fIovector\fR. For convenience, the functions +\fBpcre_copy_substring()\fR, \fBpcre_get_substring()\fR, and +\fBpcre_get_substring_list()\fR are provided for extracting captured substrings +as new, separate, zero-terminated strings. A substring that contains a binary +zero is correctly extracted and has a further zero added on the end, but the +result does not, of course, function as a C string. + +The first three arguments are the same for all three functions: \fIsubject\fR +is the subject string which has just been successfully matched, \fIovector\fR +is a pointer to the vector of integer offsets that was passed to +\fBpcre_exec()\fR, and \fIstringcount\fR is the number of substrings that +were captured by the match, including the substring that matched the entire +regular expression. This is the value returned by \fBpcre_exec\fR if it +is greater than zero. If \fBpcre_exec()\fR returned zero, indicating that it +ran out of space in \fIovector\fR, then the value passed as +\fIstringcount\fR should be the size of the vector divided by three. + +The functions \fBpcre_copy_substring()\fR and \fBpcre_get_substring()\fR +extract a single substring, whose number is given as \fIstringnumber\fR. A +value of zero extracts the substring that matched the entire pattern, while +higher values extract the captured substrings. For \fBpcre_copy_substring()\fR, +the string is placed in \fIbuffer\fR, whose length is given by +\fIbuffersize\fR, while for \fBpcre_get_substring()\fR a new block of store is +obtained via \fBpcre_malloc\fR, and its address is returned via +\fIstringptr\fR. The yield of the function is the length of the string, not +including the terminating zero, or one of + + PCRE_ERROR_NOMEMORY (-6) + +The buffer was too small for \fBpcre_copy_substring()\fR, or the attempt to get +memory failed for \fBpcre_get_substring()\fR. + + PCRE_ERROR_NOSUBSTRING (-7) + +There is no substring whose number is \fIstringnumber\fR. + +The \fBpcre_get_substring_list()\fR function extracts all available substrings +and builds a list of pointers to them. All this is done in a single block of +memory which is obtained via \fBpcre_malloc\fR. The address of the memory block +is returned via \fIlistptr\fR, which is also the start of the list of string +pointers. The end of the list is marked by a NULL pointer. The yield of the +function is zero if all went well, or + + PCRE_ERROR_NOMEMORY (-6) + +if the attempt to get the memory block failed. + +When any of these functions encounter a substring that is unset, which can +happen when capturing subpattern number \fIn+1\fR matches some part of the +subject, but subpattern \fIn\fR has not been used at all, they return an empty +string. This can be distinguished from a genuine zero-length substring by +inspecting the appropriate offset in \fIovector\fR, which is negative for unset +substrings. + + + +.SH LIMITATIONS +There are some size limitations in PCRE but it is hoped that they will never in +practice be relevant. +The maximum length of a compiled pattern is 65539 (sic) bytes. +All values in repeating quantifiers must be less than 65536. +The maximum number of capturing subpatterns is 99. +The maximum number of all parenthesized subpatterns, including capturing +subpatterns, assertions, and other types of subpattern, is 200. + +The maximum length of a subject string is the largest positive number that an +integer variable can hold. However, PCRE uses recursion to handle subpatterns +and indefinite repetition. This means that the available stack space may limit +the size of a subject string that can be processed by certain patterns. + + +.SH DIFFERENCES FROM PERL +The differences described here are with respect to Perl 5.005. + +1. By default, a whitespace character is any character that the C library +function \fBisspace()\fR recognizes, though it is possible to compile PCRE with +alternative character type tables. Normally \fBisspace()\fR matches space, +formfeed, newline, carriage return, horizontal tab, and vertical tab. Perl 5 +no longer includes vertical tab in its set of whitespace characters. The \\v +escape that was in the Perl documentation for a long time was never in fact +recognized. However, the character itself was treated as whitespace at least +up to 5.002. In 5.004 and 5.005 it does not match \\s. + +2. PCRE does not allow repeat quantifiers on lookahead assertions. Perl permits +them, but they do not mean what you might think. For example, (?!a){3} does +not assert that the next three characters are not "a". It just asserts that the +next character is not "a" three times. + +3. Capturing subpatterns that occur inside negative lookahead assertions are +counted, but their entries in the offsets vector are never set. Perl sets its +numerical variables from any such patterns that are matched before the +assertion fails to match something (thereby succeeding), but only if the +negative lookahead assertion contains just one branch. + +4. Though binary zero characters are supported in the subject string, they are +not allowed in a pattern string because it is passed as a normal C string, +terminated by zero. The escape sequence "\\0" can be used in the pattern to +represent a binary zero. + +5. The following Perl escape sequences are not supported: \\l, \\u, \\L, \\U, +\\E, \\Q. In fact these are implemented by Perl's general string-handling and +are not part of its pattern matching engine. + +6. The Perl \\G assertion is not supported as it is not relevant to single +pattern matches. + +7. Fairly obviously, PCRE does not support the (?{code}) and (?p{code}) +constructions. However, there is some experimental support for recursive +patterns using the non-Perl item (?R). + +8. There are at the time of writing some oddities in Perl 5.005_02 concerned +with the settings of captured strings when part of a pattern is repeated. For +example, matching "aba" against the pattern /^(a(b)?)+$/ sets $2 to the value +"b", but matching "aabbaa" against /^(aa(bb)?)+$/ leaves $2 unset. However, if +the pattern is changed to /^(aa(b(b))?)+$/ then $2 (and $3) get set. + +In Perl 5.004 $2 is set in both cases, and that is also true of PCRE. If in the +future Perl changes to a consistent state that is different, PCRE may change to +follow. + +9. Another as yet unresolved discrepancy is that in Perl 5.005_02 the pattern +/^(a)?(?(1)a|b)+$/ matches the string "a", whereas in PCRE it does not. +However, in both Perl and PCRE /^(a)?a/ matched against "a" leaves $1 unset. + +10. PCRE provides some extensions to the Perl regular expression facilities: + +(a) Although lookbehind assertions must match fixed length strings, each +alternative branch of a lookbehind assertion can match a different length of +string. Perl 5.005 requires them all to have the same length. + +(b) If PCRE_DOLLAR_ENDONLY is set and PCRE_MULTILINE is not set, the $ meta- +character matches only at the very end of the string. + +(c) If PCRE_EXTRA is set, a backslash followed by a letter with no special +meaning is faulted. + +(d) If PCRE_UNGREEDY is set, the greediness of the repetition quantifiers is +inverted, that is, by default they are not greedy, but if followed by a +question mark they are. + +(e) PCRE_ANCHORED can be used to force a pattern to be tried only at the start +of the subject. + +(f) The PCRE_NOTBOL, PCRE_NOTEOL, and PCRE_NOTEMPTY options for +\fBpcre_exec()\fR have no Perl equivalents. + +(g) The (?R) construct allows for recursive pattern matching (Perl 5.6 can do +this using the (?p{code}) construct, which PCRE cannot of course support.) + + +.SH REGULAR EXPRESSION DETAILS +The syntax and semantics of the regular expressions supported by PCRE are +described below. Regular expressions are also described in the Perl +documentation and in a number of other books, some of which have copious +examples. Jeffrey Friedl's "Mastering Regular Expressions", published by +O'Reilly (ISBN 1-56592-257), covers them in great detail. The description +here is intended as reference documentation. + +A regular expression is a pattern that is matched against a subject string from +left to right. Most characters stand for themselves in a pattern, and match the +corresponding characters in the subject. As a trivial example, the pattern + + The quick brown fox + +matches a portion of a subject string that is identical to itself. The power of +regular expressions comes from the ability to include alternatives and +repetitions in the pattern. These are encoded in the pattern by the use of +\fImeta-characters\fR, which do not stand for themselves but instead are +interpreted in some special way. + +There are two different sets of meta-characters: those that are recognized +anywhere in the pattern except within square brackets, and those that are +recognized in square brackets. Outside square brackets, the meta-characters are +as follows: + + \\ general escape character with several uses + ^ assert start of subject (or line, in multiline mode) + $ assert end of subject (or line, in multiline mode) + . match any character except newline (by default) + [ start character class definition + | start of alternative branch + ( start subpattern + ) end subpattern + ? extends the meaning of ( + also 0 or 1 quantifier + also quantifier minimizer + * 0 or more quantifier + + 1 or more quantifier + { start min/max quantifier + +Part of a pattern that is in square brackets is called a "character class". In +a character class the only meta-characters are: + + \\ general escape character + ^ negate the class, but only if the first character + - indicates character range + ] terminates the character class + +The following sections describe the use of each of the meta-characters. + + +.SH BACKSLASH +The backslash character has several uses. Firstly, if it is followed by a +non-alphameric character, it takes away any special meaning that character may +have. This use of backslash as an escape character applies both inside and +outside character classes. + +For example, if you want to match a "*" character, you write "\\*" in the +pattern. This applies whether or not the following character would otherwise be +interpreted as a meta-character, so it is always safe to precede a +non-alphameric with "\\" to specify that it stands for itself. In particular, +if you want to match a backslash, you write "\\\\". + +If a pattern is compiled with the PCRE_EXTENDED option, whitespace in the +pattern (other than in a character class) and characters between a "#" outside +a character class and the next newline character are ignored. An escaping +backslash can be used to include a whitespace or "#" character as part of the +pattern. + +A second use of backslash provides a way of encoding non-printing characters +in patterns in a visible manner. There is no restriction on the appearance of +non-printing characters, apart from the binary zero that terminates a pattern, +but when a pattern is being prepared by text editing, it is usually easier to +use one of the following escape sequences than the binary character it +represents: + + \\a alarm, that is, the BEL character (hex 07) + \\cx "control-x", where x is any character + \\e escape (hex 1B) + \\f formfeed (hex 0C) + \\n newline (hex 0A) + \\r carriage return (hex 0D) + \\t tab (hex 09) + \\xhh character with hex code hh + \\ddd character with octal code ddd, or backreference + +The precise effect of "\\cx" is as follows: if "x" is a lower case letter, it +is converted to upper case. Then bit 6 of the character (hex 40) is inverted. +Thus "\\cz" becomes hex 1A, but "\\c{" becomes hex 3B, while "\\c;" becomes hex +7B. + +After "\\x", up to two hexadecimal digits are read (letters can be in upper or +lower case). + +After "\\0" up to two further octal digits are read. In both cases, if there +are fewer than two digits, just those that are present are used. Thus the +sequence "\\0\\x\\07" specifies two binary zeros followed by a BEL character. +Make sure you supply two digits after the initial zero if the character that +follows is itself an octal digit. + +The handling of a backslash followed by a digit other than 0 is complicated. +Outside a character class, PCRE reads it and any following digits as a decimal +number. If the number is less than 10, or if there have been at least that many +previous capturing left parentheses in the expression, the entire sequence is +taken as a \fIback reference\fR. A description of how this works is given +later, following the discussion of parenthesized subpatterns. + +Inside a character class, or if the decimal number is greater than 9 and there +have not been that many capturing subpatterns, PCRE re-reads up to three octal +digits following the backslash, and generates a single byte from the least +significant 8 bits of the value. Any subsequent digits stand for themselves. +For example: + + \\040 is another way of writing a space + \\40 is the same, provided there are fewer than 40 + previous capturing subpatterns + \\7 is always a back reference + \\11 might be a back reference, or another way of + writing a tab + \\011 is always a tab + \\0113 is a tab followed by the character "3" + \\113 is the character with octal code 113 (since there + can be no more than 99 back references) + \\377 is a byte consisting entirely of 1 bits + \\81 is either a back reference, or a binary zero + followed by the two characters "8" and "1" + +Note that octal values of 100 or greater must not be introduced by a leading +zero, because no more than three octal digits are ever read. + +All the sequences that define a single byte value can be used both inside and +outside character classes. In addition, inside a character class, the sequence +"\\b" is interpreted as the backspace character (hex 08). Outside a character +class it has a different meaning (see below). + +The third use of backslash is for specifying generic character types: + + \\d any decimal digit + \\D any character that is not a decimal digit + \\s any whitespace character + \\S any character that is not a whitespace character + \\w any "word" character + \\W any "non-word" character + +Each pair of escape sequences partitions the complete set of characters into +two disjoint sets. Any given character matches one, and only one, of each pair. + +A "word" character is any letter or digit or the underscore character, that is, +any character which can be part of a Perl "word". The definition of letters and +digits is controlled by PCRE's character tables, and may vary if locale- +specific matching is taking place (see "Locale support" above). For example, in +the "fr" (French) locale, some character codes greater than 128 are used for +accented letters, and these are matched by \\w. + +These character type sequences can appear both inside and outside character +classes. They each match one character of the appropriate type. If the current +matching point is at the end of the subject string, all of them fail, since +there is no character to match. + +The fourth use of backslash is for certain simple assertions. An assertion +specifies a condition that has to be met at a particular point in a match, +without consuming any characters from the subject string. The use of +subpatterns for more complicated assertions is described below. The backslashed +assertions are + + \\b word boundary + \\B not a word boundary + \\A start of subject (independent of multiline mode) + \\Z end of subject or newline at end (independent of multiline mode) + \\z end of subject (independent of multiline mode) + +These assertions may not appear in character classes (but note that "\\b" has a +different meaning, namely the backspace character, inside a character class). + +A word boundary is a position in the subject string where the current character +and the previous character do not both match \\w or \\W (i.e. one matches +\\w and the other matches \\W), or the start or end of the string if the +first or last character matches \\w, respectively. + +The \\A, \\Z, and \\z assertions differ from the traditional circumflex and +dollar (described below) in that they only ever match at the very start and end +of the subject string, whatever options are set. They are not affected by the +PCRE_NOTBOL or PCRE_NOTEOL options. If the \fIstartoffset\fR argument of +\fBpcre_exec()\fR is non-zero, \\A can never match. The difference between \\Z +and \\z is that \\Z matches before a newline that is the last character of the +string as well as at the end of the string, whereas \\z matches only at the +end. + + +.SH CIRCUMFLEX AND DOLLAR +Outside a character class, in the default matching mode, the circumflex +character is an assertion which is true only if the current matching point is +at the start of the subject string. If the \fIstartoffset\fR argument of +\fBpcre_exec()\fR is non-zero, circumflex can never match. Inside a character +class, circumflex has an entirely different meaning (see below). + +Circumflex need not be the first character of the pattern if a number of +alternatives are involved, but it should be the first thing in each alternative +in which it appears if the pattern is ever to match that branch. If all +possible alternatives start with a circumflex, that is, if the pattern is +constrained to match only at the start of the subject, it is said to be an +"anchored" pattern. (There are also other constructs that can cause a pattern +to be anchored.) + +A dollar character is an assertion which is true only if the current matching +point is at the end of the subject string, or immediately before a newline +character that is the last character in the string (by default). Dollar need +not be the last character of the pattern if a number of alternatives are +involved, but it should be the last item in any branch in which it appears. +Dollar has no special meaning in a character class. + +The meaning of dollar can be changed so that it matches only at the very end of +the string, by setting the PCRE_DOLLAR_ENDONLY option at compile or matching +time. This does not affect the \\Z assertion. + +The meanings of the circumflex and dollar characters are changed if the +PCRE_MULTILINE option is set. When this is the case, they match immediately +after and immediately before an internal "\\n" character, respectively, in +addition to matching at the start and end of the subject string. For example, +the pattern /^abc$/ matches the subject string "def\\nabc" in multiline mode, +but not otherwise. Consequently, patterns that are anchored in single line mode +because all branches start with "^" are not anchored in multiline mode, and a +match for circumflex is possible when the \fIstartoffset\fR argument of +\fBpcre_exec()\fR is non-zero. The PCRE_DOLLAR_ENDONLY option is ignored if +PCRE_MULTILINE is set. + +Note that the sequences \\A, \\Z, and \\z can be used to match the start and +end of the subject in both modes, and if all branches of a pattern start with +\\A is it always anchored, whether PCRE_MULTILINE is set or not. + + +.SH FULL STOP (PERIOD, DOT) +Outside a character class, a dot in the pattern matches any one character in +the subject, including a non-printing character, but not (by default) newline. +If the PCRE_DOTALL option is set, then dots match newlines as well. The +handling of dot is entirely independent of the handling of circumflex and +dollar, the only relationship being that they both involve newline characters. +Dot has no special meaning in a character class. + + +.SH SQUARE BRACKETS +An opening square bracket introduces a character class, terminated by a closing +square bracket. A closing square bracket on its own is not special. If a +closing square bracket is required as a member of the class, it should be the +first data character in the class (after an initial circumflex, if present) or +escaped with a backslash. + +A character class matches a single character in the subject; the character must +be in the set of characters defined by the class, unless the first character in +the class is a circumflex, in which case the subject character must not be in +the set defined by the class. If a circumflex is actually required as a member +of the class, ensure it is not the first character, or escape it with a +backslash. + +For example, the character class [aeiou] matches any lower case vowel, while +[^aeiou] matches any character that is not a lower case vowel. Note that a +circumflex is just a convenient notation for specifying the characters which +are in the class by enumerating those that are not. It is not an assertion: it +still consumes a character from the subject string, and fails if the current +pointer is at the end of the string. + +When caseless matching is set, any letters in a class represent both their +upper case and lower case versions, so for example, a caseless [aeiou] matches +"A" as well as "a", and a caseless [^aeiou] does not match "A", whereas a +caseful version would. + +The newline character is never treated in any special way in character classes, +whatever the setting of the PCRE_DOTALL or PCRE_MULTILINE options is. A class +such as [^a] will always match a newline. + +The minus (hyphen) character can be used to specify a range of characters in a +character class. For example, [d-m] matches any letter between d and m, +inclusive. If a minus character is required in a class, it must be escaped with +a backslash or appear in a position where it cannot be interpreted as +indicating a range, typically as the first or last character in the class. + +It is not possible to have the literal character "]" as the end character of a +range. A pattern such as [W-]46] is interpreted as a class of two characters +("W" and "-") followed by a literal string "46]", so it would match "W46]" or +"-46]". However, if the "]" is escaped with a backslash it is interpreted as +the end of range, so [W-\\]46] is interpreted as a single class containing a +range followed by two separate characters. The octal or hexadecimal +representation of "]" can also be used to end a range. + +Ranges operate in ASCII collating sequence. They can also be used for +characters specified numerically, for example [\\000-\\037]. If a range that +includes letters is used when caseless matching is set, it matches the letters +in either case. For example, [W-c] is equivalent to [][\\^_`wxyzabc], matched +caselessly, and if character tables for the "fr" locale are in use, +[\\xc8-\\xcb] matches accented E characters in both cases. + +The character types \\d, \\D, \\s, \\S, \\w, and \\W may also appear in a +character class, and add the characters that they match to the class. For +example, [\\dABCDEF] matches any hexadecimal digit. A circumflex can +conveniently be used with the upper case character types to specify a more +restricted set of characters than the matching lower case type. For example, +the class [^\\W_] matches any letter or digit, but not underscore. + +All non-alphameric characters other than \\, -, ^ (at the start) and the +terminating ] are non-special in character classes, but it does no harm if they +are escaped. + + +.SH POSIX CHARACTER CLASSES +Perl 5.6 (not yet released at the time of writing) is going to support the +POSIX notation for character classes, which uses names enclosed by [: and :] +within the enclosing square brackets. PCRE supports this notation. For example, + + [01[:alpha:]%] + +matches "0", "1", any alphabetic character, or "%". The supported class names +are + + alnum letters and digits + alpha letters + ascii character codes 0 - 127 + cntrl control characters + digit decimal digits (same as \\d) + graph printing characters, excluding space + lower lower case letters + print printing characters, including space + punct printing characters, excluding letters and digits + space white space (same as \\s) + upper upper case letters + word "word" characters (same as \\w) + xdigit hexadecimal digits + +The names "ascii" and "word" are Perl extensions. Another Perl extension is +negation, which is indicated by a ^ character after the colon. For example, + + [12[:^digit:]] + +matches "1", "2", or any non-digit. PCRE (and Perl) also recogize the POSIX +syntax [.ch.] and [=ch=] where "ch" is a "collating element", but these are not +supported, and an error is given if they are encountered. + + +.SH VERTICAL BAR +Vertical bar characters are used to separate alternative patterns. For example, +the pattern + + gilbert|sullivan + +matches either "gilbert" or "sullivan". Any number of alternatives may appear, +and an empty alternative is permitted (matching the empty string). +The matching process tries each alternative in turn, from left to right, +and the first one that succeeds is used. If the alternatives are within a +subpattern (defined below), "succeeds" means matching the rest of the main +pattern as well as the alternative in the subpattern. + + +.SH INTERNAL OPTION SETTING +The settings of PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, and PCRE_EXTENDED +can be changed from within the pattern by a sequence of Perl option letters +enclosed between "(?" and ")". The option letters are + + i for PCRE_CASELESS + m for PCRE_MULTILINE + s for PCRE_DOTALL + x for PCRE_EXTENDED + +For example, (?im) sets caseless, multiline matching. It is also possible to +unset these options by preceding the letter with a hyphen, and a combined +setting and unsetting such as (?im-sx), which sets PCRE_CASELESS and +PCRE_MULTILINE while unsetting PCRE_DOTALL and PCRE_EXTENDED, is also +permitted. If a letter appears both before and after the hyphen, the option is +unset. + +The scope of these option changes depends on where in the pattern the setting +occurs. For settings that are outside any subpattern (defined below), the +effect is the same as if the options were set or unset at the start of +matching. The following patterns all behave in exactly the same way: + + (?i)abc + a(?i)bc + ab(?i)c + abc(?i) + +which in turn is the same as compiling the pattern abc with PCRE_CASELESS set. +In other words, such "top level" settings apply to the whole pattern (unless +there are other changes inside subpatterns). If there is more than one setting +of the same option at top level, the rightmost setting is used. + +If an option change occurs inside a subpattern, the effect is different. This +is a change of behaviour in Perl 5.005. An option change inside a subpattern +affects only that part of the subpattern that follows it, so + + (a(?i)b)c + +matches abc and aBc and no other strings (assuming PCRE_CASELESS is not used). +By this means, options can be made to have different settings in different +parts of the pattern. Any changes made in one alternative do carry on +into subsequent branches within the same subpattern. For example, + + (a(?i)b|c) + +matches "ab", "aB", "c", and "C", even though when matching "C" the first +branch is abandoned before the option setting. This is because the effects of +option settings happen at compile time. There would be some very weird +behaviour otherwise. + +The PCRE-specific options PCRE_UNGREEDY and PCRE_EXTRA can be changed in the +same way as the Perl-compatible options by using the characters U and X +respectively. The (?X) flag setting is special in that it must always occur +earlier in the pattern than any of the additional features it turns on, even +when it is at top level. It is best put at the start. + + +.SH SUBPATTERNS +Subpatterns are delimited by parentheses (round brackets), which can be nested. +Marking part of a pattern as a subpattern does two things: + +1. It localizes a set of alternatives. For example, the pattern + + cat(aract|erpillar|) + +matches one of the words "cat", "cataract", or "caterpillar". Without the +parentheses, it would match "cataract", "erpillar" or the empty string. + +2. It sets up the subpattern as a capturing subpattern (as defined above). +When the whole pattern matches, that portion of the subject string that matched +the subpattern is passed back to the caller via the \fIovector\fR argument of +\fBpcre_exec()\fR. Opening parentheses are counted from left to right (starting +from 1) to obtain the numbers of the capturing subpatterns. + +For example, if the string "the red king" is matched against the pattern + + the ((red|white) (king|queen)) + +the captured substrings are "red king", "red", and "king", and are numbered 1, +2, and 3. + +The fact that plain parentheses fulfil two functions is not always helpful. +There are often times when a grouping subpattern is required without a +capturing requirement. If an opening parenthesis is followed by "?:", the +subpattern does not do any capturing, and is not counted when computing the +number of any subsequent capturing subpatterns. For example, if the string "the +white queen" is matched against the pattern + + the ((?:red|white) (king|queen)) + +the captured substrings are "white queen" and "queen", and are numbered 1 and +2. The maximum number of captured substrings is 99, and the maximum number of +all subpatterns, both capturing and non-capturing, is 200. + +As a convenient shorthand, if any option settings are required at the start of +a non-capturing subpattern, the option letters may appear between the "?" and +the ":". Thus the two patterns + + (?i:saturday|sunday) + (?:(?i)saturday|sunday) + +match exactly the same set of strings. Because alternative branches are tried +from left to right, and options are not reset until the end of the subpattern +is reached, an option setting in one branch does affect subsequent branches, so +the above patterns match "SUNDAY" as well as "Saturday". + + +.SH REPETITION +Repetition is specified by quantifiers, which can follow any of the following +items: + + a single character, possibly escaped + the . metacharacter + a character class + a back reference (see next section) + a parenthesized subpattern (unless it is an assertion - see below) + +The general repetition quantifier specifies a minimum and maximum number of +permitted matches, by giving the two numbers in curly brackets (braces), +separated by a comma. The numbers must be less than 65536, and the first must +be less than or equal to the second. For example: + + z{2,4} + +matches "zz", "zzz", or "zzzz". A closing brace on its own is not a special +character. If the second number is omitted, but the comma is present, there is +no upper limit; if the second number and the comma are both omitted, the +quantifier specifies an exact number of required matches. Thus + + [aeiou]{3,} + +matches at least 3 successive vowels, but may match many more, while + + \\d{8} + +matches exactly 8 digits. An opening curly bracket that appears in a position +where a quantifier is not allowed, or one that does not match the syntax of a +quantifier, is taken as a literal character. For example, {,6} is not a +quantifier, but a literal string of four characters. + +The quantifier {0} is permitted, causing the expression to behave as if the +previous item and the quantifier were not present. + +For convenience (and historical compatibility) the three most common +quantifiers have single-character abbreviations: + + * is equivalent to {0,} + + is equivalent to {1,} + ? is equivalent to {0,1} + +It is possible to construct infinite loops by following a subpattern that can +match no characters with a quantifier that has no upper limit, for example: + + (a?)* + +Earlier versions of Perl and PCRE used to give an error at compile time for +such patterns. However, because there are cases where this can be useful, such +patterns are now accepted, but if any repetition of the subpattern does in fact +match no characters, the loop is forcibly broken. + +By default, the quantifiers are "greedy", that is, they match as much as +possible (up to the maximum number of permitted times), without causing the +rest of the pattern to fail. The classic example of where this gives problems +is in trying to match comments in C programs. These appear between the +sequences /* and */ and within the sequence, individual * and / characters may +appear. An attempt to match C comments by applying the pattern + + /\\*.*\\*/ + +to the string + + /* first command */ not comment /* second comment */ + +fails, because it matches the entire string due to the greediness of the .* +item. + +However, if a quantifier is followed by a question mark, then it ceases to be +greedy, and instead matches the minimum number of times possible, so the +pattern + + /\\*.*?\\*/ + +does the right thing with the C comments. The meaning of the various +quantifiers is not otherwise changed, just the preferred number of matches. +Do not confuse this use of question mark with its use as a quantifier in its +own right. Because it has two uses, it can sometimes appear doubled, as in + + \\d??\\d + +which matches one digit by preference, but can match two if that is the only +way the rest of the pattern matches. + +If the PCRE_UNGREEDY option is set (an option which is not available in Perl) +then the quantifiers are not greedy by default, but individual ones can be made +greedy by following them with a question mark. In other words, it inverts the +default behaviour. + +When a parenthesized subpattern is quantified with a minimum repeat count that +is greater than 1 or with a limited maximum, more store is required for the +compiled pattern, in proportion to the size of the minimum or maximum. + +If a pattern starts with .* or .{0,} and the PCRE_DOTALL option (equivalent +to Perl's /s) is set, thus allowing the . to match newlines, then the pattern +is implicitly anchored, because whatever follows will be tried against every +character position in the subject string, so there is no point in retrying the +overall match at any position after the first. PCRE treats such a pattern as +though it were preceded by \\A. In cases where it is known that the subject +string contains no newlines, it is worth setting PCRE_DOTALL when the pattern +begins with .* in order to obtain this optimization, or alternatively using ^ +to indicate anchoring explicitly. + +When a capturing subpattern is repeated, the value captured is the substring +that matched the final iteration. For example, after + + (tweedle[dume]{3}\\s*)+ + +has matched "tweedledum tweedledee" the value of the captured substring is +"tweedledee". However, if there are nested capturing subpatterns, the +corresponding captured values may have been set in previous iterations. For +example, after + + /(a|(b))+/ + +matches "aba" the value of the second captured substring is "b". + + +.SH BACK REFERENCES +Outside a character class, a backslash followed by a digit greater than 0 (and +possibly further digits) is a back reference to a capturing subpattern earlier +(i.e. to its left) in the pattern, provided there have been that many previous +capturing left parentheses. + +However, if the decimal number following the backslash is less than 10, it is +always taken as a back reference, and causes an error only if there are not +that many capturing left parentheses in the entire pattern. In other words, the +parentheses that are referenced need not be to the left of the reference for +numbers less than 10. See the section entitled "Backslash" above for further +details of the handling of digits following a backslash. + +A back reference matches whatever actually matched the capturing subpattern in +the current subject string, rather than anything matching the subpattern +itself. So the pattern + + (sens|respons)e and \\1ibility + +matches "sense and sensibility" and "response and responsibility", but not +"sense and responsibility". If caseful matching is in force at the time of the +back reference, then the case of letters is relevant. For example, + + ((?i)rah)\\s+\\1 + +matches "rah rah" and "RAH RAH", but not "RAH rah", even though the original +capturing subpattern is matched caselessly. + +There may be more than one back reference to the same subpattern. If a +subpattern has not actually been used in a particular match, then any back +references to it always fail. For example, the pattern + + (a|(bc))\\2 + +always fails if it starts to match "a" rather than "bc". Because there may be +up to 99 back references, all digits following the backslash are taken +as part of a potential back reference number. If the pattern continues with a +digit character, then some delimiter must be used to terminate the back +reference. If the PCRE_EXTENDED option is set, this can be whitespace. +Otherwise an empty comment can be used. + +A back reference that occurs inside the parentheses to which it refers fails +when the subpattern is first used, so, for example, (a\\1) never matches. +However, such references can be useful inside repeated subpatterns. For +example, the pattern + + (a|b\\1)+ + +matches any number of "a"s and also "aba", "ababaa" etc. At each iteration of +the subpattern, the back reference matches the character string corresponding +to the previous iteration. In order for this to work, the pattern must be such +that the first iteration does not need to match the back reference. This can be +done using alternation, as in the example above, or by a quantifier with a +minimum of zero. + + +.SH ASSERTIONS +An assertion is a test on the characters following or preceding the current +matching point that does not actually consume any characters. The simple +assertions coded as \\b, \\B, \\A, \\Z, \\z, ^ and $ are described above. More +complicated assertions are coded as subpatterns. There are two kinds: those +that look ahead of the current position in the subject string, and those that +look behind it. + +An assertion subpattern is matched in the normal way, except that it does not +cause the current matching position to be changed. Lookahead assertions start +with (?= for positive assertions and (?! for negative assertions. For example, + + \\w+(?=;) + +matches a word followed by a semicolon, but does not include the semicolon in +the match, and + + foo(?!bar) + +matches any occurrence of "foo" that is not followed by "bar". Note that the +apparently similar pattern + + (?!foo)bar + +does not find an occurrence of "bar" that is preceded by something other than +"foo"; it finds any occurrence of "bar" whatsoever, because the assertion +(?!foo) is always true when the next three characters are "bar". A +lookbehind assertion is needed to achieve this effect. + +Lookbehind assertions start with (?<= for positive assertions and (? as in this example: + + (?>\\d+)bar + +This kind of parenthesis "locks up" the part of the pattern it contains once +it has matched, and a failure further into the pattern is prevented from +backtracking into it. Backtracking past it to previous items, however, works as +normal. + +An alternative description is that a subpattern of this type matches the string +of characters that an identical standalone pattern would match, if anchored at +the current point in the subject string. + +Once-only subpatterns are not capturing subpatterns. Simple cases such as the +above example can be thought of as a maximizing repeat that must swallow +everything it can. So, while both \\d+ and \\d+? are prepared to adjust the +number of digits they match in order to make the rest of the pattern match, +(?>\\d+) can only match an entire sequence of digits. + +This construction can of course contain arbitrarily complicated subpatterns, +and it can be nested. + +Once-only subpatterns can be used in conjunction with lookbehind assertions to +specify efficient matching at the end of the subject string. Consider a simple +pattern such as + + abcd$ + +when applied to a long string which does not match. Because matching proceeds +from left to right, PCRE will look for each "a" in the subject and then see if +what follows matches the rest of the pattern. If the pattern is specified as + + ^.*abcd$ + +then the initial .* matches the entire string at first, but when this fails +(because there is no following "a"), it backtracks to match all but the last +character, then all but the last two characters, and so on. Once again the +search for "a" covers the entire string, from right to left, so we are no +better off. However, if the pattern is written as + + ^(?>.*)(?<=abcd) + +then there can be no backtracking for the .* item; it can match only the entire +string. The subsequent lookbehind assertion does a single test on the last four +characters. If it fails, the match fails immediately. For long strings, this +approach makes a significant difference to the processing time. + +When a pattern contains an unlimited repeat inside a subpattern that can itself +be repeated an unlimited number of times, the use of a once-only subpattern is +the only way to avoid some failing matches taking a very long time indeed. +The pattern + + (\\D+|<\\d+>)*[!?] + +matches an unlimited number of substrings that either consist of non-digits, or +digits enclosed in <>, followed by either ! or ?. When it matches, it runs +quickly. However, if it is applied to + + aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa + +it takes a long time before reporting failure. This is because the string can +be divided between the two repeats in a large number of ways, and all have to +be tried. (The example used [!?] rather than a single character at the end, +because both PCRE and Perl have an optimization that allows for fast failure +when a single character is used. They remember the last single character that +is required for a match, and fail early if it is not present in the string.) +If the pattern is changed to + + ((?>\\D+)|<\\d+>)*[!?] + +sequences of non-digits cannot be broken, and failure happens quickly. + + +.SH CONDITIONAL SUBPATTERNS +It is possible to cause the matching process to obey a subpattern +conditionally or to choose between two alternative subpatterns, depending on +the result of an assertion, or whether a previous capturing subpattern matched +or not. The two possible forms of conditional subpattern are + + (?(condition)yes-pattern) + (?(condition)yes-pattern|no-pattern) + +If the condition is satisfied, the yes-pattern is used; otherwise the +no-pattern (if present) is used. If there are more than two alternatives in the +subpattern, a compile-time error occurs. + +There are two kinds of condition. If the text between the parentheses consists +of a sequence of digits, then the condition is satisfied if the capturing +subpattern of that number has previously matched. Consider the following +pattern, which contains non-significant white space to make it more readable +(assume the PCRE_EXTENDED option) and to divide it into three parts for ease +of discussion: + + ( \\( )? [^()]+ (?(1) \\) ) + +The first part matches an optional opening parenthesis, and if that +character is present, sets it as the first captured substring. The second part +matches one or more characters that are not parentheses. The third part is a +conditional subpattern that tests whether the first set of parentheses matched +or not. If they did, that is, if subject started with an opening parenthesis, +the condition is true, and so the yes-pattern is executed and a closing +parenthesis is required. Otherwise, since no-pattern is not present, the +subpattern matches nothing. In other words, this pattern matches a sequence of +non-parentheses, optionally enclosed in parentheses. + +If the condition is not a sequence of digits, it must be an assertion. This may +be a positive or negative lookahead or lookbehind assertion. Consider this +pattern, again containing non-significant white space, and with the two +alternatives on the second line: + + (?(?=[^a-z]*[a-z]) + \\d{2}-[a-z]{3}-\\d{2} | \\d{2}-\\d{2}-\\d{2} ) + +The condition is a positive lookahead assertion that matches an optional +sequence of non-letters followed by a letter. In other words, it tests for the +presence of at least one letter in the subject. If a letter is found, the +subject is matched against the first alternative; otherwise it is matched +against the second. This pattern matches strings in one of the two forms +dd-aaa-dd or dd-dd-dd, where aaa are letters and dd are digits. + + +.SH COMMENTS +The sequence (?# marks the start of a comment which continues up to the next +closing parenthesis. Nested parentheses are not permitted. The characters +that make up a comment play no part in the pattern matching at all. + +If the PCRE_EXTENDED option is set, an unescaped # character outside a +character class introduces a comment that continues up to the next newline +character in the pattern. + + +.SH RECURSIVE PATTERNS +Consider the problem of matching a string in parentheses, allowing for +unlimited nested parentheses. Without the use of recursion, the best that can +be done is to use a pattern that matches up to some fixed depth of nesting. It +is not possible to handle an arbitrary nesting depth. Perl 5.6 has provided an +experimental facility that allows regular expressions to recurse (amongst other +things). It does this by interpolating Perl code in the expression at run time, +and the code can refer to the expression itself. A Perl pattern to solve the +parentheses problem can be created like this: + + $re = qr{\\( (?: (?>[^()]+) | (?p{$re}) )* \\)}x; + +The (?p{...}) item interpolates Perl code at run time, and in this case refers +recursively to the pattern in which it appears. Obviously, PCRE cannot support +the interpolation of Perl code. Instead, the special item (?R) is provided for +the specific case of recursion. This PCRE pattern solves the parentheses +problem (assume the PCRE_EXTENDED option is set so that white space is +ignored): + + \\( ( (?>[^()]+) | (?R) )* \\) + +First it matches an opening parenthesis. Then it matches any number of +substrings which can either be a sequence of non-parentheses, or a recursive +match of the pattern itself (i.e. a correctly parenthesized substring). Finally +there is a closing parenthesis. + +This particular example pattern contains nested unlimited repeats, and so the +use of a once-only subpattern for matching strings of non-parentheses is +important when applying the pattern to strings that do not match. For example, +when it is applied to + + (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa() + +it yields "no match" quickly. However, if a once-only subpattern is not used, +the match runs for a very long time indeed because there are so many different +ways the + and * repeats can carve up the subject, and all have to be tested +before failure can be reported. + +The values set for any capturing subpatterns are those from the outermost level +of the recursion at which the subpattern value is set. If the pattern above is +matched against + + (ab(cd)ef) + +the value for the capturing parentheses is "ef", which is the last value taken +on at the top level. If additional parentheses are added, giving + + \\( ( ( (?>[^()]+) | (?R) )* ) \\) + ^ ^ + ^ ^ +then the string they capture is "ab(cd)ef", the contents of the top level +parentheses. If there are more than 15 capturing parentheses in a pattern, PCRE +has to obtain extra memory to store data during a recursion, which it does by +using \fBpcre_malloc\fR, freeing it via \fBpcre_free\fR afterwards. If no +memory can be obtained, it saves data for the first 15 capturing parentheses +only, as there is no way to give an out-of-memory error from within a +recursion. + + +.SH PERFORMANCE +Certain items that may appear in patterns are more efficient than others. It is +more efficient to use a character class like [aeiou] than a set of alternatives +such as (a|e|i|o|u). In general, the simplest construction that provides the +required behaviour is usually the most efficient. Jeffrey Friedl's book +contains a lot of discussion about optimizing regular expressions for efficient +performance. + +When a pattern begins with .* and the PCRE_DOTALL option is set, the pattern is +implicitly anchored by PCRE, since it can match only at the start of a subject +string. However, if PCRE_DOTALL is not set, PCRE cannot make this optimization, +because the . metacharacter does not then match a newline, and if the subject +string contains newlines, the pattern may match from the character immediately +following one of them instead of from the very start. For example, the pattern + + (.*) second + +matches the subject "first\\nand second" (where \\n stands for a newline +character) with the first captured substring being "and". In order to do this, +PCRE has to retry the match starting after every newline in the subject. + +If you are using such a pattern with subject strings that do not contain +newlines, the best performance is obtained by setting PCRE_DOTALL, or starting +the pattern with ^.* to indicate explicit anchoring. That saves PCRE from +having to scan along the subject looking for a newline to restart at. + +Beware of patterns that contain nested indefinite repeats. These can take a +long time to run when applied to a string that does not match. Consider the +pattern fragment + + (a+)* + +This can match "aaaa" in 33 different ways, and this number increases very +rapidly as the string gets longer. (The * repeat can match 0, 1, 2, 3, or 4 +times, and for each of those cases other than 0, the + repeats can match +different numbers of times.) When the remainder of the pattern is such that the +entire match is going to fail, PCRE has in principle to try every possible +variation, and this can take an extremely long time. + +An optimization catches some of the more simple cases such as + + (a+)*b + +where a literal character follows. Before embarking on the standard matching +procedure, PCRE checks that there is a "b" later in the subject string, and if +there is not, it fails the match immediately. However, when there is no +following literal this optimization cannot be used. You can see the difference +by comparing the behaviour of + + (a+)*\\d + +with the pattern above. The former gives a failure almost instantly when +applied to a whole line of "a" characters, whereas the latter takes an +appreciable time with strings longer than about 20 characters. + +.SH AUTHOR +Philip Hazel +.br +University Computing Service, +.br +New Museums Site, +.br +Cambridge CB2 3QG, England. +.br +Phone: +44 1223 334714 + +Last updated: 27 January 2000 +.br +Copyright (c) 1997-2000 University of Cambridge. diff --git a/ext/pcre/pcrelib/doc/pcre.html b/ext/pcre/pcrelib/doc/pcre.html new file mode 100644 index 0000000000..2ce289007d --- /dev/null +++ b/ext/pcre/pcrelib/doc/pcre.html @@ -0,0 +1,2259 @@ + + +pcre specification + + +

pcre specification

+This HTML document has been generated automatically from the original man page. +If there is any nonsense in it, please consult the man page in case the +conversion went wrong. + +
  • NAME +

