\input texinfo.tex @c -*-texinfo-*-
@c %**start of header
@setfilename flex.info
-@settitle The Flex Manual
-@c %**end of header
+@settitle flex: a fast lexical analyzer generator
@include version.texi
@c Define new index types for "Examples" and "macro hooks".
@defindex ex
@defindex hk
+@dircategory Programming
+@direntry
+* flex: (flex). Fast lexical analyzer generator (lex replacement).
+@end direntry
+@c %**end of header
-@c This file is part of flex.
+@copying
+@quotation
+This file is part of flex.
-@c Copyright (c) 1990, 1997 The Regents of the University of California.
-@c All rights reserved.
+Copyright @copyright{} 1990, 1997 The Regents of the University of California.
+All rights reserved.
-@c This code is derived from software contributed to Berkeley by
-@c Vern Paxson.
+This code is derived from software contributed to Berkeley by
+Vern Paxson.
-@c The United States Government has rights in this work pursuant
-@c to contract no. DE-AC03-76SF00098 between the United States
-@c Department of Energy and the University of California.
+The United States Government has rights in this work pursuant
+to contract no. DE-AC03-76SF00098 between the United States
+Department of Energy and the University of California.
-@c Redistribution and use in source and binary forms, with or without
-@c modification, are permitted provided that the following conditions
-@c are met:
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions
+are met:
-@c 1. Redistributions of source code must retain the above copyright
-@c notice, this list of conditions and the following disclaimer.
-@c 2. Redistributions in binary form must reproduce the above copyright
-@c notice, this list of conditions and the following disclaimer in the
-@c documentation and/or other materials provided with the distribution.
+@enumerate
+@item
+ Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
-@c Neither the name of the University nor the names of its contributors
-@c may be used to endorse or promote products derived from this software
-@c without specific prior written permission.
+@item
+Redistributions in binary form must reproduce the above copyright
+notice, this list of conditions and the following disclaimer in the
+documentation and/or other materials provided with the distribution.
+@end enumerate
+
+Neither the name of the University nor the names of its contributors
+may be used to endorse or promote products derived from this software
+without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE.
+@end quotation
+@end copying
-@c THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
-@c IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
-@c WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
-@c PURPOSE.
-@dircategory Programming
-@direntry
-* flex: (flex). Fast lexical analyzer generator (lex replacement).
-@end direntry
@node Top
@top flex
@value{VERSION}. It was last updated on @value{UPDATED}.
@menu
+* Copyright::
+* Reporting Bugs::
* Introduction::
* Simple Examples::
* Format::
* Diagnostics::
* Limitations::
* Bibliography::
-* Copyright::
-* Reporting Bugs::
* FAQ::
* Appendices::
* Indices::
@end detailmenu
@end menu
+@node Copyright
+@chapter Copyright
+
+@cindex copyright of flex
+@cindex distributing flex
+
+The flex manual is placed under the same licensing conditions as the
+rest of flex:
+
+@insertcopying
+
+@node Reporting Bugs
+@chapter Reporting Bugs
+
+@cindex bugs, reporting
+@cindex reporting bugs
+
+If you have problems with @code{flex} or think you have found a bug,
+please send mail detailing your problem to
+@email{help-flex@@gnu.org}. Patches are always welcome.
+
@node Introduction
@chapter Introduction
pattern-matching techniques used by @code{flex} (deterministic finite
automata).
-@node Copyright
-@chapter Copyright
-
-@cindex copyright of flex
-@cindex distributing flex
-
-The flex manual is placed under the same licensing conditions as the
-rest of flex:
-
-Copyright @copyright{} 1990, 1997 The Regents of the University of California.
-All rights reserved.
-
-This code is derived from software contributed to Berkeley by
-Vern Paxson.
-
-The United States Government has rights in this work pursuant
-to contract no. DE-AC03-76SF00098 between the United States
-Department of Energy and the University of California.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions
-are met:
-
-@enumerate
-@item
-Redistributions of source code must retain the above copyright
-notice, this list of conditions and the following disclaimer.
-
-@item
-Redistributions in binary form must reproduce the above copyright
-notice, this list of conditions and the following disclaimer in the
-documentation and/or other materials provided with the distribution.
-@end enumerate
-
-Neither the name of the University nor the names of its contributors
-may be used to endorse or promote products derived from this software
-without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
-IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
-WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
-PURPOSE.
-
-@node Reporting Bugs
-@chapter Reporting Bugs
-
-@cindex bugs, reporting
-
-If you have problems with @code{flex} or think you have found a bug,
-please send mail detailing your problem to
-@email{help-flex@@gnu.org}. Patches are always welcome.
-
@node FAQ
@unnumbered FAQ
Note: @code{yy_init} is an "internal variable", and hasn't been tested in this
situation. It is possible that some other globals may need resetting as well.
-@c faq edit stopped here
@node How do I track the byte offset for lseek()?
@unnumberedsec How do I track the byte offset for lseek()?
@end verbatim
@end example
-While this is the right ideas, it has two problems. The first is that
-it's possible that flex will request less than YY_READ_BUF_SIZE during
-an invocation of YY_INPUT (or that your input source will return less
-even though YY_READ_BUF_SIZE bytes were requested). The second problem
-is that when refilling its internal buffer, flex keeps some characters
+While this is the right idea, it has two problems. The first is that
+it's possible that @code{flex} will request less than @code{YY_READ_BUF_SIZE} during
+an invocation of @code{YY_INPUT} (or that your input source will return less
+even though @code{YY_READ_BUF_SIZE} bytes were requested). The second problem
+is that when refilling its internal buffer, @code{flex} keeps some characters
from the previous buffer (because usually it's in the middle of a match,
-and needs those characters to construct yytext for the match once it's
-done). Because of this, yy_c_buf_p - yy_current_buffer->yy_ch_buf won't
+and needs those characters to construct @code{yytext} for the match once it's
+done). Because of this, @code{yy_c_buf_p - yy_current_buffer->yy_ch_buf} won't
be exactly the number of characters already read from the current buffer.
An alternative solution is to count the number of characters you've matched
-since starting to scan. This can be done by using YY_USER_ACTION. For
+since starting to scan. This can be done by using @code{YY_USER_ACTION}. For
example,
- #define YY_USER_ACTION num_chars += yyleng;
+@example
+@verbatim
+#define YY_USER_ACTION num_chars += yyleng;
+@end verbatim
+@end example
-(You need to be careful to update your bookkeeping if you use yymore(),
-yyless(), unput(), or input().)
+(You need to be careful to update your bookkeeping if you use @code{yymore(}),
+@code{yyless()}, @code{unput()}, or @code{input()}.)
+@c faq edit stopped here
@c TODO: Evaluate this faq.
@node unnamed-faq-16
@unnumberedsec unnamed-faq-16
projects / flex / commitdiff