]> granicus.if.org Git - python/commitdiff
New "re" regular expression support.
authorGuido van Rossum <guido@python.org>
Mon, 6 Oct 1997 14:45:17 +0000 (14:45 +0000)
committerGuido van Rossum <guido@python.org>
Mon, 6 Oct 1997 14:45:17 +0000 (14:45 +0000)
The new re module was written by Andrew Kuchling and uses the pcre
code in ../Modules/.  The old re module has been renamed to re1,
just in case you need it for comparison.

Lib/re.py
Lib/re1.py [new file with mode: 0644]

index 6c24797ffd851be40ac1b5dee6a143ec425d5d70..6c3ee0becf913d78f2d3e07d43bd0c5744179adf 100644 (file)
--- a/Lib/re.py
+++ b/Lib/re.py
@@ -2,42 +2,27 @@
 # -*- mode: python -*-
 # $Id$
 
-import string
-import reop
-
-# reop.error and re.error should be the same, since exceptions can be
-# raised from  either module.
-error = reop.error # 're error'
 
-from reop import NORMAL, CHARCLASS, REPLACEMENT
-from reop import CHAR, MEMORY_REFERENCE, SYNTAX, NOT_SYNTAX, SET
-from reop import WORD_BOUNDARY, NOT_WORD_BOUNDARY, BEGINNING_OF_BUFFER, END_OF_BUFFER
-
-# compilation flags
-
-IGNORECASE = I = 0x01
-
-MULTILINE = M = 0x02
-DOTALL = S = 0x04
-VERBOSE = X = 0x08
+import sys
+import string
+from pcre import *
 
-repetition_operators = ['*', '*?', '+', '+?', '?', '??', '{n}', '{n}?',
-                       '{n,}', '{n,}?', '{n,m}', '{n,m}?']
+[ NORMAL, CHARCLASS, REPLACEMENT ] = range(3)
+[ CHAR, MEMORY_REFERENCE, SYNTAX, NOT_SYNTAX, SET, WORD_BOUNDARY, NOT_WORD_BOUNDARY, BEGINNING_OF_BUFFER, END_OF_BUFFER ] = range(9)
 
 #
-#
+# First, the public part of the interface:
 #
 
-def valid_identifier(id):
-    if len(id) == 0:
-       return 0
-    if (not reop.syntax_table[id[0]] & reop.word) or \
-       (reop.syntax_table[id[0]] & reop.digit):
-       return 0
-    for char in id[1:]:
-       if not reop.syntax_table[char] & reop.word:
-           return 0
-    return 1
+# pcre.error and re.error should be the same, since exceptions can be
+# raised from  either module.
+
+# compilation flags
+
+I = IGNORECASE
+M = MULTILINE
+S = DOTALL 
+X = VERBOSE 
 
 #
 #
@@ -83,60 +68,17 @@ def split(pattern, string, maxsplit=0):
 #
 #
 
-def _expand(m, repl):
-    results = []
-    index = 0
-    size = len(repl)
-    while index < size:
-       found = string.find(repl, '\\', index)
-       if found < 0:
-           results.append(repl[index:])
-           break
-       if found > index:
-           results.append(repl[index:found])
-       escape_type, value, index = expand_escape(repl, found+1, REPLACEMENT)
-       if escape_type == CHAR:
-           results.append(value)
-       elif escape_type == MEMORY_REFERENCE:
-           r = m.group(value)
-           if r is None:
-               raise error, ('group "' + str(value) + '" did not contribute '
-                             'to the match')
-           results.append(m.group(value))
-       else:
-           raise error, "bad escape in replacement"
-    return string.join(results, '')
-
 class RegexObject:
-    def __init__(self, pattern, flags, code, num_regs, groupindex):
-       self.code = code
-       self.num_regs = num_regs
+    def __init__(self, pattern, flags, code, groupindex):
+       self.code = code 
        self.flags = flags
        self.pattern = pattern
        self.groupindex = groupindex
-       self.fastmap = build_fastmap(code)
-       
-       if code[0].name == 'bol':
-           self.anchor = 1
-           
-       elif code[0].name == 'begbuf':
-           self.anchor = 2
-           
-       else:
-           self.anchor = 0
-           
-       self.buffer = assemble(code)
     def search(self, string, pos=0):
-       regs = reop.search(self.buffer,
-                          self.num_regs,
-                          self.flags,
-                          self.fastmap.can_be_null,
-                          self.fastmap.fastmap(),
-                          self.anchor,
-                          string,
-                          pos)
+       regs = self.code.match(string, pos, 0)
        if regs is None:
            return None
+       self.num_regs=len(regs)
        
        return MatchObject(self,
                           string,
@@ -144,17 +86,10 @@ class RegexObject:
                           regs)
     
     def match(self, string, pos=0):
-       regs = reop.match(self.buffer,
-                         self.num_regs,
-                         self.flags,
-                         self.fastmap.can_be_null,
-                         self.fastmap.fastmap(),
-                         self.anchor,
-                         string,
-                         pos)
+       regs = self.code.match(string, pos, ANCHORED)
        if regs is None:
            return None
-       
+       self.num_regs=len(regs)/2
        return MatchObject(self,
                           string,
                           pos,
@@ -165,13 +100,13 @@ class RegexObject:
     
     def subn(self, repl, source, count=0):
        if count < 0:
-           raise ValueError, "negative substibution count"
+           raise error, "negative substitution count"
        if count == 0:
            import sys
            count = sys.maxint
        if type(repl) == type(''):
            if '\\' in repl:
-               repl = lambda m, r=repl: _expand(m, r)
+               repl = lambda m, r=repl: pcre_expand(m, r)
            else:
                repl = lambda m, r=repl: r
        n = 0           # Number of matches
@@ -275,7 +210,8 @@ class MatchObject:
                    g = self.re.groupindex[g]
                except (KeyError, TypeError):
                    raise IndexError, ('group "' + g + '" is undefined')
-           if (self.regs[g][0] == -1) or (self.regs[g][1] == -1):
+           if len(self.regs)<=g: raise IndexError, ('group "' + str(g) + '" is undefined')
+           elif (self.regs[g][0] == -1) or (self.regs[g][1] == -1):
                result.append(None)
            else:
                result.append(self.string[self.regs[g][0]:self.regs[g][1]])
@@ -286,364 +222,56 @@ class MatchObject:
        else:
            return ()
 