    +pcre - Perl-compatible regular expressions. +

    +
  • SYNOPSIS +

    +#include <pcre.h> +

    +

    +pcre *pcre_compile(const char *pattern, int options, +const char **errptr, int *erroffset, +const unsigned char *tableptr); +

    +

    +pcre_extra *pcre_study(const pcre *code, int options, +const char **errptr); +

    +

    +int pcre_exec(const pcre *code, const pcre_extra *extra, +const char *subject, int length, int startoffset, +int options, int *ovector, int ovecsize); +

    +

    +int pcre_copy_substring(const char *subject, int *ovector, +int stringcount, int stringnumber, char *buffer, +int buffersize); +

    +

    +int pcre_get_substring(const char *subject, int *ovector, +int stringcount, int stringnumber, +const char **stringptr); +

    +

    +int pcre_get_substring_list(const char *subject, +int *ovector, int stringcount, const char ***listptr); +

    +

    +const unsigned char *pcre_maketables(void); +

    +

    +int pcre_fullinfo(const pcre *code, const pcre_extra *extra, +int what, void *where); +

    +

    +int pcre_info(const pcre *code, int *optptr, int +*firstcharptr); +

    +

    +char *pcre_version(void); +

    +

    +void *(*pcre_malloc)(size_t); +

    +

    +void (*pcre_free)(void *); +

    +
  • DESCRIPTION +

    +The PCRE library is a set of functions that implement regular expression +pattern matching using the same syntax and semantics as Perl 5, with just a few +differences (see below). The current implementation corresponds to Perl 5.005, +with some additional features from the Perl development release. +

    +

    +PCRE has its own native API, which is described in this document. There is also +a set of wrapper functions that correspond to the POSIX regular expression API. +These are described in the pcreposix documentation. +

    +

    +The native API function prototypes are defined in the header file pcre.h, +and on Unix systems the library itself is called libpcre.a, so can be +accessed by adding -lpcre to the command for linking an application which +calls it. The header file defines the macros PCRE_MAJOR and PCRE_MINOR to +contain the major and minor release numbers for the library. Applications can +use these to include support for different releases. +

    +

    +The functions pcre_compile(), pcre_study(), and pcre_exec() +are used for compiling and matching regular expressions, while +pcre_copy_substring(), pcre_get_substring(), and +pcre_get_substring_list() are convenience functions for extracting +captured substrings from a matched subject string. The function +pcre_maketables() is used (optionally) to build a set of character tables +in the current locale for passing to pcre_compile(). +

    +

    +The function pcre_fullinfo() is used to find out information about a +compiled pattern; pcre_info() is an obsolete version which returns only +some of the available information, but is retained for backwards compatibility. +The function pcre_version() returns a pointer to a string containing the +version of PCRE and its date of release. +

    +

    +The global variables pcre_malloc and pcre_free initially contain +the entry points of the standard malloc() and free() functions +respectively. PCRE calls the memory management functions via these variables, +so a calling program can replace them if it wishes to intercept the calls. This +should be done before calling any PCRE functions. +

    +
  • MULTI-THREADING +

    +The PCRE functions can be used in multi-threading applications, with the +proviso that the memory management functions pointed to by pcre_malloc +and pcre_free are shared by all threads. +

    +

    +The compiled form of a regular expression is not altered during matching, so +the same compiled pattern can safely be used by several threads at once. +

    +
  • COMPILING A PATTERN +

    +The function pcre_compile() is called to compile a pattern into an +internal form. The pattern is a C string terminated by a binary zero, and +is passed in the argument pattern. A pointer to a single block of memory +that is obtained via pcre_malloc is returned. This contains the +compiled code and related data. The pcre type is defined for this for +convenience, but in fact pcre is just a typedef for void, since the +contents of the block are not externally defined. It is up to the caller to +free the memory when it is no longer required. +

    +

    +The size of a compiled pattern is roughly proportional to the length of the +pattern string, except that each character class (other than those containing +just a single character, negated or not) requires 33 bytes, and repeat +quantifiers with a minimum greater than one or a bounded maximum cause the +relevant portions of the compiled pattern to be replicated. +

    +

    +The options argument contains independent bits that affect the +compilation. It should be zero if no options are required. Some of the options, +in particular, those that are compatible with Perl, can also be set and unset +from within the pattern (see the detailed description of regular expressions +below). For these options, the contents of the options argument specifies +their initial settings at the start of compilation and execution. The +PCRE_ANCHORED option can be set at the time of matching as well as at compile +time. +

    +

    +If errptr is NULL, pcre_compile() returns NULL immediately. +Otherwise, if compilation of a pattern fails, pcre_compile() returns +NULL, and sets the variable pointed to by errptr to point to a textual +error message. The offset from the start of the pattern to the character where +the error was discovered is placed in the variable pointed to by +erroffset, which must not be NULL. If it is, an immediate error is given. +

    +

    +If the final argument, tableptr, is NULL, PCRE uses a default set of +character tables which are built when it is compiled, using the default C +locale. Otherwise, tableptr must be the result of a call to +pcre_maketables(). See the section on locale support below. +

    +

    +The following option bits are defined in the header file: +

    +

    +

    +  PCRE_ANCHORED
+
    +

    +

    +If this bit is set, the pattern is forced to be "anchored", that is, it is +constrained to match only at the start of the string which is being searched +(the "subject string"). This effect can also be achieved by appropriate +constructs in the pattern itself, which is the only way to do it in Perl. +

    +

    +

    +  PCRE_CASELESS
+
    +

    +

    +If this bit is set, letters in the pattern match both upper and lower case +letters. It is equivalent to Perl's /i option. +

    +

    +

    +  PCRE_DOLLAR_ENDONLY
+
    +

    +

    +If this bit is set, a dollar metacharacter in the pattern matches only at the +end of the subject string. Without this option, a dollar also matches +immediately before the final character if it is a newline (but not before any +other newlines). The PCRE_DOLLAR_ENDONLY option is ignored if PCRE_MULTILINE is +set. There is no equivalent to this option in Perl. +

    +

    +

    +  PCRE_DOTALL
+
    +

    +

    +If this bit is set, a dot metacharater in the pattern matches all characters, +including newlines. Without it, newlines are excluded. This option is +equivalent to Perl's /s option. A negative class such as [^a] always matches a +newline character, independent of the setting of this option. +

    +

    +

    +  PCRE_EXTENDED
+
    +

    +

    +If this bit is set, whitespace data characters in the pattern are totally +ignored except when escaped or inside a character class, and characters between +an unescaped # outside a character class and the next newline character, +inclusive, are also ignored. This is equivalent to Perl's /x option, and makes +it possible to include comments inside complicated patterns. Note, however, +that this applies only to data characters. Whitespace characters may never +appear within special character sequences in a pattern, for example within the +sequence (?( which introduces a conditional subpattern. +

    +

    +

    +  PCRE_EXTRA
+
    +

    +

    +This option was invented in order to turn on additional functionality of PCRE +that is incompatible with Perl, but it is currently of very little use. When +set, any backslash in a pattern that is followed by a letter that has no +special meaning causes an error, thus reserving these combinations for future +expansion. By default, as in Perl, a backslash followed by a letter with no +special meaning is treated as a literal. There are at present no other features +controlled by this option. It can also be set by a (?X) option setting within a +pattern. +

    +

    +

    +  PCRE_MULTILINE
+
    +

    +

    +By default, PCRE treats the subject string as consisting of a single "line" of +characters (even if it actually contains several newlines). The "start of line" +metacharacter (^) matches only at the start of the string, while the "end of +line" metacharacter ($) matches only at the end of the string, or before a +terminating newline (unless PCRE_DOLLAR_ENDONLY is set). This is the same as +Perl. +

    +

    +When PCRE_MULTILINE it is set, the "start of line" and "end of line" constructs +match immediately following or immediately before any newline in the subject +string, respectively, as well as at the very start and end. This is equivalent +to Perl's /m option. If there are no "\n" characters in a subject string, or +no occurrences of ^ or $ in a pattern, setting PCRE_MULTILINE has no +effect. +

    +

    +

    +  PCRE_UNGREEDY
+
    +

    +

    +This option inverts the "greediness" of the quantifiers so that they are not +greedy by default, but become greedy if followed by "?". It is not compatible +with Perl. It can also be set by a (?U) option setting within the pattern. +

    +
  • STUDYING A PATTERN +

    +When a pattern is going to be used several times, it is worth spending more +time analyzing it in order to speed up the time taken for matching. The +function pcre_study() takes a pointer to a compiled pattern as its first +argument, and returns a pointer to a pcre_extra block (another void +typedef) containing additional information about the pattern; this can be +passed to pcre_exec(). If no additional information is available, NULL +is returned. +

    +

    +The second argument contains option bits. At present, no options are defined +for pcre_study(), and this argument should always be zero. +

    +

    +The third argument for pcre_study() is a pointer to an error message. If +studying succeeds (even if no data is returned), the variable it points to is +set to NULL. Otherwise it points to a textual error message. +

    +

    +At present, studying a pattern is useful only for non-anchored patterns that do +not have a single fixed starting character. A bitmap of possible starting +characters is created. +

    +
  • LOCALE SUPPORT +

    +PCRE handles caseless matching, and determines whether characters are letters, +digits, or whatever, by reference to a set of tables. The library contains a +default set of tables which is created in the default C locale when PCRE is +compiled. This is used when the final argument of pcre_compile() is NULL, +and is sufficient for many applications. +

    +

    +An alternative set of tables can, however, be supplied. Such tables are built +by calling the pcre_maketables() function, which has no arguments, in the +relevant locale. The result can then be passed to pcre_compile() as often +as necessary. For example, to build and use tables that are appropriate for the +French locale (where accented characters with codes greater than 128 are +treated as letters), the following code could be used: +

    +

    +

    +  setlocale(LC_CTYPE, "fr");
+  tables = pcre_maketables();
+  re = pcre_compile(..., tables);
+
    +

    +

    +The tables are built in memory that is obtained via pcre_malloc. The +pointer that is passed to pcre_compile is saved with the compiled +pattern, and the same tables are used via this pointer by pcre_study() +and pcre_exec(). Thus for any single pattern, compilation, studying and +matching all happen in the same locale, but different patterns can be compiled +in different locales. It is the caller's responsibility to ensure that the +memory containing the tables remains available for as long as it is needed. +

    +
  • INFORMATION ABOUT A PATTERN +

    +The pcre_fullinfo() function returns information about a compiled +pattern. It replaces the obsolete pcre_info() function, which is +nevertheless retained for backwards compability (and is documented below). +

    +

    +The first argument for pcre_fullinfo() is a pointer to the compiled +pattern. The second argument is the result of pcre_study(), or NULL if +the pattern was not studied. The third argument specifies which piece of +information is required, while the fourth argument is a pointer to a variable +to receive the data. The yield of the function is zero for success, or one of +the following negative numbers: +

    +

    +

    +  PCRE_ERROR_NULL       the argument code was NULL
+                        the argument where was NULL
+  PCRE_ERROR_BADMAGIC   the "magic number" was not found
+  PCRE_ERROR_BADOPTION  the value of what was invalid
+
    +

    +

    +The possible values for the third argument are defined in pcre.h, and are +as follows: +

    +

    +

    +  PCRE_INFO_OPTIONS
+
    +

    +

    +Return a copy of the options with which the pattern was compiled. The fourth +argument should point to au unsigned long int variable. These option bits +are those specified in the call to pcre_compile(), modified by any +top-level option settings within the pattern itself, and with the PCRE_ANCHORED +bit forcibly set if the form of the pattern implies that it can match only at +the start of a subject string. +

    +

    +

    +  PCRE_INFO_SIZE
+
    +

    +

    +Return the size of the compiled pattern, that is, the value that was passed as +the argument to pcre_malloc() when PCRE was getting memory in which to +place the compiled data. The fourth argument should point to a size_t +variable. +

    +

    +

    +  PCRE_INFO_CAPTURECOUNT
+
    +

    +

    +Return the number of capturing subpatterns in the pattern. The fourth argument +should point to an \fbint\fR variable. +

    +

    +

    +  PCRE_INFO_BACKREFMAX
+
    +

    +

    +Return the number of the highest back reference in the pattern. The fourth +argument should point to an int variable. Zero is returned if there are +no back references. +

    +

    +

    +  PCRE_INFO_FIRSTCHAR
+
    +

    +

    +Return information about the first character of any matched string, for a +non-anchored pattern. If there is a fixed first character, e.g. from a pattern +such as (cat|cow|coyote), then it is returned in the integer pointed to by +where. Otherwise, if either +

    +

    +(a) the pattern was compiled with the PCRE_MULTILINE option, and every branch +starts with "^", or +

    +

    +(b) every branch of the pattern starts with ".*" and PCRE_DOTALL is not set +(if it were set, the pattern would be anchored), +

    +

    +then -1 is returned, indicating that the pattern matches only at the +start of a subject string or after any "\n" within the string. Otherwise -2 is +returned. For anchored patterns, -2 is returned. +

    +

    +

    +  PCRE_INFO_FIRSTTABLE
+
    +

    +

    +If the pattern was studied, and this resulted in the construction of a 256-bit +table indicating a fixed set of characters for the first character in any +matching string, a pointer to the table is returned. Otherwise NULL is +returned. The fourth argument should point to an unsigned char * +variable. +

    +

    +

    +  PCRE_INFO_LASTLITERAL
+
    +

    +

    +For a non-anchored pattern, return the value of the rightmost literal character +which must exist in any matched string, other than at its start. The fourth +argument should point to an int variable. If there is no such character, +or if the pattern is anchored, -1 is returned. For example, for the pattern +/a\d+z\d+/ the returned value is 'z'. +

    +

    +The pcre_info() function is now obsolete because its interface is too +restrictive to return all the available data about a compiled pattern. New +programs should use pcre_fullinfo() instead. The yield of +pcre_info() is the number of capturing subpatterns, or one of the +following negative numbers: +

    +

    +

    +  PCRE_ERROR_NULL       the argument code was NULL
+  PCRE_ERROR_BADMAGIC   the "magic number" was not found
+
    +

    +

    +If the optptr argument is not NULL, a copy of the options with which the +pattern was compiled is placed in the integer it points to (see +PCRE_INFO_OPTIONS above). +

    +

    +If the pattern is not anchored and the firstcharptr argument is not NULL, +it is used to pass back information about the first character of any matched +string (see PCRE_INFO_FIRSTCHAR above). +

    +
  • MATCHING A PATTERN +

    +The function pcre_exec() is called to match a subject string against a +pre-compiled pattern, which is passed in the code argument. If the +pattern has been studied, the result of the study should be passed in the +extra argument. Otherwise this must be NULL. +

    +

    +The PCRE_ANCHORED option can be passed in the options argument, whose +unused bits must be zero. However, if a pattern was compiled with +PCRE_ANCHORED, or turned out to be anchored by virtue of its contents, it +cannot be made unachored at matching time. +

    +

    +There are also three further options that can be set only at matching time: +

    +

    +

    +  PCRE_NOTBOL
+
    +

    +

    +The first character of the string is not the beginning of a line, so the +circumflex metacharacter should not match before it. Setting this without +PCRE_MULTILINE (at compile time) causes circumflex never to match. +

    +

    +

    +  PCRE_NOTEOL
+
    +

    +

    +The end of the string is not the end of a line, so the dollar metacharacter +should not match it nor (except in multiline mode) a newline immediately before +it. Setting this without PCRE_MULTILINE (at compile time) causes dollar never +to match. +

    +

    +

    +  PCRE_NOTEMPTY
+
    +

    +

    +An empty string is not considered to be a valid match if this option is set. If +there are alternatives in the pattern, they are tried. If all the alternatives +match the empty string, the entire match fails. For example, if the pattern +

    +

    +

    +  a?b?
+
    +

    +

    +is applied to a string not beginning with "a" or "b", it matches the empty +string at the start of the subject. With PCRE_NOTEMPTY set, this match is not +valid, so PCRE searches further into the string for occurrences of "a" or "b". +

    +

    +Perl has no direct equivalent of PCRE_NOTEMPTY, but it does make a special case +of a pattern match of the empty string within its split() function, and +when using the /g modifier. It is possible to emulate Perl's behaviour after +matching a null string by first trying the match again at the same offset with +PCRE_NOTEMPTY set, and then if that fails by advancing the starting offset (see +below) and trying an ordinary match again. +

    +

    +The subject string is passed as a pointer in subject, a length in +length, and a starting offset in startoffset. Unlike the pattern +string, it may contain binary zero characters. When the starting offset is +zero, the search for a match starts at the beginning of the subject, and this +is by far the most common case. +

    +

    +A non-zero starting offset is useful when searching for another match in the +same subject by calling pcre_exec() again after a previous success. +Setting startoffset differs from just passing over a shortened string and +setting PCRE_NOTBOL in the case of a pattern that begins with any kind of +lookbehind. For example, consider the pattern +

    +

    +

    +  \Biss\B
+
    +

    +

    +which finds occurrences of "iss" in the middle of words. (\B matches only if +the current position in the subject is not a word boundary.) When applied to +the string "Mississipi" the first call to pcre_exec() finds the first +occurrence. If pcre_exec() is called again with just the remainder of the +subject, namely "issipi", it does not match, because \B is always false at the +start of the subject, which is deemed to be a word boundary. However, if +pcre_exec() is passed the entire string again, but with startoffset +set to 4, it finds the second occurrence of "iss" because it is able to look +behind the starting point to discover that it is preceded by a letter. +

    +

    +If a non-zero starting offset is passed when the pattern is anchored, one +attempt to match at the given offset is tried. This can only succeed if the +pattern does not require the match to be at the start of the subject. +

    +

    +In general, a pattern matches a certain portion of the subject, and in +addition, further substrings from the subject may be picked out by parts of the +pattern. Following the usage in Jeffrey Friedl's book, this is called +"capturing" in what follows, and the phrase "capturing subpattern" is used for +a fragment of a pattern that picks out a substring. PCRE supports several other +kinds of parenthesized subpattern that do not cause substrings to be captured. +

    +

    +Captured substrings are returned to the caller via a vector of integer offsets +whose address is passed in ovector. The number of elements in the vector +is passed in ovecsize. The first two-thirds of the vector is used to pass +back captured substrings, each substring using a pair of integers. The +remaining third of the vector is used as workspace by pcre_exec() while +matching capturing subpatterns, and is not available for passing back +information. The length passed in ovecsize should always be a multiple of +three. If it is not, it is rounded down. +

    +

    +When a match has been successful, information about captured substrings is +returned in pairs of integers, starting at the beginning of ovector, and +continuing up to two-thirds of its length at the most. The first element of a +pair is set to the offset of the first character in a substring, and the second +is set to the offset of the first character after the end of a substring. The +first pair, ovector[0] and ovector[1], identify the portion of the +subject string matched by the entire pattern. The next pair is used for the +first capturing subpattern, and so on. The value returned by pcre_exec() +is the number of pairs that have been set. If there are no capturing +subpatterns, the return value from a successful match is 1, indicating that +just the first pair of offsets has been set. +

    +

    +Some convenience functions are provided for extracting the captured substrings +as separate strings. These are described in the following section. +

    +

    +It is possible for an capturing subpattern number n+1 to match some +part of the subject when subpattern n has not been used at all. For +example, if the string "abc" is matched against the pattern (a|(z))(bc) +subpatterns 1 and 3 are matched, but 2 is not. When this happens, both offset +values corresponding to the unused subpattern are set to -1. +

    +

    +If a capturing subpattern is matched repeatedly, it is the last portion of the +string that it matched that gets returned. +

    +

    +If the vector is too small to hold all the captured substrings, it is used as +far as possible (up to two-thirds of its length), and the function returns a +value of zero. In particular, if the substring offsets are not of interest, +pcre_exec() may be called with ovector passed as NULL and +ovecsize as zero. However, if the pattern contains back references and +the ovector isn't big enough to remember the related substrings, PCRE has +to get additional memory for use during matching. Thus it is usually advisable +to supply an ovector. +

    +

    +Note that pcre_info() can be used to find out how many capturing +subpatterns there are in a compiled pattern. The smallest size for +ovector that will allow for n captured substrings in addition to +the offsets of the substring matched by the whole pattern is (n+1)*3. +

    +

    +If pcre_exec() fails, it returns a negative number. The following are +defined in the header file: +

    +

    +

    +  PCRE_ERROR_NOMATCH        (-1)
+
    +

    +

    +The subject string did not match the pattern. +

    +

    +

    +  PCRE_ERROR_NULL           (-2)
+
    +

    +

    +Either code or subject was passed as NULL, or ovector was +NULL and ovecsize was not zero. +

    +

    +

    +  PCRE_ERROR_BADOPTION      (-3)
+
    +

    +

    +An unrecognized bit was set in the options argument. +

    +

    +

    +  PCRE_ERROR_BADMAGIC       (-4)
+
    +

    +

    +PCRE stores a 4-byte "magic number" at the start of the compiled code, to catch +the case when it is passed a junk pointer. This is the error it gives when the +magic number isn't present. +

    +

    +

    +  PCRE_ERROR_UNKNOWN_NODE   (-5)
+
    +

    +

    +While running the pattern match, an unknown item was encountered in the +compiled pattern. This error could be caused by a bug in PCRE or by overwriting +of the compiled pattern. +

    +

    +

    +  PCRE_ERROR_NOMEMORY       (-6)
+
    +

    +

    +If a pattern contains back references, but the ovector that is passed to +pcre_exec() is not big enough to remember the referenced substrings, PCRE +gets a block of memory at the start of matching to use for this purpose. If the +call via pcre_malloc() fails, this error is given. The memory is freed at +the end of matching. +

    +
  • EXTRACTING CAPTURED SUBSTRINGS +

    +Captured substrings can be accessed directly by using the offsets returned by +pcre_exec() in ovector. For convenience, the functions +pcre_copy_substring(), pcre_get_substring(), and +pcre_get_substring_list() are provided for extracting captured substrings +as new, separate, zero-terminated strings. A substring that contains a binary +zero is correctly extracted and has a further zero added on the end, but the +result does not, of course, function as a C string. +

    +

    +The first three arguments are the same for all three functions: subject +is the subject string which has just been successfully matched, ovector +is a pointer to the vector of integer offsets that was passed to +pcre_exec(), and stringcount is the number of substrings that +were captured by the match, including the substring that matched the entire +regular expression. This is the value returned by pcre_exec if it +is greater than zero. If pcre_exec() returned zero, indicating that it +ran out of space in ovector, then the value passed as +stringcount should be the size of the vector divided by three. +

    +

    +The functions pcre_copy_substring() and pcre_get_substring() +extract a single substring, whose number is given as stringnumber. A +value of zero extracts the substring that matched the entire pattern, while +higher values extract the captured substrings. For pcre_copy_substring(), +the string is placed in buffer, whose length is given by +buffersize, while for pcre_get_substring() a new block of store is +obtained via pcre_malloc, and its address is returned via +stringptr. The yield of the function is the length of the string, not +including the terminating zero, or one of +

    +

    +

    +  PCRE_ERROR_NOMEMORY       (-6)
+
    +

    +

    +The buffer was too small for pcre_copy_substring(), or the attempt to get +memory failed for pcre_get_substring(). +

    +

    +

    +  PCRE_ERROR_NOSUBSTRING    (-7)
+
    +

    +

    +There is no substring whose number is stringnumber. +

    +

    +The pcre_get_substring_list() function extracts all available substrings +and builds a list of pointers to them. All this is done in a single block of +memory which is obtained via pcre_malloc. The address of the memory block +is returned via listptr, which is also the start of the list of string +pointers. The end of the list is marked by a NULL pointer. The yield of the +function is zero if all went well, or +

    +

    +

    +  PCRE_ERROR_NOMEMORY       (-6)
+
    +

    +

    +if the attempt to get the memory block failed. +

    +

    +When any of these functions encounter a substring that is unset, which can +happen when capturing subpattern number n+1 matches some part of the +subject, but subpattern n has not been used at all, they return an empty +string. This can be distinguished from a genuine zero-length substring by +inspecting the appropriate offset in ovector, which is negative for unset +substrings. +

    +
  • LIMITATIONS +

    +There are some size limitations in PCRE but it is hoped that they will never in +practice be relevant. +The maximum length of a compiled pattern is 65539 (sic) bytes. +All values in repeating quantifiers must be less than 65536. +The maximum number of capturing subpatterns is 99. +The maximum number of all parenthesized subpatterns, including capturing +subpatterns, assertions, and other types of subpattern, is 200. +

    +

    +The maximum length of a subject string is the largest positive number that an +integer variable can hold. However, PCRE uses recursion to handle subpatterns +and indefinite repetition. This means that the available stack space may limit +the size of a subject string that can be processed by certain patterns. +

    +
  • DIFFERENCES FROM PERL +

    +The differences described here are with respect to Perl 5.005. +

    +

    +1. By default, a whitespace character is any character that the C library +function isspace() recognizes, though it is possible to compile PCRE with +alternative character type tables. Normally isspace() matches space, +formfeed, newline, carriage return, horizontal tab, and vertical tab. Perl 5 +no longer includes vertical tab in its set of whitespace characters. The \v +escape that was in the Perl documentation for a long time was never in fact +recognized. However, the character itself was treated as whitespace at least +up to 5.002. In 5.004 and 5.005 it does not match \s. +

    +

    +2. PCRE does not allow repeat quantifiers on lookahead assertions. Perl permits +them, but they do not mean what you might think. For example, (?!a){3} does +not assert that the next three characters are not "a". It just asserts that the +next character is not "a" three times. +

    +

    +3. Capturing subpatterns that occur inside negative lookahead assertions are +counted, but their entries in the offsets vector are never set. Perl sets its +numerical variables from any such patterns that are matched before the +assertion fails to match something (thereby succeeding), but only if the +negative lookahead assertion contains just one branch. +

    +

    +4. Though binary zero characters are supported in the subject string, they are +not allowed in a pattern string because it is passed as a normal C string, +terminated by zero. The escape sequence "\0" can be used in the pattern to +represent a binary zero. +

    +

    +5. The following Perl escape sequences are not supported: \l, \u, \L, \U, +\E, \Q. In fact these are implemented by Perl's general string-handling and +are not part of its pattern matching engine. +

    +

    +6. The Perl \G assertion is not supported as it is not relevant to single +pattern matches. +

    +

    +7. Fairly obviously, PCRE does not support the (?{code}) and (?p{code}) +constructions. However, there is some experimental support for recursive +patterns using the non-Perl item (?R). +

    +

    +8. There are at the time of writing some oddities in Perl 5.005_02 concerned +with the settings of captured strings when part of a pattern is repeated. For +example, matching "aba" against the pattern /^(a(b)?)+$/ sets $2 to the value +"b", but matching "aabbaa" against /^(aa(bb)?)+$/ leaves $2 unset. However, if +the pattern is changed to /^(aa(b(b))?)+$/ then $2 (and $3) get set. +

    +

    +In Perl 5.004 $2 is set in both cases, and that is also true of PCRE. If in the +future Perl changes to a consistent state that is different, PCRE may change to +follow. +

    +

    +9. Another as yet unresolved discrepancy is that in Perl 5.005_02 the pattern +/^(a)?(?(1)a|b)+$/ matches the string "a", whereas in PCRE it does not. +However, in both Perl and PCRE /^(a)?a/ matched against "a" leaves $1 unset. +

    +

    +10. PCRE provides some extensions to the Perl regular expression facilities: +

    +

    +(a) Although lookbehind assertions must match fixed length strings, each +alternative branch of a lookbehind assertion can match a different length of +string. Perl 5.005 requires them all to have the same length. +

    +

    +(b) If PCRE_DOLLAR_ENDONLY is set and PCRE_MULTILINE is not set, the $ meta- +character matches only at the very end of the string. +

    +

    +(c) If PCRE_EXTRA is set, a backslash followed by a letter with no special +meaning is faulted. +

    +

    +(d) If PCRE_UNGREEDY is set, the greediness of the repetition quantifiers is +inverted, that is, by default they are not greedy, but if followed by a +question mark they are. +

    +

    +(e) PCRE_ANCHORED can be used to force a pattern to be tried only at the start +of the subject. +

    +

    +(f) The PCRE_NOTBOL, PCRE_NOTEOL, and PCRE_NOTEMPTY options for +pcre_exec() have no Perl equivalents. +

    +

    +(g) The (?R) construct allows for recursive pattern matching (Perl 5.6 can do +this using the (?p{code}) construct, which PCRE cannot of course support.) +

    +
  • REGULAR EXPRESSION DETAILS +

    +The syntax and semantics of the regular expressions supported by PCRE are +described below. Regular expressions are also described in the Perl +documentation and in a number of other books, some of which have copious +examples. Jeffrey Friedl's "Mastering Regular Expressions", published by +O'Reilly (ISBN 1-56592-257), covers them in great detail. The description +here is intended as reference documentation. +

    +

    +A regular expression is a pattern that is matched against a subject string from +left to right. Most characters stand for themselves in a pattern, and match the +corresponding characters in the subject. As a trivial example, the pattern +

    +

    +

    +  The quick brown fox
+
    +

    +

    +matches a portion of a subject string that is identical to itself. The power of +regular expressions comes from the ability to include alternatives and +repetitions in the pattern. These are encoded in the pattern by the use of +meta-characters, which do not stand for themselves but instead are +interpreted in some special way. +

    +

    +There are two different sets of meta-characters: those that are recognized +anywhere in the pattern except within square brackets, and those that are +recognized in square brackets. Outside square brackets, the meta-characters are +as follows: +

    +

    +

    +  \      general escape character with several uses
+  ^      assert start of subject (or line, in multiline mode)
+  $      assert end of subject (or line, in multiline mode)
+  .      match any character except newline (by default)
+  [      start character class definition
+  |      start of alternative branch
+  (      start subpattern
+  )      end subpattern
+  ?      extends the meaning of (
+         also 0 or 1 quantifier
+         also quantifier minimizer
+  *      0 or more quantifier
+  +      1 or more quantifier
+  {      start min/max quantifier
+
    +

    +

    +Part of a pattern that is in square brackets is called a "character class". In +a character class the only meta-characters are: +

    +

    +

    +  \      general escape character
+  ^      negate the class, but only if the first character
+  -      indicates character range
+  ]      terminates the character class
+
    +

    +

    +The following sections describe the use of each of the meta-characters. +

    +
  • BACKSLASH +

    +The backslash character has several uses. Firstly, if it is followed by a +non-alphameric character, it takes away any special meaning that character may +have. This use of backslash as an escape character applies both inside and +outside character classes. +

    +

    +For example, if you want to match a "*" character, you write "\*" in the +pattern. This applies whether or not the following character would otherwise be +interpreted as a meta-character, so it is always safe to precede a +non-alphameric with "\" to specify that it stands for itself. In particular, +if you want to match a backslash, you write "\\". +

    +

    +If a pattern is compiled with the PCRE_EXTENDED option, whitespace in the +pattern (other than in a character class) and characters between a "#" outside +a character class and the next newline character are ignored. An escaping +backslash can be used to include a whitespace or "#" character as part of the +pattern. +

    +

    +A second use of backslash provides a way of encoding non-printing characters +in patterns in a visible manner. There is no restriction on the appearance of +non-printing characters, apart from the binary zero that terminates a pattern, +but when a pattern is being prepared by text editing, it is usually easier to +use one of the following escape sequences than the binary character it +represents: +

    +

    +

    +  \a     alarm, that is, the BEL character (hex 07)
+  \cx    "control-x", where x is any character
+  \e     escape (hex 1B)
+  \f     formfeed (hex 0C)
+  \n     newline (hex 0A)
+  \r     carriage return (hex 0D)
+  \t     tab (hex 09)
+  \xhh   character with hex code hh
+  \ddd   character with octal code ddd, or backreference
+
    +

    +

    +The precise effect of "\cx" is as follows: if "x" is a lower case letter, it +is converted to upper case. Then bit 6 of the character (hex 40) is inverted. +Thus "\cz" becomes hex 1A, but "\c{" becomes hex 3B, while "\c;" becomes hex +7B. +

    +

    +After "\x", up to two hexadecimal digits are read (letters can be in upper or +lower case). +

    +

    +After "\0" up to two further octal digits are read. In both cases, if there +are fewer than two digits, just those that are present are used. Thus the +sequence "\0\x\07" specifies two binary zeros followed by a BEL character. +Make sure you supply two digits after the initial zero if the character that +follows is itself an octal digit. +

    +

    +The handling of a backslash followed by a digit other than 0 is complicated. +Outside a character class, PCRE reads it and any following digits as a decimal +number. If the number is less than 10, or if there have been at least that many +previous capturing left parentheses in the expression, the entire sequence is +taken as a back reference. A description of how this works is given +later, following the discussion of parenthesized subpatterns. +

    +

    +Inside a character class, or if the decimal number is greater than 9 and there +have not been that many capturing subpatterns, PCRE re-reads up to three octal +digits following the backslash, and generates a single byte from the least +significant 8 bits of the value. Any subsequent digits stand for themselves. +For example: +

    +

    +

    +  \040   is another way of writing a space
+  \40    is the same, provided there are fewer than 40
+            previous capturing subpatterns
+  \7     is always a back reference
+  \11    might be a back reference, or another way of
+            writing a tab
+  \011   is always a tab
+  \0113  is a tab followed by the character "3"
+  \113   is the character with octal code 113 (since there
+            can be no more than 99 back references)
+  \377   is a byte consisting entirely of 1 bits
+  \81    is either a back reference, or a binary zero
+            followed by the two characters "8" and "1"
+
    +

    +

    +Note that octal values of 100 or greater must not be introduced by a leading +zero, because no more than three octal digits are ever read. +

    +

    +All the sequences that define a single byte value can be used both inside and +outside character classes. In addition, inside a character class, the sequence +"\b" is interpreted as the backspace character (hex 08). Outside a character +class it has a different meaning (see below). +

    +

    +The third use of backslash is for specifying generic character types: +

    +

    +

    +  \d     any decimal digit
+  \D     any character that is not a decimal digit
+  \s     any whitespace character
+  \S     any character that is not a whitespace character
+  \w     any "word" character
+  \W     any "non-word" character
+
    +

    +

    +Each pair of escape sequences partitions the complete set of characters into +two disjoint sets. Any given character matches one, and only one, of each pair. +

    +

    +A "word" character is any letter or digit or the underscore character, that is, +any character which can be part of a Perl "word". The definition of letters and +digits is controlled by PCRE's character tables, and may vary if locale- +specific matching is taking place (see "Locale support" above). For example, in +the "fr" (French) locale, some character codes greater than 128 are used for +accented letters, and these are matched by \w. +

    +

    +These character type sequences can appear both inside and outside character +classes. They each match one character of the appropriate type. If the current +matching point is at the end of the subject string, all of them fail, since +there is no character to match. +

    +

    +The fourth use of backslash is for certain simple assertions. An assertion +specifies a condition that has to be met at a particular point in a match, +without consuming any characters from the subject string. The use of +subpatterns for more complicated assertions is described below. The backslashed +assertions are +

    +

    +

    +  \b     word boundary
+  \B     not a word boundary
+  \A     start of subject (independent of multiline mode)
+  \Z     end of subject or newline at end (independent of multiline mode)
+  \z     end of subject (independent of multiline mode)
+
    +

    +

    +These assertions may not appear in character classes (but note that "\b" has a +different meaning, namely the backspace character, inside a character class). +

    +

    +A word boundary is a position in the subject string where the current character +and the previous character do not both match \w or \W (i.e. one matches +\w and the other matches \W), or the start or end of the string if the +first or last character matches \w, respectively. +

    +

    +The \A, \Z, and \z assertions differ from the traditional circumflex and +dollar (described below) in that they only ever match at the very start and end +of the subject string, whatever options are set. They are not affected by the +PCRE_NOTBOL or PCRE_NOTEOL options. If the startoffset argument of +pcre_exec() is non-zero, \A can never match. The difference between \Z +and \z is that \Z matches before a newline that is the last character of the +string as well as at the end of the string, whereas \z matches only at the +end. +

    +
  • CIRCUMFLEX AND DOLLAR +

    +Outside a character class, in the default matching mode, the circumflex +character is an assertion which is true only if the current matching point is +at the start of the subject string. If the startoffset argument of +pcre_exec() is non-zero, circumflex can never match. Inside a character +class, circumflex has an entirely different meaning (see below). +

    +

    +Circumflex need not be the first character of the pattern if a number of +alternatives are involved, but it should be the first thing in each alternative +in which it appears if the pattern is ever to match that branch. If all +possible alternatives start with a circumflex, that is, if the pattern is +constrained to match only at the start of the subject, it is said to be an +"anchored" pattern. (There are also other constructs that can cause a pattern +to be anchored.) +

    +

    +A dollar character is an assertion which is true only if the current matching +point is at the end of the subject string, or immediately before a newline +character that is the last character in the string (by default). Dollar need +not be the last character of the pattern if a number of alternatives are +involved, but it should be the last item in any branch in which it appears. +Dollar has no special meaning in a character class. +

    +

    +The meaning of dollar can be changed so that it matches only at the very end of +the string, by setting the PCRE_DOLLAR_ENDONLY option at compile or matching +time. This does not affect the \Z assertion. +

    +

    +The meanings of the circumflex and dollar characters are changed if the +PCRE_MULTILINE option is set. When this is the case, they match immediately +after and immediately before an internal "\n" character, respectively, in +addition to matching at the start and end of the subject string. For example, +the pattern /^abc$/ matches the subject string "def\nabc" in multiline mode, +but not otherwise. Consequently, patterns that are anchored in single line mode +because all branches start with "^" are not anchored in multiline mode, and a +match for circumflex is possible when the startoffset argument of +pcre_exec() is non-zero. The PCRE_DOLLAR_ENDONLY option is ignored if +PCRE_MULTILINE is set. +

    +

    +Note that the sequences \A, \Z, and \z can be used to match the start and +end of the subject in both modes, and if all branches of a pattern start with +\A is it always anchored, whether PCRE_MULTILINE is set or not. +

    +
  • FULL STOP (PERIOD, DOT) +

    +Outside a character class, a dot in the pattern matches any one character in +the subject, including a non-printing character, but not (by default) newline. +If the PCRE_DOTALL option is set, then dots match newlines as well. The +handling of dot is entirely independent of the handling of circumflex and +dollar, the only relationship being that they both involve newline characters. +Dot has no special meaning in a character class. +

    +
  • SQUARE BRACKETS +

    +An opening square bracket introduces a character class, terminated by a closing +square bracket. A closing square bracket on its own is not special. If a +closing square bracket is required as a member of the class, it should be the +first data character in the class (after an initial circumflex, if present) or +escaped with a backslash. +

    +

    +A character class matches a single character in the subject; the character must +be in the set of characters defined by the class, unless the first character in +the class is a circumflex, in which case the subject character must not be in +the set defined by the class. If a circumflex is actually required as a member +of the class, ensure it is not the first character, or escape it with a +backslash. +

    +

    +For example, the character class [aeiou] matches any lower case vowel, while +[^aeiou] matches any character that is not a lower case vowel. Note that a +circumflex is just a convenient notation for specifying the characters which +are in the class by enumerating those that are not. It is not an assertion: it +still consumes a character from the subject string, and fails if the current +pointer is at the end of the string. +

    +

    +When caseless matching is set, any letters in a class represent both their +upper case and lower case versions, so for example, a caseless [aeiou] matches +"A" as well as "a", and a caseless [^aeiou] does not match "A", whereas a +caseful version would. +

    +

    +The newline character is never treated in any special way in character classes, +whatever the setting of the PCRE_DOTALL or PCRE_MULTILINE options is. A class +such as [^a] will always match a newline. +

    +

    +The minus (hyphen) character can be used to specify a range of characters in a +character class. For example, [d-m] matches any letter between d and m, +inclusive. If a minus character is required in a class, it must be escaped with +a backslash or appear in a position where it cannot be interpreted as +indicating a range, typically as the first or last character in the class. +

    +

    +It is not possible to have the literal character "]" as the end character of a +range. A pattern such as [W-]46] is interpreted as a class of two characters +("W" and "-") followed by a literal string "46]", so it would match "W46]" or +"-46]". However, if the "]" is escaped with a backslash it is interpreted as +the end of range, so [W-\]46] is interpreted as a single class containing a +range followed by two separate characters. The octal or hexadecimal +representation of "]" can also be used to end a range. +

    +

    +Ranges operate in ASCII collating sequence. They can also be used for +characters specified numerically, for example [\000-\037]. If a range that +includes letters is used when caseless matching is set, it matches the letters +in either case. For example, [W-c] is equivalent to [][\^_`wxyzabc], matched +caselessly, and if character tables for the "fr" locale are in use, +[\xc8-\xcb] matches accented E characters in both cases. +

    +

    +The character types \d, \D, \s, \S, \w, and \W may also appear in a +character class, and add the characters that they match to the class. For +example, [\dABCDEF] matches any hexadecimal digit. A circumflex can +conveniently be used with the upper case character types to specify a more +restricted set of characters than the matching lower case type. For example, +the class [^\W_] matches any letter or digit, but not underscore. +

    +

    +All non-alphameric characters other than \, -, ^ (at the start) and the +terminating ] are non-special in character classes, but it does no harm if they +are escaped. +

    +
  • POSIX CHARACTER CLASSES +

    +Perl 5.6 (not yet released at the time of writing) is going to support the +POSIX notation for character classes, which uses names enclosed by [: and :] +within the enclosing square brackets. PCRE supports this notation. For example, +

    +

    +

    +  [01[:alpha:]%]
+
    +

    +

    +matches "0", "1", any alphabetic character, or "%". The supported class names +are +

    +

    +

    +  alnum    letters and digits
+  alpha    letters
+  ascii    character codes 0 - 127
+  cntrl    control characters
+  digit    decimal digits (same as \d)
+  graph    printing characters, excluding space
+  lower    lower case letters
+  print    printing characters, including space
+  punct    printing characters, excluding letters and digits
+  space    white space (same as \s)
+  upper    upper case letters
+  word     "word" characters (same as \w)
+  xdigit   hexadecimal digits
+
    +

    +

    +The names "ascii" and "word" are Perl extensions. Another Perl extension is +negation, which is indicated by a ^ character after the colon. For example, +

    +

    +

    +  [12[:^digit:]]
+
    +

    +

    +matches "1", "2", or any non-digit. PCRE (and Perl) also recogize the POSIX +syntax [.ch.] and [=ch=] where "ch" is a "collating element", but these are not +supported, and an error is given if they are encountered. +

    +
  • VERTICAL BAR +

    +Vertical bar characters are used to separate alternative patterns. For example, +the pattern +

    +

    +

    +  gilbert|sullivan
+
    +

    +

    +matches either "gilbert" or "sullivan". Any number of alternatives may appear, +and an empty alternative is permitted (matching the empty string). +The matching process tries each alternative in turn, from left to right, +and the first one that succeeds is used. If the alternatives are within a +subpattern (defined below), "succeeds" means matching the rest of the main +pattern as well as the alternative in the subpattern. +

    +
  • INTERNAL OPTION SETTING +

    +The settings of PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, and PCRE_EXTENDED +can be changed from within the pattern by a sequence of Perl option letters +enclosed between "(?" and ")". The option letters are +

    +

    +

    +  i  for PCRE_CASELESS
+  m  for PCRE_MULTILINE
+  s  for PCRE_DOTALL
+  x  for PCRE_EXTENDED
+
    +

    +

    +For example, (?im) sets caseless, multiline matching. It is also possible to +unset these options by preceding the letter with a hyphen, and a combined +setting and unsetting such as (?im-sx), which sets PCRE_CASELESS and +PCRE_MULTILINE while unsetting PCRE_DOTALL and PCRE_EXTENDED, is also +permitted. If a letter appears both before and after the hyphen, the option is +unset. +

    +

    +The scope of these option changes depends on where in the pattern the setting +occurs. For settings that are outside any subpattern (defined below), the +effect is the same as if the options were set or unset at the start of +matching. The following patterns all behave in exactly the same way: +

    +

    +

    +  (?i)abc
+  a(?i)bc
+  ab(?i)c
+  abc(?i)
+
    +

    +

    +which in turn is the same as compiling the pattern abc with PCRE_CASELESS set. +In other words, such "top level" settings apply to the whole pattern (unless +there are other changes inside subpatterns). If there is more than one setting +of the same option at top level, the rightmost setting is used. +

    +

    +If an option change occurs inside a subpattern, the effect is different. This +is a change of behaviour in Perl 5.005. An option change inside a subpattern +affects only that part of the subpattern that follows it, so +

    +

    +

    +  (a(?i)b)c
+
    +

    +

    +matches abc and aBc and no other strings (assuming PCRE_CASELESS is not used). +By this means, options can be made to have different settings in different +parts of the pattern. Any changes made in one alternative do carry on +into subsequent branches within the same subpattern. For example, +

    +

    +

    +  (a(?i)b|c)
+
    +

    +

    +matches "ab", "aB", "c", and "C", even though when matching "C" the first +branch is abandoned before the option setting. This is because the effects of +option settings happen at compile time. There would be some very weird +behaviour otherwise. +

    +

    +The PCRE-specific options PCRE_UNGREEDY and PCRE_EXTRA can be changed in the +same way as the Perl-compatible options by using the characters U and X +respectively. The (?X) flag setting is special in that it must always occur +earlier in the pattern than any of the additional features it turns on, even +when it is at top level. It is best put at the start. +

    +
  • SUBPATTERNS +

    +Subpatterns are delimited by parentheses (round brackets), which can be nested. +Marking part of a pattern as a subpattern does two things: +

    +

    +1. It localizes a set of alternatives. For example, the pattern +

    +

    +

    +  cat(aract|erpillar|)
+
    +

    +

    +matches one of the words "cat", "cataract", or "caterpillar". Without the +parentheses, it would match "cataract", "erpillar" or the empty string. +

    +

    +2. It sets up the subpattern as a capturing subpattern (as defined above). +When the whole pattern matches, that portion of the subject string that matched +the subpattern is passed back to the caller via the ovector argument of +pcre_exec(). Opening parentheses are counted from left to right (starting +from 1) to obtain the numbers of the capturing subpatterns. +

    +

    +For example, if the string "the red king" is matched against the pattern +

    +

    +

    +  the ((red|white) (king|queen))
+
    +

    +

    +the captured substrings are "red king", "red", and "king", and are numbered 1, +2, and 3. +

    +

    +The fact that plain parentheses fulfil two functions is not always helpful. +There are often times when a grouping subpattern is required without a +capturing requirement. If an opening parenthesis is followed by "?:", the +subpattern does not do any capturing, and is not counted when computing the +number of any subsequent capturing subpatterns. For example, if the string "the +white queen" is matched against the pattern +

    +

    +

    +  the ((?:red|white) (king|queen))
+
    +

    +

    +the captured substrings are "white queen" and "queen", and are numbered 1 and +2. The maximum number of captured substrings is 99, and the maximum number of +all subpatterns, both capturing and non-capturing, is 200. +

    +

    +As a convenient shorthand, if any option settings are required at the start of +a non-capturing subpattern, the option letters may appear between the "?" and +the ":". Thus the two patterns +

    +

    +

    +  (?i:saturday|sunday)
+  (?:(?i)saturday|sunday)
+
    +

    +

    +match exactly the same set of strings. Because alternative branches are tried +from left to right, and options are not reset until the end of the subpattern +is reached, an option setting in one branch does affect subsequent branches, so +the above patterns match "SUNDAY" as well as "Saturday". +

    +
  • REPETITION +

    +Repetition is specified by quantifiers, which can follow any of the following +items: +

    +

    +

    +  a single character, possibly escaped
+  the . metacharacter
+  a character class
+  a back reference (see next section)
+  a parenthesized subpattern (unless it is an assertion - see below)
+
    +

    +

    +The general repetition quantifier specifies a minimum and maximum number of +permitted matches, by giving the two numbers in curly brackets (braces), +separated by a comma. The numbers must be less than 65536, and the first must +be less than or equal to the second. For example: +

    +

    +

    +  z{2,4}
+
    +

    +

    +matches "zz", "zzz", or "zzzz". A closing brace on its own is not a special +character. If the second number is omitted, but the comma is present, there is +no upper limit; if the second number and the comma are both omitted, the +quantifier specifies an exact number of required matches. Thus +

    +

    +

    +  [aeiou]{3,}
+
    +

    +

    +matches at least 3 successive vowels, but may match many more, while +

    +

    +

    +  \d{8}
+
    +

    +

    +matches exactly 8 digits. An opening curly bracket that appears in a position +where a quantifier is not allowed, or one that does not match the syntax of a +quantifier, is taken as a literal character. For example, {,6} is not a +quantifier, but a literal string of four characters. +

    +

    +The quantifier {0} is permitted, causing the expression to behave as if the +previous item and the quantifier were not present. +

    +

    +For convenience (and historical compatibility) the three most common +quantifiers have single-character abbreviations: +

    +

    +

    +  *    is equivalent to {0,}
+  +    is equivalent to {1,}
+  ?    is equivalent to {0,1}
+
    +

    +

    +It is possible to construct infinite loops by following a subpattern that can +match no characters with a quantifier that has no upper limit, for example: +

    +

    +

    +  (a?)*
+
    +

    +

    +Earlier versions of Perl and PCRE used to give an error at compile time for +such patterns. However, because there are cases where this can be useful, such +patterns are now accepted, but if any repetition of the subpattern does in fact +match no characters, the loop is forcibly broken. +

    +

    +By default, the quantifiers are "greedy", that is, they match as much as +possible (up to the maximum number of permitted times), without causing the +rest of the pattern to fail. The classic example of where this gives problems +is in trying to match comments in C programs. These appear between the +sequences /* and */ and within the sequence, individual * and / characters may +appear. An attempt to match C comments by applying the pattern +

    +

    +

    +  /\*.*\*/
+
    +

    +

    +to the string +

    +

    +

    +  /* first command */  not comment  /* second comment */
+
    +

    +

    +fails, because it matches the entire string due to the greediness of the .* +item. +

    +

    +However, if a quantifier is followed by a question mark, then it ceases to be +greedy, and instead matches the minimum number of times possible, so the +pattern +

    +

    +

    +  /\*.*?\*/
+
    +

    +

    +does the right thing with the C comments. The meaning of the various +quantifiers is not otherwise changed, just the preferred number of matches. +Do not confuse this use of question mark with its use as a quantifier in its +own right. Because it has two uses, it can sometimes appear doubled, as in +

    +

    +

    +  \d??\d
+
    +

    +

    +which matches one digit by preference, but can match two if that is the only +way the rest of the pattern matches. +

    +

    +If the PCRE_UNGREEDY option is set (an option which is not available in Perl) +then the quantifiers are not greedy by default, but individual ones can be made +greedy by following them with a question mark. In other words, it inverts the +default behaviour. +

    +

    +When a parenthesized subpattern is quantified with a minimum repeat count that +is greater than 1 or with a limited maximum, more store is required for the +compiled pattern, in proportion to the size of the minimum or maximum. +

    +

    +If a pattern starts with .* or .{0,} and the PCRE_DOTALL option (equivalent +to Perl's /s) is set, thus allowing the . to match newlines, then the pattern +is implicitly anchored, because whatever follows will be tried against every +character position in the subject string, so there is no point in retrying the +overall match at any position after the first. PCRE treats such a pattern as +though it were preceded by \A. In cases where it is known that the subject +string contains no newlines, it is worth setting PCRE_DOTALL when the pattern +begins with .* in order to obtain this optimization, or alternatively using ^ +to indicate anchoring explicitly. +

    +

    +When a capturing subpattern is repeated, the value captured is the substring +that matched the final iteration. For example, after +

    +

    +

    +  (tweedle[dume]{3}\s*)+
+
    +

    +

    +has matched "tweedledum tweedledee" the value of the captured substring is +"tweedledee". However, if there are nested capturing subpatterns, the +corresponding captured values may have been set in previous iterations. For +example, after +

    +

    +

    +  /(a|(b))+/
+
    +

    +

    +matches "aba" the value of the second captured substring is "b". +

    +
  • BACK REFERENCES +

    +Outside a character class, a backslash followed by a digit greater than 0 (and +possibly further digits) is a back reference to a capturing subpattern earlier +(i.e. to its left) in the pattern, provided there have been that many previous +capturing left parentheses. +

    +

    +However, if the decimal number following the backslash is less than 10, it is +always taken as a back reference, and causes an error only if there are not +that many capturing left parentheses in the entire pattern. In other words, the +parentheses that are referenced need not be to the left of the reference for +numbers less than 10. See the section entitled "Backslash" above for further +details of the handling of digits following a backslash. +

    +

    +A back reference matches whatever actually matched the capturing subpattern in +the current subject string, rather than anything matching the subpattern +itself. So the pattern +

    +

    +

    +  (sens|respons)e and \1ibility
+
    +

    +

    +matches "sense and sensibility" and "response and responsibility", but not +"sense and responsibility". If caseful matching is in force at the time of the +back reference, then the case of letters is relevant. For example, +

    +

    +

    +  ((?i)rah)\s+\1
+
    +

    +

    +matches "rah rah" and "RAH RAH", but not "RAH rah", even though the original +capturing subpattern is matched caselessly. +

    +

    +There may be more than one back reference to the same subpattern. If a +subpattern has not actually been used in a particular match, then any back +references to it always fail. For example, the pattern +

    +

    +

    +  (a|(bc))\2
+
    +

    +

    +always fails if it starts to match "a" rather than "bc". Because there may be +up to 99 back references, all digits following the backslash are taken +as part of a potential back reference number. If the pattern continues with a +digit character, then some delimiter must be used to terminate the back +reference. If the PCRE_EXTENDED option is set, this can be whitespace. +Otherwise an empty comment can be used. +

    +

    +A back reference that occurs inside the parentheses to which it refers fails +when the subpattern is first used, so, for example, (a\1) never matches. +However, such references can be useful inside repeated subpatterns. For +example, the pattern +

    +

    +

    +  (a|b\1)+
+
    +

    +

    +matches any number of "a"s and also "aba", "ababaa" etc. At each iteration of +the subpattern, the back reference matches the character string corresponding +to the previous iteration. In order for this to work, the pattern must be such +that the first iteration does not need to match the back reference. This can be +done using alternation, as in the example above, or by a quantifier with a +minimum of zero. +

    +
  • ASSERTIONS +

    +An assertion is a test on the characters following or preceding the current +matching point that does not actually consume any characters. The simple +assertions coded as \b, \B, \A, \Z, \z, ^ and $ are described above. More +complicated assertions are coded as subpatterns. There are two kinds: those +that look ahead of the current position in the subject string, and those that +look behind it. +

    +

    +An assertion subpattern is matched in the normal way, except that it does not +cause the current matching position to be changed. Lookahead assertions start +with (?= for positive assertions and (?! for negative assertions. For example, +

    +

    +

    +  \w+(?=;)
+
    +

    +

    +matches a word followed by a semicolon, but does not include the semicolon in +the match, and +

    +

    +

    +  foo(?!bar)
+
    +

    +

    +matches any occurrence of "foo" that is not followed by "bar". Note that the +apparently similar pattern +

    +

    +

    +  (?!foo)bar
+
    +

    +

    +does not find an occurrence of "bar" that is preceded by something other than +"foo"; it finds any occurrence of "bar" whatsoever, because the assertion +(?!foo) is always true when the next three characters are "bar". A +lookbehind assertion is needed to achieve this effect. +

    +

    +Lookbehind assertions start with (?<= for positive assertions and (?<! for +negative assertions. For example, +

    +

    +

    +  (?<!foo)bar
+
    +

    +

    +does find an occurrence of "bar" that is not preceded by "foo". The contents of +a lookbehind assertion are restricted such that all the strings it matches must +have a fixed length. However, if there are several alternatives, they do not +all have to have the same fixed length. Thus +

    +

    +

    +  (?<=bullock|donkey)
+
    +

    +

    +is permitted, but +

    +

    +

    +  (?<!dogs?|cats?)
+
    +

    +

    +causes an error at compile time. Branches that match different length strings +are permitted only at the top level of a lookbehind assertion. This is an +extension compared with Perl 5.005, which requires all branches to match the +same length of string. An assertion such as +

    +

    +

    +  (?<=ab(c|de))
+
    +

    +

    +is not permitted, because its single top-level branch can match two different +lengths, but it is acceptable if rewritten to use two top-level branches: +

    +

    +

    +  (?<=abc|abde)
+
    +

    +

    +The implementation of lookbehind assertions is, for each alternative, to +temporarily move the current position back by the fixed width and then try to +match. If there are insufficient characters before the current position, the +match is deemed to fail. Lookbehinds in conjunction with once-only subpatterns +can be particularly useful for matching at the ends of strings; an example is +given at the end of the section on once-only subpatterns. +

    +

    +Several assertions (of any sort) may occur in succession. For example, +

    +

    +

    +  (?<=\d{3})(?<!999)foo
+
    +

    +

    +matches "foo" preceded by three digits that are not "999". Notice that each of +the assertions is applied independently at the same point in the subject +string. First there is a check that the previous three characters are all +digits, then there is a check that the same three characters are not "999". +This pattern does not match "foo" preceded by six characters, the first +of which are digits and the last three of which are not "999". For example, it +doesn't match "123abcfoo". A pattern to do that is +

    +

    +

    +  (?<=\d{3}...)(?<!999)foo
+
    +

    +

    +This time the first assertion looks at the preceding six characters, checking +that the first three are digits, and then the second assertion checks that the +preceding three characters are not "999". +

    +

    +Assertions can be nested in any combination. For example, +

    +

    +

    +  (?<=(?<!foo)bar)baz
+
    +

    +

    +matches an occurrence of "baz" that is preceded by "bar" which in turn is not +preceded by "foo", while +

    +

    +

    +  (?<=\d{3}(?!999)...)foo
+
    +

    +

    +is another pattern which matches "foo" preceded by three digits and any three +characters that are not "999". +

    +

    +Assertion subpatterns are not capturing subpatterns, and may not be repeated, +because it makes no sense to assert the same thing several times. If any kind +of assertion contains capturing subpatterns within it, these are counted for +the purposes of numbering the capturing subpatterns in the whole pattern. +However, substring capturing is carried out only for positive assertions, +because it does not make sense for negative assertions. +

    +

    +Assertions count towards the maximum of 200 parenthesized subpatterns. +

    +
  • ONCE-ONLY SUBPATTERNS +

    +With both maximizing and minimizing repetition, failure of what follows +normally causes the repeated item to be re-evaluated to see if a different +number of repeats allows the rest of the pattern to match. Sometimes it is +useful to prevent this, either to change the nature of the match, or to cause +it fail earlier than it otherwise might, when the author of the pattern knows +there is no point in carrying on. +

    +

    +Consider, for example, the pattern \d+foo when applied to the subject line +

    +

    +

    +  123456bar
+
    +

    +

    +After matching all 6 digits and then failing to match "foo", the normal +action of the matcher is to try again with only 5 digits matching the \d+ +item, and then with 4, and so on, before ultimately failing. Once-only +subpatterns provide the means for specifying that once a portion of the pattern +has matched, it is not to be re-evaluated in this way, so the matcher would +give up immediately on failing to match "foo" the first time. The notation is +another kind of special parenthesis, starting with (?> as in this example: +

    +

    +

    +  (?>\d+)bar
+
    +

    +

    +This kind of parenthesis "locks up" the part of the pattern it contains once +it has matched, and a failure further into the pattern is prevented from +backtracking into it. Backtracking past it to previous items, however, works as +normal. +

    +

    +An alternative description is that a subpattern of this type matches the string +of characters that an identical standalone pattern would match, if anchored at +the current point in the subject string. +

    +

    +Once-only subpatterns are not capturing subpatterns. Simple cases such as the +above example can be thought of as a maximizing repeat that must swallow +everything it can. So, while both \d+ and \d+? are prepared to adjust the +number of digits they match in order to make the rest of the pattern match, +(?>\d+) can only match an entire sequence of digits. +

    +

    +This construction can of course contain arbitrarily complicated subpatterns, +and it can be nested. +

    +

    +Once-only subpatterns can be used in conjunction with lookbehind assertions to +specify efficient matching at the end of the subject string. Consider a simple +pattern such as +

    +

    +

    +  abcd$
+
    +

    +

    +when applied to a long string which does not match. Because matching proceeds +from left to right, PCRE will look for each "a" in the subject and then see if +what follows matches the rest of the pattern. If the pattern is specified as +

    +

    +

    +  ^.*abcd$
+
    +

    +

    +then the initial .* matches the entire string at first, but when this fails +(because there is no following "a"), it backtracks to match all but the last +character, then all but the last two characters, and so on. Once again the +search for "a" covers the entire string, from right to left, so we are no +better off. However, if the pattern is written as +

    +

    +

    +  ^(?>.*)(?<=abcd)
+
    +

    +

    +then there can be no backtracking for the .* item; it can match only the entire +string. The subsequent lookbehind assertion does a single test on the last four +characters. If it fails, the match fails immediately. For long strings, this +approach makes a significant difference to the processing time. +

    +

    +When a pattern contains an unlimited repeat inside a subpattern that can itself +be repeated an unlimited number of times, the use of a once-only subpattern is +the only way to avoid some failing matches taking a very long time indeed. +The pattern +

    +

    +

    +  (\D+|<\d+>)*[!?]
+
    +

    +

    +matches an unlimited number of substrings that either consist of non-digits, or +digits enclosed in <>, followed by either ! or ?. When it matches, it runs +quickly. However, if it is applied to +

    +

    +

    +  aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+
    +

    +

    +it takes a long time before reporting failure. This is because the string can +be divided between the two repeats in a large number of ways, and all have to +be tried. (The example used [!?] rather than a single character at the end, +because both PCRE and Perl have an optimization that allows for fast failure +when a single character is used. They remember the last single character that +is required for a match, and fail early if it is not present in the string.) +If the pattern is changed to +

    +

    +

    +  ((?>\D+)|<\d+>)*[!?]
+
    +

    +

    +sequences of non-digits cannot be broken, and failure happens quickly. +

    +
  • CONDITIONAL SUBPATTERNS +

    +It is possible to cause the matching process to obey a subpattern +conditionally or to choose between two alternative subpatterns, depending on +the result of an assertion, or whether a previous capturing subpattern matched +or not. The two possible forms of conditional subpattern are +

    +

    +

    +  (?(condition)yes-pattern)
+  (?(condition)yes-pattern|no-pattern)
+
    +

    +

    +If the condition is satisfied, the yes-pattern is used; otherwise the +no-pattern (if present) is used. If there are more than two alternatives in the +subpattern, a compile-time error occurs. +

    +

    +There are two kinds of condition. If the text between the parentheses consists +of a sequence of digits, then the condition is satisfied if the capturing +subpattern of that number has previously matched. Consider the following +pattern, which contains non-significant white space to make it more readable +(assume the PCRE_EXTENDED option) and to divide it into three parts for ease +of discussion: +

    +

    +

    +  ( \( )?    [^()]+    (?(1) \) )
+
    +

    +

    +The first part matches an optional opening parenthesis, and if that +character is present, sets it as the first captured substring. The second part +matches one or more characters that are not parentheses. The third part is a +conditional subpattern that tests whether the first set of parentheses matched +or not. If they did, that is, if subject started with an opening parenthesis, +the condition is true, and so the yes-pattern is executed and a closing +parenthesis is required. Otherwise, since no-pattern is not present, the +subpattern matches nothing. In other words, this pattern matches a sequence of +non-parentheses, optionally enclosed in parentheses. +

    +

    +If the condition is not a sequence of digits, it must be an assertion. This may +be a positive or negative lookahead or lookbehind assertion. Consider this +pattern, again containing non-significant white space, and with the two +alternatives on the second line: +

    +

    +

    +  (?(?=[^a-z]*[a-z])
+  \d{2}-[a-z]{3}-\d{2}  |  \d{2}-\d{2}-\d{2} )
+
    +

    +

    +The condition is a positive lookahead assertion that matches an optional +sequence of non-letters followed by a letter. In other words, it tests for the +presence of at least one letter in the subject. If a letter is found, the +subject is matched against the first alternative; otherwise it is matched +against the second. This pattern matches strings in one of the two forms +dd-aaa-dd or dd-dd-dd, where aaa are letters and dd are digits. +

    +
  • COMMENTS +

    +The sequence (?# marks the start of a comment which continues up to the next +closing parenthesis. Nested parentheses are not permitted. The characters +that make up a comment play no part in the pattern matching at all. +

    +

    +If the PCRE_EXTENDED option is set, an unescaped # character outside a +character class introduces a comment that continues up to the next newline +character in the pattern. +

    +
  • RECURSIVE PATTERNS +

    +Consider the problem of matching a string in parentheses, allowing for +unlimited nested parentheses. Without the use of recursion, the best that can +be done is to use a pattern that matches up to some fixed depth of nesting. It +is not possible to handle an arbitrary nesting depth. Perl 5.6 has provided an +experimental facility that allows regular expressions to recurse (amongst other +things). It does this by interpolating Perl code in the expression at run time, +and the code can refer to the expression itself. A Perl pattern to solve the +parentheses problem can be created like this: +

    +

    +

    +  $re = qr{\( (?: (?>[^()]+) | (?p{$re}) )* \)}x;
+
    +

    +

    +The (?p{...}) item interpolates Perl code at run time, and in this case refers +recursively to the pattern in which it appears. Obviously, PCRE cannot support +the interpolation of Perl code. Instead, the special item (?R) is provided for +the specific case of recursion. This PCRE pattern solves the parentheses +problem (assume the PCRE_EXTENDED option is set so that white space is +ignored): +

    +

    +

    +  \( ( (?>[^()]+) | (?R) )* \)
+
    +

    +

    +First it matches an opening parenthesis. Then it matches any number of +substrings which can either be a sequence of non-parentheses, or a recursive +match of the pattern itself (i.e. a correctly parenthesized substring). Finally +there is a closing parenthesis. +

    +

    +This particular example pattern contains nested unlimited repeats, and so the +use of a once-only subpattern for matching strings of non-parentheses is +important when applying the pattern to strings that do not match. For example, +when it is applied to +

    +

    +

    +  (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa()
+
    +

    +

    +it yields "no match" quickly. However, if a once-only subpattern is not used, +the match runs for a very long time indeed because there are so many different +ways the + and * repeats can carve up the subject, and all have to be tested +before failure can be reported. +

    +

    +The values set for any capturing subpatterns are those from the outermost level +of the recursion at which the subpattern value is set. If the pattern above is +matched against +

    +

    +

    +  (ab(cd)ef)
+
    +

    +

    +the value for the capturing parentheses is "ef", which is the last value taken +on at the top level. If additional parentheses are added, giving +

    +

    +

    +  \( ( ( (?>[^()]+) | (?R) )* ) \)
+     ^                        ^
+     ^                        ^
+
    +then the string they capture is "ab(cd)ef", the contents of the top level +parentheses. If there are more than 15 capturing parentheses in a pattern, PCRE +has to obtain extra memory to store data during a recursion, which it does by +using pcre_malloc, freeing it via pcre_free afterwards. If no +memory can be obtained, it saves data for the first 15 capturing parentheses +only, as there is no way to give an out-of-memory error from within a +recursion. +

    +
  • PERFORMANCE +

    +Certain items that may appear in patterns are more efficient than others. It is +more efficient to use a character class like [aeiou] than a set of alternatives +such as (a|e|i|o|u). In general, the simplest construction that provides the +required behaviour is usually the most efficient. Jeffrey Friedl's book +contains a lot of discussion about optimizing regular expressions for efficient +performance. +

    +

    +When a pattern begins with .* and the PCRE_DOTALL option is set, the pattern is +implicitly anchored by PCRE, since it can match only at the start of a subject +string. However, if PCRE_DOTALL is not set, PCRE cannot make this optimization, +because the . metacharacter does not then match a newline, and if the subject +string contains newlines, the pattern may match from the character immediately +following one of them instead of from the very start. For example, the pattern +

    +

    +

    +  (.*) second
+
    +

    +

    +matches the subject "first\nand second" (where \n stands for a newline +character) with the first captured substring being "and". In order to do this, +PCRE has to retry the match starting after every newline in the subject. +

    +

    +If you are using such a pattern with subject strings that do not contain +newlines, the best performance is obtained by setting PCRE_DOTALL, or starting +the pattern with ^.* to indicate explicit anchoring. That saves PCRE from +having to scan along the subject looking for a newline to restart at. +

    +

    +Beware of patterns that contain nested indefinite repeats. These can take a +long time to run when applied to a string that does not match. Consider the +pattern fragment +

    +

    +

    +  (a+)*
+
    +

    +

    +This can match "aaaa" in 33 different ways, and this number increases very +rapidly as the string gets longer. (The * repeat can match 0, 1, 2, 3, or 4 +times, and for each of those cases other than 0, the + repeats can match +different numbers of times.) When the remainder of the pattern is such that the +entire match is going to fail, PCRE has in principle to try every possible +variation, and this can take an extremely long time. +

    +

    +An optimization catches some of the more simple cases such as +

    +

    +

    +  (a+)*b
+
    +

    +

    +where a literal character follows. Before embarking on the standard matching +procedure, PCRE checks that there is a "b" later in the subject string, and if +there is not, it fails the match immediately. However, when there is no +following literal this optimization cannot be used. You can see the difference +by comparing the behaviour of +

    +

    +

    +  (a+)*\d
+
    +

    +

    +with the pattern above. The former gives a failure almost instantly when +applied to a whole line of "a" characters, whereas the latter takes an +appreciable time with strings longer than about 20 characters. +

    +
  • AUTHOR +

    +Philip Hazel <ph10@cam.ac.uk> +
    +University Computing Service, +
    +New Museums Site, +
    +Cambridge CB2 3QG, England. +
    +Phone: +44 1223 334714 +