-#
-# A set of classes to make assembly a bit easier, if a bit verbose.
-#
-
-class Instruction:
-    def __init__(self, opcode, size=1):
-       self.opcode = opcode
-       self.size = size
-    def assemble(self, position, labels):
-       return self.opcode
-    def __repr__(self):
-       return '%-15s' % (self.name)
-
-class End(Instruction):
-    name = 'end'
-    def __init__(self):
-       Instruction.__init__(self, chr(0))
-
-class Bol(Instruction):
-    name = 'bol'
-    def __init__(self):
-       self.name = 'bol'
-       Instruction.__init__(self, chr(1))
-
-class Eol(Instruction):
-    name = 'eol'
-    def __init__(self):
-       Instruction.__init__(self, chr(2))
-
-class Set(Instruction):
-    name = 'set'
-    def __init__(self, set, flags=0):
-       self.set = set
-       if flags & IGNORECASE: self.set=map(string.lower, self.set)
-       if len(set)==1: 
-           # If only one element, use the "exact" opcode (it'll be faster)
-           Instruction.__init__(self, chr(4), 2)
-       else:
-           # Use the "set" opcode
-           Instruction.__init__(self, chr(3), 33)
-    def assemble(self, position, labels):
-       if len(self.set)==1:
-           # If only one character in set, generate an "exact" opcode
-           return self.opcode + self.set[0]
-       result = self.opcode
-       temp = 0
-       for i, c in map(lambda x: (x, chr(x)), range(256)):
-           if c in self.set:
-               temp = temp | (1 << (i & 7))
-           if (i % 8) == 7:
-               result = result + chr(temp)
-               temp = 0
-       return result
-    def __repr__(self):
-       result = '%-15s' % (self.name)
-       self.set.sort()
-       # XXX this should print more intelligently
-       for char in self.set:
-           result = result + char
-       return result
-    
-class Exact(Instruction):
-    name = 'exact'
-    def __init__(self, char, flags):
-       self.char = char
-       if flags & IGNORECASE: self.char=string.lower(self.char)
-       Instruction.__init__(self, chr(4), 2)
-    def assemble(self, position, labels):
-       return self.opcode + self.char
-    def __repr__(self):
-       return '%-15s %s' % (self.name, `self.char`)
-    
-class AnyChar(Instruction):
-    name = 'anychar'
-    def __init__(self):
-       Instruction.__init__(self, chr(5))
-    def assemble(self, position, labels):
-       return self.opcode
-
-class MemoryInstruction(Instruction):
-    def __init__(self, opcode, register):
-       self.register = register
-       Instruction.__init__(self, opcode, 2)
-    def assemble(self, position, labels):
-       return self.opcode + chr(self.register)
-    def __repr__(self):
-       return '%-15s %i' % (self.name, self.register)
-
-class StartMemory(MemoryInstruction):
-    name = 'start_memory'
-    def __init__(self, register):
-       MemoryInstruction.__init__(self, chr(6), register)
-
-class EndMemory(MemoryInstruction):
-    name = 'end_memory'
-    def __init__(self, register):
-       MemoryInstruction.__init__(self, chr(7), register)
-
-class MatchMemory(MemoryInstruction):
-    name = 'match_memory'
-    def __init__(self, register):
-       MemoryInstruction.__init__(self, chr(8), register)
-
-class JumpInstruction(Instruction):
-    def __init__(self, opcode, label):
-       self.label = label
-       Instruction.__init__(self, opcode, 3)
-    def compute_offset(self, start, dest):
-       return dest - (start + 3)
-    def pack_offset(self, offset):
-       if offset > 32767:
-           raise error, 'offset out of range (pos)'
-       elif offset < -32768:
-           raise error, 'offset out of range (neg)'
-       elif offset < 0:
-           offset = offset + 65536
-       return chr(offset & 0xff) + chr((offset >> 8) & 0xff)
-    def assemble(self, position, labels):
-       return self.opcode + \
-              self.pack_offset(self.compute_offset(position,
-                                                   labels[self.label]))
-    def __repr__(self):
-       return '%-15s %i' % (self.name, self.label)
-
-class Jump(JumpInstruction):
-    name = 'jump'
-    def __init__(self, label):
-       JumpInstruction.__init__(self, chr(9), label)
-
-class StarJump(JumpInstruction):
-    name = 'star_jump'
-    def __init__(self, label):
-       JumpInstruction.__init__(self, chr(10), label)
-
-class FailureJump(JumpInstruction):
-    name = 'failure_jump'
-    def __init__(self, label):
-       JumpInstruction.__init__(self, chr(11), label)
-
-class UpdateFailureJump(JumpInstruction):
-    name = 'update_failure_jump'
-    def __init__(self, label):
-       JumpInstruction.__init__(self, chr(12), label)
-
-class DummyFailureJump(JumpInstruction):
-    name = 'dummy_failure_jump'
-    def __init__(self, label):
-       JumpInstruction.__init__(self, chr(13), label)
-       
-class BegBuf(Instruction):
-    name = 'begbuf'
-    def __init__(self):
-       Instruction.__init__(self, chr(14))
-
-class EndBuf(Instruction):
-    name = 'endbuf'
-    def __init__(self):
-       Instruction.__init__(self, chr(15))
-
-class WordBeg(Instruction):
-    name = 'wordbeg'
-    def __init__(self):
-       Instruction.__init__(self, chr(16))
-
-class WordEnd(Instruction):
-    name = 'wordend'
-    def __init__(self):
-       Instruction.__init__(self, chr(17))
-
-class WordBound(Instruction):
-    name = 'wordbound'
-    def __init__(self):
-       Instruction.__init__(self, chr(18))
-
-class NotWordBound(Instruction):
-    name = 'notwordbound'
-    def __init__(self):
-       Instruction.__init__(self, chr(19))
-
-class SyntaxSpec(Instruction):
-    name = 'syntaxspec'
-    def __init__(self, syntax):
-       self.syntax = syntax
-       Instruction.__init__(self, chr(20), 2)
-    def assemble(self, postition, labels):
-       return self.opcode + chr(self.syntax)
-
-class NotSyntaxSpec(Instruction):
-    name = 'notsyntaxspec'
-    def __init__(self, syntax):
-       self.syntax = syntax
-       Instruction.__init__(self, chr(21), 2)
-    def assemble(self, postition, labels):
-       return self.opcode + chr(self.syntax)
-
-class Label(Instruction):
-    name = 'label'
-    def __init__(self, label):
-       self.label = label
-       Instruction.__init__(self, '', 0)
-    def __repr__(self):
-       return '%-15s %i' % (self.name, self.label)
-
-class OpenParen(Instruction):
-    name = '('
-    def __init__(self, register):
-       self.register = register
-       Instruction.__init__(self, '', 0)
-    def assemble(self, position, labels):
-       raise error, 'unmatched open parenthesis'
-
-class Alternation(Instruction):
-    name = '|'
-    def __init__(self):
-       Instruction.__init__(self, '', 0)
-    def assemble(self, position, labels):
-       raise error, 'an alternation was not taken care of'
-
-#
-#
-#
-
-def assemble(instructions):
-    labels = {}
-    position = 0
-    pass1 = []
-    for instruction in instructions:
-       if instruction.name == 'label':
-           labels[instruction.label] = position
-       else:
-           pass1.append((position, instruction))
-           position = position + instruction.size
-    pass2 = ''
-    for position, instruction in pass1:
-       pass2 = pass2 + instruction.assemble(position, labels)
-    return pass2
-
-#
-#
-#
-
 def escape(pattern):
     result = []
+    alphanum=string.letters+'_'+string.digits
     for char in pattern:
-       if not reop.syntax_table[char] & reop.word:
+       if char not in alphanum:
            result.append('\\')
        result.append(char)
     return string.join(result, '')
 
-#
-#
-#
-
-def registers_used(instructions):
-    result = []
-    for instruction in instructions:
-       if (instruction.name in ['set_memory', 'end_memory']) and \
-          (instruction.register not in result):
-           result.append(instruction.register)
-    return result
-
-#
-#
-#
-
-class Fastmap:
-    def __init__(self):
-       self.map = ['\000']*256
-       self.can_be_null = 0
-    def add(self, char):
-       self.map[ord(char)] = '\001'
-    def fastmap(self):
-       return string.join(self.map, '')
-    def __getitem__(self, char):
-       return ord(self.map[ord(char)])
-    def __repr__(self):
-       self.map.sort()
-       return 'Fastmap(' + `self.can_be_null` + ', ' + `self.map` + ')'
-
-#
-#
-#
-
-def find_label(code, label):
-    line = 0
-    for instruction in code:
-       if (instruction.name == 'label') and (instruction.label == label):
-           return line + 1
-       line = line + 1
-       
-def build_fastmap_aux(code, pos, visited, fastmap):
-    if visited[pos]:
-       return
-    while 1:
-       instruction = code[pos]
-       visited[pos] = 1
-       pos = pos + 1
-       if instruction.name == 'end':
-           fastmap.can_be_null = 1
-           return
-       elif instruction.name == 'syntaxspec':
-           for char in map(chr, range(256)):
-               if reop.syntax_table[char] & instruction.syntax:
-                   fastmap.add(char)
-           return
-       elif instruction.name == 'notsyntaxspec':
-           for char in map(chr, range(256)):
-               if not reop.syntax_table[char] & instruction.syntax:
-                   fastmap.add(char)
-           return
-       elif instruction.name == 'eol':
-           fastmap.add('\n')
-           if fastmap.can_be_null == 0:
-               fastmap.can_be_null = 2
-           return
-       elif instruction.name == 'set':
-           for char in instruction.set:
-               fastmap.add(char)
-           return
-       elif instruction.name == 'exact':
-           fastmap.add(instruction.char)
-       elif instruction.name == 'anychar':
-           for char in map(chr, range(256)):
-               if char != '\n':
-                   fastmap.add(char)
-           return
-       elif instruction.name == 'match_memory':
-           for char in map(chr, range(256)):
-               fastmap.add(char)
-           fastmap.can_be_null = 1
-           return
-       elif instruction.name in ['jump', 'dummy_failure_jump', \
-                                 'update_failure_jump', 'star_jump']:
-           pos = find_label(code, instruction.label)
-           if visited[pos]:
-               return
-           visited[pos] = 1
-       elif instruction.name  == 'failure_jump':
-           build_fastmap_aux(code,
-                             find_label(code, instruction.label),
-                             visited,
-                             fastmap)
-       
-def build_fastmap(code, pos=0):
-    visited = [0] * len(code)
-    fastmap = Fastmap()
-    build_fastmap_aux(code, pos, visited, fastmap)
-    return fastmap
-
-#
-#
-#
+def valid_identifier(id):
+    import string
+    if len(id) == 0:
+       return 0
+    if id[0] not in string.letters+'_':
+       return 0
+    for char in id[1:]:
+       if not syntax_table[char] & word:
+           return 0
+    return 1
 
-#[NORMAL, CHARCLASS, REPLACEMENT] = range(3)
-#[CHAR, MEMORY_REFERENCE, SYNTAX, NOT_SYNTAX, SET, WORD_BOUNDARY,
-# NOT_WORD_BOUNDARY, BEGINNING_OF_BUFFER, END_OF_BUFFER] = range(9)
+def compile(pattern, flags=0):
+    groupindex={}
+    code=pcre_compile(pattern, flags, groupindex)
+    return RegexObject(pattern, flags, code, groupindex)
+    
+def _expand(m, repl):
+    results = []
+    index = 0
+    size = len(repl)
+    while index < size:
+       found = string.find(repl, '\\', index)
+       if found < 0:
+           results.append(repl[index:])
+           break
+       if found > index:
+           results.append(repl[index:found])
+       escape_type, value, index = _expand_escape(repl, found+1, REPLACEMENT)
+       if escape_type == CHAR:
+           results.append(value)
+       elif escape_type == MEMORY_REFERENCE:
+           r = m.group(value)
+           if r is None:
+               raise error, ('group "' + str(value) + '" did not contribute '
+                             'to the match')
+           results.append(m.group(value))
+       else:
+           raise error, "bad escape in replacement"
+    return string.join(results, '')
 
-def expand_escape(pattern, index, context=NORMAL):
+def _expand_escape(pattern, index, context=NORMAL):
     if index >= len(pattern):
        raise error, 'escape ends too soon'
 
@@ -676,7 +304,7 @@ def expand_escape(pattern, index, context=NORMAL):
        # what it's doing (and Python in turn passes it on to sscanf,
        # so that *it* doesn't incorrectly 2nd-guess what C does!)
        char = eval ('"' + pattern[index-1:end] + '"')
-       assert len(char) == 1
+#      assert len(char) == 1
        return CHAR, char, end
 
     elif pattern[index] == 'b':
@@ -707,75 +335,21 @@ def expand_escape(pattern, index, context=NORMAL):
        raise error, ('\\' + pattern[index] + ' is not allowed')
     
     elif pattern[index] == 'w':
-       if context == NORMAL:
-           return SYNTAX, reop.word, index + 1
-       elif context == CHARCLASS:
-           set = []
-           for char in reop.syntax_table.keys():
-               if reop.syntax_table[char] & reop.word:
-                   set.append(char)
-           return SET, set, index + 1
-       else:
            return CHAR, 'w', index + 1
        
     elif pattern[index] == 'W':
-       if context == NORMAL:
-           return NOT_SYNTAX, reop.word, index + 1
-       elif context == CHARCLASS:
-           set = []
-           for char in reop.syntax_table.keys():
-               if not reop.syntax_table[char] & reop.word:
-                   set.append(char)
-           return SET, set, index + 1
-       else:
            return CHAR, 'W', index + 1
        
     elif pattern[index] == 's':
-       if context == NORMAL:
-           return SYNTAX, reop.whitespace, index + 1
-       elif context == CHARCLASS:
-           set = []
-           for char in reop.syntax_table.keys():
-               if reop.syntax_table[char] & reop.whitespace:
-                   set.append(char)
-           return SET, set, index + 1
-       else:
            return CHAR, 's', index + 1
        
     elif pattern[index] == 'S':
-       if context == NORMAL:
-           return NOT_SYNTAX, reop.whitespace, index + 1
-       elif context == CHARCLASS:
-           set = []
-           for char in reop.syntax_table.keys():
-               if not reop.syntax_table[char] & reop.whitespace:
-                   set.append(char)
-           return SET, set, index + 1
-       else:
            return CHAR, 'S', index + 1
        
     elif pattern[index] == 'd':
-       if context == NORMAL:
-           return SYNTAX, reop.digit, index + 1
-       elif context == CHARCLASS:
-           set = []
-           for char in reop.syntax_table.keys():
-               if reop.syntax_table[char] & reop.digit:
-                   set.append(char)
-           return SET, set, index + 1
-       else:
            return CHAR, 'd', index + 1
        
     elif pattern[index] == 'D':
-       if context == NORMAL:
-           return NOT_SYNTAX, reop.digit, index + 1
-       elif context == CHARCLASS:
-           set = []
-           for char in reop.syntax_table.keys():
-               if not reop.syntax_table[char] & reop.digit:
-                   set.append(char)
-           return SET, set, index + 1
-       else:
            return CHAR, 'D', index + 1
 
     elif pattern[index] in '0123456789':
@@ -854,655 +428,3 @@ def expand_escape(pattern, index, context=NORMAL):
     else:
        return CHAR, pattern[index], index + 1
 