    +

    +Last updated: 27 January 2000 +
    +Copyright (c) 1997-2000 University of Cambridge. diff --git a/ext/pcre/pcrelib/doc/pcre.txt b/ext/pcre/pcrelib/doc/pcre.txt new file mode 100644 index 0000000000..f28ee99e8b --- /dev/null +++ b/ext/pcre/pcrelib/doc/pcre.txt @@ -0,0 +1,1978 @@ +NAME + pcre - Perl-compatible regular expressions. + + + +SYNOPSIS + #include + + pcre *pcre_compile(const char *pattern, int options, + const char **errptr, int *erroffset, + const unsigned char *tableptr); + + pcre_extra *pcre_study(const pcre *code, int options, + const char **errptr); + + int pcre_exec(const pcre *code, const pcre_extra *extra, + const char *subject, int length, int startoffset, + int options, int *ovector, int ovecsize); + + int pcre_copy_substring(const char *subject, int *ovector, + int stringcount, int stringnumber, char *buffer, + int buffersize); + + int pcre_get_substring(const char *subject, int *ovector, + int stringcount, int stringnumber, + const char **stringptr); + + int pcre_get_substring_list(const char *subject, + int *ovector, int stringcount, const char ***listptr); + + const unsigned char *pcre_maketables(void); + + int pcre_fullinfo(const pcre *code, const pcre_extra *extra, + int what, void *where); + + int pcre_info(const pcre *code, int *optptr, *firstcharptr); + + char *pcre_version(void); + + void *(*pcre_malloc)(size_t); + + void (*pcre_free)(void *); + + + + +DESCRIPTION + The PCRE library is a set of functions that implement regu- + lar expression pattern matching using the same syntax and + semantics as Perl 5, with just a few differences (see + below). The current implementation corresponds to Perl + 5.005, with some additional features from the Perl develop- + ment release. + + PCRE has its own native API, which is described in this + document. There is also a set of wrapper functions that + correspond to the POSIX regular expression API. These are + described in the pcreposix documentation. + + The native API function prototypes are defined in the header + file pcre.h, and on Unix systems the library itself is + called libpcre.a, so can be accessed by adding -lpcre to the + command for linking an application which calls it. The + header file defines the macros PCRE_MAJOR and PCRE_MINOR to + contain the major and minor release numbers for the library. + Applications can use these to include support for different + releases. + + The functions pcre_compile(), pcre_study(), and pcre_exec() + are used for compiling and matching regular expressions, + while pcre_copy_substring(), pcre_get_substring(), and + pcre_get_substring_list() are convenience functions for + extracting captured substrings from a matched subject + string. The function pcre_maketables() is used (optionally) + to build a set of character tables in the current locale for + passing to pcre_compile(). + + The function pcre_fullinfo() is used to find out information + about a compiled pattern; pcre_info() is an obsolete version + which returns only some of the available information, but is + retained for backwards compatibility. The function + pcre_version() returns a pointer to a string containing the + version of PCRE and its date of release. + + The global variables pcre_malloc and pcre_free initially + contain the entry points of the standard malloc() and free() + functions respectively. PCRE calls the memory management + functions via these variables, so a calling program can + replace them if it wishes to intercept the calls. This + should be done before calling any PCRE functions. + + + +MULTI-THREADING + The PCRE functions can be used in multi-threading applica- + tions, with the proviso that the memory management functions + pointed to by pcre_malloc and pcre_free are shared by all + threads. + + The compiled form of a regular expression is not altered + during matching, so the same compiled pattern can safely be + used by several threads at once. + + + + +COMPILING A PATTERN + The function pcre_compile() is called to compile a pattern + into an internal form. The pattern is a C string terminated + by a binary zero, and is passed in the argument pattern. A + pointer to a single block of memory that is obtained via + pcre_malloc is returned. This contains the compiled code and + related data. The pcre type is defined for this for conveni- + ence, but in fact pcre is just a typedef for void, since the + contents of the block are not externally defined. It is up + to the caller to free the memory when it is no longer + required. + + The size of a compiled pattern is roughly proportional to + the length of the pattern string, except that each character + class (other than those containing just a single character, + negated or not) requires 33 bytes, and repeat quantifiers + with a minimum greater than one or a bounded maximum cause + the relevant portions of the compiled pattern to be repli- + cated. + + The options argument contains independent bits that affect + the compilation. It should be zero if no options are + required. Some of the options, in particular, those that are + compatible with Perl, can also be set and unset from within + the pattern (see the detailed description of regular expres- + sions below). For these options, the contents of the options + argument specifies their initial settings at the start of + compilation and execution. The PCRE_ANCHORED option can be + set at the time of matching as well as at compile time. + + If errptr is NULL, pcre_compile() returns NULL immediately. + Otherwise, if compilation of a pattern fails, pcre_compile() + returns NULL, and sets the variable pointed to by errptr to + point to a textual error message. The offset from the start + of the pattern to the character where the error was + discovered is placed in the variable pointed to by + erroffset, which must not be NULL. If it is, an immediate + error is given. + + If the final argument, tableptr, is NULL, PCRE uses a + default set of character tables which are built when it is + compiled, using the default C locale. Otherwise, tableptr + must be the result of a call to pcre_maketables(). See the + section on locale support below. + + The following option bits are defined in the header file: + + PCRE_ANCHORED + + If this bit is set, the pattern is forced to be "anchored", + that is, it is constrained to match only at the start of the + string which is being searched (the "subject string"). This + effect can also be achieved by appropriate constructs in the + pattern itself, which is the only way to do it in Perl. + + PCRE_CASELESS + + If this bit is set, letters in the pattern match both upper + and lower case letters. It is equivalent to Perl's /i + option. + + PCRE_DOLLAR_ENDONLY + + If this bit is set, a dollar metacharacter in the pattern + matches only at the end of the subject string. Without this + option, a dollar also matches immediately before the final + character if it is a newline (but not before any other new- + lines). The PCRE_DOLLAR_ENDONLY option is ignored if + PCRE_MULTILINE is set. There is no equivalent to this option + in Perl. + + PCRE_DOTALL + + If this bit is set, a dot metacharater in the pattern + matches all characters, including newlines. Without it, new- + lines are excluded. This option is equivalent to Perl's /s + option. A negative class such as [^a] always matches a new- + line character, independent of the setting of this option. + + PCRE_EXTENDED + + If this bit is set, whitespace data characters in the pat- + tern are totally ignored except when escaped or inside a + character class, and characters between an unescaped # out- + side a character class and the next newline character, + inclusive, are also ignored. This is equivalent to Perl's /x + option, and makes it possible to include comments inside + complicated patterns. Note, however, that this applies only + to data characters. Whitespace characters may never appear + within special character sequences in a pattern, for example + within the sequence (?( which introduces a conditional sub- + pattern. + + PCRE_EXTRA + + This option was invented in order to turn on additional + functionality of PCRE that is incompatible with Perl, but it + is currently of very little use. When set, any backslash in + a pattern that is followed by a letter that has no special + meaning causes an error, thus reserving these combinations + for future expansion. By default, as in Perl, a backslash + followed by a letter with no special meaning is treated as a + literal. There are at present no other features controlled + by this option. It can also be set by a (?X) option setting + within a pattern. + + PCRE_MULTILINE + + By default, PCRE treats the subject string as consisting of + a single "line" of characters (even if it actually contains + several newlines). The "start of line" metacharacter (^) + matches only at the start of the string, while the "end of + line" metacharacter ($) matches only at the end of the + string, or before a terminating newline (unless + PCRE_DOLLAR_ENDONLY is set). This is the same as Perl. + + When PCRE_MULTILINE it is set, the "start of line" and "end + of line" constructs match immediately following or immedi- + ately before any newline in the subject string, respec- + tively, as well as at the very start and end. This is + equivalent to Perl's /m option. If there are no "\n" charac- + ters in a subject string, or no occurrences of ^ or $ in a + pattern, setting PCRE_MULTILINE has no effect. + + PCRE_UNGREEDY + + This option inverts the "greediness" of the quantifiers so + that they are not greedy by default, but become greedy if + followed by "?". It is not compatible with Perl. It can also + be set by a (?U) option setting within the pattern. + + + +STUDYING A PATTERN + When a pattern is going to be used several times, it is + worth spending more time analyzing it in order to speed up + the time taken for matching. The function pcre_study() takes + a pointer to a compiled pattern as its first argument, and + returns a pointer to a pcre_extra block (another void + typedef) containing additional information about the pat- + tern; this can be passed to pcre_exec(). If no additional + information is available, NULL is returned. + + The second argument contains option bits. At present, no + options are defined for pcre_study(), and this argument + should always be zero. + + The third argument for pcre_study() is a pointer to an error + message. If studying succeeds (even if no data is returned), + the variable it points to is set to NULL. Otherwise it + points to a textual error message. + + At present, studying a pattern is useful only for non- + anchored patterns that do not have a single fixed starting + character. A bitmap of possible starting characters is + created. + + + +LOCALE SUPPORT + PCRE handles caseless matching, and determines whether char- + acters are letters, digits, or whatever, by reference to a + set of tables. The library contains a default set of tables + which is created in the default C locale when PCRE is com- + piled. This is used when the final argument of + pcre_compile() is NULL, and is sufficient for many applica- + tions. + + An alternative set of tables can, however, be supplied. Such + tables are built by calling the pcre_maketables() function, + which has no arguments, in the relevant locale. The result + can then be passed to pcre_compile() as often as necessary. + For example, to build and use tables that are appropriate + for the French locale (where accented characters with codes + greater than 128 are treated as letters), the following code + could be used: + + setlocale(LC_CTYPE, "fr"); + tables = pcre_maketables(); + re = pcre_compile(..., tables); + + The tables are built in memory that is obtained via + pcre_malloc. The pointer that is passed to pcre_compile is + saved with the compiled pattern, and the same tables are + used via this pointer by pcre_study() and pcre_exec(). Thus + for any single pattern, compilation, studying and matching + all happen in the same locale, but different patterns can be + compiled in different locales. It is the caller's responsi- + bility to ensure that the memory containing the tables + remains available for as long as it is needed. + + + +INFORMATION ABOUT A PATTERN + The pcre_fullinfo() function returns information about a + compiled pattern. It replaces the obsolete pcre_info() func- + tion, which is nevertheless retained for backwards compabil- + ity (and is documented below). + + The first argument for pcre_fullinfo() is a pointer to the + compiled pattern. The second argument is the result of + pcre_study(), or NULL if the pattern was not studied. The + third argument specifies which piece of information is + required, while the fourth argument is a pointer to a vari- + able to receive the data. The yield of the function is zero + for success, or one of the following negative numbers: + + PCRE_ERROR_NULL the argument code was NULL + the argument where was NULL + PCRE_ERROR_BADMAGIC the "magic number" was not found + PCRE_ERROR_BADOPTION the value of what was invalid + + The possible values for the third argument are defined in + pcre.h, and are as follows: + + PCRE_INFO_OPTIONS + + Return a copy of the options with which the pattern was com- + piled. The fourth argument should point to au unsigned long + int variable. These option bits are those specified in the + call to pcre_compile(), modified by any top-level option + settings within the pattern itself, and with the + PCRE_ANCHORED bit forcibly set if the form of the pattern + implies that it can match only at the start of a subject + string. + + PCRE_INFO_SIZE + + Return the size of the compiled pattern, that is, the value + that was passed as the argument to pcre_malloc() when PCRE + was getting memory in which to place the compiled data. The + fourth argument should point to a size_t variable. + + PCRE_INFO_CAPTURECOUNT + + Return the number of capturing subpatterns in the pattern. + The fourth argument should point to an int variable. + + PCRE_INFO_BACKREFMAX + + Return the number of the highest back reference in the pat- + tern. The fourth argument should point to an int variable. + Zero is returned if there are no back references. + + PCRE_INFO_FIRSTCHAR + + Return information about the first character of any matched + string, for a non-anchored pattern. If there is a fixed + first character, e.g. from a pattern such as + (cat|cow|coyote), then it is returned in the integer pointed + to by where. Otherwise, if either + + (a) the pattern was compiled with the PCRE_MULTILINE option, + and every branch starts with "^", or + + (b) every branch of the pattern starts with ".*" and + PCRE_DOTALL is not set (if it were set, the pattern would be + anchored), + + then -1 is returned, indicating that the pattern matches + only at the start of a subject string or after any "\n" + within the string. Otherwise -2 is returned. For anchored + patterns, -2 is returned. + + PCRE_INFO_FIRSTTABLE + + If the pattern was studied, and this resulted in the con- + struction of a 256-bit table indicating a fixed set of char- + acters for the first character in any matching string, a + pointer to the table is returned. Otherwise NULL is + returned. The fourth argument should point to an unsigned + char * variable. + + PCRE_INFO_LASTLITERAL + + For a non-anchored pattern, return the value of the right- + most literal character which must exist in any matched + string, other than at its start. The fourth argument should + point to an int variable. If there is no such character, or + if the pattern is anchored, -1 is returned. For example, for + the pattern /a\d+z\d+/ the returned value is 'z'. + + The pcre_info() function is now obsolete because its inter- + face is too restrictive to return all the available data + about a compiled pattern. New programs should use + pcre_fullinfo() instead. The yield of pcre_info() is the + number of capturing subpatterns, or one of the following + negative numbers: + + PCRE_ERROR_NULL the argument code was NULL + PCRE_ERROR_BADMAGIC the "magic number" was not found + + If the optptr argument is not NULL, a copy of the options + with which the pattern was compiled is placed in the integer + it points to (see PCRE_INFO_OPTIONS above). + + If the pattern is not anchored and the firstcharptr argument + is not NULL, it is used to pass back information about the + first character of any matched string (see + PCRE_INFO_FIRSTCHAR above). + + + +MATCHING A PATTERN + The function pcre_exec() is called to match a subject string + against a pre-compiled pattern, which is passed in the code + argument. If the pattern has been studied, the result of the + study should be passed in the extra argument. Otherwise this + must be NULL. + + The PCRE_ANCHORED option can be passed in the options argu- + ment, whose unused bits must be zero. However, if a pattern + was compiled with PCRE_ANCHORED, or turned out to be + anchored by virtue of its contents, it cannot be made + unachored at matching time. + + There are also three further options that can be set only at + matching time: + + PCRE_NOTBOL + + The first character of the string is not the beginning of a + line, so the circumflex metacharacter should not match + before it. Setting this without PCRE_MULTILINE (at compile + time) causes circumflex never to match. + + PCRE_NOTEOL + + The end of the string is not the end of a line, so the dol- + lar metacharacter should not match it nor (except in multi- + line mode) a newline immediately before it. Setting this + without PCRE_MULTILINE (at compile time) causes dollar never + to match. + + PCRE_NOTEMPTY + + An empty string is not considered to be a valid match if + this option is set. If there are alternatives in the pat- + tern, they are tried. If all the alternatives match the + empty string, the entire match fails. For example, if the + pattern + + a?b? + + is applied to a string not beginning with "a" or "b", it + matches the empty string at the start of the subject. With + PCRE_NOTEMPTY set, this match is not valid, so PCRE searches + further into the string for occurrences of "a" or "b". + + Perl has no direct equivalent of PCRE_NOTEMPTY, but it does + make a special case of a pattern match of the empty string + within its split() function, and when using the /g modifier. + It is possible to emulate Perl's behaviour after matching a + null string by first trying the match again at the same + offset with PCRE_NOTEMPTY set, and then if that fails by + advancing the starting offset (see below) and trying an + ordinary match again. + + The subject string is passed as a pointer in subject, a + length in length, and a starting offset in startoffset. + Unlike the pattern string, it may contain binary zero char- + acters. When the starting offset is zero, the search for a + match starts at the beginning of the subject, and this is by + far the most common case. + + A non-zero starting offset is useful when searching for + another match in the same subject by calling pcre_exec() + again after a previous success. Setting startoffset differs + from just passing over a shortened string and setting + PCRE_NOTBOL in the case of a pattern that begins with any + kind of lookbehind. For example, consider the pattern + + \Biss\B + + which finds occurrences of "iss" in the middle of words. (\B + matches only if the current position in the subject is not a + word boundary.) When applied to the string "Mississipi" the + first call to pcre_exec() finds the first occurrence. If + pcre_exec() is called again with just the remainder of the + subject, namely "issipi", it does not match, because \B is + always false at the start of the subject, which is deemed to + be a word boundary. However, if pcre_exec() is passed the + entire string again, but with startoffset set to 4, it finds + the second occurrence of "iss" because it is able to look + behind the starting point to discover that it is preceded by + a letter. + + If a non-zero starting offset is passed when the pattern is + anchored, one attempt to match at the given offset is tried. + This can only succeed if the pattern does not require the + match to be at the start of the subject. + + In general, a pattern matches a certain portion of the sub- + ject, and in addition, further substrings from the subject + may be picked out by parts of the pattern. Following the + usage in Jeffrey Friedl's book, this is called "capturing" + in what follows, and the phrase "capturing subpattern" is + used for a fragment of a pattern that picks out a substring. + PCRE supports several other kinds of parenthesized subpat- + tern that do not cause substrings to be captured. + + Captured substrings are returned to the caller via a vector + of integer offsets whose address is passed in ovector. The + number of elements in the vector is passed in ovecsize. The + first two-thirds of the vector is used to pass back captured + substrings, each substring using a pair of integers. The + remaining third of the vector is used as workspace by + pcre_exec() while matching capturing subpatterns, and is not + available for passing back information. The length passed in + ovecsize should always be a multiple of three. If it is not, + it is rounded down. + + When a match has been successful, information about captured + substrings is returned in pairs of integers, starting at the + beginning of ovector, and continuing up to two-thirds of its + length at the most. The first element of a pair is set to + the offset of the first character in a substring, and the + second is set to the offset of the first character after the + end of a substring. The first pair, ovector[0] and ovec- + tor[1], identify the portion of the subject string matched + by the entire pattern. The next pair is used for the first + capturing subpattern, and so on. The value returned by + pcre_exec() is the number of pairs that have been set. If + there are no capturing subpatterns, the return value from a + successful match is 1, indicating that just the first pair + of offsets has been set. + + Some convenience functions are provided for extracting the + captured substrings as separate strings. These are described + in the following section. + + It is possible for an capturing subpattern number n+1 to + match some part of the subject when subpattern n has not + been used at all. For example, if the string "abc" is + matched against the pattern (a|(z))(bc) subpatterns 1 and 3 + are matched, but 2 is not. When this happens, both offset + values corresponding to the unused subpattern are set to -1. + + If a capturing subpattern is matched repeatedly, it is the + last portion of the string that it matched that gets + returned. + + If the vector is too small to hold all the captured sub- + strings, it is used as far as possible (up to two-thirds of + its length), and the function returns a value of zero. In + particular, if the substring offsets are not of interest, + pcre_exec() may be called with ovector passed as NULL and + ovecsize as zero. However, if the pattern contains back + references and the ovector isn't big enough to remember the + related substrings, PCRE has to get additional memory for + use during matching. Thus it is usually advisable to supply + an ovector. + + Note that pcre_info() can be used to find out how many cap- + turing subpatterns there are in a compiled pattern. The + smallest size for ovector that will allow for n captured + substrings in addition to the offsets of the substring + matched by the whole pattern is (n+1)*3. + + If pcre_exec() fails, it returns a negative number. The fol- + lowing are defined in the header file: + + PCRE_ERROR_NOMATCH (-1) + + The subject string did not match the pattern. + + PCRE_ERROR_NULL (-2) + + Either code or subject was passed as NULL, or ovector was + NULL and ovecsize was not zero. + + PCRE_ERROR_BADOPTION (-3) + + An unrecognized bit was set in the options argument. + + PCRE_ERROR_BADMAGIC (-4) + + PCRE stores a 4-byte "magic number" at the start of the com- + piled code, to catch the case when it is passed a junk + pointer. This is the error it gives when the magic number + isn't present. + + PCRE_ERROR_UNKNOWN_NODE (-5) + + While running the pattern match, an unknown item was encoun- + tered in the compiled pattern. This error could be caused by + a bug in PCRE or by overwriting of the compiled pattern. + + PCRE_ERROR_NOMEMORY (-6) + + If a pattern contains back references, but the ovector that + is passed to pcre_exec() is not big enough to remember the + referenced substrings, PCRE gets a block of memory at the + start of matching to use for this purpose. If the call via + pcre_malloc() fails, this error is given. The memory is + freed at the end of matching. + + + +EXTRACTING CAPTURED SUBSTRINGS + Captured substrings can be accessed directly by using the + offsets returned by pcre_exec() in ovector. For convenience, + the functions pcre_copy_substring(), pcre_get_substring(), + and pcre_get_substring_list() are provided for extracting + captured substrings as new, separate, zero-terminated + strings. A substring that contains a binary zero is + correctly extracted and has a further zero added on the end, + but the result does not, of course, function as a C string. + + The first three arguments are the same for all three func- + tions: subject is the subject string which has just been + successfully matched, ovector is a pointer to the vector of + integer offsets that was passed to pcre_exec(), and + stringcount is the number of substrings that were captured + by the match, including the substring that matched the + entire regular expression. This is the value returned by + pcre_exec if it is greater than zero. If pcre_exec() + returned zero, indicating that it ran out of space in ovec- + tor, then the value passed as stringcount should be the size + of the vector divided by three. + + The functions pcre_copy_substring() and pcre_get_substring() + extract a single substring, whose number is given as string- + number. A value of zero extracts the substring that matched + the entire pattern, while higher values extract the captured + substrings. For pcre_copy_substring(), the string is placed + in buffer, whose length is given by buffersize, while for + pcre_get_substring() a new block of store is obtained via + pcre_malloc, and its address is returned via stringptr. The + yield of the function is the length of the string, not + including the terminating zero, or one of + + PCRE_ERROR_NOMEMORY (-6) + + The buffer was too small for pcre_copy_substring(), or the + attempt to get memory failed for pcre_get_substring(). + + PCRE_ERROR_NOSUBSTRING (-7) + + There is no substring whose number is stringnumber. + + The pcre_get_substring_list() function extracts all avail- + able substrings and builds a list of pointers to them. All + this is done in a single block of memory which is obtained + via pcre_malloc. The address of the memory block is returned + via listptr, which is also the start of the list of string + pointers. The end of the list is marked by a NULL pointer. + The yield of the function is zero if all went well, or + + PCRE_ERROR_NOMEMORY (-6) + + if the attempt to get the memory block failed. + + When any of these functions encounter a substring that is + unset, which can happen when capturing subpattern number n+1 + matches some part of the subject, but subpattern n has not + been used at all, they return an empty string. This can be + distinguished from a genuine zero-length substring by + inspecting the appropriate offset in ovector, which is nega- + tive for unset substrings. + + + + +LIMITATIONS + There are some size limitations in PCRE but it is hoped that + they will never in practice be relevant. The maximum length + of a compiled pattern is 65539 (sic) bytes. All values in + repeating quantifiers must be less than 65536. The maximum + number of capturing subpatterns is 99. The maximum number + of all parenthesized subpatterns, including capturing sub- + patterns, assertions, and other types of subpattern, is 200. + + The maximum length of a subject string is the largest posi- + tive number that an integer variable can hold. However, PCRE + uses recursion to handle subpatterns and indefinite repeti- + tion. This means that the available stack space may limit + the size of a subject string that can be processed by cer- + tain patterns. + + + +DIFFERENCES FROM PERL + The differences described here are with respect to Perl + 5.005. + + 1. By default, a whitespace character is any character that + the C library function isspace() recognizes, though it is + possible to compile PCRE with alternative character type + tables. Normally isspace() matches space, formfeed, newline, + carriage return, horizontal tab, and vertical tab. Perl 5 no + longer includes vertical tab in its set of whitespace char- + acters. The \v escape that was in the Perl documentation for + a long time was never in fact recognized. However, the char- + acter itself was treated as whitespace at least up to 5.002. + In 5.004 and 5.005 it does not match \s. + + 2. PCRE does not allow repeat quantifiers on lookahead + assertions. Perl permits them, but they do not mean what you + might think. For example, (?!a){3} does not assert that the + next three characters are not "a". It just asserts that the + next character is not "a" three times. + + 3. Capturing subpatterns that occur inside negative looka- + head assertions are counted, but their entries in the + offsets vector are never set. Perl sets its numerical vari- + ables from any such patterns that are matched before the + assertion fails to match something (thereby succeeding), but + only if the negative lookahead assertion contains just one + branch. + + 4. Though binary zero characters are supported in the sub- + ject string, they are not allowed in a pattern string + because it is passed as a normal C string, terminated by + zero. The escape sequence "\0" can be used in the pattern to + represent a binary zero. + + 5. The following Perl escape sequences are not supported: + \l, \u, \L, \U, \E, \Q. In fact these are implemented by + Perl's general string-handling and are not part of its pat- + tern matching engine. + + 6. The Perl \G assertion is not supported as it is not + relevant to single pattern matches. + + 7. Fairly obviously, PCRE does not support the (?{code}) and + (?p{code}) constructions. However, there is some experimen- + tal support for recursive patterns using the non-Perl item + (?R). + 8. There are at the time of writing some oddities in Perl + 5.005_02 concerned with the settings of captured strings + when part of a pattern is repeated. For example, matching + "aba" against the pattern /^(a(b)?)+$/ sets $2 to the value + "b", but matching "aabbaa" against /^(aa(bb)?)+$/ leaves $2 + unset. However, if the pattern is changed to + /^(aa(b(b))?)+$/ then $2 (and $3) get set. + + In Perl 5.004 $2 is set in both cases, and that is also true + of PCRE. If in the future Perl changes to a consistent state + that is different, PCRE may change to follow. + + 9. Another as yet unresolved discrepancy is that in Perl + 5.005_02 the pattern /^(a)?(?(1)a|b)+$/ matches the string + "a", whereas in PCRE it does not. However, in both Perl and + PCRE /^(a)?a/ matched against "a" leaves $1 unset. + + 10. PCRE provides some extensions to the Perl regular + expression facilities: + + (a) Although lookbehind assertions must match fixed length + strings, each alternative branch of a lookbehind assertion + can match a different length of string. Perl 5.005 requires + them all to have the same length. + + (b) If PCRE_DOLLAR_ENDONLY is set and PCRE_MULTILINE is not + set, the $ meta- character matches only at the very end of + the string. + + (c) If PCRE_EXTRA is set, a backslash followed by a letter + with no special meaning is faulted. + + (d) If PCRE_UNGREEDY is set, the greediness of the repeti- + tion quantifiers is inverted, that is, by default they are + not greedy, but if followed by a question mark they are. + + (e) PCRE_ANCHORED can be used to force a pattern to be tried + only at the start of the subject. + + (f) The PCRE_NOTBOL, PCRE_NOTEOL, and PCRE_NOTEMPTY options + for pcre_exec() have no Perl equivalents. + + (g) The (?R) construct allows for recursive pattern matching + (Perl 5.6 can do this using the (?p{code}) construct, which + PCRE cannot of course support.) + + + +REGULAR EXPRESSION DETAILS + The syntax and semantics of the regular expressions sup- + ported by PCRE are described below. Regular expressions are + also described in the Perl documentation and in a number of + + other books, some of which have copious examples. Jeffrey + Friedl's "Mastering Regular Expressions", published by + O'Reilly (ISBN 1-56592-257), covers them in great detail. + The description here is intended as reference documentation. + + A regular expression is a pattern that is matched against a + subject string from left to right. Most characters stand for + themselves in a pattern, and match the corresponding charac- + ters in the subject. As a trivial example, the pattern + + The quick brown fox + + matches a portion of a subject string that is identical to + itself. The power of regular expressions comes from the + ability to include alternatives and repetitions in the pat- + tern. These are encoded in the pattern by the use of meta- + characters, which do not stand for themselves but instead + are interpreted in some special way. + + There are two different sets of meta-characters: those that + are recognized anywhere in the pattern except within square + brackets, and those that are recognized in square brackets. + Outside square brackets, the meta-characters are as follows: + + \ general escape character with several uses + ^ assert start of subject (or line, in multiline + mode) + $ assert end of subject (or line, in multiline mode) + . match any character except newline (by default) + [ start character class definition + | start of alternative branch + ( start subpattern + ) end subpattern + ? extends the meaning of ( + also 0 or 1 quantifier + also quantifier minimizer + * 0 or more quantifier + + 1 or more quantifier + { start min/max quantifier + + Part of a pattern that is in square brackets is called a + "character class". In a character class the only meta- + characters are: + + \ general escape character + ^ negate the class, but only if the first character + - indicates character range + ] terminates the character class + + The following sections describe the use of each of the + meta-characters. + + + +BACKSLASH + The backslash character has several uses. Firstly, if it is + followed by a non-alphameric character, it takes away any + special meaning that character may have. This use of + backslash as an escape character applies both inside and + outside character classes. + + For example, if you want to match a "*" character, you write + "\*" in the pattern. This applies whether or not the follow- + ing character would otherwise be interpreted as a meta- + character, so it is always safe to precede a non-alphameric + with "\" to specify that it stands for itself. In particu- + lar, if you want to match a backslash, you write "\\". + + If a pattern is compiled with the PCRE_EXTENDED option, whi- + tespace in the pattern (other than in a character class) and + characters between a "#" outside a character class and the + next newline character are ignored. An escaping backslash + can be used to include a whitespace or "#" character as part + of the pattern. + + A second use of backslash provides a way of encoding non- + printing characters in patterns in a visible manner. There + is no restriction on the appearance of non-printing charac- + ters, apart from the binary zero that terminates a pattern, + but when a pattern is being prepared by text editing, it is + usually easier to use one of the following escape sequences + than the binary character it represents: + + \a alarm, that is, the BEL character (hex 07) + \cx "control-x", where x is any character + \e escape (hex 1B) + \f formfeed (hex 0C) + \n newline (hex 0A) + \r carriage return (hex 0D) + \t tab (hex 09) + \xhh character with hex code hh + \ddd character with octal code ddd, or backreference + + The precise effect of "\cx" is as follows: if "x" is a lower + case letter, it is converted to upper case. Then bit 6 of + the character (hex 40) is inverted. Thus "\cz" becomes hex + 1A, but "\c{" becomes hex 3B, while "\c;" becomes hex 7B. + + After "\x", up to two hexadecimal digits are read (letters + can be in upper or lower case). + + After "\0" up to two further octal digits are read. In both + cases, if there are fewer than two digits, just those that + are present are used. Thus the sequence "\0\x\07" specifies + two binary zeros followed by a BEL character. Make sure you + supply two digits after the initial zero if the character + that follows is itself an octal digit. + + The handling of a backslash followed by a digit other than 0 + is complicated. Outside a character class, PCRE reads it + and any following digits as a decimal number. If the number + is less than 10, or if there have been at least that many + previous capturing left parentheses in the expression, the + entire sequence is taken as a back reference. A description + of how this works is given later, following the discussion + of parenthesized subpatterns. + + Inside a character class, or if the decimal number is + greater than 9 and there have not been that many capturing + subpatterns, PCRE re-reads up to three octal digits follow- + ing the backslash, and generates a single byte from the + least significant 8 bits of the value. Any subsequent digits + stand for themselves. For example: + + \040 is another way of writing a space + \40 is the same, provided there are fewer than 40 + previous capturing subpatterns + \7 is always a back reference + \11 might be a back reference, or another way of + writing a tab + \011 is always a tab + \0113 is a tab followed by the character "3" + \113 is the character with octal code 113 (since there + can be no more than 99 back references) + \377 is a byte consisting entirely of 1 bits + \81 is either a back reference, or a binary zero + followed by the two characters "8" and "1" + + Note that octal values of 100 or greater must not be intro- + duced by a leading zero, because no more than three octal + digits are ever read. + + All the sequences that define a single byte value can be + used both inside and outside character classes. In addition, + inside a character class, the sequence "\b" is interpreted + as the backspace character (hex 08). Outside a character + class it has a different meaning (see below). + + The third use of backslash is for specifying generic charac- + ter types: + + \d any decimal digit + \D any character that is not a decimal digit + \s any whitespace character + \S any character that is not a whitespace character + \w any "word" character + \W any "non-word" character + + Each pair of escape sequences partitions the complete set of + characters into two disjoint sets. Any given character + matches one, and only one, of each pair. + + A "word" character is any letter or digit or the underscore + character, that is, any character which can be part of a + Perl "word". The definition of letters and digits is con- + trolled by PCRE's character tables, and may vary if locale- + specific matching is taking place (see "Locale support" + above). For example, in the "fr" (French) locale, some char- + acter codes greater than 128 are used for accented letters, + and these are matched by \w. + + These character type sequences can appear both inside and + outside character classes. They each match one character of + the appropriate type. If the current matching point is at + the end of the subject string, all of them fail, since there + is no character to match. + + The fourth use of backslash is for certain simple asser- + tions. An assertion specifies a condition that has to be met + at a particular point in a match, without consuming any + characters from the subject string. The use of subpatterns + for more complicated assertions is described below. The + backslashed assertions are + + \b word boundary + \B not a word boundary + \A start of subject (independent of multiline mode) + \Z end of subject or newline at end (independent of + multiline mode) + \z end of subject (independent of multiline mode) + + These assertions may not appear in character classes (but + note that "\b" has a different meaning, namely the backspace + character, inside a character class). + + A word boundary is a position in the subject string where + the current character and the previous character do not both + match \w or \W (i.e. one matches \w and the other matches + \W), or the start or end of the string if the first or last + character matches \w, respectively. + + The \A, \Z, and \z assertions differ from the traditional + circumflex and dollar (described below) in that they only + ever match at the very start and end of the subject string, + whatever options are set. They are not affected by the + PCRE_NOTBOL or PCRE_NOTEOL options. If the startoffset argu- + ment of pcre_exec() is non-zero, \A can never match. The + difference between \Z and \z is that \Z matches before a + newline that is the last character of the string as well as + at the end of the string, whereas \z matches only at the + end. + + + +CIRCUMFLEX AND DOLLAR + Outside a character class, in the default matching mode, the + circumflex character is an assertion which is true only if + the current matching point is at the start of the subject + string. If the startoffset argument of pcre_exec() is non- + zero, circumflex can never match. Inside a character class, + circumflex has an entirely different meaning (see below). + + Circumflex need not be the first character of the pattern if + a number of alternatives are involved, but it should be the + first thing in each alternative in which it appears if the + pattern is ever to match that branch. If all possible alter- + natives start with a circumflex, that is, if the pattern is + constrained to match only at the start of the subject, it is + said to be an "anchored" pattern. (There are also other con- + structs that can cause a pattern to be anchored.) + + A dollar character is an assertion which is true only if the + current matching point is at the end of the subject string, + or immediately before a newline character that is the last + character in the string (by default). Dollar need not be the + last character of the pattern if a number of alternatives + are involved, but it should be the last item in any branch + in which it appears. Dollar has no special meaning in a + character class. + + The meaning of dollar can be changed so that it matches only + at the very end of the string, by setting the + PCRE_DOLLAR_ENDONLY option at compile or matching time. This + does not affect the \Z assertion. + + The meanings of the circumflex and dollar characters are + changed if the PCRE_MULTILINE option is set. When this is + the case, they match immediately after and immediately + before an internal "\n" character, respectively, in addition + to matching at the start and end of the subject string. For + example, the pattern /^abc$/ matches the subject string + "def\nabc" in multiline mode, but not otherwise. Conse- + quently, patterns that are anchored in single line mode + because all branches start with "^" are not anchored in mul- + tiline mode, and a match for circumflex is possible when the + startoffset argument of pcre_exec() is non-zero. The + PCRE_DOLLAR_ENDONLY option is ignored if PCRE_MULTILINE is + set. + + Note that the sequences \A, \Z, and \z can be used to match + the start and end of the subject in both modes, and if all + branches of a pattern start with \A is it always anchored, + whether PCRE_MULTILINE is set or not. + + + +FULL STOP (PERIOD, DOT) + Outside a character class, a dot in the pattern matches any + one character in the subject, including a non-printing char- + acter, but not (by default) newline. If the PCRE_DOTALL + option is set, then dots match newlines as well. The han- + dling of dot is entirely independent of the handling of cir- + cumflex and dollar, the only relationship being that they + both involve newline characters. Dot has no special meaning + in a character class. + + + +SQUARE BRACKETS + An opening square bracket introduces a character class, ter- + minated by a closing square bracket. A closing square + bracket on its own is not special. If a closing square + bracket is required as a member of the class, it should be + the first data character in the class (after an initial cir- + cumflex, if present) or escaped with a backslash. + + A character class matches a single character in the subject; + the character must be in the set of characters defined by + the class, unless the first character in the class is a cir- + cumflex, in which case the subject character must not be in + the set defined by the class. If a circumflex is actually + required as a member of the class, ensure it is not the + first character, or escape it with a backslash. + + For example, the character class [aeiou] matches any lower + case vowel, while [^aeiou] matches any character that is not + a lower case vowel. Note that a circumflex is just a con- + venient notation for specifying the characters which are in + the class by enumerating those that are not. It is not an + assertion: it still consumes a character from the subject + string, and fails if the current pointer is at the end of + the string. + + When caseless matching is set, any letters in a class + represent both their upper case and lower case versions, so + for example, a caseless [aeiou] matches "A" as well as "a", + and a caseless [^aeiou] does not match "A", whereas a case- + ful version would. + + The newline character is never treated in any special way in + character classes, whatever the setting of the PCRE_DOTALL + or PCRE_MULTILINE options is. A class such as [^a] will + always match a newline. + + The minus (hyphen) character can be used to specify a range + of characters in a character class. For example, [d-m] + matches any letter between d and m, inclusive. If a minus + character is required in a class, it must be escaped with a + backslash or appear in a position where it cannot be inter- + preted as indicating a range, typically as the first or last + character in the class. + + It is not possible to have the literal character "]" as the + end character of a range. A pattern such as [W-]46] is + interpreted as a class of two characters ("W" and "-") fol- + lowed by a literal string "46]", so it would match "W46]" or + "-46]". However, if the "]" is escaped with a backslash it + is interpreted as the end of range, so [W-\]46] is inter- + preted as a single class containing a range followed by two + separate characters. The octal or hexadecimal representation + of "]" can also be used to end a range. + + Ranges operate in ASCII collating sequence. They can also be + used for characters specified numerically, for example + [\000-\037]. If a range that includes letters is used when + caseless matching is set, it matches the letters in either + case. For example, [W-c] is equivalent to [][\^_`wxyzabc], + matched caselessly, and if character tables for the "fr" + locale are in use, [\xc8-\xcb] matches accented E characters + in both cases. + + The character types \d, \D, \s, \S, \w, and \W may also + appear in a character class, and add the characters that + they match to the class. For example, [\dABCDEF] matches any + hexadecimal digit. A circumflex can conveniently be used + with the upper case character types to specify a more res- + tricted set of characters than the matching lower case type. + For example, the class [^\W_] matches any letter or digit, + but not underscore. + + All non-alphameric characters other than \, -, ^ (at the + start) and the terminating ] are non-special in character + classes, but it does no harm if they are escaped. + + + +POSIX CHARACTER CLASSES + Perl 5.6 (not yet released at the time of writing) is going + to support the POSIX notation for character classes, which + uses names enclosed by [: and :] within the enclosing + square brackets. PCRE supports this notation. For example, + + [01[:alpha:]%] + + matches "0", "1", any alphabetic character, or "%". The sup- + ported class names are + + alnum letters and digits + alpha letters + ascii character codes 0 - 127 + cntrl control characters + digit decimal digits (same as \d) + graph printing characters, excluding space + lower lower case letters + print printing characters, including space + punct printing characters, excluding letters and digits + space white space (same as \s) + upper upper case letters + word "word" characters (same as \w) + xdigit hexadecimal digits + + The names "ascii" and "word" are Perl extensions. Another + Perl extension is negation, which is indicated by a ^ char- + acter after the colon. For example, + + [12[:^digit:]] + + matches "1", "2", or any non-digit. PCRE (and Perl) also + recogize the POSIX syntax [.ch.] and [=ch=] where "ch" is a + "collating element", but these are not supported, and an + error is given if they are encountered. + + + +VERTICAL BAR + Vertical bar characters are used to separate alternative + patterns. For example, the pattern + + gilbert|sullivan + + matches either "gilbert" or "sullivan". Any number of alter- + natives may appear, and an empty alternative is permitted + (matching the empty string). The matching process tries + each alternative in turn, from left to right, and the first + one that succeeds is used. If the alternatives are within a + subpattern (defined below), "succeeds" means matching the + rest of the main pattern as well as the alternative in the + subpattern. + + + +INTERNAL OPTION SETTING + The settings of PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, + and PCRE_EXTENDED can be changed from within the pattern by + a sequence of Perl option letters enclosed between "(?" and + ")". The option letters are + + i for PCRE_CASELESS + m for PCRE_MULTILINE + s for PCRE_DOTALL + x for PCRE_EXTENDED + + For example, (?im) sets caseless, multiline matching. It is + also possible to unset these options by preceding the letter + with a hyphen, and a combined setting and unsetting such as + (?im-sx), which sets PCRE_CASELESS and PCRE_MULTILINE while + unsetting PCRE_DOTALL and PCRE_EXTENDED, is also permitted. + If a letter appears both before and after the hyphen, the + option is unset. + + The scope of these option changes depends on where in the + pattern the setting occurs. For settings that are outside + any subpattern (defined below), the effect is the same as if + the options were set or unset at the start of matching. The + following patterns all behave in exactly the same way: + + (?i)abc + a(?i)bc + ab(?i)c + abc(?i) + + which in turn is the same as compiling the pattern abc with + PCRE_CASELESS set. In other words, such "top level" set- + tings apply to the whole pattern (unless there are other + changes inside subpatterns). If there is more than one set- + ting of the same option at top level, the rightmost setting + is used. + + If an option change occurs inside a subpattern, the effect + is different. This is a change of behaviour in Perl 5.005. + An option change inside a subpattern affects only that part + of the subpattern that follows it, so + + (a(?i)b)c + + matches abc and aBc and no other strings (assuming + PCRE_CASELESS is not used). By this means, options can be + made to have different settings in different parts of the + pattern. Any changes made in one alternative do carry on + into subsequent branches within the same subpattern. For + example, + + (a(?i)b|c) + + matches "ab", "aB", "c", and "C", even though when matching + "C" the first branch is abandoned before the option setting. + This is because the effects of option settings happen at + compile time. There would be some very weird behaviour oth- + erwise. + + The PCRE-specific options PCRE_UNGREEDY and PCRE_EXTRA can + be changed in the same way as the Perl-compatible options by + using the characters U and X respectively. The (?X) flag + setting is special in that it must always occur earlier in + the pattern than any of the additional features it turns on, + even when it is at top level. It is best put at the start. + + + +SUBPATTERNS + Subpatterns are delimited by parentheses (round brackets), + which can be nested. Marking part of a pattern as a subpat- + tern does two things: + + 1. It localizes a set of alternatives. For example, the pat- + tern + + cat(aract|erpillar|) + + matches one of the words "cat", "cataract", or "caterpil- + lar". Without the parentheses, it would match "cataract", + "erpillar" or the empty string. + + 2. It sets up the subpattern as a capturing subpattern (as + defined above). When the whole pattern matches, that por- + tion of the subject string that matched the subpattern is + passed back to the caller via the ovector argument of + pcre_exec(). Opening parentheses are counted from left to + right (starting from 1) to obtain the numbers of the captur- + ing subpatterns. + + For example, if the string "the red king" is matched against + the pattern + + the ((red|white) (king|queen)) + + the captured substrings are "red king", "red", and "king", + and are numbered 1, 2, and 3. + + The fact that plain parentheses fulfil two functions is not + always helpful. There are often times when a grouping sub- + pattern is required without a capturing requirement. If an + opening parenthesis is followed by "?:", the subpattern does + not do any capturing, and is not counted when computing the + number of any subsequent capturing subpatterns. For example, + if the string "the white queen" is matched against the pat- + tern + + the ((?:red|white) (king|queen)) + + the captured substrings are "white queen" and "queen", and + are numbered 1 and 2. The maximum number of captured sub- + strings is 99, and the maximum number of all subpatterns, + both capturing and non-capturing, is 200. + + As a convenient shorthand, if any option settings are + required at the start of a non-capturing subpattern, the + option letters may appear between the "?" and the ":". Thus + the two patterns + + (?i:saturday|sunday) + (?:(?i)saturday|sunday) + + match exactly the same set of strings. Because alternative + branches are tried from left to right, and options are not + reset until the end of the subpattern is reached, an option + setting in one branch does affect subsequent branches, so + the above patterns match "SUNDAY" as well as "Saturday". + + + +REPETITION + Repetition is specified by quantifiers, which can follow any + of the following items: + + a single character, possibly escaped + the . metacharacter + a character class + a back reference (see next section) + a parenthesized subpattern (unless it is an assertion - + see below) + + The general repetition quantifier specifies a minimum and + maximum number of permitted matches, by giving the two + numbers in curly brackets (braces), separated by a comma. + The numbers must be less than 65536, and the first must be + less than or equal to the second. For example: + + z{2,4} + + matches "zz", "zzz", or "zzzz". A closing brace on its own + is not a special character. If the second number is omitted, + but the comma is present, there is no upper limit; if the + second number and the comma are both omitted, the quantifier + specifies an exact number of required matches. Thus + + [aeiou]{3,} + + matches at least 3 successive vowels, but may match many + more, while + + \d{8} + + matches exactly 8 digits. An opening curly bracket that + appears in a position where a quantifier is not allowed, or + one that does not match the syntax of a quantifier, is taken + as a literal character. For example, {,6} is not a quantif- + ier, but a literal string of four characters. + + The quantifier {0} is permitted, causing the expression to + behave as if the previous item and the quantifier were not + present. + + For convenience (and historical compatibility) the three + most common quantifiers have single-character abbreviations: + + * is equivalent to {0,} + + is equivalent to {1,} + ? is equivalent to {0,1} + + It is possible to construct infinite loops by following a + subpattern that can match no characters with a quantifier + that has no upper limit, for example: + + (a?)* + + Earlier versions of Perl and PCRE used to give an error at + compile time for such patterns. However, because there are + cases where this can be useful, such patterns are now + accepted, but if any repetition of the subpattern does in + fact match no characters, the loop is forcibly broken. + + By default, the quantifiers are "greedy", that is, they + match as much as possible (up to the maximum number of per- + mitted times), without causing the rest of the pattern to + fail. The classic example of where this gives problems is in + trying to match comments in C programs. These appear between + the sequences /* and */ and within the sequence, individual + * and / characters may appear. An attempt to match C com- + ments by applying the pattern + + /\*.*\*/ + + to the string + + /* first command */ not comment /* second comment */ + + fails, because it matches the entire string due to the + greediness of the .* item. + + However, if a quantifier is followed by a question mark, + then it ceases to be greedy, and instead matches the minimum + number of times possible, so the pattern + + /\*.*?\*/ + + does the right thing with the C comments. The meaning of the + various quantifiers is not otherwise changed, just the pre- + ferred number of matches. Do not confuse this use of ques- + tion mark with its use as a quantifier in its own right. + Because it has two uses, it can sometimes appear doubled, as + in + + \d??\d + + which matches one digit by preference, but can match two if + that is the only way the rest of the pattern matches. + + If the PCRE_UNGREEDY option is set (an option which is not + available in Perl) then the quantifiers are not greedy by + default, but individual ones can be made greedy by following + them with a question mark. In other words, it inverts the + default behaviour. + + When a parenthesized subpattern is quantified with a minimum + repeat count that is greater than 1 or with a limited max- + imum, more store is required for the compiled pattern, in + proportion to the size of the minimum or maximum. + + If a pattern starts with .* or .{0,} and the PCRE_DOTALL + option (equivalent to Perl's /s) is set, thus allowing the . + to match newlines, then the pattern is implicitly anchored, + because whatever follows will be tried against every charac- + ter position in the subject string, so there is no point in + retrying the overall match at any position after the first. + PCRE treats such a pattern as though it were preceded by \A. + In cases where it is known that the subject string contains + no newlines, it is worth setting PCRE_DOTALL when the pat- + tern begins with .* in order to obtain this optimization, or + alternatively using ^ to indicate anchoring explicitly. + + When a capturing subpattern is repeated, the value captured + is the substring that matched the final iteration. For exam- + ple, after + + (tweedle[dume]{3}\s*)+ + + has matched "tweedledum tweedledee" the value of the cap- + tured substring is "tweedledee". However, if there are + nested capturing subpatterns, the corresponding captured + values may have been set in previous iterations. For exam- + ple, after + + /(a|(b))+/ + + matches "aba" the value of the second captured substring is + "b". + + + +BACK REFERENCES + Outside a character class, a backslash followed by a digit + greater than 0 (and possibly further digits) is a back + reference to a capturing subpattern earlier (i.e. to its + left) in the pattern, provided there have been that many + previous capturing left parentheses. + + However, if the decimal number following the backslash is + less than 10, it is always taken as a back reference, and + causes an error only if there are not that many capturing + left parentheses in the entire pattern. In other words, the + parentheses that are referenced need not be to the left of + the reference for numbers less than 10. See the section + entitled "Backslash" above for further details of the han- + dling of digits following a backslash. + + A back reference matches whatever actually matched the cap- + turing subpattern in the current subject string, rather than + anything matching the subpattern itself. So the pattern + + (sens|respons)e and \1ibility + + matches "sense and sensibility" and "response and responsi- + bility", but not "sense and responsibility". If caseful + matching is in force at the time of the back reference, then + the case of letters is relevant. For example, + + ((?i)rah)\s+\1 + + matches "rah rah" and "RAH RAH", but not "RAH rah", even + though the original capturing subpattern is matched case- + lessly. + + There may be more than one back reference to the same sub- + pattern. If a subpattern has not actually been used in a + particular match, then any back references to it always + fail. For example, the pattern + + (a|(bc))\2 + + always fails if it starts to match "a" rather than "bc". + Because there may be up to 99 back references, all digits + following the backslash are taken as part of a potential + back reference number. If the pattern continues with a digit + character, then some delimiter must be used to terminate the + back reference. If the PCRE_EXTENDED option is set, this can + be whitespace. Otherwise an empty comment can be used. + + A back reference that occurs inside the parentheses to which + it refers fails when the subpattern is first used, so, for + example, (a\1) never matches. However, such references can + be useful inside repeated subpatterns. For example, the + pattern + + (a|b\1)+ + + matches any number of "a"s and also "aba", "ababaa" etc. At + each iteration of the subpattern, the back reference matches + the character string corresponding to the previous itera- + tion. In order for this to work, the pattern must be such + that the first iteration does not need to match the back + reference. This can be done using alternation, as in the + example above, or by a quantifier with a minimum of zero. + + + +ASSERTIONS + An assertion is a test on the characters following or + preceding the current matching point that does not actually + consume any characters. The simple assertions coded as \b, + \B, \A, \Z, \z, ^ and $ are described above. More compli- + cated assertions are coded as subpatterns. There are two + kinds: those that look ahead of the current position in the + subject string, and those that look behind it. + + An assertion subpattern is matched in the normal way, except + that it does not cause the current matching position to be + changed. Lookahead assertions start with (?= for positive + assertions and (?! for negative assertions. For example, + + \w+(?=;) + + matches a word followed by a semicolon, but does not include + the semicolon in the match, and + + foo(?!bar) + + matches any occurrence of "foo" that is not followed by + "bar". Note that the apparently similar pattern + + (?!foo)bar + + does not find an occurrence of "bar" that is preceded by + something other than "foo"; it finds any occurrence of "bar" + whatsoever, because the assertion (?!foo) is always true + when the next three characters are "bar". A lookbehind + assertion is needed to achieve this effect. + + Lookbehind assertions start with (?<= for positive asser- + tions and (? as in this example: + + (?>\d+)bar + + This kind of parenthesis "locks up" the part of the pattern + it contains once it has matched, and a failure further into + the pattern is prevented from backtracking into it. Back- + tracking past it to previous items, however, works as nor- + mal. + + An alternative description is that a subpattern of this type + matches the string of characters that an identical stan- + dalone pattern would match, if anchored at the current point + in the subject string. + + Once-only subpatterns are not capturing subpatterns. Simple + cases such as the above example can be thought of as a max- + imizing repeat that must swallow everything it can. So, + while both \d+ and \d+? are prepared to adjust the number of + digits they match in order to make the rest of the pattern + match, (?>\d+) can only match an entire sequence of digits. + + This construction can of course contain arbitrarily compli- + cated subpatterns, and it can be nested. + + Once-only subpatterns can be used in conjunction with look- + behind assertions to specify efficient matching at the end + of the subject string. Consider a simple pattern such as + + abcd$ + + when applied to a long string which does not match. Because + matching proceeds from left to right, PCRE will look for + each "a" in the subject and then see if what follows matches + the rest of the pattern. If the pattern is specified as + + ^.*abcd$ + + then the initial .* matches the entire string at first, but + when this fails (because there is no following "a"), it + backtracks to match all but the last character, then all but + the last two characters, and so on. Once again the search + for "a" covers the entire string, from right to left, so we + are no better off. However, if the pattern is written as + + ^(?>.*)(?<=abcd) + + then there can be no backtracking for the .* item; it can + match only the entire string. The subsequent lookbehind + assertion does a single test on the last four characters. If + it fails, the match fails immediately. For long strings, + this approach makes a significant difference to the process- + ing time. + + When a pattern contains an unlimited repeat inside a subpat- + tern that can itself be repeated an unlimited number of + times, the use of a once-only subpattern is the only way to + avoid some failing matches taking a very long time indeed. + The pattern + + (\D+|<\d+>)*[!?] + + matches an unlimited number of substrings that either con- + sist of non-digits, or digits enclosed in <>, followed by + either ! or ?. When it matches, it runs quickly. However, if + it is applied to + + aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa + + it takes a long time before reporting failure. This is + because the string can be divided between the two repeats in + a large number of ways, and all have to be tried. (The exam- + ple used [!?] rather than a single character at the end, + because both PCRE and Perl have an optimization that allows + for fast failure when a single character is used. They + remember the last single character that is required for a + match, and fail early if it is not present in the string.) + If the pattern is changed to + + ((?>\D+)|<\d+>)*[!?] + + sequences of non-digits cannot be broken, and failure hap- + pens quickly. + + + +CONDITIONAL SUBPATTERNS + It is possible to cause the matching process to obey a sub- + pattern conditionally or to choose between two alternative + subpatterns, depending on the result of an assertion, or + whether a previous capturing subpattern matched or not. The + two possible forms of conditional subpattern are + + (?(condition)yes-pattern) + (?(condition)yes-pattern|no-pattern) + + If the condition is satisfied, the yes-pattern is used; oth- + erwise the no-pattern (if present) is used. If there are + more than two alternatives in the subpattern, a compile-time + error occurs. + + There are two kinds of condition. If the text between the + parentheses consists of a sequence of digits, then the + condition is satisfied if the capturing subpattern of that + number has previously matched. Consider the following pat- + tern, which contains non-significant white space to make it + more readable (assume the PCRE_EXTENDED option) and to + divide it into three parts for ease of discussion: + + ( \( )? [^()]+ (?(1) \) ) + + The first part matches an optional opening parenthesis, and + if that character is present, sets it as the first captured + substring. The second part matches one or more characters + that are not parentheses. The third part is a conditional + subpattern that tests whether the first set of parentheses + matched or not. If they did, that is, if subject started + with an opening parenthesis, the condition is true, and so + the yes-pattern is executed and a closing parenthesis is + required. Otherwise, since no-pattern is not present, the + subpattern matches nothing. In other words, this pattern + matches a sequence of non-parentheses, optionally enclosed + in parentheses. + + If the condition is not a sequence of digits, it must be an + assertion. This may be a positive or negative lookahead or + lookbehind assertion. Consider this pattern, again contain- + ing non-significant white space, and with the two alterna- + tives on the second line: + + (?(?=[^a-z]*[a-z]) + \d{2}-[a-z]{3}-\d{2} | \d{2}-\d{2}-\d{2} ) + + The condition is a positive lookahead assertion that matches + an optional sequence of non-letters followed by a letter. In + other words, it tests for the presence of at least one + letter in the subject. If a letter is found, the subject is + matched against the first alternative; otherwise it is + matched against the second. This pattern matches strings in + one of the two forms dd-aaa-dd or dd-dd-dd, where aaa are + letters and dd are digits. + + + +COMMENTS + The sequence (?# marks the start of a comment which contin- + ues up to the next closing parenthesis. Nested parentheses + are not permitted. The characters that make up a comment + play no part in the pattern matching at all. + + If the PCRE_EXTENDED option is set, an unescaped # character + outside a character class introduces a comment that contin- + ues up to the next newline character in the pattern. + + + +RECURSIVE PATTERNS + Consider the problem of matching a string in parentheses, + allowing for unlimited nested parentheses. Without the use + of recursion, the best that can be done is to use a pattern + that matches up to some fixed depth of nesting. It is not + possible to handle an arbitrary nesting depth. Perl 5.6 has + provided an experimental facility that allows regular + expressions to recurse (amongst other things). It does this + by interpolating Perl code in the expression at run time, + and the code can refer to the expression itself. A Perl pat- + tern to solve the parentheses problem can be created like + this: + + $re = qr{\( (?: (?>[^()]+) | (?p{$re}) )* \)}x; + + The (?p{...}) item interpolates Perl code at run time, and + in this case refers recursively to the pattern in which it + appears. Obviously, PCRE cannot support the interpolation of + Perl code. Instead, the special item (?R) is provided for + the specific case of recursion. This PCRE pattern solves the + parentheses problem (assume the PCRE_EXTENDED option is set + so that white space is ignored): + + \( ( (?>[^()]+) | (?R) )* \) + + First it matches an opening parenthesis. Then it matches any + number of substrings which can either be a sequence of non- + parentheses, or a recursive match of the pattern itself + (i.e. a correctly parenthesized substring). Finally there is + a closing parenthesis. + + This particular example pattern contains nested unlimited + repeats, and so the use of a once-only subpattern for match- + ing strings of non-parentheses is important when applying + the pattern to strings that do not match. For example, when + it is applied to + + (aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa() + + it yields "no match" quickly. However, if a once-only sub- + pattern is not used, the match runs for a very long time + indeed because there are so many different ways the + and * + repeats can carve up the subject, and all have to be tested + before failure can be reported. + + The values set for any capturing subpatterns are those from + the outermost level of the recursion at which the subpattern + value is set. If the pattern above is matched against + + (ab(cd)ef) + + the value for the capturing parentheses is "ef", which is + the last value taken on at the top level. If additional + parentheses are added, giving + + \( ( ( (?>[^()]+) | (?R) )* ) \) + ^ ^ + ^ ^ then the string they capture + is "ab(cd)ef", the contents of the top level parentheses. If + there are more than 15 capturing parentheses in a pattern, + PCRE has to obtain extra memory to store data during a + recursion, which it does by using pcre_malloc, freeing it + via pcre_free afterwards. If no memory can be obtained, it + saves data for the first 15 capturing parentheses only, as + there is no way to give an out-of-memory error from within a + recursion. + + + +PERFORMANCE + Certain items that may appear in patterns are more efficient + than others. It is more efficient to use a character class + like [aeiou] than a set of alternatives such as (a|e|i|o|u). + In general, the simplest construction that provides the + required behaviour is usually the most efficient. Jeffrey + Friedl's book contains a lot of discussion about optimizing + regular expressions for efficient performance. + + When a pattern begins with .* and the PCRE_DOTALL option is + set, the pattern is implicitly anchored by PCRE, since it + can match only at the start of a subject string. However, if + PCRE_DOTALL is not set, PCRE cannot make this optimization, + because the . metacharacter does not then match a newline, + and if the subject string contains newlines, the pattern may + match from the character immediately following one of them + instead of from the very start. For example, the pattern + + (.*) second + + matches the subject "first\nand second" (where \n stands for + a newline character) with the first captured substring being + "and". In order to do this, PCRE has to retry the match + starting after every newline in the subject. + + If you are using such a pattern with subject strings that do + not contain newlines, the best performance is obtained by + setting PCRE_DOTALL, or starting the pattern with ^.* to + indicate explicit anchoring. That saves PCRE from having to + scan along the subject looking for a newline to restart at. + + Beware of patterns that contain nested indefinite repeats. + These can take a long time to run when applied to a string + that does not match. Consider the pattern fragment + + (a+)* + + This can match "aaaa" in 33 different ways, and this number + increases very rapidly as the string gets longer. (The * + repeat can match 0, 1, 2, 3, or 4 times, and for each of + those cases other than 0, the + repeats can match different + numbers of times.) When the remainder of the pattern is such + that the entire match is going to fail, PCRE has in princi- + ple to try every possible variation, and this can take an + extremely long time. + + An optimization catches some of the more simple cases such + as + + (a+)*b + + where a literal character follows. Before embarking on the + standard matching procedure, PCRE checks that there is a "b" + later in the subject string, and if there is not, it fails + the match immediately. However, when there is no following + literal this optimization cannot be used. You can see the + difference by comparing the behaviour of + + (a+)*\d + + with the pattern above. The former gives a failure almost + instantly when applied to a whole line of "a" characters, + whereas the latter takes an appreciable time with strings + longer than about 20 characters. + + + +AUTHOR + Philip Hazel + University Computing Service, + New Museums Site, + Cambridge CB2 3QG, England. + Phone: +44 1223 334714 + + Last updated: 27 January 2000 + Copyright (c) 1997-2000 University of Cambridge. diff --git a/ext/pcre/pcrelib/doc/pcreposix.3 b/ext/pcre/pcrelib/doc/pcreposix.3 new file mode 100644 index 0000000000..1be5d9ac6f --- /dev/null +++ b/ext/pcre/pcrelib/doc/pcreposix.3 @@ -0,0 +1,141 @@ +.TH PCRE 3 +.SH NAME +pcreposix - POSIX API for Perl-compatible regular expressions. +.SH SYNOPSIS +.B #include +.PP +.SM +.br +.B int regcomp(regex_t *\fIpreg\fR, const char *\fIpattern\fR, +.ti +5n +.B int \fIcflags\fR); +.PP +.br +.B int regexec(regex_t *\fIpreg\fR, const char *\fIstring\fR, +.ti +5n +.B size_t \fInmatch\fR, regmatch_t \fIpmatch\fR[], int \fIeflags\fR); +.PP +.br +.B size_t regerror(int \fIerrcode\fR, const regex_t *\fIpreg\fR, +.ti +5n +.B char *\fIerrbuf\fR, size_t \fIerrbuf_size\fR); +.PP +.br +.B void regfree(regex_t *\fIpreg\fR); + + +.SH DESCRIPTION +This set of functions provides a POSIX-style API to the PCRE regular expression +package. See the \fBpcre\fR documentation for a description of the native API, +which contains additional functionality. + +The functions described here are just wrapper functions that ultimately call +the native API. Their prototypes are defined in the \fBpcreposix.h\fR header +file, and on Unix systems the library itself is called \fBpcreposix.a\fR, so +can be accessed by adding \fB-lpcreposix\fR to the command for linking an +application which uses them. Because the POSIX functions call the native ones, +it is also necessary to add \fR-lpcre\fR. + +I have implemented only those option bits that can be reasonably mapped to PCRE +native options. In addition, the options REG_EXTENDED and REG_NOSUB are defined +with the value zero. They have no effect, but since programs that are written +to the POSIX interface often use them, this makes it easier to slot in PCRE as +a replacement library. Other POSIX options are not even defined. + +When PCRE is called via these functions, it is only the API that is POSIX-like +in style. The syntax and semantics of the regular expressions themselves are +still those of Perl, subject to the setting of various PCRE options, as +described below. + +The header for these functions is supplied as \fBpcreposix.h\fR to avoid any +potential clash with other POSIX libraries. It can, of course, be renamed or +aliased as \fBregex.h\fR, which is the "correct" name. It provides two +structure types, \fIregex_t\fR for compiled internal forms, and +\fIregmatch_t\fR for returning captured substrings. It also defines some +constants whose names start with "REG_"; these are used for setting options and +identifying error codes. + + +.SH COMPILING A PATTERN + +The function \fBregcomp()\fR is called to compile a pattern into an +internal form. The pattern is a C string terminated by a binary zero, and +is passed in the argument \fIpattern\fR. The \fIpreg\fR argument is a pointer +to a regex_t structure which is used as a base for storing information about +the compiled expression. + +The argument \fIcflags\fR is either zero, or contains one or more of the bits +defined by the following macros: + + REG_ICASE + +The PCRE_CASELESS option is set when the expression is passed for compilation +to the native function. + + REG_NEWLINE + +The PCRE_MULTILINE option is set when the expression is passed for compilation +to the native function. + +The yield of \fBregcomp()\fR is zero on success, and non-zero otherwise. The +\fIpreg\fR structure is filled in on success, and one member of the structure +is publicized: \fIre_nsub\fR contains the number of capturing subpatterns in +the regular expression. Various error codes are defined in the header file. + + +.SH MATCHING A PATTERN +The function \fBregexec()\fR is called to match a pre-compiled pattern +\fIpreg\fR against a given \fIstring\fR, which is terminated by a zero byte, +subject to the options in \fIeflags\fR. These can be: + + REG_NOTBOL + +The PCRE_NOTBOL option is set when calling the underlying PCRE matching +function. + + REG_NOTEOL + +The PCRE_NOTEOL option is set when calling the underlying PCRE matching +function. + +The portion of the string that was matched, and also any captured substrings, +are returned via the \fIpmatch\fR argument, which points to an array of +\fInmatch\fR structures of type \fIregmatch_t\fR, containing the members +\fIrm_so\fR and \fIrm_eo\fR. These contain the offset to the first character of +each substring and the offset to the first character after the end of each +substring, respectively. The 0th element of the vector relates to the entire +portion of \fIstring\fR that was matched; subsequent elements relate to the +capturing subpatterns of the regular expression. Unused entries in the array +have both structure members set to -1. + +A successful match yields a zero return; various error codes are defined in the +header file, of which REG_NOMATCH is the "expected" failure code. + + +.SH ERROR MESSAGES +The \fBregerror()\fR function maps a non-zero errorcode from either +\fBregcomp\fR or \fBregexec\fR to a printable message. If \fIpreg\fR is not +NULL, the error should have arisen from the use of that structure. A message +terminated by a binary zero is placed in \fIerrbuf\fR. The length of the +message, including the zero, is limited to \fIerrbuf_size\fR. The yield of the +function is the size of buffer needed to hold the whole message. + + +.SH STORAGE +Compiling a regular expression causes memory to be allocated and associated +with the \fIpreg\fR structure. The function \fBregfree()\fR frees all such +memory, after which \fIpreg\fR may no longer be used as a compiled expression. + + +.SH AUTHOR +Philip Hazel +.br +University Computing Service, +.br +New Museums Site, +.br +Cambridge CB2 3QG, England. +.br +Phone: +44 1223 334714 + +Copyright (c) 1997-1999 University of Cambridge. diff --git a/ext/pcre/pcrelib/doc/pcreposix.html b/ext/pcre/pcrelib/doc/pcreposix.html new file mode 100644 index 0000000000..121d90f867 --- /dev/null +++ b/ext/pcre/pcrelib/doc/pcreposix.html @@ -0,0 +1,182 @@ + + +pcreposix specification + + +