-def compile(pattern, flags=0):
-    stack = []
-    label = 0
-    register = 1
-    groupindex = {}
-    lastop = ''
-
-    # look for embedded pattern modifiers at the beginning of the pattern
-
-    index = 0
-
-    if len(pattern) >= 3 and \
-       (pattern[:2] == '(?') and \
-       (pattern[2] in 'iImMsSxX'):
-       index = 2
-       while (index < len(pattern)) and (pattern[index] != ')'):
-           if pattern[index] in 'iI':
-               flags = flags | IGNORECASE
-           elif pattern[index] in 'mM':
-               flags = flags | MULTILINE
-           elif pattern[index] in 'sS':
-               flags = flags | DOTALL
-           elif pattern[index] in 'xX':
-               flags = flags | VERBOSE
-           else:
-               raise error, 'unknown modifier'
-           index = index + 1
-       index = index + 1
-
-    # compile the rest of the pattern
-    
-    while (index < len(pattern)):
-       char = pattern[index]
-       index = index + 1
-       if char == '\\':
-           escape_type, value, index = expand_escape(pattern, index)
-
-           if escape_type == CHAR:
-               stack.append([Exact(value, flags)])
-               lastop = '\\' + value
-               
-           elif escape_type == MEMORY_REFERENCE:
-               if value >= register:
-                   raise error, ('cannot reference a register '
-                                 'not yet used')
-               stack.append([MatchMemory(value)])
-               lastop = '\\1'
-               
-           elif escape_type == BEGINNING_OF_BUFFER:
-               stack.append([BegBuf()])
-               lastop = '\\A'
-               
-           elif escape_type == END_OF_BUFFER:
-               stack.append([EndBuf()])
-               lastop = '\\Z'
-               
-           elif escape_type == WORD_BOUNDARY:
-               stack.append([WordBound()])
-               lastop = '\\b'
-               
-           elif escape_type == NOT_WORD_BOUNDARY:
-               stack.append([NotWordBound()])
-               lastop = '\\B'
-               
-           elif escape_type == SYNTAX:
-               stack.append([SyntaxSpec(value)])
-               if value == reop.word:
-                   lastop = '\\w'
-               elif value == reop.whitespace:
-                   lastop = '\\s'
-               elif value == reop.digit:
-                   lastop = '\\d'
-               else:
-                   lastop = '\\?'
-                   
-           elif escape_type == NOT_SYNTAX:
-               stack.append([NotSyntaxSpec(value)])
-               if value == reop.word:
-                   lastop = '\\W'
-               elif value == reop.whitespace:
-                   lastop = '\\S'
-               elif value == reop.digit:
-                   lastop = '\\D'
-               else:
-                   lastop = '\\?'
-               
-           elif escape_type == SET:
-               raise error, 'cannot use set escape type here'
-           
-           else:
-               raise error, 'unknown escape type'
-
-       elif char == '|':
-           expr = []
-           
-           while (len(stack) != 0) and \
-                 (stack[-1][0].name != '(') and \
-                 (stack[-1][0].name != '|'):
-               expr = stack[-1] + expr
-               del stack[-1]
-           stack.append([FailureJump(label)] + \
-                        expr + \
-                        [Jump(-1),
-                         Label(label)])
-           stack.append([Alternation()])
-           label = label + 1
-           lastop = '|'
-           
-       elif char == '(':
-           if index >= len(pattern):
-               raise error, 'no matching close paren'
-
-           elif pattern[index] == '?':
-               # Perl style (?...) extensions
-               index = index + 1
-               if index >= len(pattern):
-                   raise error, 'extension ends prematurely'
-
-               elif pattern[index] == 'P':
-                   # Python extensions
-                   index = index + 1
-                   if index >= len(pattern):
-                       raise error, 'extension ends prematurely'
-
-                   elif pattern[index] == '<':
-                       # Handle Python symbolic group names (?P<...>...)
-                       index = index + 1
-                       end = string.find(pattern, '>', index)
-                       if end == -1:
-                           raise error, 'no end to symbolic group name'
-                       name = pattern[index:end]
-                       if not valid_identifier(name):
-                           raise error, ('symbolic group name must be a '
-                                         'valid identifier')
-                       index = end + 1
-                       groupindex[name] = register
-                       stack.append([OpenParen(register)])
-                       register = register + 1
-                       lastop = '('
-
-                   elif pattern[index] == '=':
-                       # backreference to symbolic group name
-                       if index >= len(pattern):
-                           raise error, '(?P= at the end of the pattern'
-                       start = index + 1
-                       end = string.find(pattern, ')', start)
-                       if end == -1:
-                           raise error, 'no ) to end symbolic group name'
-                       name = pattern[start:end]
-                       if name not in groupindex.keys():
-                           raise error, ('symbolic group name ' + name + \
-                                         ' has not been used yet')
-                       stack.append([MatchMemory(groupindex[name])])
-                       index = end + 1
-                       lastop = '(?P=)'
-                       
-                   else:
-                       raise error, ('unknown Python extension: ' + \
-                                     pattern[index])
-                   
-               elif pattern[index] == ':':
-                   # grouping, but no registers
-                   index = index + 1
-                   stack.append([OpenParen(-1)])
-                   lastop = '('
-                   
-               elif pattern[index] == '#':
-                   # comment
-                   index = index + 1
-                   end = string.find(pattern, ')', index)
-                   if end == -1:
-                       raise error, 'no end to comment'
-                   index = end + 1
-                   # do not change lastop
-                   
-               elif pattern[index] == '=':
-                   raise error, ('zero-width positive lookahead '
-                                 'assertion is unsupported')
-
-               elif pattern[index] == '!':
-                   raise error, ('zero-width negative lookahead '
-                                 'assertion is unsupported')
-
-               elif pattern[index] in 'iImMsSxX':
-                   raise error, ('embedded pattern modifiers are only '
-                                 'allowed at the beginning of the pattern')
-
-               else:
-                   raise error, 'unknown extension'
-
-           else:
-               stack.append([OpenParen(register)])
-               register = register + 1
-               lastop = '('
-
-       elif char == ')':
-           # make one expression out of everything on the stack up to
-           # the marker left by the last parenthesis
-           expr = []
-           while (len(stack) > 0) and (stack[-1][0].name != '('):
-               expr = stack[-1] + expr
-               del stack[-1]
-
-           if len(stack) == 0:
-               raise error, 'too many close parens'
-           
-           # remove markers left by alternation
-           expr = filter(lambda x: x.name != '|', expr)
-
-           # clean up jumps inserted by alternation
-           need_label = 0
-           for i in range(len(expr)):
-               if (expr[i].name == 'jump') and (expr[i].label == -1):
-                   expr[i] = Jump(label)
-                   need_label = 1
-           if need_label:
-               expr.append(Label(label))
-               label = label + 1
-
-           if stack[-1][0].register > 0:
-               expr = [StartMemory(stack[-1][0].register)] + \
-                      expr + \
-                      [EndMemory(stack[-1][0].register)]
-           del stack[-1]
-           stack.append(expr)
-           lastop = ')'
-
-       elif char == '{':
-           if len(stack) == 0:
-               raise error, 'no expression to repeat'
-           end = string.find(pattern, '}', index)
-           if end == -1:
-               raise error, ('no close curly bracket to match'