    pcreposix specification

    +This HTML document has been generated automatically from the original man page. +If there is any nonsense in it, please consult the man page in case the +conversion went wrong. + +
  • NAME +

    +pcreposix - POSIX API for Perl-compatible regular expressions. +

    +
  • SYNOPSIS +

    +#include <pcreposix.h> +

    +

    +int regcomp(regex_t *preg, const char *pattern, +int cflags); +

    +

    +int regexec(regex_t *preg, const char *string, +size_t nmatch, regmatch_t pmatch[], int eflags); +

    +

    +size_t regerror(int errcode, const regex_t *preg, +char *errbuf, size_t errbuf_size); +

    +

    +void regfree(regex_t *preg); +

    +
  • DESCRIPTION +

    +This set of functions provides a POSIX-style API to the PCRE regular expression +package. See the pcre documentation for a description of the native API, +which contains additional functionality. +

    +

    +The functions described here are just wrapper functions that ultimately call +the native API. Their prototypes are defined in the pcreposix.h header +file, and on Unix systems the library itself is called pcreposix.a, so +can be accessed by adding -lpcreposix to the command for linking an +application which uses them. Because the POSIX functions call the native ones, +it is also necessary to add \fR-lpcre\fR. +

    +

    +I have implemented only those option bits that can be reasonably mapped to PCRE +native options. In addition, the options REG_EXTENDED and REG_NOSUB are defined +with the value zero. They have no effect, but since programs that are written +to the POSIX interface often use them, this makes it easier to slot in PCRE as +a replacement library. Other POSIX options are not even defined. +

    +

    +When PCRE is called via these functions, it is only the API that is POSIX-like +in style. The syntax and semantics of the regular expressions themselves are +still those of Perl, subject to the setting of various PCRE options, as +described below. +

    +

    +The header for these functions is supplied as pcreposix.h to avoid any +potential clash with other POSIX libraries. It can, of course, be renamed or +aliased as regex.h, which is the "correct" name. It provides two +structure types, regex_t for compiled internal forms, and +regmatch_t for returning captured substrings. It also defines some +constants whose names start with "REG_"; these are used for setting options and +identifying error codes. +

    +
  • COMPILING A PATTERN +

    +The function regcomp() is called to compile a pattern into an +internal form. The pattern is a C string terminated by a binary zero, and +is passed in the argument pattern. The preg argument is a pointer +to a regex_t structure which is used as a base for storing information about +the compiled expression. +

    +

    +The argument cflags is either zero, or contains one or more of the bits +defined by the following macros: +

    +

    +

    +  REG_ICASE
+
    +

    +

    +The PCRE_CASELESS option is set when the expression is passed for compilation +to the native function. +

    +

    +

    +  REG_NEWLINE
+
    +

    +

    +The PCRE_MULTILINE option is set when the expression is passed for compilation +to the native function. +

    +

    +The yield of regcomp() is zero on success, and non-zero otherwise. The +preg structure is filled in on success, and one member of the structure +is publicized: re_nsub contains the number of capturing subpatterns in +the regular expression. Various error codes are defined in the header file. +

    +
  • MATCHING A PATTERN +

    +The function regexec() is called to match a pre-compiled pattern +preg against a given string, which is terminated by a zero byte, +subject to the options in eflags. These can be: +

    +

    +

    +  REG_NOTBOL
+
    +

    +

    +The PCRE_NOTBOL option is set when calling the underlying PCRE matching +function. +

    +

    +

    +  REG_NOTEOL
+
    +

    +

    +The PCRE_NOTEOL option is set when calling the underlying PCRE matching +function. +

    +

    +The portion of the string that was matched, and also any captured substrings, +are returned via the pmatch argument, which points to an array of +nmatch structures of type regmatch_t, containing the members +rm_so and rm_eo. These contain the offset to the first character of +each substring and the offset to the first character after the end of each +substring, respectively. The 0th element of the vector relates to the entire +portion of string that was matched; subsequent elements relate to the +capturing subpatterns of the regular expression. Unused entries in the array +have both structure members set to -1. +

    +

    +A successful match yields a zero return; various error codes are defined in the +header file, of which REG_NOMATCH is the "expected" failure code. +

    +
  • ERROR MESSAGES +

    +The regerror() function maps a non-zero errorcode from either +regcomp or regexec to a printable message. If preg is not +NULL, the error should have arisen from the use of that structure. A message +terminated by a binary zero is placed in errbuf. The length of the +message, including the zero, is limited to errbuf_size. The yield of the +function is the size of buffer needed to hold the whole message. +

    +
  • STORAGE +

    +Compiling a regular expression causes memory to be allocated and associated +with the preg structure. The function regfree() frees all such +memory, after which preg may no longer be used as a compiled expression. +

    +
  • AUTHOR +

    +Philip Hazel <ph10@cam.ac.uk> +
    +University Computing Service, +
    +New Museums Site, +
    +Cambridge CB2 3QG, England. +
    +Phone: +44 1223 334714 +

    +

    +Copyright (c) 1997-1999 University of Cambridge. diff --git a/ext/pcre/pcrelib/doc/pcreposix.txt b/ext/pcre/pcrelib/doc/pcreposix.txt new file mode 100644 index 0000000000..4a7036f340 --- /dev/null +++ b/ext/pcre/pcrelib/doc/pcreposix.txt @@ -0,0 +1,150 @@ +NAME + pcreposix - POSIX API for Perl-compatible regular expres- + sions. + + + +SYNOPSIS + #include + + int regcomp(regex_t *preg, const char *pattern, + int cflags); + + int regexec(regex_t *preg, const char *string, + size_t nmatch, regmatch_t pmatch[], int eflags); + + size_t regerror(int errcode, const regex_t *preg, + char *errbuf, size_t errbuf_size); + + void regfree(regex_t *preg); + + + +DESCRIPTION + This set of functions provides a POSIX-style API to the PCRE + regular expression package. See the pcre documentation for a + description of the native API, which contains additional + functionality. + + The functions described here are just wrapper functions that + ultimately call the native API. Their prototypes are defined + in the pcreposix.h header file, and on Unix systems the + library itself is called pcreposix.a, so can be accessed by + adding -lpcreposix to the command for linking an application + which uses them. Because the POSIX functions call the native + ones, it is also necessary to add -lpcre. + + I have implemented only those option bits that can be rea- + sonably mapped to PCRE native options. In addition, the + options REG_EXTENDED and REG_NOSUB are defined with the + value zero. They have no effect, but since programs that are + written to the POSIX interface often use them, this makes it + easier to slot in PCRE as a replacement library. Other POSIX + options are not even defined. + + When PCRE is called via these functions, it is only the API + that is POSIX-like in style. The syntax and semantics of the + regular expressions themselves are still those of Perl, sub- + ject to the setting of various PCRE options, as described + below. + + The header for these functions is supplied as pcreposix.h to + avoid any potential clash with other POSIX libraries. It + can, of course, be renamed or aliased as regex.h, which is + the "correct" name. It provides two structure types, regex_t + for compiled internal forms, and regmatch_t for returning + captured substrings. It also defines some constants whose + names start with "REG_"; these are used for setting options + and identifying error codes. + + + +COMPILING A PATTERN + The function regcomp() is called to compile a pattern into + an internal form. The pattern is a C string terminated by a + binary zero, and is passed in the argument pattern. The preg + argument is a pointer to a regex_t structure which is used + as a base for storing information about the compiled expres- + sion. + + The argument cflags is either zero, or contains one or more + of the bits defined by the following macros: + + REG_ICASE + + The PCRE_CASELESS option is set when the expression is + passed for compilation to the native function. + + REG_NEWLINE + + The PCRE_MULTILINE option is set when the expression is + passed for compilation to the native function. + + The yield of regcomp() is zero on success, and non-zero oth- + erwise. The preg structure is filled in on success, and one + member of the structure is publicized: re_nsub contains the + number of capturing subpatterns in the regular expression. + Various error codes are defined in the header file. + + + +MATCHING A PATTERN + The function regexec() is called to match a pre-compiled + pattern preg against a given string, which is terminated by + a zero byte, subject to the options in eflags. These can be: + + REG_NOTBOL + + The PCRE_NOTBOL option is set when calling the underlying + PCRE matching function. + + REG_NOTEOL + + The PCRE_NOTEOL option is set when calling the underlying + PCRE matching function. + + The portion of the string that was matched, and also any + captured substrings, are returned via the pmatch argument, + which points to an array of nmatch structures of type + regmatch_t, containing the members rm_so and rm_eo. These + contain the offset to the first character of each substring + and the offset to the first character after the end of each + substring, respectively. The 0th element of the vector + relates to the entire portion of string that was matched; + subsequent elements relate to the capturing subpatterns of + the regular expression. Unused entries in the array have + both structure members set to -1. + + A successful match yields a zero return; various error codes + are defined in the header file, of which REG_NOMATCH is the + "expected" failure code. + + + +ERROR MESSAGES + The regerror() function maps a non-zero errorcode from + either regcomp or regexec to a printable message. If preg is + not NULL, the error should have arisen from the use of that + structure. A message terminated by a binary zero is placed + in errbuf. The length of the message, including the zero, is + limited to errbuf_size. The yield of the function is the + size of buffer needed to hold the whole message. + + + +STORAGE + Compiling a regular expression causes memory to be allocated + and associated with the preg structure. The function reg- + free() frees all such memory, after which preg may no longer + be used as a compiled expression. + + + +AUTHOR + Philip Hazel + University Computing Service, + New Museums Site, + Cambridge CB2 3QG, England. + Phone: +44 1223 334714 + + Copyright (c) 1997-1999 University of Cambridge. diff --git a/ext/pcre/pcrelib/doc/pcretest.txt b/ext/pcre/pcrelib/doc/pcretest.txt new file mode 100644 index 0000000000..831fdac987 --- /dev/null +++ b/ext/pcre/pcrelib/doc/pcretest.txt @@ -0,0 +1,216 @@ +The pcretest program +-------------------- + +This program is intended for testing PCRE, but it can also be used for +experimenting with regular expressions. + +If it is given two filename arguments, it reads from the first and writes to +the second. If it is given only one filename argument, it reads from that file +and writes to stdout. Otherwise, it reads from stdin and writes to stdout, and +prompts for each line of input, using "re>" to prompt for regular expressions, +and "data>" to prompt for data lines. + +The program handles any number of sets of input on a single input file. Each +set starts with a regular expression, and continues with any number of data +lines to be matched against the pattern. An empty line signals the end of the +data lines, at which point a new regular expression is read. The regular +expressions are given enclosed in any non-alphameric delimiters other than +backslash, for example + + /(a|bc)x+yz/ + +White space before the initial delimiter is ignored. A regular expression may +be continued over several input lines, in which case the newline characters are +included within it. See the test input files in the testdata directory for many +examples. It is possible to include the delimiter within the pattern by +escaping it, for example + + /abc\/def/ + +If you do so, the escape and the delimiter form part of the pattern, but since +delimiters are always non-alphameric, this does not affect its interpretation. +If the terminating delimiter is immediately followed by a backslash, for +example, + + /abc/\ + +then a backslash is added to the end of the pattern. This is done to provide a +way of testing the error condition that arises if a pattern finishes with a +backslash, because + + /abc\/ + +is interpreted as the first line of a pattern that starts with "abc/", causing +pcretest to read the next line as a continuation of the regular expression. + +The pattern may be followed by i, m, s, or x to set the PCRE_CASELESS, +PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively. For +example: + + /caseless/i + +These modifier letters have the same effect as they do in Perl. There are +others which set PCRE options that do not correspond to anything in Perl: /A, +/E, and /X set PCRE_ANCHORED, PCRE_DOLLAR_ENDONLY, and PCRE_EXTRA respectively. + +Searching for all possible matches within each subject string can be requested +by the /g or /G modifier. After finding a match, PCRE is called again to search +the remainder of the subject string. The difference between /g and /G is that +the former uses the startoffset argument to pcre_exec() to start searching at +a new point within the entire string (which is in effect what Perl does), +whereas the latter passes over a shortened substring. This makes a difference +to the matching process if the pattern begins with a lookbehind assertion +(including \b or \B). + +If any call to pcre_exec() in a /g or /G sequence matches an empty string, the +next call is done with the PCRE_NOTEMPTY flag set so that it cannot match an +empty string again at the same point. If however, this second match fails, the +start offset is advanced by one, and the match is retried. This imitates the +way Perl handles such cases when using the /g modifier or the split() function. + +There are a number of other modifiers for controlling the way pcretest +operates. + +The /+ modifier requests that as well as outputting the substring that matched +the entire pattern, pcretest should in addition output the remainder of the +subject string. This is useful for tests where the subject contains multiple +copies of the same substring. + +The /L modifier must be followed directly by the name of a locale, for example, + + /pattern/Lfr + +For this reason, it must be the last modifier letter. The given locale is set, +pcre_maketables() is called to build a set of character tables for the locale, +and this is then passed to pcre_compile() when compiling the regular +expression. Without an /L modifier, NULL is passed as the tables pointer; that +is, /L applies only to the expression on which it appears. + +The /I modifier requests that pcretest output information about the compiled +expression (whether it is anchored, has a fixed first character, and so on). It +does this by calling pcre_fullinfo() after compiling an expression, and +outputting the information it gets back. If the pattern is studied, the results +of that are also output. + +The /D modifier is a PCRE debugging feature, which also assumes /I. It causes +the internal form of compiled regular expressions to be output after +compilation. + +The /S modifier causes pcre_study() to be called after the expression has been +compiled, and the results used when the expression is matched. + +The /M modifier causes the size of memory block used to hold the compiled +pattern to be output. + +Finally, the /P modifier causes pcretest to call PCRE via the POSIX wrapper API +rather than its native API. When this is done, all other modifiers except /i, +/m, and /+ are ignored. REG_ICASE is set if /i is present, and REG_NEWLINE is +set if /m is present. The wrapper functions force PCRE_DOLLAR_ENDONLY always, +and PCRE_DOTALL unless REG_NEWLINE is set. + +Before each data line is passed to pcre_exec(), leading and trailing whitespace +is removed, and it is then scanned for \ escapes. The following are recognized: + + \a alarm (= BEL) + \b backspace + \e escape + \f formfeed + \n newline + \r carriage return + \t tab + \v vertical tab + \nnn octal character (up to 3 octal digits) + \xhh hexadecimal character (up to 2 hex digits) + + \A pass the PCRE_ANCHORED option to pcre_exec() + \B pass the PCRE_NOTBOL option to pcre_exec() + \Cdd call pcre_copy_substring() for substring dd after a successful match + (any decimal number less than 32) + \Gdd call pcre_get_substring() for substring dd after a successful match + (any decimal number less than 32) + \L call pcre_get_substringlist() after a successful match + \N pass the PCRE_NOTEMPTY option to pcre_exec() + \Odd set the size of the output vector passed to pcre_exec() to dd + (any number of decimal digits) + \Z pass the PCRE_NOTEOL option to pcre_exec() + +A backslash followed by anything else just escapes the anything else. If the +very last character is a backslash, it is ignored. This gives a way of passing +an empty line as data, since a real empty line terminates the data input. + +If /P was present on the regex, causing the POSIX wrapper API to be used, only +\B, and \Z have any effect, causing REG_NOTBOL and REG_NOTEOL to be passed to +regexec() respectively. + +When a match succeeds, pcretest outputs the list of captured substrings that +pcre_exec() returns, starting with number 0 for the string that matched the +whole pattern. Here is an example of an interactive pcretest run. + + $ pcretest + PCRE version 2.06 08-Jun-1999 + + re> /^abc(\d+)/ + data> abc123 + 0: abc123 + 1: 123 + data> xyz + No match + +If the strings contain any non-printing characters, they are output as \0x +escapes. If the pattern has the /+ modifier, then the output for substring 0 is +followed by the the rest of the subject string, identified by "0+" like this: + + re> /cat/+ + data> cataract + 0: cat + 0+ aract + +If the pattern has the /g or /G modifier, the results of successive matching +attempts are output in sequence, like this: + + re> /\Bi(\w\w)/g + data> Mississippi + 0: iss + 1: ss + 0: iss + 1: ss + 0: ipp + 1: pp + +"No match" is output only if the first match attempt fails. + +If any of \C, \G, or \L are present in a data line that is successfully +matched, the substrings extracted by the convenience functions are output with +C, G, or L after the string number instead of a colon. This is in addition to +the normal full list. The string length (that is, the return from the +extraction function) is given in parentheses after each string for \C and \G. + +Note that while patterns can be continued over several lines (a plain ">" +prompt is used for continuations), data lines may not. However newlines can be +included in data by means of the \n escape. + +If the -p option is given to pcretest, it is equivalent to adding /P to each +regular expression: the POSIX wrapper API is used to call PCRE. None of the +following flags has any effect in this case. + +If the option -d is given to pcretest, it is equivalent to adding /D to each +regular expression: the internal form is output after compilation. + +If the option -i is given to pcretest, it is equivalent to adding /I to each +regular expression: information about the compiled pattern is given after +compilation. + +If the option -m is given to pcretest, it outputs the size of each compiled +pattern after it has been compiled. It is equivalent to adding /M to each +regular expression. For compatibility with earlier versions of pcretest, -s is +a synonym for -m. + +If the -t option is given, each compile, study, and match is run 20000 times +while being timed, and the resulting time per compile or match is output in +milliseconds. Do not set -t with -s, because you will then get the size output +20000 times and the timing will be distorted. If you want to change the number +of repetitions used for timing, edit the definition of LOOPREPEAT at the top of +pcretest.c + +Philip Hazel +January 2000 diff --git a/ext/pcre/pcrelib/doc/perltest.txt b/ext/pcre/pcrelib/doc/perltest.txt new file mode 100644 index 0000000000..6c38ebe19f --- /dev/null +++ b/ext/pcre/pcrelib/doc/perltest.txt @@ -0,0 +1,23 @@ +The perltest program +-------------------- + +The perltest program tests Perl's regular expressions; it has the same +specification as pcretest, and so can be given identical input, except that +input patterns can be followed only by Perl's lower case modifiers and /+ (as +used by pcretest), which is recognized and handled by the program. + +The data lines are processed as Perl double-quoted strings, so if they contain +" \ $ or @ characters, these have to be escaped. For this reason, all such +characters in testinput1 and testinput3 are escaped so that they can be used +for perltest as well as for pcretest, and the special upper case modifiers such +as /A that pcretest recognizes are not used in these files. The output should +be identical, apart from the initial identifying banner. + +The testinput2 and testinput4 files are not suitable for feeding to perltest, +since they do make use of the special upper case modifiers and escapes that +pcretest uses to test some features of PCRE. The first of these files also +contains malformed regular expressions, in order to check that PCRE diagnoses +them correctly. + +Philip Hazel +January 2000 diff --git a/ext/pcre/pcrelib/doc/pgrep.1 b/ext/pcre/pcrelib/doc/pgrep.1 new file mode 100644 index 0000000000..d9e9b575e0 --- /dev/null +++ b/ext/pcre/pcrelib/doc/pgrep.1 @@ -0,0 +1,76 @@ +.TH PGREP 1 +.SH NAME +pgrep - a grep with Perl-compatible regular expressions. +.SH SYNOPSIS +.B pgrep [-Vchilnsvx] pattern [file] ... + + +.SH DESCRIPTION +\fBpgrep\fR searches files for character patterns, in the same way as other +grep commands do, but it uses the PCRE regular expression library to support +patterns that are compatible with the regular expressions of Perl 5. See +\fBpcre(3)\fR for a full description of syntax and semantics. + +If no files are specified, \fBpgrep\fR reads the standard input. By default, +each line that matches the pattern is copied to the standard output, and if +there is more than one file, the file name is printed before each line of +output. However, there are options that can change how \fBpgrep\fR behaves. + +Lines are limited to BUFSIZ characters. BUFSIZ is defined in \fB\fR. +The newline character is removed from the end of each line before it is matched +against the pattern. + + +.SH OPTIONS +.TP 10 +\fB-V\fR +Write the version number of the PCRE library being used to the standard error +stream. +.TP +\fB-c\fR +Do not print individual lines; instead just print a count of the number of +lines that would otherwise have been printed. If several files are given, a +count is printed for each of them. +.TP +\fB-h\fR +Suppress printing of filenames when searching multiple files. +.TP +\fB-i\fR +Ignore upper/lower case distinctions during comparisons. +.TP +\fB-l\fR +Instead of printing lines from the files, just print the names of the files +containing lines that would have been printed. Each file name is printed +once, on a separate line. +.TP +\fB-n\fR +Precede each line by its line number in the file. +.TP +\fB-s\fR +Work silently, that is, display nothing except error messages. +The exit status indicates whether any matches were found. +.TP +\fB-v\fR +Invert the sense of the match, so that lines which do \fInot\fR match the +pattern are now the ones that are found. +.TP +\fB-x\fR +Force the pattern to be anchored (it must start matching at the beginning of +the line) and in addition, require it to match the entire line. This is +equivalent to having ^ and $ characters at the start and end of each +alternative branch in the regular expression. + + +.SH SEE ALSO +\fBpcre(3)\fR, Perl 5 documentation + + +.SH DIAGNOSTICS +Exit status is 0 if any matches were found, 1 if no matches were found, and 2 +for syntax errors or inacessible files (even if matches were found). + + +.SH AUTHOR +Philip Hazel +.br +Copyright (c) 1997-1999 University of Cambridge. diff --git a/ext/pcre/pcrelib/doc/pgrep.html b/ext/pcre/pcrelib/doc/pgrep.html new file mode 100644 index 0000000000..54efed6785 --- /dev/null +++ b/ext/pcre/pcrelib/doc/pgrep.html @@ -0,0 +1,105 @@ + + +pgrep specification + + +

    pgrep specification

    +This HTML document has been generated automatically from the original man page. +If there is any nonsense in it, please consult the man page in case the +conversion went wrong. + +
  • NAME +

    +pgrep - a grep with Perl-compatible regular expressions. +

    +
  • SYNOPSIS +

    +pgrep [-Vchilnsvx] pattern [file] ... +

    +
  • DESCRIPTION +

    +pgrep searches files for character patterns, in the same way as other +grep commands do, but it uses the PCRE regular expression library to support +patterns that are compatible with the regular expressions of Perl 5. See +pcre(3) for a full description of syntax and semantics. +

    +

    +If no files are specified, pgrep reads the standard input. By default, +each line that matches the pattern is copied to the standard output, and if +there is more than one file, the file name is printed before each line of +output. However, there are options that can change how pgrep behaves. +

    +

    +Lines are limited to BUFSIZ characters. BUFSIZ is defined in <stdio.h>. +The newline character is removed from the end of each line before it is matched +against the pattern. +

    +
  • OPTIONS +

    +-V +Write the version number of the PCRE library being used to the standard error +stream. +

    +

    +-c +Do not print individual lines; instead just print a count of the number of +lines that would otherwise have been printed. If several files are given, a +count is printed for each of them. +

    +

    +-h +Suppress printing of filenames when searching multiple files. +

    +

    +-i +Ignore upper/lower case distinctions during comparisons. +

    +

    +-l +Instead of printing lines from the files, just print the names of the files +containing lines that would have been printed. Each file name is printed +once, on a separate line. +

    +

    +-n +Precede each line by its line number in the file. +

    +

    +-s +Work silently, that is, display nothing except error messages. +The exit status indicates whether any matches were found. +

    +

    +-v +Invert the sense of the match, so that lines which do not match the +pattern are now the ones that are found. +

    +

    +-x +Force the pattern to be anchored (it must start matching at the beginning of +the line) and in addition, require it to match the entire line. This is +equivalent to having ^ and $ characters at the start and end of each +alternative branch in the regular expression. +

    +
  • SEE ALSO +

    +pcre(3), Perl 5 documentation +

    +
  • DIAGNOSTICS +

    +Exit status is 0 if any matches were found, 1 if no matches were found, and 2 +for syntax errors or inacessible files (even if matches were found). +

    +
  • AUTHOR +

    +Philip Hazel <ph10@cam.ac.uk> +
    +Copyright (c) 1997-1999 University of Cambridge. diff --git a/ext/pcre/pcrelib/doc/pgrep.txt b/ext/pcre/pcrelib/doc/pgrep.txt new file mode 100644 index 0000000000..bcd08c0aab --- /dev/null +++ b/ext/pcre/pcrelib/doc/pgrep.txt @@ -0,0 +1,86 @@ +NAME + pgrep - a grep with Perl-compatible regular expressions. + + + +SYNOPSIS + pgrep [-Vchilnsvx] pattern [file] ... + + + +DESCRIPTION + pgrep searches files for character patterns, in the same way + as other grep commands do, but it uses the PCRE regular + expression library to support patterns that are compatible + with the regular expressions of Perl 5. See pcre(3) for a + full description of syntax and semantics. + + If no files are specified, pgrep reads the standard input. + By default, each line that matches the pattern is copied to + the standard output, and if there is more than one file, the + file name is printed before each line of output. However, + there are options that can change how pgrep behaves. + + Lines are limited to BUFSIZ characters. BUFSIZ is defined in + . The newline character is removed from the end of + each line before it is matched against the pattern. + + + +OPTIONS + -V Write the version number of the PCRE library being + used to the standard error stream. + + -c Do not print individual lines; instead just print + a count of the number of lines that would other- + wise have been printed. If several files are + given, a count is printed for each of them. + + -h Suppress printing of filenames when searching mul- + tiple files. + + -i Ignore upper/lower case distinctions during com- + parisons. + + -l Instead of printing lines from the files, just + print the names of the files containing lines that + would have been printed. Each file name is printed + once, on a separate line. + + -n Precede each line by its line number in the file. + + -s Work silently, that is, display nothing except + error messages. The exit status indicates whether + any matches were found. + + -v Invert the sense of the match, so that lines which + do not match the pattern are now the ones that are + found. + + -x Force the pattern to be anchored (it must start + matching at the beginning of the line) and in + addition, require it to match the entire line. + This is equivalent to having ^ and $ characters at + the start and end of each alternative branch in + the regular expression. + + + +SEE ALSO + pcre(3), Perl 5 documentation + + + + + +DIAGNOSTICS + Exit status is 0 if any matches were found, 1 if no matches + were found, and 2 for syntax errors or inacessible files + (even if matches were found). + + + +AUTHOR + Philip Hazel + Copyright (c) 1997-1999 University of Cambridge. + diff --git a/ext/pcre/pcrelib/testdata/testinput1 b/ext/pcre/pcrelib/testdata/testinput1 new file mode 100644 index 0000000000..2f56b155df --- /dev/null +++ b/ext/pcre/pcrelib/testdata/testinput1 @@ -0,0 +1,1902 @@ +/the quick brown fox/ + the quick brown fox + The quick brown FOX + What do you know about the quick brown fox? + What do you know about THE QUICK BROWN FOX? + +/The quick brown fox/i + the quick brown fox + The quick brown FOX + What do you know about the quick brown fox? + What do you know about THE QUICK BROWN FOX? + +/abcd\t\n\r\f\a\e\071\x3b\$\\\?caxyz/ + abcd\t\n\r\f\a\e9;\$\\?caxyz + +/a*abc?xyz+pqr{3}ab{2,}xy{4,5}pq{0,6}AB{0,}zz/ + abxyzpqrrrabbxyyyypqAzz + abxyzpqrrrabbxyyyypqAzz + aabxyzpqrrrabbxyyyypqAzz + aaabxyzpqrrrabbxyyyypqAzz + aaaabxyzpqrrrabbxyyyypqAzz + abcxyzpqrrrabbxyyyypqAzz + aabcxyzpqrrrabbxyyyypqAzz + aaabcxyzpqrrrabbxyyyypAzz + aaabcxyzpqrrrabbxyyyypqAzz + aaabcxyzpqrrrabbxyyyypqqAzz + aaabcxyzpqrrrabbxyyyypqqqAzz + aaabcxyzpqrrrabbxyyyypqqqqAzz + aaabcxyzpqrrrabbxyyyypqqqqqAzz + aaabcxyzpqrrrabbxyyyypqqqqqqAzz + aaaabcxyzpqrrrabbxyyyypqAzz + abxyzzpqrrrabbxyyyypqAzz + aabxyzzzpqrrrabbxyyyypqAzz + aaabxyzzzzpqrrrabbxyyyypqAzz + aaaabxyzzzzpqrrrabbxyyyypqAzz + abcxyzzpqrrrabbxyyyypqAzz + aabcxyzzzpqrrrabbxyyyypqAzz + aaabcxyzzzzpqrrrabbxyyyypqAzz + aaaabcxyzzzzpqrrrabbxyyyypqAzz + aaaabcxyzzzzpqrrrabbbxyyyypqAzz + aaaabcxyzzzzpqrrrabbbxyyyyypqAzz + aaabcxyzpqrrrabbxyyyypABzz + aaabcxyzpqrrrabbxyyyypABBzz + >>>aaabxyzpqrrrabbxyyyypqAzz + >aaaabxyzpqrrrabbxyyyypqAzz + >>>>abcxyzpqrrrabbxyyyypqAzz + *** Failers + abxyzpqrrabbxyyyypqAzz + abxyzpqrrrrabbxyyyypqAzz + abxyzpqrrrabxyyyypqAzz + aaaabcxyzzzzpqrrrabbbxyyyyyypqAzz + aaaabcxyzzzzpqrrrabbbxyyypqAzz + aaabcxyzpqrrrabbxyyyypqqqqqqqAzz + +/^(abc){1,2}zz/ + abczz + abcabczz + *** Failers + zz + abcabcabczz + >>abczz + +/^(b+?|a){1,2}?c/ + bc + bbc + bbbc + bac + bbac + aac + abbbbbbbbbbbc + bbbbbbbbbbbac + *** Failers + aaac + abbbbbbbbbbbac + +/^(b+|a){1,2}c/ + bc + bbc + bbbc + bac + bbac + aac + abbbbbbbbbbbc + bbbbbbbbbbbac + *** Failers + aaac + abbbbbbbbbbbac + +/^(b+|a){1,2}?bc/ + bbc + +/^(b*|ba){1,2}?bc/ + babc + bbabc + bababc + *** Failers + bababbc + babababc + +/^(ba|b*){1,2}?bc/ + babc + bbabc + bababc + *** Failers + bababbc + babababc + +/^\ca\cA\c[\c{\c:/ + \x01\x01\e;z + +/^[ab\]cde]/ + athing + bthing + ]thing + cthing + dthing + ething + *** Failers + fthing + [thing + \\thing + +/^[]cde]/ + ]thing + cthing + dthing + ething + *** Failers + athing + fthing + +/^[^ab\]cde]/ + fthing + [thing + \\thing + *** Failers + athing + bthing + ]thing + cthing + dthing + ething + +/^[^]cde]/ + athing + fthing + *** Failers + ]thing + cthing + dthing + ething + +/^\/ +  + +/^ÿ/ + ÿ + +/^[0-9]+$/ + 0 + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 100 + *** Failers + abc + +/^.*nter/ + enter + inter + uponter + +/^xxx[0-9]+$/ + xxx0 + xxx1234 + *** Failers + xxx + +/^.+[0-9][0-9][0-9]$/ + x123 + xx123 + 123456 + *** Failers + 123 + x1234 + +/^.+?[0-9][0-9][0-9]$/ + x123 + xx123 + 123456 + *** Failers + 123 + x1234 + +/^([^!]+)!(.+)=apquxz\.ixr\.zzz\.ac\.uk$/ + abc!pqr=apquxz.ixr.zzz.ac.uk + *** Failers + !pqr=apquxz.ixr.zzz.ac.uk + abc!=apquxz.ixr.zzz.ac.uk + abc!pqr=apquxz:ixr.zzz.ac.uk + abc!pqr=apquxz.ixr.zzz.ac.ukk + +/:/ + Well, we need a colon: somewhere + *** Fail if we don't + +/([\da-f:]+)$/i + 0abc + abc + fed + E + :: + 5f03:12C0::932e + fed def + Any old stuff + *** Failers + 0zzz + gzzz + fed\x20 + Any old rubbish + +/^.*\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$/ + .1.2.3 + A.12.123.0 + *** Failers + .1.2.3333 + 1.2.3 + 1234.2.3 + +/^(\d+)\s+IN\s+SOA\s+(\S+)\s+(\S+)\s*\(\s*$/ + 1 IN SOA non-sp1 non-sp2( + 1 IN SOA non-sp1 non-sp2 ( + *** Failers + 1IN SOA non-sp1 non-sp2( + +/^[a-zA-Z\d][a-zA-Z\d\-]*(\.[a-zA-Z\d][a-zA-z\d\-]*)*\.$/ + a. + Z. + 2. + ab-c.pq-r. + sxk.zzz.ac.uk. + x-.y-. + *** Failers + -abc.peq. + +/^\*\.[a-z]([a-z\-\d]*[a-z\d]+)?(\.[a-z]([a-z\-\d]*[a-z\d]+)?)*$/ + *.a + *.b0-a + *.c3-b.c + *.c-a.b-c + *** Failers + *.0 + *.a- + *.a-b.c- + *.c-a.0-c + +/^(?=ab(de))(abd)(e)/ + abde + +/^(?!(ab)de|x)(abd)(f)/ + abdf + +/^(?=(ab(cd)))(ab)/ + abcd + +/^[\da-f](\.[\da-f])*$/i + a.b.c.d + A.B.C.D + a.b.c.1.2.3.C + +/^\".*\"\s*(;.*)?$/ + \"1234\" + \"abcd\" ; + \"\" ; rhubarb + *** Failers + \"1234\" : things + +/^$/ + \ + *** Failers + +/ ^ a (?# begins with a) b\sc (?# then b c) $ (?# then end)/x + ab c + *** Failers + abc + ab cde + +/(?x) ^ a (?# begins with a) b\sc (?# then b c) $ (?# then end)/ + ab c + *** Failers + abc + ab cde + +/^ a\ b[c ]d $/x + a bcd + a b d + *** Failers + abcd + ab d + +/^(a(b(c)))(d(e(f)))(h(i(j)))(k(l(m)))$/ + abcdefhijklm + +/^(?:a(b(c)))(?:d(e(f)))(?:h(i(j)))(?:k(l(m)))$/ + abcdefhijklm + +/^[\w][\W][\s][\S][\d][\D][\b][\n][\c]][\022]/ + a+ Z0+\x08\n\x1d\x12 + +/^[.^$|()*+?{,}]+/ + .^\$(*+)|{?,?} + +/^a*\w/ + z + az + aaaz + a + aa + aaaa + a+ + aa+ + +/^a*?\w/ + z + az + aaaz + a + aa + aaaa + a+ + aa+ + +/^a+\w/ + az + aaaz + aa + aaaa + aa+ + +/^a+?\w/ + az + aaaz + aa + aaaa + aa+ + +/^\d{8}\w{2,}/ + 1234567890 + 12345678ab + 12345678__ + *** Failers + 1234567 + +/^[aeiou\d]{4,5}$/ + uoie + 1234 + 12345 + aaaaa + *** Failers + 123456 + +/^[aeiou\d]{4,5}?/ + uoie + 1234 + 12345 + aaaaa + 123456 + +/\A(abc|def)=(\1){2,3}\Z/ + abc=abcabc + def=defdefdef + *** Failers + abc=defdef + +/^(a)(b)(c)(d)(e)(f)(g)(h)(i)(j)(k)\11*(\3\4)\1(?#)2$/ + abcdefghijkcda2 + abcdefghijkkkkcda2 + +/(cat(a(ract|tonic)|erpillar)) \1()2(3)/ + cataract cataract23 + catatonic catatonic23 + caterpillar caterpillar23 + + +/^From +([^ ]+) +[a-zA-Z][a-zA-Z][a-zA-Z] +[a-zA-Z][a-zA-Z][a-zA-Z] +[0-9]?[0-9] +[0-9][0-9]:[0-9][0-9]/ + From abcd Mon Sep 01 12:33:02 1997 + +/^From\s+\S+\s+([a-zA-Z]{3}\s+){2}\d{1,2}\s+\d\d:\d\d/ + From abcd Mon Sep 01 12:33:02 1997 + From abcd Mon Sep 1 12:33:02 1997 + *** Failers + From abcd Sep 01 12:33:02 1997 + +/^12.34/s + 12\n34 + 12\r34 + +/\w+(?=\t)/ + the quick brown\t fox + +/foo(?!bar)(.*)/ + foobar is foolish see? + +/(?:(?!foo)...|^.{0,2})bar(.*)/ + foobar crowbar etc + barrel + 2barrel + A barrel + +/^(\D*)(?=\d)(?!123)/ + abc456 + *** Failers + abc123 + +/^1234(?# test newlines + inside)/ + 1234 + +/^1234 #comment in extended re + /x + 1234 + +/#rhubarb + abcd/x + abcd + +/^abcd#rhubarb/x + abcd + +/^(a)\1{2,3}(.)/ + aaab + aaaab + aaaaab + aaaaaab + +/(?!^)abc/ + the abc + *** Failers + abc + +/(?=^)abc/ + abc + *** Failers + the abc + +/^[ab]{1,3}(ab*|b)/ + aabbbbb + +/^[ab]{1,3}?(ab*|b)/ + aabbbbb + +/^[ab]{1,3}?(ab*?|b)/ + aabbbbb + +/^[ab]{1,3}(ab*?|b)/ + aabbbbb + +/ (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* # optional leading comment +(?: (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +" (?: # opening quote... +[^\\\x80-\xff\n\015"] # Anything except backslash and quote +| # or +\\ [^\x80-\xff] # Escaped something (something != CR) +)* " # closing quote +) # initial word +(?: (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* \. (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +" (?: # opening quote... +[^\\\x80-\xff\n\015"] # Anything except backslash and quote +| # or +\\ [^\x80-\xff] # Escaped something (something != CR) +)* " # closing quote +) )* # further okay, if led by a period +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* @ (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| \[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) # initial subdomain +(?: # +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* \. # if led by a period... +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| \[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) # ...further okay +)* +# address +| # or +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +" (?: # opening quote... +[^\\\x80-\xff\n\015"] # Anything except backslash and quote +| # or +\\ [^\x80-\xff] # Escaped something (something != CR) +)* " # closing quote +) # one word, optionally followed by.... +(?: +[^()<>@,;:".\\\[\]\x80-\xff\000-\010\012-\037] | # atom and space parts, or... +\( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) | # comments, or... + +" (?: # opening quote... +[^\\\x80-\xff\n\015"] # Anything except backslash and quote +| # or +\\ [^\x80-\xff] # Escaped something (something != CR) +)* " # closing quote +# quoted strings +)* +< (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* # leading < +(?: @ (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| \[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) # initial subdomain +(?: # +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* \. # if led by a period... +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| \[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) # ...further okay +)* + +(?: (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* , (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* @ (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| \[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) # initial subdomain +(?: # +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* \. # if led by a period... +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| \[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) # ...further okay +)* +)* # further okay, if led by comma +: # closing colon +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* )? # optional route +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +" (?: # opening quote... +[^\\\x80-\xff\n\015"] # Anything except backslash and quote +| # or +\\ [^\x80-\xff] # Escaped something (something != CR) +)* " # closing quote +) # initial word +(?: (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* \. (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +" (?: # opening quote... +[^\\\x80-\xff\n\015"] # Anything except backslash and quote +| # or +\\ [^\x80-\xff] # Escaped something (something != CR) +)* " # closing quote +) )* # further okay, if led by a period +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* @ (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| \[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) # initial subdomain +(?: # +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* \. # if led by a period... +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| \[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) # ...further okay +)* +# address spec +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* > # trailing > +# name and address +) (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* # optional trailing comment +/x + Alan Other + + user\@dom.ain + \"A. Other\" (a comment) + A. Other (a comment) + \"/s=user/ou=host/o=place/prmd=uu.yy/admd= /c=gb/\"\@x400-re.lay + A missing angle @,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +# Atom +| # or +" # " +[^\\\x80-\xff\n\015"] * # normal +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015"] * )* # ( special normal* )* +" # " +# Quoted string +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +\. +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +# Atom +| # or +" # " +[^\\\x80-\xff\n\015"] * # normal +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015"] * )* # ( special normal* )* +" # " +# Quoted string +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# additional words +)* +@ +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +\[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# optional trailing comments +(?: +\. +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +\[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# optional trailing comments +)* +# address +| # or +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +# Atom +| # or +" # " +[^\\\x80-\xff\n\015"] * # normal +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015"] * )* # ( special normal* )* +" # " +# Quoted string +) +# leading word +[^()<>@,;:".\\\[\]\x80-\xff\000-\010\012-\037] * # "normal" atoms and or spaces +(?: +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +| +" # " +[^\\\x80-\xff\n\015"] * # normal +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015"] * )* # ( special normal* )* +" # " +) # "special" comment or quoted string +[^()<>@,;:".\\\[\]\x80-\xff\000-\010\012-\037] * # more "normal" +)* +< +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# < +(?: +@ +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +\[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# optional trailing comments +(?: +\. +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +\[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# optional trailing comments +)* +(?: , +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +@ +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +\[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# optional trailing comments +(?: +\. +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +\[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# optional trailing comments +)* +)* # additional domains +: +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# optional trailing comments +)? # optional route +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +# Atom +| # or +" # " +[^\\\x80-\xff\n\015"] * # normal +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015"] * )* # ( special normal* )* +" # " +# Quoted string +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +\. +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +# Atom +| # or +" # " +[^\\\x80-\xff\n\015"] * # normal +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015"] * )* # ( special normal* )* +" # " +# Quoted string +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# additional words +)* +@ +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +\[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# optional trailing comments +(?: +\. +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +\[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# optional trailing comments +)* +# address spec +> # > +# name and address +) +/x + Alan Other + + user\@dom.ain + \"A. Other\" (a comment) + A. Other (a comment) + \"/s=user/ou=host/o=place/prmd=uu.yy/admd= /c=gb/\"\@x400-re.lay + A missing angle / + abcghinop + +/<.*?>/ + abcghinop + +/<.*>/U + abcghinop + +/<.*>(?U)/ + abcghinop + +/<.*?>/U + abcghinop + +/={3,}/U + abc========def + +/(?U)={3,}?/ + abc========def + +/(?^abc)/m + abc + def\nabc + *** Failers + defabc + +/(?<=ab(c+)d)ef/ + +/(?<=ab(?<=c+)d)ef/ + +/(?<=ab(c|de)f)g/ + +/The next three are in testinput2 because they have variable length branches/ + +/(?<=bullock|donkey)-cart/ + the bullock-cart + a donkey-cart race + *** Failers + cart + horse-and-cart + +/(?<=ab(?i)x|y|z)/ + +/(?>.*)(?<=(abcd)|(xyz))/ + alphabetabcd + endingxyz + +/(?<=ab(?i)x(?-i)y|(?i)z|b)ZZ/ + abxyZZ + abXyZZ + ZZZ + zZZ + bZZ + BZZ + *** Failers + ZZ + abXYZZ + zzz + bzz + +/(?[^()]+) # Either a sequence of non-brackets (no backtracking) + | # Or + (?R) # Recurse - i.e. nested bracketed string + )* # Zero or more contents + \) # Closing ) + /x + (abcd) + (abcd)xyz + xyz(abcd) + (ab(xy)cd)pqr + (ab(xycd)pqr + () abc () + 12(abcde(fsh)xyz(foo(bar))lmno)89 + *** Failers + abcd + abcd) + (abcd + +/\( ( (?>[^()]+) | (?R) )* \) /xg + (ab(xy)cd)pqr + 1(abcd)(x(y)z)pqr + +/\( (?: (?>[^()]+) | (?R) ) \) /x + (abcd) + (ab(xy)cd) + (a(b(c)d)e) + ((ab)) + *** Failers + () + +/\( (?: (?>[^()]+) | (?R) )? \) /x + () + 12(abcde(fsh)xyz(foo(bar))lmno)89 + +/\( ( (?>[^()]+) | (?R) )* \) /x + (ab(xy)cd) + +/\( ( ( (?>[^()]+) | (?R) )* ) \) /x + (ab(xy)cd) + +/\( (123)? ( ( (?>[^()]+) | (?R) )* ) \) /x + (ab(xy)cd) + (123ab(xy)cd) + +/\( ( (123)? ( (?>[^()]+) | (?R) )* ) \) /x + (ab(xy)cd) + (123ab(xy)cd) + +/\( (((((((((( ( (?>[^()]+) | (?R) )* )))))))))) \) /x + (ab(xy)cd) + +/\( ( ( (?>[^()<>]+) | ((?>[^()]+)) | (?R) )* ) \) /x + (abcd(xyz