-                             ' open curly bracket')
-
-           fields = map(string.strip,
-                        string.split(pattern[index:end], ','))
-           index = end + 1
-
-           minimal = 0
-           if (index < len(pattern)) and (pattern[index] == '?'):
-               minimal = 1
-               index = index + 1
-
-           if len(fields) == 1:
-               # {n} or {n}? (there's really no difference)
-               try:
-                   count = string.atoi(fields[0])
-               except ValueError:
-                   raise error, ('count must be an integer '
-                                 'inside curly braces')
-               if count > 65535:
-                   raise error, 'repeat count out of range'
-               expr = []
-               while count > 0:
-                   expr = expr + stack[-1]
-                   count = count - 1
-               del stack[-1]
-               stack.append(expr)
-               if minimal:
-                   lastop = '{n}?'
-               else:
-                   lastop = '{n}'
-
-           elif len(fields) == 2:
-               # {n,} or {n,m}
-               if fields[1] == '':
-                   # {n,}
-                   try:
-                       min = string.atoi(fields[0])
-                   except ValueError:
-                       raise error, ('minimum must be an integer '
-                                     'inside curly braces')
-                   if min > 65535:
-                       raise error, 'minimum repeat count out of range'
-
-                   expr = []
-                   while min > 0:
-                       expr = expr + stack[-1]
-                       min = min - 1
-                   if minimal:
-                       expr = expr + \
-                              ([Jump(label + 1),
-                                Label(label)] + \
-                               stack[-1] + \
-                               [Label(label + 1),
-                                FailureJump(label)])
-                       lastop = '{n,}?'
-                   else:
-                       expr = expr + \
-                              ([Label(label),
-                                FailureJump(label + 1)] +
-                               stack[-1] +
-                               [StarJump(label),
-                                Label(label + 1)])
-                       lastop = '{n,}'
-
-                   del stack[-1]
-                   stack.append(expr)
-                   label = label + 2
-
-               else:
-                   # {n,m}
-                   try:
-                       min = string.atoi(fields[0])
-                   except ValueError:
-                       raise error, ('minimum must be an integer '
-                                     'inside curly braces')
-                   try:
-                       max = string.atoi(fields[1])
-                   except ValueError:
-                       raise error, ('maximum must be an integer '
-                                     'inside curly braces')
-                   if min > 65535:
-                       raise error, ('minumim repeat count out '
-                                     'of range')
-                   if max > 65535:
-                       raise error, ('maximum repeat count out '
-                                     'of range')
-                   if min > max:
-                       raise error, ('minimum repeat count must be '
-                                     'less than the maximum '
-                                     'repeat count')
-                   expr = []
-                   while min > 0:
-                       expr = expr + stack[-1]
-                       min = min - 1
-                       max = max - 1
-                   if minimal:
-                       while max > 0:
-                           expr = expr + \
-                                  [FailureJump(label),
-                                   Jump(label + 1),
-                                   Label(label)] + \
-                                  stack[-1] + \
-                                  [Label(label + 1)]
-                           max = max - 1
-                           label = label + 2
-                       del stack[-1]
-                       stack.append(expr)
-                       lastop = '{n,m}?'
-                   else:
-                       while max > 0:
-                           expr = expr + \
-                                  [FailureJump(label)] + \
-                                  stack[-1]
-                           max = max - 1
-                       del stack[-1]
-                       stack.append(expr + [Label(label)])
-                       label = label + 1
-                       lastop = '{n,m}'
-
-           else:
-               raise error, ('there need to be one or two fields '
-                             'in a {} expression')
-
-       elif char == '}':
-           raise error, 'unbalanced close curly brace'
-
-       elif char == '*':
-           # Kleene closure
-           if len(stack) == 0:
-               raise error, '* needs something to repeat'
-
-           if lastop in ['(', '|']:
-               raise error, '* needs something to repeat'
-
-           if lastop in repetition_operators:
-               raise error, 'nested repetition operators'
-           
-           if (index < len(pattern)) and (pattern[index] == '?'):
-               # non-greedy matching
-               expr = [Jump(label + 1),
-                       Label(label)] + \
-                      stack[-1] + \
-                      [Label(label + 1),
-                       FailureJump(label)]
-               index = index + 1
-               lastop = '*?'
-           else:
-               # greedy matching
-               expr = [Label(label),
-                       FailureJump(label + 1)] + \
-                      stack[-1] + \
-                      [StarJump(label),
-                       Label(label + 1)]
-               lastop = '*'
-           del stack[-1]
-           stack.append(expr)
-           label = label + 2
-
-       elif char == '+':
-           # positive closure
-           if len(stack) == 0:
-               raise error, '+ needs something to repeat'
-           
-           if lastop in ['(', '|']:
-               raise error, '+ needs something to repeat'
-
-           if lastop in repetition_operators:
-               raise error, 'nested repetition operators'
-
-           if (index < len(pattern)) and (pattern[index] == '?'):
-               # non-greedy
-               expr = [Label(label)] + \
-                      stack[-1] + \
-                      [FailureJump(label)]
-               label = label + 1
-               index = index + 1
-               lastop = '+?'
-               
-           else:
-               # greedy
-               expr = [DummyFailureJump(label + 1),
-                       Label(label),
-                       FailureJump(label + 2),
-                       Label(label + 1)] + \
-                      stack[-1] + \
-                      [StarJump(label),
-                       Label(label + 2)]
-               label = label + 3
-               lastop = '+'
-               
-           del stack[-1]
-           stack.append(expr)
-
-       elif char == '?':
-           if len(stack) == 0:
-               raise error, 'need something to be optional'
-           
-           if len(stack) == 0:
-               raise error, '? needs something to repeat'
-           
-           if lastop in ['(', '|']:
-               raise error, '? needs something to repeat'
-
-           if lastop in repetition_operators:
-               raise error, 'nested repetition operators'
-
-           if (index < len(pattern)) and (pattern[index] == '?'):
-               # non-greedy matching
-               expr = [FailureJump(label),
-                       Jump(label + 1),
-                       Label(label)] + \
-                      stack[-1] + \
-                      [Label(label + 1)]
-               label = label + 2
-               index = index + 1
-               lastop = '??'
-               
-           else:
-               # greedy matching
-               expr = [FailureJump(label)] + \
-                      stack[-1] + \
-                      [Label(label)]
-               label = label + 1
-               lastop = '?'
-               
-           del stack[-1]
-           stack.append(expr)
-
-       elif char == '.':
-           if flags & DOTALL:
-               stack.append([Set(map(chr, range(256)), flags)])
-           else:
-               stack.append([AnyChar()])
-           lastop = '.'
-
-       elif char == '^':
-           if flags & MULTILINE:
-               stack.append([Bol()])
-           else:
-               stack.append([BegBuf()])
-           lastop = '^'
-
-       elif char == '$':
-           if flags & MULTILINE:
-               stack.append([Eol()])
-           else:
-               stack.append([EndBuf()])
-           lastop = '$'
-
-       elif char == '#':
-           if flags & VERBOSE:
-               # comment
-               index = index + 1
-               end = string.find(pattern, '\n', index)
-               if end == -1:
-                   index = len(pattern)
-               else:
-                   index = end + 1
-               # do not change lastop
-           else:
-               stack.append([Exact(char, flags)])
-               lastop = '#'
-
-       elif char in string.whitespace:
-           if not (flags & VERBOSE):
-               stack.append([Exact(char, flags)])
-               lastop = char
-
-       elif char == '[':
-           # compile character class
-           
-           if index >= len(pattern):
-               raise error, 'unclosed character class'
-           
-           negate = 0
-           last = ''
-           set = []
-
-           if pattern[index] == '^':
-               negate = 1
-               index = index + 1
-               if index >= len(pattern):
-                   raise error, 'unclosed character class'
-
-           if pattern[index] == ']':
-               set.append(']')
-               index = index + 1
-               if index >= len(pattern):
-                   raise error, 'unclosed character class'
-               
-           elif pattern[index] == '-':
-               set.append('-')
-               index = index + 1
-               if index >= len(pattern):
-                   raise error, 'unclosed character class'
-               
-           while (index < len(pattern)) and (pattern[index] != ']'):
-               next = pattern[index]
-               index = index + 1
-               if next == '-':
-                   if index >= len(pattern):
-                       raise error, 'incomplete range in character class'
-
-                   elif pattern[index] == ']':
-                       set.append('-')
-                       
-                   else:
-                       if last == '':
-                           raise error, ('improper use of range in '
-                                         'character class')
-
-                       start = last
-                       
-                       if pattern[index] == '\\':
-                           escape_type,
-                           value,
-                           index = expand_escape(pattern,
-                                                 index + 1,
-                                                 CHARCLASS)
-
-                           if escape_type == CHAR:
-                               end = value
-                               
-                           else:
-                               raise error, ('illegal escape in character '
-                                             'class range')
-                       else:
-                           end = pattern[index]
-                           index = index + 1
-
-                       if start > end:
-                           raise error, ('range arguments out of order '
-                                         'in character class')
-                       
-                       for char in map(chr, range(ord(start), ord(end) + 1)):
-                           if char not in set:
-                               set.append(char)
-                           
-                       last = ''
-
-               elif next == '\\':
-                   # expand syntax meta-characters and add to set
-                   if index >= len(pattern):
-                       raise error, 'incomplete set'
-
-                   escape_type, value, index = expand_escape(pattern,
-                                                             index,
-                                                             CHARCLASS)
-
-                   if escape_type == CHAR:
-                       set.append(value)
-                       last = value
-
-                   elif escape_type == SET:
-                       for char in value:
-                           if char not in set:
-                               set.append(char)
-                       last = ''
-
-                   else:
-                       raise error, 'illegal escape type in character class'
-
-               else:
-                   if next not in set:
-                       set.append(next)
-                   last = next
-                   
-           if (index >= len(pattern)) or ( pattern[index] != ']'):
-               raise error, 'incomplete set'
-
-           index = index + 1
-
-           if negate:
-               # If case is being ignored, then both upper- and lowercase
-               # versions of the letters must be excluded.
-               if flags & IGNORECASE: set=set+map(string.upper, set)
-               notset = []
-               for char in map(chr, range(256)):
-                   if char not in set:
-                       notset.append(char)
-               if len(notset) == 0:
-                   raise error, 'empty negated set'
-               stack.append([Set(notset, flags)])
-           else:
-               if len(set) == 0:
-                   raise error, 'empty set'
-               stack.append([Set(set, flags)])
-
-           lastop = '[]'
-
-       else:
-           stack.append([Exact(char, flags)])
-           lastop = char
-
-    code = []
-    while len(stack) > 0:
-       if stack[-1][0].name == '(':
-           raise error, 'too many open parens'
-       code = stack[-1] + code
-       del stack[-1]
-    if len(code) == 0:
-       raise error, 'no code generated'
-    code = filter(lambda x: x.name != '|', code)
-    need_label = 0
-    for i in range(len(code)):
-       if (code[i].name == 'jump') and (code[i].label == -1):
-           code[i] = Jump(label)
-           need_label = 1
-    if need_label:
-       code.append(Label(label))
-       label = label + 1
-    code.append(End())
-#    print code
-    return RegexObject(pattern, flags, code, register, groupindex)
-
-# Replace expand_escape and _expand functions with their C equivalents.
-# If you suspect bugs in the C versions, comment out the next two lines
-expand_escape = reop.expand_escape
-_expand  = reop._expand
diff --git a/Lib/re1.py b/Lib/re1.py
new file mode 100644 (file)
index 0000000..6c24797
--- /dev/null
@@ -0,0 +1,1508 @@
+#!/usr/bin/env python
+# -*- mode: python -*-
+# $Id$
+
+import string
+import reop
+
+# reop.error and re.error should be the same, since exceptions can be
+# raised from  either module.
+error = reop.error # 're error'
+
+from reop import NORMAL, CHARCLASS, REPLACEMENT
+from reop import CHAR, MEMORY_REFERENCE, SYNTAX, NOT_SYNTAX, SET
+from reop import WORD_BOUNDARY, NOT_WORD_BOUNDARY, BEGINNING_OF_BUFFER, END_OF_BUFFER
+
+# compilation flags
+
+IGNORECASE = I = 0x01
+
+MULTILINE = M = 0x02
+DOTALL = S = 0x04
+VERBOSE = X = 0x08
+
+repetition_operators = ['*', '*?', '+', '+?', '?', '??', '{n}', '{n}?',
+                       '{n,}', '{n,}?', '{n,m}', '{n,m}?']
+
+#
+#
+#
+
+def valid_identifier(id):
+    if len(id) == 0:
+       return 0
+    if (not reop.syntax_table[id[0]] & reop.word) or \
+       (reop.syntax_table[id[0]] & reop.digit):
+       return 0
+    for char in id[1:]:
+       if not reop.syntax_table[char] & reop.word:
+           return 0
+    return 1
+
+#
+#
+#
+
+_cache = {}
+_MAXCACHE = 20
+
+def _cachecompile(pattern, flags=0):
+    key = (pattern, flags)
+    try:
+       return _cache[key]
+    except KeyError:
+       pass
+    value = compile(pattern, flags)
+    if len(_cache) >= _MAXCACHE:
+       _cache.clear()
+    _cache[key] = value
+    return value
+
+def match(pattern, string, flags=0):
+    return _cachecompile(pattern, flags).match(string)
+  
+def search(pattern, string, flags=0):
+    return _cachecompile(pattern, flags).search(string)
+  
+def sub(pattern, repl, string, count=0):
+    if type(pattern) == type(''):
+       pattern = _cachecompile(pattern)
+    return pattern.sub(repl, string, count)
+
+def subn(pattern, repl, string, count=0):
+    if type(pattern) == type(''):
+       pattern = _cachecompile(pattern)
+    return pattern.subn(repl, string, count)
+  
+def split(pattern, string, maxsplit=0):
+    if type(pattern) == type(''):
+       pattern = _cachecompile(pattern)
+    return pattern.split(string, maxsplit)
+
+#
+#
+#
+
+def _expand(m, repl):
+    results = []
+    index = 0
+    size = len(repl)
+    while index < size:
+       found = string.find(repl, '\\', index)
+       if found < 0:
+           results.append(repl[index:])
+           break
+       if found > index:
+           results.append(repl[index:found])
+       escape_type, value, index = expand_escape(repl, found+1, REPLACEMENT)
+       if escape_type == CHAR:
+           results.append(value)
+       elif escape_type == MEMORY_REFERENCE:
+           r = m.group(value)
+           if r is None:
+               raise error, ('group "' + str(value) + '" did not contribute '
+                             'to the match')
+           results.append(m.group(value))
+       else:
+           raise error, "bad escape in replacement"
+    return string.join(results, '')
+
+class RegexObject:
+    def __init__(self, pattern, flags, code, num_regs, groupindex):
+       self.code = code
+       self.num_regs = num_regs
+       self.flags = flags
+       self.pattern = pattern
+       self.groupindex = groupindex
+       self.fastmap = build_fastmap(code)
+       
+       if code[0].name == 'bol':
+           self.anchor = 1
+           
+       elif code[0].name == 'begbuf':
+           self.anchor = 2
+           
+       else:
+           self.anchor = 0
+           
+       self.buffer = assemble(code)
+    def search(self, string, pos=0):
+       regs = reop.search(self.buffer,
+                          self.num_regs,
+                          self.flags,
+                          self.fastmap.can_be_null,
+                          self.fastmap.fastmap(),
+                          self.anchor,
+                          string,
+                          pos)
+       if regs is None:
+           return None
+       
+       return MatchObject(self,
+                          string,
+                          pos,
+                          regs)
+    
+    def match(self, string, pos=0):
+       regs = reop.match(self.buffer,
+                         self.num_regs,
+                         self.flags,
+                         self.fastmap.can_be_null,
+                         self.fastmap.fastmap(),
+                         self.anchor,
+                         string,
+                         pos)
+       if regs is None:
+           return None
+       
+       return MatchObject(self,
+                          string,
+                          pos,
+                          regs)
+    
+    def sub(self, repl, string, count=0):
+        return self.subn(repl, string, count)[0]
+    
+    def subn(self, repl, source, count=0):
+       if count < 0:
+           raise ValueError, "negative substibution count"
+       if count == 0:
+           import sys
+           count = sys.maxint
+       if type(repl) == type(''):
+           if '\\' in repl:
+               repl = lambda m, r=repl: _expand(m, r)
+           else:
+               repl = lambda m, r=repl: r
+       n = 0           # Number of matches
+       pos = 0         # Where to start searching
+       lastmatch = -1  # End of last match
+       results = []    # Substrings making up the result
+       end = len(source)
+       while n < count and pos <= end:
+           m = self.search(source, pos)
+           if not m:
+               break
+           i, j = m.span(0)
+           if i == j == lastmatch:
+               # Empty match adjacent to previous match
+               pos = pos + 1
+               results.append(source[lastmatch:pos])
+               continue
+           if pos < i:
+               results.append(source[pos:i])
+           results.append(repl(m))
+           pos = lastmatch = j
+           if i == j:
+               # Last match was empty; don't try here again
+               pos = pos + 1
+               results.append(source[lastmatch:pos])
+           n = n + 1
+       results.append(source[pos:])
+       return (string.join(results, ''), n)
+                                                                           
+    def split(self, source, maxsplit=0):
+       if maxsplit < 0:
+           raise error, "negative split count"
+       if maxsplit == 0:
+           import sys
+           maxsplit = sys.maxint
+       n = 0
+       pos = 0
+       lastmatch = 0
+       results = []
+       end = len(source)
+       while n < maxsplit:
+           m = self.search(source, pos)
+           if not m:
+               break
+           i, j = m.span(0)
+           if i == j:
+               # Empty match
+               if pos >= end:
+                   break
+               pos = pos+1
+               continue
+           results.append(source[lastmatch:i])
+           g = m.group()
+           if g:
+               results[len(results):] = list(g)
+           pos = lastmatch = j
+       results.append(source[lastmatch:])
+       return results
+
+class MatchObject:
+    def __init__(self, re, string, pos, regs):
+       self.re = re
+       self.string = string
+       self.pos = pos
+       self.regs = regs
+       
+    def start(self, g):
+       if type(g) == type(''):
+           try:
+               g = self.re.groupindex[g]
+           except (KeyError, TypeError):
+               raise IndexError, ('group "' + g + '" is undefined')
+       return self.regs[g][0]
+    
+    def end(self, g):
+       if type(g) == type(''):
+           try:
+               g = self.re.groupindex[g]
+           except (KeyError, TypeError):
+               raise IndexError, ('group "' + g + '" is undefined')
+       return self.regs[g][1]
+    
+    def span(self, g):
+       if type(g) == type(''):
+           try:
+               g = self.re.groupindex[g]
+           except (KeyError, TypeError):
+               raise IndexError, ('group "' + g + '" is undefined')
+       return self.regs[g]
+    
+    def group(self, *groups):
+       if len(groups) == 0:
+           groups = range(1, self.re.num_regs)
+           use_all = 1
+       else:
+           use_all = 0
+       result = []
+       for g in groups:
+           if type(g) == type(''):
+               try:
+                   g = self.re.groupindex[g]
+               except (KeyError, TypeError):
+                   raise IndexError, ('group "' + g + '" is undefined')
+           if (self.regs[g][0] == -1) or (self.regs[g][1] == -1):
+               result.append(None)
+           else:
+               result.append(self.string[self.regs[g][0]:self.regs[g][1]])
+       if use_all or len(result) > 1:
+           return tuple(result)
+       elif len(result) == 1:
+           return result[0]
+       else:
+           return ()
+
+#
+# A set of classes to make assembly a bit easier, if a bit verbose.
+#
+
+class Instruction:
+    def __init__(self, opcode, size=1):
+       self.opcode = opcode
+       self.size = size
+    def assemble(self, position, labels):
+       return self.opcode
+    def __repr__(self):
+       return '%-15s' % (self.name)
+
+class End(Instruction):
+    name = 'end'
+    def __init__(self):
+       Instruction.__init__(self, chr(0))
+
+class Bol(Instruction):
+    name = 'bol'
+    def __init__(self):
+       self.name = 'bol'
+       Instruction.__init__(self, chr(1))
+
+class Eol(Instruction):
+    name = 'eol'
+    def __init__(self):
+       Instruction.__init__(self, chr(2))
+
+class Set(Instruction):
+    name = 'set'
+    def __init__(self, set, flags=0):
+       self.set = set
+       if flags & IGNORECASE: self.set=map(string.lower, self.set)
+       if len(set)==1: 
+           # If only one element, use the "exact" opcode (it'll be faster)
+           Instruction.__init__(self, chr(4), 2)
+       else:
+           # Use the "set" opcode
+           Instruction.__init__(self, chr(3), 33)
+    def assemble(self, position, labels):
+       if len(self.set)==1:
+           # If only one character in set, generate an "exact" opcode
+           return self.opcode + self.set[0]
+       result = self.opcode
+       temp = 0
+       for i, c in map(lambda x: (x, chr(x)), range(256)):
+           if c in self.set:
+               temp = temp | (1 << (i & 7))
+           if (i % 8) == 7:
+               result = result + chr(temp)
+               temp = 0
+       return result
+    def __repr__(self):
+       result = '%-15s' % (self.name)
+       self.set.sort()
+       # XXX this should print more intelligently
+       for char in self.set:
+           result = result + char
+       return result
+    
+class Exact(Instruction):
+    name = 'exact'
+    def __init__(self, char, flags):
+       self.char = char
+       if flags & IGNORECASE: self.char=string.lower(self.char)
+       Instruction.__init__(self, chr(4), 2)
+    def assemble(self, position, labels):
+       return self.opcode + self.char
+    def __repr__(self):
+       return '%-15s %s' % (self.name, `self.char`)
+    
+class AnyChar(Instruction):
+    name = 'anychar'
+    def __init__(self):
+       Instruction.__init__(self, chr(5))
+    def assemble(self, position, labels):
+       return self.opcode
+