    qrs)123) + +/\( ( ( (?>[^()]+) | ((?R)) )* ) \) /x + (ab(cd)ef) + (ab(cd(ef)gh)ij) + +/^[[:alnum:]]/D + +/^[[:alpha:]]/D + +/^[[:ascii:]]/D + +/^[[:cntrl:]]/D + +/^[[:digit:]]/D + +/^[[:graph:]]/D + +/^[[:lower:]]/D + +/^[[:print:]]/D + +/^[[:punct:]]/D + +/^[[:space:]]/D + +/^[[:upper:]]/D + +/^[[:xdigit:]]/D + +/^[[:word:]]/D + +/^[[:^cntrl:]]/D + +/^[12[:^digit:]]/D + +/[01[:alpha:]%]/D + +/[[.ch.]]/ + +/[[=ch=]]/ + +/[[:rhubarb:]]/ + +/[[:upper:]]/i + A + a + +/[[:lower:]]/i + A + a + +/((?-i)[[:lower:]])[[:lower:]]/i + ab + aB + *** Failers + Ab + AB + +/ End of test input / diff --git a/ext/pcre/pcrelib/testdata/testinput3 b/ext/pcre/pcrelib/testdata/testinput3 new file mode 100644 index 0000000000..0c884d3b7c --- /dev/null +++ b/ext/pcre/pcrelib/testdata/testinput3 @@ -0,0 +1,1692 @@ +/(?.*/)foo" + /this/is/a/very/long/line/in/deed/with/very/many/slashes/in/it/you/see/ + +"(?>.*/)foo" + /this/is/a/very/long/line/in/deed/with/very/many/slashes/in/and/foo + +/(?>(\.\d\d[1-9]?))\d+/ + 1.230003938 + 1.875000282 + *** Failers + 1.235 + +/^((?>\w+)|(?>\s+))*$/ + now is the time for all good men to come to the aid of the party + *** Failers + this is not a line with only words and spaces! + +/(\d+)(\w)/ + 12345a + 12345+ + +/((?>\d+))(\w)/ + 12345a + *** Failers + 12345+ + +/(?>a+)b/ + aaab + +/((?>a+)b)/ + aaab + +/(?>(a+))b/ + aaab + +/(?>b)+/ + aaabbbccc + +/(?>a+|b+|c+)*c/ + aaabbbbccccd + +/((?>[^()]+)|\([^()]*\))+/ + ((abc(ade)ufh()()x + +/\(((?>[^()]+)|\([^()]+\))+\)/ + (abc) + (abc(def)xyz) + *** Failers + ((()aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa + +/a(?-i)b/i + ab + *** Failers + Ab + aB + AB + +/(a (?x)b c)d e/ + a bcd e + *** Failers + a b cd e + abcd e + a bcde + +/(a b(?x)c d (?-x)e f)/ + a bcde f + *** Failers + abcdef + +/(a(?i)b)c/ + abc + aBc + *** Failers + abC + aBC + Abc + ABc + ABC + AbC + +/a(?i:b)c/ + abc + aBc + *** Failers + ABC + abC + aBC + +/a(?i:b)*c/ + aBc + aBBc + *** Failers + aBC + aBBC + +/a(?=b(?i)c)\w\wd/ + abcd + abCd + *** Failers + aBCd + abcD + +/(?s-i:more.*than).*million/i + more than million + more than MILLION + more \n than Million + *** Failers + MORE THAN MILLION + more \n than \n million + +/(?:(?s-i)more.*than).*million/i + more than million + more than MILLION + more \n than Million + *** Failers + MORE THAN MILLION + more \n than \n million + +/(?>a(?i)b+)+c/ + abc + aBbc + aBBc + *** Failers + Abc + abAb + abbC + +/(?=a(?i)b)\w\wc/ + abc + aBc + *** Failers + Ab + abC + aBC + +/(?<=a(?i)b)(\w\w)c/ + abxxc + aBxxc + *** Failers + Abxxc + ABxxc + abxxC + +/(?:(a)|b)(?(1)A|B)/ + aA + bB + *** Failers + aB + bA + +/^(a)?(?(1)a|b)+$/ + aa + b + bb + *** Failers + ab + +/^(?(?=abc)\w{3}:|\d\d)$/ + abc: + 12 + *** Failers + 123 + xyz + +/^(?(?!abc)\d\d|\w{3}:)$/ + abc: + 12 + *** Failers + 123 + xyz + +/(?(?<=foo)bar|cat)/ + foobar + cat + fcat + focat + *** Failers + foocat + +/(?(?a*)*/ + a + aa + aaaa + +/(abc|)+/ + abc + abcabc + abcabcabc + xyz + +/([a]*)*/ + a + aaaaa + +/([ab]*)*/ + a + b + ababab + aaaabcde + bbbb + +/([^a]*)*/ + b + bbbb + aaa + +/([^ab]*)*/ + cccc + abab + +/([a]*?)*/ + a + aaaa + +/([ab]*?)*/ + a + b + abab + baba + +/([^a]*?)*/ + b + bbbb + aaa + +/([^ab]*?)*/ + c + cccc + baba + +/(?>a*)*/ + a + aaabcde + +/((?>a*))*/ + aaaaa + aabbaa + +/((?>a*?))*/ + aaaaa + aabbaa + +/(?(?=[^a-z]+[a-z]) \d{2}-[a-z]{3}-\d{2} | \d{2}-\d{2}-\d{2} ) /x + 12-sep-98 + 12-09-98 + *** Failers + sep-12-98 + +/(?<=(foo))bar\1/ + foobarfoo + foobarfootling + *** Failers + foobar + barfoo + +/(?i:saturday|sunday)/ + saturday + sunday + Saturday + Sunday + SATURDAY + SUNDAY + SunDay + +/(a(?i)bc|BB)x/ + abcx + aBCx + bbx + BBx + *** Failers + abcX + aBCX + bbX + BBX + +/^([ab](?i)[cd]|[ef])/ + ac + aC + bD + elephant + Europe + frog + France + *** Failers + Africa + +/^(ab|a(?i)[b-c](?m-i)d|x(?i)y|z)/ + ab + aBd + xy + xY + zebra + Zambesi + *** Failers + aCD + XY + +/(?<=foo\n)^bar/m + foo\nbar + *** Failers + bar + baz\nbar + +/(?<=(?]&/ + <&OUT + +/^(a\1?){4}$/ + aaaaaaaaaa + *** Failers + AB + aaaaaaaaa + aaaaaaaaaaa + +/^(a(?(1)\1)){4}$/ + aaaaaaaaaa + *** Failers + aaaaaaaaa + aaaaaaaaaaa + +/(?:(f)(o)(o)|(b)(a)(r))*/ + foobar + +/(?<=a)b/ + ab + *** Failers + cb + b + +/(?a+)ab/ + +/(?>a+)b/ + aaab + +/([[:]+)/ + a:[b]: + +/([[=]+)/ + a=[b]= + +/([[.]+)/ + a.[b]. + +/((?>a+)b)/ + aaab + +/(?>(a+))b/ + aaab + +/((?>[^()]+)|\([^()]*\))+/ + ((abc(ade)ufh()()x + +/a\Z/ + *** Failers + aaab + a\nb\n + +/b\Z/ + a\nb\n + +/b\z/ + +/b\Z/ + a\nb + +/b\z/ + a\nb + *** Failers + +/^(?>(?(1)\.|())[^\W_](?>[a-z0-9-]*[^\W_])?)+$/ + a + abc + a-b + 0-9 + a.b + 5.6.7 + the.quick.brown.fox + a100.b200.300c + 12-ab.1245 + ***Failers + \ + .a + -a + a- + a. + a_b + a.- + a.. + ab..bc + the.quick.brown.fox- + the.quick.brown.fox. + the.quick.brown.fox_ + the.quick.brown.fox+ + +/(?>.*)(?<=(abcd|wxyz))/ + alphabetabcd + endingwxyz + *** Failers + a rather long string that doesn't end with one of them + +/word (?>(?:(?!otherword)[a-zA-Z0-9]+ ){0,30})otherword/ + word cat dog elephant mussel cow horse canary baboon snake shark otherword + word cat dog elephant mussel cow horse canary baboon snake shark + +/word (?>[a-zA-Z0-9]+ ){0,30}otherword/ + word cat dog elephant mussel cow horse canary baboon snake shark the quick brown fox and the lazy dog and several other words getting close to thirty by now I hope + +/(?<=\d{3}(?!999))foo/ + 999foo + 123999foo + *** Failers + 123abcfoo + +/(?<=(?!...999)\d{3})foo/ + 999foo + 123999foo + *** Failers + 123abcfoo + +/(?<=\d{3}(?!999)...)foo/ + 123abcfoo + 123456foo + *** Failers + 123999foo + +/(?<=\d{3}...)(?\s*)=(?>\s*) # find >>aaabxyzpqrrrabbxyyyypqAzz + 0: aaabxyzpqrrrabbxyyyypqAzz + >aaaabxyzpqrrrabbxyyyypqAzz + 0: aaaabxyzpqrrrabbxyyyypqAzz + >>>>abcxyzpqrrrabbxyyyypqAzz + 0: abcxyzpqrrrabbxyyyypqAzz + *** Failers +No match + abxyzpqrrabbxyyyypqAzz +No match + abxyzpqrrrrabbxyyyypqAzz +No match + abxyzpqrrrabxyyyypqAzz +No match + aaaabcxyzzzzpqrrrabbbxyyyyyypqAzz +No match + aaaabcxyzzzzpqrrrabbbxyyypqAzz +No match + aaabcxyzpqrrrabbxyyyypqqqqqqqAzz +No match + +/^(abc){1,2}zz/ + abczz + 0: abczz + 1: abc + abcabczz + 0: abcabczz + 1: abc + *** Failers +No match + zz +No match + abcabcabczz +No match + >>abczz +No match + +/^(b+?|a){1,2}?c/ + bc + 0: bc + 1: b + bbc + 0: bbc + 1: b + bbbc + 0: bbbc + 1: bb + bac + 0: bac + 1: a + bbac + 0: bbac + 1: a + aac + 0: aac + 1: a + abbbbbbbbbbbc + 0: abbbbbbbbbbbc + 1: bbbbbbbbbbb + bbbbbbbbbbbac + 0: bbbbbbbbbbbac + 1: a + *** Failers +No match + aaac +No match + abbbbbbbbbbbac +No match + +/^(b+|a){1,2}c/ + bc + 0: bc + 1: b + bbc + 0: bbc + 1: bb + bbbc + 0: bbbc + 1: bbb + bac + 0: bac + 1: a + bbac + 0: bbac + 1: a + aac + 0: aac + 1: a + abbbbbbbbbbbc + 0: abbbbbbbbbbbc + 1: bbbbbbbbbbb + bbbbbbbbbbbac + 0: bbbbbbbbbbbac + 1: a + *** Failers +No match + aaac +No match + abbbbbbbbbbbac +No match + +/^(b+|a){1,2}?bc/ + bbc + 0: bbc + 1: b + +/^(b*|ba){1,2}?bc/ + babc + 0: babc + 1: ba + bbabc + 0: bbabc + 1: ba + bababc + 0: bababc + 1: ba + *** Failers +No match + bababbc +No match + babababc +No match + +/^(ba|b*){1,2}?bc/ + babc + 0: babc + 1: ba + bbabc + 0: bbabc + 1: ba + bababc + 0: bababc + 1: ba + *** Failers +No match + bababbc +No match + babababc +No match + +/^\ca\cA\c[\c{\c:/ + \x01\x01\e;z + 0: \x01\x01\x1b;z + +/^[ab\]cde]/ + athing + 0: a + bthing + 0: b + ]thing + 0: ] + cthing + 0: c + dthing + 0: d + ething + 0: e + *** Failers +No match + fthing +No match + [thing +No match + \\thing +No match + +/^[]cde]/ + ]thing + 0: ] + cthing + 0: c + dthing + 0: d + ething + 0: e + *** Failers +No match + athing +No match + fthing +No match + +/^[^ab\]cde]/ + fthing + 0: f + [thing + 0: [ + \\thing + 0: \ + *** Failers + 0: * + athing +No match + bthing +No match + ]thing +No match + cthing +No match + dthing +No match + ething +No match + +/^[^]cde]/ + athing + 0: a + fthing + 0: f + *** Failers + 0: * + ]thing +No match + cthing +No match + dthing +No match + ething +No match + +/^\/ +  + 0: \x81 + +/^ÿ/ + ÿ + 0: \xff + +/^[0-9]+$/ + 0 + 0: 0 + 1 + 0: 1 + 2 + 0: 2 + 3 + 0: 3 + 4 + 0: 4 + 5 + 0: 5 + 6 + 0: 6 + 7 + 0: 7 + 8 + 0: 8 + 9 + 0: 9 + 10 + 0: 10 + 100 + 0: 100 + *** Failers +No match + abc +No match + +/^.*nter/ + enter + 0: enter + inter + 0: inter + uponter + 0: uponter + +/^xxx[0-9]+$/ + xxx0 + 0: xxx0 + xxx1234 + 0: xxx1234 + *** Failers +No match + xxx +No match + +/^.+[0-9][0-9][0-9]$/ + x123 + 0: x123 + xx123 + 0: xx123 + 123456 + 0: 123456 + *** Failers +No match + 123 +No match + x1234 + 0: x1234 + +/^.+?[0-9][0-9][0-9]$/ + x123 + 0: x123 + xx123 + 0: xx123 + 123456 + 0: 123456 + *** Failers +No match + 123 +No match + x1234 + 0: x1234 + +/^([^!]+)!(.+)=apquxz\.ixr\.zzz\.ac\.uk$/ + abc!pqr=apquxz.ixr.zzz.ac.uk + 0: abc!pqr=apquxz.ixr.zzz.ac.uk + 1: abc + 2: pqr + *** Failers +No match + !pqr=apquxz.ixr.zzz.ac.uk +No match + abc!=apquxz.ixr.zzz.ac.uk +No match + abc!pqr=apquxz:ixr.zzz.ac.uk +No match + abc!pqr=apquxz.ixr.zzz.ac.ukk +No match + +/:/ + Well, we need a colon: somewhere + 0: : + *** Fail if we don't +No match + +/([\da-f:]+)$/i + 0abc + 0: 0abc + 1: 0abc + abc + 0: abc + 1: abc + fed + 0: fed + 1: fed + E + 0: E + 1: E + :: + 0: :: + 1: :: + 5f03:12C0::932e + 0: 5f03:12C0::932e + 1: 5f03:12C0::932e + fed def + 0: def + 1: def + Any old stuff + 0: ff + 1: ff + *** Failers +No match + 0zzz +No match + gzzz +No match + fed\x20 +No match + Any old rubbish +No match + +/^.*\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$/ + .1.2.3 + 0: .1.2.3 + 1: 1 + 2: 2 + 3: 3 + A.12.123.0 + 0: A.12.123.0 + 1: 12 + 2: 123 + 3: 0 + *** Failers +No match + .1.2.3333 +No match + 1.2.3 +No match + 1234.2.3 +No match + +/^(\d+)\s+IN\s+SOA\s+(\S+)\s+(\S+)\s*\(\s*$/ + 1 IN SOA non-sp1 non-sp2( + 0: 1 IN SOA non-sp1 non-sp2( + 1: 1 + 2: non-sp1 + 3: non-sp2 + 1 IN SOA non-sp1 non-sp2 ( + 0: 1 IN SOA non-sp1 non-sp2 ( + 1: 1 + 2: non-sp1 + 3: non-sp2 + *** Failers +No match + 1IN SOA non-sp1 non-sp2( +No match + +/^[a-zA-Z\d][a-zA-Z\d\-]*(\.[a-zA-Z\d][a-zA-z\d\-]*)*\.$/ + a. + 0: a. + Z. + 0: Z. + 2. + 0: 2. + ab-c.pq-r. + 0: ab-c.pq-r. + 1: .pq-r + sxk.zzz.ac.uk. + 0: sxk.zzz.ac.uk. + 1: .uk + x-.y-. + 0: x-.y-. + 1: .y- + *** Failers +No match + -abc.peq. +No match + +/^\*\.[a-z]([a-z\-\d]*[a-z\d]+)?(\.[a-z]([a-z\-\d]*[a-z\d]+)?)*$/ + *.a + 0: *.a + *.b0-a + 0: *.b0-a + 1: 0-a + *.c3-b.c + 0: *.c3-b.c + 1: 3-b + 2: .c + *.c-a.b-c + 0: *.c-a.b-c + 1: -a + 2: .b-c + 3: -c + *** Failers +No match + *.0 +No match + *.a- +No match + *.a-b.c- +No match + *.c-a.0-c +No match + +/^(?=ab(de))(abd)(e)/ + abde + 0: abde + 1: de + 2: abd + 3: e + +/^(?!(ab)de|x)(abd)(f)/ + abdf + 0: abdf + 1: + 2: abd + 3: f + +/^(?=(ab(cd)))(ab)/ + abcd + 0: ab + 1: abcd + 2: cd + 3: ab + +/^[\da-f](\.[\da-f])*$/i + a.b.c.d + 0: a.b.c.d + 1: .d + A.B.C.D + 0: A.B.C.D + 1: .D + a.b.c.1.2.3.C + 0: a.b.c.1.2.3.C + 1: .C + +/^\".*\"\s*(;.*)?$/ + \"1234\" + 0: "1234" + \"abcd\" ; + 0: "abcd" ; + 1: ; + \"\" ; rhubarb + 0: "" ; rhubarb + 1: ; rhubarb + *** Failers +No match + \"1234\" : things +No match + +/^$/ + \ + 0: + *** Failers +No match + +/ ^ a (?# begins with a) b\sc (?# then b c) $ (?# then end)/x + ab c + 0: ab c + *** Failers +No match + abc +No match + ab cde +No match + +/(?x) ^ a (?# begins with a) b\sc (?# then b c) $ (?# then end)/ + ab c + 0: ab c + *** Failers +No match + abc +No match + ab cde +No match + +/^ a\ b[c ]d $/x + a bcd + 0: a bcd + a b d + 0: a b d + *** Failers +No match + abcd +No match + ab d +No match + +/^(a(b(c)))(d(e(f)))(h(i(j)))(k(l(m)))$/ + abcdefhijklm + 0: abcdefhijklm + 1: abc + 2: bc + 3: c + 4: def + 5: ef + 6: f + 7: hij + 8: ij + 9: j +10: klm +11: lm +12: m + +/^(?:a(b(c)))(?:d(e(f)))(?:h(i(j)))(?:k(l(m)))$/ + abcdefhijklm + 0: abcdefhijklm + 1: bc + 2: c + 3: ef + 4: f + 5: ij + 6: j + 7: lm + 8: m + +/^[\w][\W][\s][\S][\d][\D][\b][\n][\c]][\022]/ + a+ Z0+\x08\n\x1d\x12 + 0: a+ Z0+\x08\x0a\x1d\x12 + +/^[.^$|()*+?{,}]+/ + .^\$(*+)|{?,?} + 0: .^$(*+)|{?,?} + +/^a*\w/ + z + 0: z + az + 0: az + aaaz + 0: aaaz + a + 0: a + aa + 0: aa + aaaa + 0: aaaa + a+ + 0: a + aa+ + 0: aa + +/^a*?\w/ + z + 0: z + az + 0: a + aaaz + 0: a + a + 0: a + aa + 0: a + aaaa + 0: a + a+ + 0: a + aa+ + 0: a + +/^a+\w/ + az + 0: az + aaaz + 0: aaaz + aa + 0: aa + aaaa + 0: aaaa + aa+ + 0: aa + +/^a+?\w/ + az + 0: az + aaaz + 0: aa + aa + 0: aa + aaaa + 0: aa + aa+ + 0: aa + +/^\d{8}\w{2,}/ + 1234567890 + 0: 1234567890 + 12345678ab + 0: 12345678ab + 12345678__ + 0: 12345678__ + *** Failers +No match + 1234567 +No match + +/^[aeiou\d]{4,5}$/ + uoie + 0: uoie + 1234 + 0: 1234 + 12345 + 0: 12345 + aaaaa + 0: aaaaa + *** Failers +No match + 123456 +No match + +/^[aeiou\d]{4,5}?/ + uoie + 0: uoie + 1234 + 0: 1234 + 12345 + 0: 1234 + aaaaa + 0: aaaa + 123456 + 0: 1234 + +/\A(abc|def)=(\1){2,3}\Z/ + abc=abcabc + 0: abc=abcabc + 1: abc + 2: abc + def=defdefdef + 0: def=defdefdef + 1: def + 2: def + *** Failers +No match + abc=defdef +No match + +/^(a)(b)(c)(d)(e)(f)(g)(h)(i)(j)(k)\11*(\3\4)\1(?#)2$/ + abcdefghijkcda2 + 0: abcdefghijkcda2 + 1: a + 2: b + 3: c + 4: d + 5: e + 6: f + 7: g + 8: h + 9: i +10: j +11: k +12: cd + abcdefghijkkkkcda2 + 0: abcdefghijkkkkcda2 + 1: a + 2: b + 3: c + 4: d + 5: e + 6: f + 7: g + 8: h + 9: i +10: j +11: k +12: cd + +/(cat(a(ract|tonic)|erpillar)) \1()2(3)/ + cataract cataract23 + 0: cataract cataract23 + 1: cataract + 2: aract + 3: ract + 4: + 5: 3 + catatonic catatonic23 + 0: catatonic catatonic23 + 1: catatonic + 2: atonic + 3: tonic + 4: + 5: 3 + caterpillar caterpillar23 + 0: caterpillar caterpillar23 + 1: caterpillar + 2: erpillar + 3: + 4: + 5: 3 + + +/^From +([^ ]+) +[a-zA-Z][a-zA-Z][a-zA-Z] +[a-zA-Z][a-zA-Z][a-zA-Z] +[0-9]?[0-9] +[0-9][0-9]:[0-9][0-9]/ + From abcd Mon Sep 01 12:33:02 1997 + 0: From abcd Mon Sep 01 12:33 + 1: abcd + +/^From\s+\S+\s+([a-zA-Z]{3}\s+){2}\d{1,2}\s+\d\d:\d\d/ + From abcd Mon Sep 01 12:33:02 1997 + 0: From abcd Mon Sep 01 12:33 + 1: Sep + From abcd Mon Sep 1 12:33:02 1997 + 0: From abcd Mon Sep 1 12:33 + 1: Sep + *** Failers +No match + From abcd Sep 01 12:33:02 1997 +No match + +/^12.34/s + 12\n34 + 0: 12\x0a34 + 12\r34 + 0: 12\x0d34 + +/\w+(?=\t)/ + the quick brown\t fox + 0: brown + +/foo(?!bar)(.*)/ + foobar is foolish see? + 0: foolish see? + 1: lish see? + +/(?:(?!foo)...|^.{0,2})bar(.*)/ + foobar crowbar etc + 0: rowbar etc + 1: etc + barrel + 0: barrel + 1: rel + 2barrel + 0: 2barrel + 1: rel + A barrel + 0: A barrel + 1: rel + +/^(\D*)(?=\d)(?!123)/ + abc456 + 0: abc + 1: abc + *** Failers +No match + abc123 +No match + +/^1234(?# test newlines + inside)/ + 1234 + 0: 1234 + +/^1234 #comment in extended re + /x + 1234 + 0: 1234 + +/#rhubarb + abcd/x + abcd + 0: abcd + +/^abcd#rhubarb/x + abcd + 0: abcd + +/^(a)\1{2,3}(.)/ + aaab + 0: aaab + 1: a + 2: b + aaaab + 0: aaaab + 1: a + 2: b + aaaaab + 0: aaaaa + 1: a + 2: a + aaaaaab + 0: aaaaa + 1: a + 2: a + +/(?!^)abc/ + the abc + 0: abc + *** Failers +No match + abc +No match + +/(?=^)abc/ + abc + 0: abc + *** Failers +No match + the abc +No match + +/^[ab]{1,3}(ab*|b)/ + aabbbbb + 0: aabb + 1: b + +/^[ab]{1,3}?(ab*|b)/ + aabbbbb + 0: aabbbbb + 1: abbbbb + +/^[ab]{1,3}?(ab*?|b)/ + aabbbbb + 0: aa + 1: a + +/^[ab]{1,3}(ab*?|b)/ + aabbbbb + 0: aabb + 1: b + +/ (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* # optional leading comment +(?: (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +" (?: # opening quote... +[^\\\x80-\xff\n\015"] # Anything except backslash and quote +| # or +\\ [^\x80-\xff] # Escaped something (something != CR) +)* " # closing quote +) # initial word +(?: (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* \. (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +" (?: # opening quote... +[^\\\x80-\xff\n\015"] # Anything except backslash and quote +| # or +\\ [^\x80-\xff] # Escaped something (something != CR) +)* " # closing quote +) )* # further okay, if led by a period +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* @ (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| \[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) # initial subdomain +(?: # +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* \. # if led by a period... +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| \[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) # ...further okay +)* +# address +| # or +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +" (?: # opening quote... +[^\\\x80-\xff\n\015"] # Anything except backslash and quote +| # or +\\ [^\x80-\xff] # Escaped something (something != CR) +)* " # closing quote +) # one word, optionally followed by.... +(?: +[^()<>@,;:".\\\[\]\x80-\xff\000-\010\012-\037] | # atom and space parts, or... +\( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) | # comments, or... + +" (?: # opening quote... +[^\\\x80-\xff\n\015"] # Anything except backslash and quote +| # or +\\ [^\x80-\xff] # Escaped something (something != CR) +)* " # closing quote +# quoted strings +)* +< (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* # leading < +(?: @ (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| \[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) # initial subdomain +(?: # +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* \. # if led by a period... +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| \[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) # ...further okay +)* + +(?: (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* , (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* @ (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| \[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) # initial subdomain +(?: # +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* \. # if led by a period... +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| \[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) # ...further okay +)* +)* # further okay, if led by comma +: # closing colon +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* )? # optional route +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +" (?: # opening quote... +[^\\\x80-\xff\n\015"] # Anything except backslash and quote +| # or +\\ [^\x80-\xff] # Escaped something (something != CR) +)* " # closing quote +) # initial word +(?: (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* \. (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +" (?: # opening quote... +[^\\\x80-\xff\n\015"] # Anything except backslash and quote +| # or +\\ [^\x80-\xff] # Escaped something (something != CR) +)* " # closing quote +) )* # further okay, if led by a period +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* @ (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| \[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) # initial subdomain +(?: # +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* \. # if led by a period... +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* (?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| \[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) # ...further okay +)* +# address spec +(?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* > # trailing > +# name and address +) (?: [\040\t] | \( +(?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] | \( (?: [^\\\x80-\xff\n\015()] | \\ [^\x80-\xff] )* \) )* +\) )* # optional trailing comment +/x + Alan Other + 0: Alan Other + + 0: user@dom.ain + user\@dom.ain + 0: user@dom.ain + \"A. Other\" (a comment) + 0: "A. Other" (a comment) + A. Other (a comment) + 0: Other (a comment) + \"/s=user/ou=host/o=place/prmd=uu.yy/admd= /c=gb/\"\@x400-re.lay + 0: "/s=user/ou=host/o=place/prmd=uu.yy/admd= /c=gb/"@x400-re.lay + A missing angle @,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +# Atom +| # or +" # " +[^\\\x80-\xff\n\015"] * # normal +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015"] * )* # ( special normal* )* +" # " +# Quoted string +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +\. +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +# Atom +| # or +" # " +[^\\\x80-\xff\n\015"] * # normal +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015"] * )* # ( special normal* )* +" # " +# Quoted string +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# additional words +)* +@ +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +\[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# optional trailing comments +(?: +\. +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +\[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# optional trailing comments +)* +# address +| # or +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +# Atom +| # or +" # " +[^\\\x80-\xff\n\015"] * # normal +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015"] * )* # ( special normal* )* +" # " +# Quoted string +) +# leading word +[^()<>@,;:".\\\[\]\x80-\xff\000-\010\012-\037] * # "normal" atoms and or spaces +(?: +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +| +" # " +[^\\\x80-\xff\n\015"] * # normal +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015"] * )* # ( special normal* )* +" # " +) # "special" comment or quoted string +[^()<>@,;:".\\\[\]\x80-\xff\000-\010\012-\037] * # more "normal" +)* +< +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# < +(?: +@ +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +\[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# optional trailing comments +(?: +\. +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +\[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# optional trailing comments +)* +(?: , +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +@ +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +\[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# optional trailing comments +(?: +\. +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +\[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# optional trailing comments +)* +)* # additional domains +: +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# optional trailing comments +)? # optional route +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +# Atom +| # or +" # " +[^\\\x80-\xff\n\015"] * # normal +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015"] * )* # ( special normal* )* +" # " +# Quoted string +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +\. +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +# Atom +| # or +" # " +[^\\\x80-\xff\n\015"] * # normal +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015"] * )* # ( special normal* )* +" # " +# Quoted string +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# additional words +)* +@ +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +\[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# optional trailing comments +(?: +\. +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +(?: +[^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]+ # some number of atom characters... +(?![^(\040)<>@,;:".\\\[\]\000-\037\x80-\xff]) # ..not followed by something that could be part of an atom +| +\[ # [ +(?: [^\\\x80-\xff\n\015\[\]] | \\ [^\x80-\xff] )* # stuff +\] # ] +) +[\040\t]* # Nab whitespace. +(?: +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: # ( +(?: \\ [^\x80-\xff] | +\( # ( +[^\\\x80-\xff\n\015()] * # normal* +(?: \\ [^\x80-\xff] [^\\\x80-\xff\n\015()] * )* # (special normal*)* +\) # ) +) # special +[^\\\x80-\xff\n\015()] * # normal* +)* # )* +\) # ) +[\040\t]* )* # If comment found, allow more spaces. +# optional trailing comments +)* +# address spec +> # > +# name and address +) +/x + Alan Other + 0: Alan Other + + 0: user@dom.ain + user\@dom.ain + 0: user@dom.ain + \"A. Other\" (a comment) + 0: "A. Other" + A. Other (a comment) + 0: Other + \"/s=user/ou=host/o=place/prmd=uu.yy/admd= /c=gb/\"\@x400-re.lay + 0: "/s=user/ou=host/o=place/prmd=uu.yy/admd= /c=gb/"@x400-re.lay + A missing angle ?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~\x7f\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8a\x8b\x8c\x8d\x8e\x8f\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9a\x9b\x9c\x9d\x9e\x9f\xa0\xa1\xa2\xa3\xa4\xa5\xa6\xa7\xa8\xa9\xaa\xab\xac\xad\xae\xaf\xb0\xb1\xb2\xb3\xb4\xb5\xb6\xb7\xb8\xb9\xba\xbb\xbc\xbd\xbe\xbf\xc0\xc1\xc2\xc3\xc4\xc5\xc6\xc7\xc8\xc9\xca\xcb\xcc\xcd\xce\xcf\xd0\xd1\xd2\xd3\xd4\xd5\xd6\xd7\xd8\xd9\xda\xdb\xdc\xdd\xde\xdf\xe0\xe1\xe2\xe3\xe4\xe5\xe6\xe7\xe8\xe9\xea\xeb\xec\xed\xee\xef\xf0\xf1\xf2\xf3\xf4\xf5\xf6\xf7\xf8\xf9\xfa\xfb\xfc\xfd\xfe\xff + +/P[^*]TAIRE[^*]{1,6}?LL/ + xxxxxxxxxxxPSTAIREISLLxxxxxxxxx + 0: PSTAIREISLL + +/P[^*]TAIRE[^*]{1,}?LL/ + xxxxxxxxxxxPSTAIREISLLxxxxxxxxx + 0: PSTAIREISLL + +/(\.\d\d[1-9]?)\d+/ + 1.230003938 + 0: .230003938 + 1: .23 + 1.875000282 + 0: .875000282 + 1: .875 + 1.235 + 0: .235 + 1: .23 + +/(\.\d\d((?=0)|\d(?=\d)))/ + 1.230003938 + 0: .23 + 1: .23 + 2: + 1.875000282 + 0: .875 + 1: .875 + 2: 5 + *** Failers +No match + 1.235 +No match + +/a(?)b/ + ab + 0: ab + +/\b(foo)\s+(\w+)/i + Food is on the foo table + 0: foo table + 1: foo + 2: table + +/foo(.*)bar/ + The food is under the bar in the barn. + 0: food is under the bar in the bar + 1: d is under the bar in the + +/foo(.*?)bar/ + The food is under the bar in the barn. + 0: food is under the bar + 1: d is under the + +/(.*)(\d*)/ + I have 2 numbers: 53147 + 0: I have 2 numbers: 53147 + 1: I have 2 numbers: 53147 + 2: + +/(.*)(\d+)/ + I have 2 numbers: 53147 + 0: I have 2 numbers: 53147 + 1: I have 2 numbers: 5314 + 2: 7 + +/(.*?)(\d*)/ + I have 2 numbers: 53147 + 0: + 1: + 2: + +/(.*?)(\d+)/ + I have 2 numbers: 53147 + 0: I have 2 + 1: I have + 2: 2 + +/(.*)(\d+)$/ + I have 2 numbers: 53147 + 0: I have 2 numbers: 53147 + 1: I have 2 numbers: 5314 + 2: 7 + +/(.*?)(\d+)$/ + I have 2 numbers: 53147 + 0: I have 2 numbers: 53147 + 1: I have 2 numbers: + 2: 53147 + +/(.*)\b(\d+)$/ + I have 2 numbers: 53147 + 0: I have 2 numbers: 53147 + 1: I have 2 numbers: + 2: 53147 + +/(.*\D)(\d+)$/ + I have 2 numbers: 53147 + 0: I have 2 numbers: 53147 + 1: I have 2 numbers: + 2: 53147 + +/^\D*(?!123)/ + ABC123 + 0: AB + +/^(\D*)(?=\d)(?!123)/ + ABC445 + 0: ABC + 1: ABC + *** Failers +No match + ABC123 +No match + +/^[W-]46]/ + W46]789 + 0: W46] + -46]789 + 0: -46] + *** Failers +No match + Wall +No match + Zebra +No match + 42 +No match + [abcd] +No match + ]abcd[ +No match + +/^[W-\]46]/ + W46]789 + 0: W + Wall + 0: W + Zebra + 0: Z + Xylophone + 0: X + 42 + 0: 4 + [abcd] + 0: [ + ]abcd[ + 0: ] + \\backslash + 0: \ + *** Failers +No match + -46]789 +No match + well +No match + +/\d\d\/\d\d\/\d\d\d\d/ + 01/01/2000 + 0: 01/01/2000 + +/word (?:[a-zA-Z0-9]+ ){0,10}otherword/ + word cat dog elephant mussel cow horse canary baboon snake shark otherword + 0: word cat dog elephant mussel cow horse canary baboon snake shark otherword + word cat dog elephant mussel cow horse canary baboon snake shark +No match + +/word (?:[a-zA-Z0-9]+ ){0,300}otherword/ + word cat dog elephant mussel cow horse canary baboon snake shark the quick brown fox and the lazy dog and several other words getting close to thirty by now I hope +No match + +/^(a){0,0}/ + bcd + 0: + abc + 0: + aab + 0: + +/^(a){0,1}/ + bcd + 0: + abc + 0: a + 1: a + aab + 0: a + 1: a + +/^(a){0,2}/ + bcd + 0: + abc + 0: a + 1: a + aab + 0: aa + 1: a + +/^(a){0,3}/ + bcd + 0: + abc + 0: a + 1: a + aab + 0: aa + 1: a + aaa + 0: aaa + 1: a + +/^(a){0,}/ + bcd + 0: + abc + 0: a + 1: a + aab + 0: aa + 1: a + aaa + 0: aaa + 1: a + aaaaaaaa + 0: aaaaaaaa + 1: a + +/^(a){1,1}/ + bcd +No match + abc + 0: a + 1: a + aab + 0: a + 1: a + +/^(a){1,2}/ + bcd +No match + abc + 0: a + 1: a + aab + 0: aa + 1: a + +/^(a){1,3}/ + bcd +No match + abc + 0: a + 1: a + aab + 0: aa + 1: a + aaa + 0: aaa + 1: a + +/^(a){1,}/ + bcd +No match + abc + 0: a + 1: a + aab + 0: aa + 1: a + aaa + 0: aaa + 1: a + aaaaaaaa + 0: aaaaaaaa + 1: a + +/.*\.gif/ + borfle\nbib.gif\nno + 0: bib.gif + +/.{0,}\.gif/ + borfle\nbib.gif\nno + 0: bib.gif + +/.*\.gif/m + borfle\nbib.gif\nno + 0: bib.gif + +/.*\.gif/s + borfle\nbib.gif\nno + 0: borfle\x0abib.gif + +/.*\.gif/ms + borfle\nbib.gif\nno + 0: borfle\x0abib.gif + +/.*$/ + borfle\nbib.gif\nno + 0: no + +/.*$/m + borfle\nbib.gif\nno + 0: borfle + +/.*$/s + borfle\nbib.gif\nno + 0: borfle\x0abib.gif\x0ano + +/.*$/ms + borfle\nbib.gif\nno + 0: borfle\x0abib.gif\x0ano + +/.*$/ + borfle\nbib.gif\nno\n + 0: no + +/.*$/m + borfle\nbib.gif\nno\n + 0: borfle + +/.*$/s + borfle\nbib.gif\nno\n + 0: borfle\x0abib.gif\x0ano\x0a + +/.*$/ms + borfle\nbib.gif\nno\n + 0: borfle\x0abib.gif\x0ano\x0a + +/(.*X|^B)/ + abcde\n1234Xyz + 0: 1234X + 1: 1234X + BarFoo + 0: B + 1: B + *** Failers +No match + abcde\nBar +No match + +/(.*X|^B)/m + abcde\n1234Xyz + 0: 1234X + 1: 1234X + BarFoo + 0: B + 1: B + abcde\nBar + 0: B + 1: B + +/(.*X|^B)/s + abcde\n1234Xyz + 0: abcde\x0a1234X + 1: abcde\x0a1234X + BarFoo + 0: B + 1: B + *** Failers +No match + abcde\nBar +No match + +/(.*X|^B)/ms + abcde\n1234Xyz + 0: abcde\x0a1234X + 1: abcde\x0a1234X + BarFoo + 0: B + 1: B + abcde\nBar + 0: B + 1: B + +/(?s)(.*X|^B)/ + abcde\n1234Xyz + 0: abcde\x0a1234X + 1: abcde\x0a1234X + BarFoo + 0: B + 1: B + *** Failers +No match + abcde\nBar +No match + +/(?s:.*X|^B)/ + abcde\n1234Xyz + 0: abcde\x0a1234X + BarFoo + 0: B + *** Failers +No match + abcde\nBar +No match + +/^.*B/ + **** Failers +No match + abc\nB +No match + +/(?s)^.*B/ + abc\nB + 0: abc\x0aB + +/(?m)^.*B/ + abc\nB + 0: B + +/(?ms)^.*B/ + abc\nB + 0: abc\x0aB + +/(?ms)^B/ + abc\nB + 0: B + +/(?s)B$/ + B\n + 0: B + +/^[0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9][0-9]/ + 123456654321 + 0: 123456654321 + +/^\d\d\d\d\d\d\d\d\d\d\d\d/ + 123456654321 + 0: 123456654321 + +/^[\d][\d][\d][\d][\d][\d][\d][\d][\d][\d][\d][\d]/ + 123456654321 + 0: 123456654321 + +/^[abc]{12}/ + abcabcabcabc + 0: abcabcabcabc + +/^[a-c]{12}/ + abcabcabcabc + 0: abcabcabcabc + +/^(a|b|c){12}/ + abcabcabcabc + 0: abcabcabcabc + 1: c + +/^[abcdefghijklmnopqrstuvwxy0123456789]/ + n + 0: n + *** Failers +No match + z +No match + +/abcde{0,0}/ + abcd + 0: abcd + *** Failers +No match + abce +No match + +/ab[cd]{0,0}e/ + abe + 0: abe + *** Failers +No match + abcde +No match + +/ab(c){0,0}d/ + abd + 0: abd + *** Failers +No match + abcd +No match + +/a(b*)/ + a + 0: a + 1: + ab + 0: ab + 1: b + abbbb + 0: abbbb + 1: bbbb + *** Failers + 0: a + 1: + bbbbb +No match + +/ab\d{0}e/ + abe + 0: abe + *** Failers +No match + ab1e +No match + +/"([^\\"]+|\\.)*"/ + the \"quick\" brown fox + 0: "quick" + 1: quick + \"the \\\"quick\\\" brown fox\" + 0: "the \"quick\" brown fox" + 1: brown fox + +/.*?/g+ + abc + 0: + 0+ abc + 0: a + 0+ bc + 0: + 0+ bc + 0: b + 0+ c + 0: + 0+ c + 0: c + 0+ + 0: + 0+ + +/\b/g+ + abc + 0: + 0+ abc + 0: + 0+ + +/\b/+g + abc + 0: + 0+ abc + 0: + 0+ + +//g + abc + 0: + 0: + 0: + 0: + +/ End of test input / + diff --git a/ext/pcre/pcrelib/testdata/testoutput2 b/ext/pcre/pcrelib/testdata/testoutput2 new file mode 100644 index 0000000000..d0fc036f0f --- /dev/null +++ b/ext/pcre/pcrelib/testdata/testoutput2 @@ -0,0 +1,2072 @@ +PCRE version 3.1 09-Feb-2000 + +/(a)b|/ +Capturing subpattern count = 1 +No options +No first char +No need char + +/abc/ +Capturing subpattern count = 0 +No options +First char = 'a' +Need char = 'c' + abc + 0: abc + defabc + 0: abc + \Aabc + 0: abc + *** Failers +No match + \Adefabc +No match + ABC +No match + +/^abc/ +Capturing subpattern count = 0 +Options: anchored +No first char +Need char = 'c' + abc + 0: abc + \Aabc + 0: abc + *** Failers +No match + defabc +No match + \Adefabc +No match + +/a+bc/ +Capturing subpattern count = 0 +No options +First char = 'a' +Need char = 'c' + +/a*bc/ +Capturing subpattern count = 0 +No options +No first char +Need char = 'c' + +/a{3}bc/ +Capturing subpattern count = 0 +No options +First char = 'a' +Need char = 'c' + +/(abc|a+z)/ +Capturing subpattern count = 1 +No options +First char = 'a' +No need char + +/^abc$/ +Capturing subpattern count = 0 +Options: anchored +No first char +Need char = 'c' + abc + 0: abc + *** Failers +No match + def\nabc +No match + +/ab\gdef/X +Failed: unrecognized character follows \ at offset 3 + +/(?X)ab\gdef/X +Failed: unrecognized character follows \ at offset 7 + +/x{5,4}/ +Failed: numbers out of order in {} quantifier at offset 5 + +/z{65536}/ +Failed: number too big in {} quantifier at offset 7 + +/[abcd/ +Failed: missing terminating ] for character class at offset 5 + +/[\B]/ +Failed: invalid escape sequence in character class at offset 2 + +/[a-\w]/ +Failed: invalid escape sequence in character class at offset 4 + +/[z-a]/ +Failed: range out of order in character class at offset 3 + +/^*/ +Failed: nothing to repeat at offset 1 + +/(abc/ +Failed: missing ) at offset 4 + +/(?# abc/ +Failed: missing ) after comment at offset 7 + +/(?z)abc/ +Failed: unrecognized character after (? at offset 2 + +/.*b/ +Capturing subpattern count = 0 +No options +First char at start or follows \n +Need char = 'b' + +/.*?b/ +Capturing subpattern count = 0 +No options +First char at start or follows \n +Need char = 'b' + +/cat|dog|elephant/ +Capturing subpattern count = 0 +No options +No first char +No need char + this sentence eventually mentions a cat + 0: cat + this sentences rambles on and on for a while and then reaches elephant + 0: elephant + +/cat|dog|elephant/S +Capturing subpattern count = 0 +No options +No first char +No need char +Starting character set: c d e + this sentence eventually mentions a cat + 0: cat + this sentences rambles on and on for a while and then reaches elephant + 0: elephant + +/cat|dog|elephant/iS +Capturing subpattern count = 0 +Options: caseless +No first char +No need char +Starting character set: C D E c d e + this sentence eventually mentions a CAT cat + 0: CAT + this sentences rambles on and on for a while to elephant ElePhant + 0: elephant + +/a|[bcd]/S +Capturing subpattern count = 0 +No options +No first char +No need char +Starting character set: a b c d + +/(a|[^\dZ])/S +Capturing subpattern count = 1 +No options +No first char +No need char +Starting character set: \x00 \x01 \x02 \x03 \x04 \x05 \x06 \x07 \x08 \x09 \x0a + \x0b \x0c \x0d \x0e \x0f \x10 \x11 \x12 \x13 \x14 \x15 \x16 \x17 \x18 \x19 + \x1a \x1b \x1c \x1d \x1e \x1f \x20 ! " # $ % & ' ( ) * + , - . / : ; < = > + ? @ A B C D E F G H I J K L M N O P Q R S T U V W X Y [ \ ] ^ _ ` a b c d + e f g h i j k l m n o p q r s t u v w x y z { | } ~ \x7f \x80 \x81 \x82 \x83 + \x84 \x85 \x86 \x87 \x88 \x89 \x8a \x8b \x8c \x8d \x8e \x8f \x90 \x91 \x92 + \x93 \x94 \x95 \x96 \x97 \x98 \x99 \x9a \x9b \x9c \x9d \x9e \x9f \xa0 \xa1 + \xa2 \xa3 \xa4 \xa5 \xa6 \xa7 \xa8 \xa9 \xaa \xab \xac \xad \xae \xaf \xb0 + \xb1 \xb2 \xb3 \xb4 \xb5 \xb6 \xb7 \xb8 \xb9 \xba \xbb \xbc \xbd \xbe \xbf + \xc0 \xc1 \xc2 \xc3 \xc4 \xc5 \xc6 \xc7 \xc8 \xc9 \xca \xcb \xcc \xcd \xce + \xcf \xd0 \xd1 \xd2 \xd3 \xd4 \xd5 \xd6 \xd7 \xd8 \xd9 \xda \xdb \xdc \xdd + \xde \xdf \xe0 \xe1 \xe2 \xe3 \xe4 \xe5 \xe6 \xe7 \xe8 \xe9 \xea \xeb \xec + \xed \xee \xef \xf0 \xf1 \xf2 \xf3 \xf4 \xf5 \xf6 \xf7 \xf8 \xf9 \xfa \xfb + \xfc \xfd \xfe \xff + +/(a|b)*[\s]/S +Capturing subpattern count = 1 +No options +No first char +No need char +Starting character set: \x09 \x0a \x0b \x0c \x0d \x20 a b + +/(ab\2)/ +Failed: back reference to non-existent subpattern at offset 6 + +/{4,5}abc/ +Failed: nothing to repeat at offset 4 + +/(a)(b)(c)\2/ +Capturing subpattern count = 3 +Max back reference = 2 +No options +First char = 'a' +Need char = 'c' + abcb + 0: abcb + 1: a + 2: b + 3: c + \O0abcb +Matched, but too many substrings + \O3abcb +Matched, but too many substrings + 0: abcb + \O6abcb +Matched, but too many substrings + 0: abcb + 1: a + \O9abcb +Matched, but too many substrings + 0: abcb + 1: a + 2: b + \O12abcb + 0: abcb + 1: a + 2: b + 3: c + +/(a)bc|(a)(b)\2/ +Capturing subpattern count = 3 +Max back reference = 2 +No options +First char = 'a' +No need char + abc + 0: abc + 1: a + \O0abc +Matched, but too many substrings + \O3abc +Matched, but too many substrings + 0: abc + \O6abc + 0: abc + 1: a + aba + 0: aba + 1: + 2: a + 3: b + \O0aba +Matched, but too many substrings + \O3aba +Matched, but too many substrings + 0: aba + \O6aba +Matched, but too many substrings + 0: aba + 1: + \O9aba +Matched, but too many substrings + 0: aba + 1: + 2: a + \O12aba + 0: aba + 1: + 2: a + 3: b + +/abc$/E +Capturing subpattern count = 0 +Options: dollar_endonly +First char = 'a' +Need char = 'c' + abc + 0: abc + *** Failers +No match + abc\n +No match + abc\ndef +No match + +/(a)(b)(c)(d)(e)\6/ +Failed: back reference to non-existent subpattern at offset 17 + +/the quick brown fox/ +Capturing subpattern count = 0 +No options +First char = 't' +Need char = 'x' + the quick brown fox + 0: the quick brown fox + this is a line with the quick brown fox + 0: the quick brown fox + +/the quick brown fox/A +Capturing subpattern count = 0 +Options: anchored +No first char +Need char = 'x' + the quick brown fox + 0: the quick brown fox + *** Failers +No match + this is a line with the quick brown fox +No match + +/ab(?z)cd/ +Failed: unrecognized character after (? at offset 4 + +/^abc|def/ +Capturing subpattern count = 0 +No options +No first char +No need char + abcdef + 0: abc + abcdef\B + 0: def + +/.*((abc)$|(def))/ +Capturing subpattern count = 3 +No options +First char at start or follows \n +No need char + defabc + 0: defabc + 1: abc + 2: abc + \Zdefabc + 0: def + 1: def + 2: + 3: def + +/abc/P + abc + 0: abc + *** Failers +No match: POSIX code 17: match failed + +/^abc|def/P + abcdef + 0: abc + abcdef\B + 0: def + +/.*((abc)$|(def))/P + defabc + 0: defabc + 1: abc + 2: abc + \Zdefabc + 0: def + 1: def + 3: def + +/the quick brown fox/P + the quick brown fox + 0: the quick brown fox + *** Failers +No match: POSIX code 17: match failed + The Quick Brown Fox +No match: POSIX code 17: match failed + +/the quick brown fox/Pi + the quick brown fox + 0: the quick brown fox + The Quick Brown Fox + 0: The Quick Brown Fox + +/abc.def/P + *** Failers +No match: POSIX code 17: match failed + abc\ndef +No match: POSIX code 17: match failed + +/abc$/P + abc + 0: abc + abc\n + 0: abc + +/(abc)\2/P +Failed: POSIX code 15: bad back reference at offset 7 + +/(abc\1)/P + abc +No match: POSIX code 17: match failed + +/)/ +Failed: unmatched parentheses at offset 0 + +/a[]b/ +Failed: missing terminating ] for character class at offset 4 + +/[^aeiou ]{3,}/ +Capturing subpattern count = 0 +No options +No first char +No need char + co-processors, and for + 0: -pr + +/<.*>/ +Capturing subpattern count = 0 +No options +First char = '<' +Need char = '>' + abcghinop + 0: ghi + +/<.*?>/ +Capturing subpattern count = 0 +No options +First char = '<' +Need char = '>' + abcghinop + 0: + +/<.*>/U +Capturing subpattern count = 0 +Options: ungreedy +First char = '<' +Need char = '>' + abcghinop + 0: + +/<.*>(?U)/ +Capturing subpattern count = 0 +Options: ungreedy +First char = '<' +Need char = '>' + abcghinop + 0: + +/<.*?>/U +Capturing subpattern count = 0 +Options: ungreedy +First char = '<' +Need char = '>' + abcghinop + 0: ghi + +/={3,}/U +Capturing subpattern count = 0 +Options: ungreedy +First char = '=' +Need char = '=' + abc========def + 0: === + +/(?U)={3,}?/ +Capturing subpattern count = 0 +Options: ungreedy +First char = '=' +Need char = '=' + abc========def + 0: ======== + +/(?^abc)/m +Capturing subpattern count = 0 +Options: multiline +First char at start or follows \n +Need char = 'c' + abc + 0: abc + def\nabc + 0: abc + *** Failers +No match + defabc +No match + +/(?<=ab(c+)d)ef/ +Failed: lookbehind assertion is not fixed length at offset 11 + +/(?<=ab(?<=c+)d)ef/ +Failed: lookbehind assertion is not fixed length at offset 12 + +/(?<=ab(c|de)f)g/ +Failed: lookbehind assertion is not fixed length at offset 13 + +/The next three are in testinput2 because they have variable length branches/ +Capturing subpattern count = 0 +No options +First char = 'T' +Need char = 's' + +/(?<=bullock|donkey)-cart/ +Capturing subpattern count = 0 +No options +First char = '-' +Need char = 't' + the bullock-cart + 0: -cart + a donkey-cart race + 0: -cart + *** Failers +No match + cart +No match + horse-and-cart +No match + +/(?<=ab(?i)x|y|z)/ +Capturing subpattern count = 0 +No options +Case state changes +No first char +No need char + +/(?>.*)(?<=(abcd)|(xyz))/ +Capturing subpattern count = 2 +No options +First char at start or follows \n +No need char + alphabetabcd + 0: alphabetabcd + 1: abcd + endingxyz + 0: endingxyz + 1: + 2: xyz + +/(?<=ab(?i)x(?-i)y|(?i)z|b)ZZ/ +Capturing subpattern count = 0 +No options +Case state changes +First char = 'Z' +Need char = 'Z' + abxyZZ + 0: ZZ + abXyZZ + 0: ZZ + ZZZ + 0: ZZ + zZZ + 0: ZZ + bZZ + 0: ZZ + BZZ + 0: ZZ + *** Failers +No match + ZZ +No match + abXYZZ +No match + zzz +No match + bzz +No match + +/(? + 3: f + 1G a (1) + 2G (0) + 3G f (1) +get substring 4 failed -7 + 0L adef + 1L a + 2L + 3L f + bcdef\G1\G2\G3\G4\L + 0: bcdef + 1: bc + 2: bc + 3: f + 1G bc (2) + 2G bc (2) + 3G f (1) +get substring 4 failed -7 + 0L bcdef + 1L bc + 2L bc + 3L f + adefghijk\C0 + 0: adef + 1: a + 2: + 3: f + 0C adef (4) + +/^abc\00def/ +Capturing subpattern count = 0 +Options: anchored +No first char +Need char = 'f' + abc\00def\L\C0 + 0: abc\x00def + 0C abc (7) + 0L abc + +/word ((?:[a-zA-Z0-9]+ )((?:[a-zA-Z0-9]+ )((?:[a-zA-Z0-9]+ )((?:[a-zA-Z0-9]+ +)((?:[a-zA-Z0-9]+ )((?:[a-zA-Z0-9]+ )((?:[a-zA-Z0-9]+ )((?:[a-zA-Z0-9]+ +)?)?)?)?)?)?)?)?)?otherword/M +Memory allocation (code space): 428 +Capturing subpattern count = 8 +No options +First char = 'w' +Need char = 'd' + +/.*X/D +------------------------------------------------------------------ + 0 8 Bra 0 + 3 Any* + 5 1 X + 8 8 Ket + 11 End +------------------------------------------------------------------ +Capturing subpattern count = 0 +No options +First char at start or follows \n +Need char = 'X' + +/.*X/Ds +------------------------------------------------------------------ + 0 8 Bra 0 + 3 Any* + 5 1 X + 8 8 Ket + 11 End +------------------------------------------------------------------ +Capturing subpattern count = 0 +Options: anchored dotall +No first char +Need char = 'X' + +/(.*X|^B)/D +------------------------------------------------------------------ + 0 21 Bra 0 + 3 8 Bra 1 + 6 Any* + 8 1 X + 11 7 Alt + 14 ^ + 15 1 B + 18 15 Ket + 21 21 Ket + 24 End +------------------------------------------------------------------ +Capturing subpattern count = 1 +No options +First char at start or follows \n +No need char + +/(.*X|^B)/Ds +------------------------------------------------------------------ + 0 21 Bra 0 + 3 8 Bra 1 + 6 Any* + 8 1 X + 11 7 Alt + 14 ^ + 15 1 B + 18 15 Ket + 21 21 Ket + 24 End +------------------------------------------------------------------ +Capturing subpattern count = 1 +Options: anchored dotall +No first char +No need char + +/(?s)(.*X|^B)/D +------------------------------------------------------------------ + 0 21 Bra 0 + 3 8 Bra 1 + 6 Any* + 8 1 X + 11 7 Alt + 14 ^ + 15 1 B + 18 15 Ket + 21 21 Ket + 24 End +------------------------------------------------------------------ +Capturing subpattern count = 1 +Options: anchored dotall +No first char +No need char + +/(?s:.*X|^B)/D +------------------------------------------------------------------ + 0 27 Bra 0 + 3 10 Bra 0 + 6 04 Opt + 8 Any* + 10 1 X + 13 9 Alt + 16 04 Opt + 18 ^ + 19 1 B + 22 19 Ket + 25 00 Opt + 27 27 Ket + 30 End +------------------------------------------------------------------ +Capturing subpattern count = 0 +No options +First char at start or follows \n +No need char + +/\Biss\B/+ +Capturing subpattern count = 0 +No options +First char = 'i' +Need char = 's' + Mississippi + 0: iss + 0+ issippi + +/\Biss\B/+P + Mississippi + 0: iss + 0+ issippi + +/iss/G+ +Capturing subpattern count = 0 +No options +First char = 'i' +Need char = 's' + Mississippi + 0: iss + 0+ issippi + 0: iss + 0+ ippi + +/\Biss\B/G+ +Capturing subpattern count = 0 +No options +First char = 'i' +Need char = 's' + Mississippi + 0: iss + 0+ issippi + +/\Biss\B/g+ +Capturing subpattern count = 0 +No options +First char = 'i' +Need char = 's' + Mississippi + 0: iss + 0+ issippi + 0: iss + 0+ ippi + *** Failers +No match + Mississippi\A +No match + +/(?<=[Ms])iss/g+ +Capturing subpattern count = 0 +No options +First char = 'i' +Need char = 's' + Mississippi + 0: iss + 0+ issippi + 0: iss + 0+ ippi + +/(?<=[Ms])iss/G+ +Capturing subpattern count = 0 +No options +First char = 'i' +Need char = 's' + Mississippi + 0: iss + 0+ issippi + +/^iss/g+ +Capturing subpattern count = 0 +Options: anchored +No first char +Need char = 's' + ississippi + 0: iss + 0+ issippi + +/.*iss/g+ +Capturing subpattern count = 0 +No options +First char at start or follows \n +Need char = 's' + abciss\nxyzisspqr + 0: abciss + 0+ \x0axyzisspqr + 0: xyziss + 0+ pqr + +/.i./+g +Capturing subpattern count = 0 +No options +No first char +Need char = 'i' + Mississippi + 0: Mis + 0+ sissippi + 0: sis + 0+ sippi + 0: sip + 0+ pi + Mississippi\A + 0: Mis + 0+ sissippi + 0: sis + 0+ sippi + 0: sip + 0+ pi + Missouri river + 0: Mis + 0+ souri river + 0: ri + 0+ river + 0: riv + 0+ er + Missouri river\A + 0: Mis + 0+ souri river + +/^.is/+g +Capturing subpattern count = 0 +Options: anchored +No first char +Need char = 's' + Mississippi + 0: Mis + 0+ sissippi + +/^ab\n/g+ +Capturing subpattern count = 0 +Options: anchored +No first char +Need char = 10 + ab\nab\ncd + 0: ab\x0a + 0+ ab\x0acd + +/^ab\n/mg+ +Capturing subpattern count = 0 +Options: multiline +First char at start or follows \n +Need char = 10 + ab\nab\ncd + 0: ab\x0a + 0+ ab\x0acd + 0: ab\x0a + 0+ cd + +/abc/ +Capturing subpattern count = 0 +No options +First char = 'a' +Need char = 'c' + +/abc|bac/ +Capturing subpattern count = 0 +No options +No first char +Need char = 'c' + +/(abc|bac)/ +Capturing subpattern count = 1 +No options +No first char +Need char = 'c' + +/(abc|(c|dc))/ +Capturing subpattern count = 2 +No options +No first char +Need char = 'c' + +/(abc|(d|de)c)/ +Capturing subpattern count = 2 +No options +No first char +Need char = 'c' + +/a*/ +Capturing subpattern count = 0 +No options +No first char +No need char + +/a+/ +Capturing subpattern count = 0 +No options +First char = 'a' +No need char + +/(baa|a+)/ +Capturing subpattern count = 1 +No options +No first char +Need char = 'a' + +/a{0,3}/ +Capturing subpattern count = 0 +No options +No first char +No need char + +/baa{3,}/ +Capturing subpattern count = 0 +No options +First char = 'b' +Need char = 'a' + +/"([^\\"]+|\\.)*"/ +Capturing subpattern count = 1 +No options +First char = '"' +Need char = '"' + +/(abc|ab[cd])/ +Capturing subpattern count = 1 +No options +First char = 'a' +No need char + +/(a|.)/ +Capturing subpattern count = 1 +No options +No first char +No need char + +/a|ba|\w/ +Capturing subpattern count = 0 +No options +No first char +No need char + +/abc(?=pqr)/ +Capturing subpattern count = 0 +No options +First char = 'a' +Need char = 'r' + +/...(?<=abc)/ +Capturing subpattern count = 0 +No options +No first char +No need char + +/abc(?!pqr)/ +Capturing subpattern count = 0 +No options +First char = 'a' +Need char = 'c' + +/ab./ +Capturing subpattern count = 0 +No options +First char = 'a' +Need char = 'b' + +/ab[xyz]/ +Capturing subpattern count = 0 +No options +First char = 'a' +Need char = 'b' + +/abc*/ +Capturing subpattern count = 0 +No options +First char = 'a' +Need char = 'b' + +/ab.c*/ +Capturing subpattern count = 0 +No options +First char = 'a' +Need char = 'b' + +/a.c*/ +Capturing subpattern count = 0 +No options +First char = 'a' +No need char + +/.c*/ +Capturing subpattern count = 0 +No options +No first char +No need char + +/ac*/ +Capturing subpattern count = 0 +No options +First char = 'a' +No need char + +/(a.c*|b.c*)/ +Capturing subpattern count = 1 +No options +No first char +No need char + +/a.c*|aba/ +Capturing subpattern count = 0 +No options +First char = 'a' +No need char + +/.+a/ +Capturing subpattern count = 0 +No options +No first char +Need char = 'a' + +/(?=abcda)a.*/ +Capturing subpattern count = 0 +No options +First char = 'a' +No need char + +/(?=a)a.*/ +Capturing subpattern count = 0 +No options +First char = 'a' +No need char + +/a(b)*/ +Capturing subpattern count = 1 +No options +First char = 'a' +No need char + +/a\d*/ +Capturing subpattern count = 0 +No options +First char = 'a' +No need char + +/ab\d*/ +Capturing subpattern count = 0 +No options +First char = 'a' +Need char = 'b' + +/a(\d)*/ +Capturing subpattern count = 1 +No options +First char = 'a' +No need char + +/abcde{0,0}/ +Capturing subpattern count = 0 +No options +First char = 'a' +Need char = 'd' + +/ab\d+/ +Capturing subpattern count = 0 +No options +First char = 'a' +Need char = 'b' + +/a(?(1)b)/ +Capturing subpattern count = 0 +No options +First char = 'a' +No need char + +/a(?(1)bag|big)/ +Capturing subpattern count = 0 +No options +First char = 'a' +Need char = 'g' + +/a(?(1)bag|big)*/ +Capturing subpattern count = 0 +No options +First char = 'a' +No need char + +/a(?(1)bag|big)+/ +Capturing subpattern count = 0 +No options +First char = 'a' +Need char = 'g' + +/a(?(1)b..|b..)/ +Capturing subpattern count = 0 +No options +First char = 'a' +Need char = 'b' + +/ab\d{0}e/ +Capturing subpattern count = 0 +No options +First char = 'a' +Need char = 'e' + +/a?b?/ +Capturing subpattern count = 0 +No options +No first char +No need char + a + 0: a + b + 0: b + ab + 0: ab + \ + 0: + *** Failers + 0: + \N +No match + +/|-/ +Capturing subpattern count = 0 +No options +No first char +No need char + abcd + 0: + -abc + 0: + \Nab-c + 0: - + *** Failers + 0: + \Nabc +No match + +/a*(b+)(z)(z)/P + aaaabbbbzzzz + 0: aaaabbbbzz + 1: bbbb + 2: z + 3: z + aaaabbbbzzzz\O0 + aaaabbbbzzzz\O1 + 0: aaaabbbbzz + aaaabbbbzzzz\O2 + 0: aaaabbbbzz + 1: bbbb + aaaabbbbzzzz\O3 + 0: aaaabbbbzz + 1: bbbb + 2: z + aaaabbbbzzzz\O4 + 0: aaaabbbbzz + 1: bbbb + 2: z + 3: z + aaaabbbbzzzz\O5 + 0: aaaabbbbzz + 1: bbbb + 2: z + 3: z + +/^.?abcd/S +Capturing subpattern count = 0 +Options: anchored +No first char +Need char = 'd' +Study returned NULL + +/\( # ( at start + (?: # Non-capturing bracket + (?>[^()]+) # Either a sequence of non-brackets (no backtracking) + | # Or + (?R) # Recurse - i.e. nested bracketed string + )* # Zero or more contents + \) # Closing ) + /x +Capturing subpattern count = 0 +Options: extended +First char = '(' +Need char = ')' + (abcd) + 0: (abcd) + (abcd)xyz + 0: (abcd) + xyz(abcd) + 0: (abcd) + (ab(xy)cd)pqr + 0: (ab(xy)cd) + (ab(xycd)pqr + 0: (xycd) + () abc () + 0: () + 12(abcde(fsh)xyz(foo(bar))lmno)89 + 0: (abcde(fsh)xyz(foo(bar))lmno) + *** Failers +No match + abcd +No match + abcd) +No match + (abcd +No match + +/\( ( (?>[^()]+) | (?R) )* \) /xg +Capturing subpattern count = 1 +Options: extended +First char = '(' +Need char = ')' + (ab(xy)cd)pqr + 0: (ab(xy)cd) + 1: cd + 1(abcd)(x(y)z)pqr + 0: (abcd) + 1: abcd + 0: (x(y)z) + 1: z + +/\( (?: (?>[^()]+) | (?R) ) \) /x +Capturing subpattern count = 0 +Options: extended +First char = '(' +Need char = ')' + (abcd) + 0: (abcd) + (ab(xy)cd) + 0: (xy) + (a(b(c)d)e) + 0: (c) + ((ab)) + 0: ((ab)) + *** Failers +No match + () +No match + +/\( (?: (?>[^()]+) | (?R) )? \) /x +Capturing subpattern count = 0 +Options: extended +First char = '(' +Need char = ')' + () + 0: () + 12(abcde(fsh)xyz(foo(bar))lmno)89 + 0: (fsh) + +/\( ( (?>[^()]+) | (?R) )* \) /x +Capturing subpattern count = 1 +Options: extended +First char = '(' +Need char = ')' + (ab(xy)cd) + 0: (ab(xy)cd) + 1: cd + +/\( ( ( (?>[^()]+) | (?R) )* ) \) /x +Capturing subpattern count = 2 +Options: extended +First char = '(' +Need char = ')' + (ab(xy)cd) + 0: (ab(xy)cd) + 1: ab(xy)cd + 2: cd + +/\( (123)? ( ( (?>[^()]+) | (?R) )* ) \) /x +Capturing subpattern count = 3 +Options: extended +First char = '(' +Need char = ')' + (ab(xy)cd) + 0: (ab(xy)cd) + 1: + 2: ab(xy)cd + 3: cd + (123ab(xy)cd) + 0: (123ab(xy)cd) + 1: 123 + 2: ab(xy)cd + 3: cd + +/\( ( (123)? ( (?>[^()]+) | (?R) )* ) \) /x +Capturing subpattern count = 3 +Options: extended +First char = '(' +Need char = ')' + (ab(xy)cd) + 0: (ab(xy)cd) + 1: ab(xy)cd + 2: + 3: cd + (123ab(xy)cd) + 0: (123ab(xy)cd) + 1: 123ab(xy)cd + 2: 123 + 3: cd + +/\( (((((((((( ( (?>[^()]+) | (?R) )* )))))))))) \) /x +Capturing subpattern count = 11 +Options: extended +First char = '(' +Need char = ')' + (ab(xy)cd) + 0: (ab(xy)cd) + 1: ab(xy)cd + 2: ab(xy)cd + 3: ab(xy)cd + 4: ab(xy)cd + 5: ab(xy)cd + 6: ab(xy)cd + 7: ab(xy)cd + 8: ab(xy)cd + 9: ab(xy)cd +10: ab(xy)cd +11: cd + +/\( ( ( (?>[^()<>]+) | ((?>[^()]+)) | (?R) )* ) \) /x +Capturing subpattern count = 3 +Options: extended +First char = '(' +Need char = ')' + (abcd(xyz

    qrs)123) + 0: (abcd(xyz

    qrs)123) + 1: abcd(xyz

    qrs)123 + 2: 123 + 3:

    qrs + +/\( ( ( (?>[^()]+) | ((?R)) )* ) \) /x +Capturing subpattern count = 3 +Options: extended +First char = '(' +Need char = ')' + (ab(cd)ef) + 0: (ab(cd)ef) + 1: ab(cd)ef + 2: ef + 3: (cd) + (ab(cd(ef)gh)ij) + 0: (ab(cd(ef)gh)ij) + 1: ab(cd(ef)gh)ij + 2: ij + 3: (cd(ef)gh) + +/^[[:alnum:]]/D +------------------------------------------------------------------ + 0 37 Bra 0 + 3 ^ + 4 [0-9A-Za-z] + 37 37 Ket + 40 End +------------------------------------------------------------------ +Capturing subpattern count = 0 +Options: anchored +No first char +No need char + +/^[[:alpha:]]/D +------------------------------------------------------------------ + 0 37 Bra 0 + 3 ^ + 4 [A-Za-z] + 37 37 Ket + 40 End +------------------------------------------------------------------ +Capturing subpattern count = 0 +Options: anchored +No first char +No need char + +/^[[:ascii:]]/D +------------------------------------------------------------------ + 0 37 Bra 0 + 3 ^ + 4 [\x00-\x7f] + 37 37 Ket + 40 End +------------------------------------------------------------------ +Capturing subpattern count = 0 +Options: anchored +No first char +No need char + +/^[[:cntrl:]]/D +------------------------------------------------------------------ + 0 37 Bra 0 + 3 ^ + 4 [\x00-\x1f\x7f] + 37 37 Ket + 40 End +------------------------------------------------------------------ +Capturing subpattern count = 0 +Options: anchored +No first char +No need char + +/^[[:digit:]]/D +------------------------------------------------------------------ + 0 37 Bra 0 + 3 ^ + 4 [0-9] + 37 37 Ket + 40 End +------------------------------------------------------------------ +Capturing subpattern count = 0 +Options: anchored +No first char +No need char + +/^[[:graph:]]/D +------------------------------------------------------------------ + 0 37 Bra 0 + 3 ^ + 4 [!-~] + 37 37 Ket + 40 End +------------------------------------------------------------------ +Capturing subpattern count = 0 +Options: anchored +No first char +No need char + +/^[[:lower:]]/D +------------------------------------------------------------------ + 0 37 Bra 0 + 3 ^ + 4 [a-z] + 37 37 Ket + 40 End +------------------------------------------------------------------ +Capturing subpattern count = 0 +Options: anchored +No first char +No need char + +/^[[:print:]]/D +------------------------------------------------------------------ + 0 37 Bra 0 + 3 ^ + 4 [ -~] + 37 37 Ket + 40 End +------------------------------------------------------------------ +Capturing subpattern count = 0 +Options: anchored +No first char +No need char + +/^[[:punct:]]/D +------------------------------------------------------------------ + 0 37 Bra 0 + 3 ^ + 4 [!-/:-@[-`{-~] + 37 37 Ket + 40 End +------------------------------------------------------------------ +Capturing subpattern count = 0 +Options: anchored +No first char +No need char + +/^[[:space:]]/D +------------------------------------------------------------------ + 0 37 Bra 0 + 3 ^ + 4 [\x09-\x0d ] + 37 37 Ket + 40 End +------------------------------------------------------------------ +Capturing subpattern count = 0 +Options: anchored +No first char +No need char + +/^[[:upper:]]/D +------------------------------------------------------------------ + 0 37 Bra 0 + 3 ^ + 4 [A-Z] + 37 37 Ket + 40 End +------------------------------------------------------------------ +Capturing subpattern count = 0 +Options: anchored +No first char +No need char + +/^[[:xdigit:]]/D +------------------------------------------------------------------ + 0 37 Bra 0 + 3 ^ + 4 [0-9A-Fa-f] + 37 37 Ket + 40 End +------------------------------------------------------------------ +Capturing subpattern count = 0 +Options: anchored +No first char +No need char + +/^[[:word:]]/D +------------------------------------------------------------------ + 0 37 Bra 0 + 3 ^ + 4 [0-9A-Z_a-z] + 37 37 Ket + 40 End +------------------------------------------------------------------ +Capturing subpattern count = 0 +Options: anchored +No first char +No need char + +/^[[:^cntrl:]]/D +------------------------------------------------------------------ + 0 37 Bra 0 + 3 ^ + 4 [ -~\x80-\xff] + 37 37 Ket + 40 End +------------------------------------------------------------------ +Capturing subpattern count = 0 +Options: anchored +No first char +No need char + +/^[12[:^digit:]]/D +------------------------------------------------------------------ + 0 37 Bra 0 + 3 ^ + 4 [\x00-/1-2:-\xff] + 37 37 Ket + 40 End +------------------------------------------------------------------ +Capturing subpattern count = 0 +Options: anchored +No first char +No need char + +/[01[:alpha:]%]/D +------------------------------------------------------------------ + 0 36 Bra 0 + 3 [%0-1A-Za-z] + 36 36 Ket + 39 End +------------------------------------------------------------------ +Capturing subpattern count = 0 +No options +No first char +No need char + +/[[.ch.]]/ +Failed: POSIX collating elements are not supported at offset 1 + +/[[=ch=]]/ +Failed: POSIX collating elements are not supported at offset 1 + +/[[:rhubarb:]]/ +Failed: unknown POSIX class name at offset 3 + +/[[:upper:]]/i +Capturing subpattern count = 0 +Options: caseless +No first char +No need char + A + 0: A + a + 0: a + +/[[:lower:]]/i +Capturing subpattern count = 0 +Options: caseless +No first char +No need char + A + 0: A + a + 0: a + +/((?-i)[[:lower:]])[[:lower:]]/i +Capturing subpattern count = 1 +Options: caseless +Case state changes +No first char +No need char + ab + 0: ab + 1: a + aB + 0: aB + 1: a + *** Failers + 0: ai + 1: a + Ab +No match + AB +No match + +/ End of test input / +Capturing subpattern count = 0 +No options +First char = ' ' +Need char = ' ' + diff --git a/ext/pcre/pcrelib/testdata/testoutput3 b/ext/pcre/pcrelib/testdata/testoutput3 new file mode 100644 index 0000000000..8eb215eb59 --- /dev/null +++ b/ext/pcre/pcrelib/testdata/testoutput3 @@ -0,0 +1,2929 @@ +PCRE version 3.1 09-Feb-2000 + +/(?.*/)foo" + /this/is/a/very/long/line/in/deed/with/very/many/slashes/in/it/you/see/ +No match + +"(?>.*/)foo" + /this/is/a/very/long/line/in/deed/with/very/many/slashes/in/and/foo + 0: /this/is/a/very/long/line/in/deed/with/very/many/slashes/in/and/foo + +/(?>(\.\d\d[1-9]?))\d+/ + 1.230003938 + 0: .230003938 + 1: .23 + 1.875000282 + 0: .875000282 + 1: .875 + *** Failers +No match + 1.235 +No match + +/^((?>\w+)|(?>\s+))*$/ + now is the time for all good men to come to the aid of the party + 0: now is the time for all good men to come to the aid of the party + 1: party + *** Failers +No match + this is not a line with only words and spaces! +No match + +/(\d+)(\w)/ + 12345a + 0: 12345a + 1: 12345 + 2: a + 12345+ + 0: 12345 + 1: 1234 + 2: 5 + +/((?>\d+))(\w)/ + 12345a + 0: 12345a + 1: 12345 + 2: a + *** Failers +No match + 12345+ +No match + +/(?>a+)b/ + aaab + 0: aaab + +/((?>a+)b)/ + aaab + 0: aaab + 1: aaab + +/(?>(a+))b/ + aaab + 0: aaab + 1: aaa + +/(?>b)+/ + aaabbbccc + 0: bbb + +/(?>a+|b+|c+)*c/ + aaabbbbccccd + 0: aaabbbbc + +/((?>[^()]+)|\([^()]*\))+/ + ((abc(ade)ufh()()x + 0: abc(ade)ufh()()x + 1: x + +/\(((?>[^()]+)|\([^()]+\))+\)/ + (abc) + 0: (abc) + 1: abc + (abc(def)xyz) + 0: (abc(def)xyz) + 1: xyz + *** Failers +No match + ((()aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa +No match + +/a(?-i)b/i + ab + 0: ab + *** Failers +No match + Ab +No match + aB +No match + AB +No match + +/(a (?x)b c)d e/ + a bcd e + 0: a bcd e + 1: a bc + *** Failers +No match + a b cd e +No match + abcd e +No match + a bcde +No match + +/(a b(?x)c d (?-x)e f)/ + a bcde f + 0: a bcde f + 1: a bcde f + *** Failers +No match + abcdef +No match + +/(a(?i)b)c/ + abc + 0: abc + 1: ab + aBc + 0: aBc + 1: aB + *** Failers +No match + abC +No match + aBC +No match + Abc +No match + ABc +No match + ABC +No match + AbC +No match + +/a(?i:b)c/ + abc + 0: abc + aBc + 0: aBc + *** Failers +No match + ABC +No match + abC +No match + aBC +No match + +/a(?i:b)*c/ + aBc + 0: aBc + aBBc + 0: aBBc + *** Failers +No match + aBC +No match + aBBC +No match + +/a(?=b(?i)c)\w\wd/ + abcd + 0: abcd + abCd + 0: abCd + *** Failers +No match + aBCd +No match + abcD +No match + +/(?s-i:more.*than).*million/i + more than million + 0: more than million + more than MILLION + 0: more than MILLION + more \n than Million + 0: more \x0a than Million + *** Failers +No match + MORE THAN MILLION +No match + more \n than \n million +No match + +/(?:(?s-i)more.*than).*million/i + more than million + 0: more than million + more than MILLION + 0: more than MILLION + more \n than Million + 0: more \x0a than Million + *** Failers +No match + MORE THAN MILLION +No match + more \n than \n million +No match + +/(?>a(?i)b+)+c/ + abc + 0: abc + aBbc + 0: aBbc + aBBc + 0: aBBc + *** Failers +No match + Abc +No match + abAb +No match + abbC +No match + +/(?=a(?i)b)\w\wc/ + abc + 0: abc + aBc + 0: aBc + *** Failers +No match + Ab +No match + abC +No match + aBC +No match + +/(?<=a(?i)b)(\w\w)c/ + abxxc + 0: xxc + 1: xx + aBxxc + 0: xxc + 1: xx + *** Failers +No match + Abxxc +No match + ABxxc +No match + abxxC +No match + +/(?:(a)|b)(?(1)A|B)/ + aA + 0: aA + 1: a + bB + 0: bB + *** Failers +No match + aB +No match + bA +No match + +/^(a)?(?(1)a|b)+$/ + aa + 0: aa + 1: a + b + 0: b + bb + 0: bb + *** Failers +No match + ab +No match + +/^(?(?=abc)\w{3}:|\d\d)$/ + abc: + 0: abc: + 12 + 0: 12 + *** Failers +No match + 123 +No match + xyz +No match + +/^(?(?!abc)\d\d|\w{3}:)$/ + abc: + 0: abc: + 12 + 0: 12 + *** Failers +No match + 123 +No match + xyz +No match + +/(?(?<=foo)bar|cat)/ + foobar + 0: bar + cat + 0: cat + fcat + 0: cat + focat + 0: cat + *** Failers +No match + foocat +No match + +/(?(?a*)*/ + a + 0: a + aa + 0: aa + aaaa + 0: aaaa + +/(abc|)+/ + abc + 0: abc + 1: + abcabc + 0: abcabc + 1: + abcabcabc + 0: abcabcabc + 1: + xyz + 0: + 1: + +/([a]*)*/ + a + 0: a + 1: + aaaaa + 0: aaaaa + 1: + +/([ab]*)*/ + a + 0: a + 1: + b + 0: b + 1: + ababab + 0: ababab + 1: + aaaabcde + 0: aaaab + 1: + bbbb + 0: bbbb + 1: + +/([^a]*)*/ + b + 0: b + 1: + bbbb + 0: bbbb + 1: + aaa + 0: + 1: + +/([^ab]*)*/ + cccc + 0: cccc + 1: + abab + 0: + 1: + +/([a]*?)*/ + a + 0: + 1: + aaaa + 0: + 1: + +/([ab]*?)*/ + a + 0: + 1: + b + 0: + 1: + abab + 0: + 1: + baba + 0: + 1: + +/([^a]*?)*/ + b + 0: + 1: + bbbb + 0: + 1: + aaa + 0: + 1: + +/([^ab]*?)*/ + c + 0: + 1: + cccc + 0: + 1: + baba + 0: + 1: + +/(?>a*)*/ + a + 0: a + aaabcde + 0: aaa + +/((?>a*))*/ + aaaaa + 0: aaaaa + 1: + aabbaa + 0: aa + 1: + +/((?>a*?))*/ + aaaaa + 0: + 1: + aabbaa + 0: + 1: + +/(?(?=[^a-z]+[a-z]) \d{2}-[a-z]{3}-\d{2} | \d{2}-\d{2}-\d{2} ) /x + 12-sep-98 + 0: 12-sep-98 + 12-09-98 + 0: 12-09-98 + *** Failers +No match + sep-12-98 +No match + +/(?<=(foo))bar\1/ + foobarfoo + 0: barfoo + 1: foo + foobarfootling + 0: barfoo + 1: foo + *** Failers +No match + foobar +No match + barfoo +No match + +/(?i:saturday|sunday)/ + saturday + 0: saturday + sunday + 0: sunday + Saturday + 0: Saturday + Sunday + 0: Sunday + SATURDAY + 0: SATURDAY + SUNDAY + 0: SUNDAY + SunDay + 0: SunDay + +/(a(?i)bc|BB)x/ + abcx + 0: abcx + 1: abc + aBCx + 0: aBCx + 1: aBC + bbx + 0: bbx + 1: bb + BBx + 0: BBx + 1: BB + *** Failers +No match + abcX +No match + aBCX +No match + bbX +No match + BBX +No match + +/^([ab](?i)[cd]|[ef])/ + ac + 0: ac + 1: ac + aC + 0: aC + 1: aC + bD + 0: bD + 1: bD + elephant + 0: e + 1: e + Europe + 0: E + 1: E + frog + 0: f + 1: f + France + 0: F + 1: F + *** Failers +No match + Africa +No match + +/^(ab|a(?i)[b-c](?m-i)d|x(?i)y|z)/ + ab + 0: ab + 1: ab + aBd + 0: aBd + 1: aBd + xy + 0: xy + 1: xy + xY + 0: xY + 1: xY + zebra + 0: z + 1: z + Zambesi + 0: Z + 1: Z + *** Failers +No match + aCD +No match + XY +No match + +/(?<=foo\n)^bar/m + foo\nbar + 0: bar + *** Failers +No match + bar +No match + baz\nbar +No match + +/(?<=(?]&/ + <&OUT + 0: <& + +/^(a\1?){4}$/ + aaaaaaaaaa + 0: aaaaaaaaaa + 1: aaaa + *** Failers +No match + AB +No match + aaaaaaaaa +No match + aaaaaaaaaaa +No match + +/^(a(?(1)\1)){4}$/ + aaaaaaaaaa + 0: aaaaaaaaaa + 1: aaaa + *** Failers +No match + aaaaaaaaa +No match + aaaaaaaaaaa +No match + +/(?:(f)(o)(o)|(b)(a)(r))*/ + foobar + 0: foobar + 1: f + 2: o + 3: o + 4: b + 5: a + 6: r + +/(?<=a)b/ + ab + 0: b + *** Failers +No match + cb +No match + b +No match + +/(? + 2: abcd + xy:z:::abcd + 0: xy:z:::abcd + 1: xy:z::: + 2: abcd + +/^[^bcd]*(c+)/ + aexycd + 0: aexyc + 1: c + +/(a*)b+/ + caab + 0: aab + 1: aa + +/([\w:]+::)?(\w+)$/ + abcd + 0: abcd + 1: + 2: abcd + xy:z:::abcd + 0: xy:z:::abcd + 1: xy:z::: + 2: abcd + *** Failers + 0: Failers + 1: + 2: Failers + abcd: +No match + abcd: +No match + +/^[^bcd]*(c+)/ + aexycd + 0: aexyc + 1: c + +/(>a+)ab/ + +/(?>a+)b/ + aaab + 0: aaab + +/([[:]+)/ + a:[b]: + 0: :[ + 1: :[ + +/([[=]+)/ + a=[b]= + 0: =[ + 1: =[ + +/([[.]+)/ + a.[b]. + 0: .[ + 1: .[ + +/((?>a+)b)/ + aaab + 0: aaab + 1: aaab + +/(?>(a+))b/ + aaab + 0: aaab + 1: aaa + +/((?>[^()]+)|\([^()]*\))+/ + ((abc(ade)ufh()()x + 0: abc(ade)ufh()()x + 1: x + +/a\Z/ + *** Failers +No match + aaab +No match + a\nb\n +No match + +/b\Z/ + a\nb\n + 0: b + +/b\z/ + +/b\Z/ + a\nb + 0: b + +/b\z/ + a\nb + 0: b + *** Failers +No match + +/^(?>(?(1)\.|())[^\W_](?>[a-z0-9-]*[^\W_])?)+$/ + a + 0: a + 1: + abc + 0: abc + 1: + a-b + 0: a-b + 1: + 0-9 + 0: 0-9 + 1: + a.b + 0: a.b + 1: + 5.6.7 + 0: 5.6.7 + 1: + the.quick.brown.fox + 0: the.quick.brown.fox + 1: + a100.b200.300c + 0: a100.b200.300c + 1: + 12-ab.1245 + 0: 12-ab.1245 + 1: + ***Failers +No match + \ +No match + .a +No match + -a +No match + a- +No match + a. +No match + a_b +No match + a.- +No match + a.. +No match + ab..bc +No match + the.quick.brown.fox- +No match + the.quick.brown.fox. +No match + the.quick.brown.fox_ +No match + the.quick.brown.fox+ +No match + +/(?>.*)(?<=(abcd|wxyz))/ + alphabetabcd + 0: alphabetabcd + 1: abcd + endingwxyz + 0: endingwxyz + 1: wxyz + *** Failers +No match + a rather long string that doesn't end with one of them +No match + +/word (?>(?:(?!otherword)[a-zA-Z0-9]+ ){0,30})otherword/ + word cat dog elephant mussel cow horse canary baboon snake shark otherword + 0: word cat dog elephant mussel cow horse canary baboon snake shark otherword + word cat dog elephant mussel cow horse canary baboon snake shark +No match + +/word (?>[a-zA-Z0-9]+ ){0,30}otherword/ + word cat dog elephant mussel cow horse canary baboon snake shark the quick brown fox and the lazy dog and several other words getting close to thirty by now I hope +No match + +/(?<=\d{3}(?!999))foo/ + 999foo + 0: foo + 123999foo + 0: foo + *** Failers +No match + 123abcfoo +No match + +/(?<=(?!...999)\d{3})foo/ + 999foo + 0: foo + 123999foo + 0: foo + *** Failers +No match + 123abcfoo +No match + +/(?<=\d{3}(?!999)...)foo/ + 123abcfoo + 0: foo + 123456foo + 0: foo + *** Failers +No match + 123999foo +No match + +/(?<=\d{3}...)(? + 2: + 3: abcd + + 2: + 3: abcd + \s*)=(?>\s*) # find + 2: + 3: abcd +