+class MemoryInstruction(Instruction):
+    def __init__(self, opcode, register):
+       self.register = register
+       Instruction.__init__(self, opcode, 2)
+    def assemble(self, position, labels):
+       return self.opcode + chr(self.register)
+    def __repr__(self):
+       return '%-15s %i' % (self.name, self.register)
+
+class StartMemory(MemoryInstruction):
+    name = 'start_memory'
+    def __init__(self, register):
+       MemoryInstruction.__init__(self, chr(6), register)
+
+class EndMemory(MemoryInstruction):
+    name = 'end_memory'
+    def __init__(self, register):
+       MemoryInstruction.__init__(self, chr(7), register)
+
+class MatchMemory(MemoryInstruction):
+    name = 'match_memory'
+    def __init__(self, register):
+       MemoryInstruction.__init__(self, chr(8), register)
+
+class JumpInstruction(Instruction):
+    def __init__(self, opcode, label):
+       self.label = label
+       Instruction.__init__(self, opcode, 3)
+    def compute_offset(self, start, dest):
+       return dest - (start + 3)
+    def pack_offset(self, offset):
+       if offset > 32767:
+           raise error, 'offset out of range (pos)'
+       elif offset < -32768:
+           raise error, 'offset out of range (neg)'
+       elif offset < 0:
+           offset = offset + 65536
+       return chr(offset & 0xff) + chr((offset >> 8) & 0xff)
+    def assemble(self, position, labels):
+       return self.opcode + \
+              self.pack_offset(self.compute_offset(position,
+                                                   labels[self.label]))
+    def __repr__(self):
+       return '%-15s %i' % (self.name, self.label)
+
+class Jump(JumpInstruction):
+    name = 'jump'
+    def __init__(self, label):
+       JumpInstruction.__init__(self, chr(9), label)
+
+class StarJump(JumpInstruction):
+    name = 'star_jump'
+    def __init__(self, label):
+       JumpInstruction.__init__(self, chr(10), label)
+
+class FailureJump(JumpInstruction):
+    name = 'failure_jump'
+    def __init__(self, label):
+       JumpInstruction.__init__(self, chr(11), label)
+
+class UpdateFailureJump(JumpInstruction):
+    name = 'update_failure_jump'
+    def __init__(self, label):
+       JumpInstruction.__init__(self, chr(12), label)
+
+class DummyFailureJump(JumpInstruction):
+    name = 'dummy_failure_jump'
+    def __init__(self, label):
+       JumpInstruction.__init__(self, chr(13), label)
+       
+class BegBuf(Instruction):
+    name = 'begbuf'
+    def __init__(self):
+       Instruction.__init__(self, chr(14))
+
+class EndBuf(Instruction):
+    name = 'endbuf'
+    def __init__(self):
+       Instruction.__init__(self, chr(15))
+
+class WordBeg(Instruction):
+    name = 'wordbeg'
+    def __init__(self):
+       Instruction.__init__(self, chr(16))
+
+class WordEnd(Instruction):
+    name = 'wordend'
+    def __init__(self):
+       Instruction.__init__(self, chr(17))
+
+class WordBound(Instruction):
+    name = 'wordbound'
+    def __init__(self):
+       Instruction.__init__(self, chr(18))
+
+class NotWordBound(Instruction):
+    name = 'notwordbound'
+    def __init__(self):
+       Instruction.__init__(self, chr(19))
+
+class SyntaxSpec(Instruction):
+    name = 'syntaxspec'
+    def __init__(self, syntax):
+       self.syntax = syntax
+       Instruction.__init__(self, chr(20), 2)
+    def assemble(self, postition, labels):
+       return self.opcode + chr(self.syntax)
+
+class NotSyntaxSpec(Instruction):
+    name = 'notsyntaxspec'
+    def __init__(self, syntax):
+       self.syntax = syntax
+       Instruction.__init__(self, chr(21), 2)
+    def assemble(self, postition, labels):
+       return self.opcode + chr(self.syntax)
+
+class Label(Instruction):
+    name = 'label'
+    def __init__(self, label):
+       self.label = label
+       Instruction.__init__(self, '', 0)
+    def __repr__(self):
+       return '%-15s %i' % (self.name, self.label)
+
+class OpenParen(Instruction):
+    name = '('
+    def __init__(self, register):
+       self.register = register
+       Instruction.__init__(self, '', 0)
+    def assemble(self, position, labels):
+       raise error, 'unmatched open parenthesis'
+
+class Alternation(Instruction):
+    name = '|'
+    def __init__(self):
+       Instruction.__init__(self, '', 0)
+    def assemble(self, position, labels):
+       raise error, 'an alternation was not taken care of'
+
+#
+#
+#
+
+def assemble(instructions):
+    labels = {}
+    position = 0
+    pass1 = []
+    for instruction in instructions:
+       if instruction.name == 'label':
+           labels[instruction.label] = position
+       else:
+           pass1.append((position, instruction))
+           position = position + instruction.size
+    pass2 = ''
+    for position, instruction in pass1:
+       pass2 = pass2 + instruction.assemble(position, labels)
+    return pass2
+
+#
+#
+#
+
+def escape(pattern):
+    result = []
+    for char in pattern:
+       if not reop.syntax_table[char] & reop.word:
+           result.append('\\')
+       result.append(char)
+    return string.join(result, '')
+
+#
+#
+#
+
+def registers_used(instructions):
+    result = []
+    for instruction in instructions:
+       if (instruction.name in ['set_memory', 'end_memory']) and \
+          (instruction.register not in result):
+           result.append(instruction.register)
+    return result
+
+#
+#
+#
+
+class Fastmap:
+    def __init__(self):
+       self.map = ['\000']*256
+       self.can_be_null = 0
+    def add(self, char):
+       self.map[ord(char)] = '\001'
+    def fastmap(self):
+       return string.join(self.map, '')
+    def __getitem__(self, char):
+       return ord(self.map[ord(char)])
+    def __repr__(self):
+       self.map.sort()
+       return 'Fastmap(' + `self.can_be_null` + ', ' + `self.map` + ')'
+
+#
+#
+#
+
+def find_label(code, label):
+    line = 0
+    for instruction in code:
+       if (instruction.name == 'label') and (instruction.label == label):
+           return line + 1
+       line = line + 1
+       
+def build_fastmap_aux(code, pos, visited, fastmap):
+    if visited[pos]:
+       return
+    while 1:
+       instruction = code[pos]
+       visited[pos] = 1
+       pos = pos + 1
+       if instruction.name == 'end':
+           fastmap.can_be_null = 1
+           return
+       elif instruction.name == 'syntaxspec':
+           for char in map(chr, range(256)):
+               if reop.syntax_table[char] & instruction.syntax:
+                   fastmap.add(char)
+           return
+       elif instruction.name == 'notsyntaxspec':
+           for char in map(chr, range(256)):
+               if not reop.syntax_table[char] & instruction.syntax:
+                   fastmap.add(char)
+           return
+       elif instruction.name == 'eol':
+           fastmap.add('\n')
+           if fastmap.can_be_null == 0:
+               fastmap.can_be_null = 2
+           return
+       elif instruction.name == 'set':
+           for char in instruction.set:
+               fastmap.add(char)
+           return
+       elif instruction.name == 'exact':
+           fastmap.add(instruction.char)
+       elif instruction.name == 'anychar':
+           for char in map(chr, range(256)):
+               if char != '\n':
+                   fastmap.add(char)
+           return
+       elif instruction.name == 'match_memory':
+           for char in map(chr, range(256)):
+               fastmap.add(char)
+           fastmap.can_be_null = 1
+           return
+       elif instruction.name in ['jump', 'dummy_failure_jump', \
+                                 'update_failure_jump', 'star_jump']:
+           pos = find_label(code, instruction.label)
+           if visited[pos]:
+               return
+           visited[pos] = 1
+       elif instruction.name  == 'failure_jump':
+           build_fastmap_aux(code,
+                             find_label(code, instruction.label),
+                             visited,
+                             fastmap)
+       
+def build_fastmap(code, pos=0):
+    visited = [0] * len(code)
+    fastmap = Fastmap()
+    build_fastmap_aux(code, pos, visited, fastmap)
+    return fastmap
+
+#
+#
+#
+
+#[NORMAL, CHARCLASS, REPLACEMENT] = range(3)
+#[CHAR, MEMORY_REFERENCE, SYNTAX, NOT_SYNTAX, SET, WORD_BOUNDARY,
+# NOT_WORD_BOUNDARY, BEGINNING_OF_BUFFER, END_OF_BUFFER] = range(9)
+
+def expand_escape(pattern, index, context=NORMAL):
+    if index >= len(pattern):
+       raise error, 'escape ends too soon'
+
+    elif pattern[index] == 't':
+       return CHAR, chr(9), index + 1
+    
+    elif pattern[index] == 'n':
+       return CHAR, chr(10), index + 1
+    
+    elif pattern[index] == 'v':
+       return CHAR, chr(11), index + 1
+    
+    elif pattern[index] == 'r':
+       return CHAR, chr(13), index + 1
+    
+    elif pattern[index] == 'f':
+       return CHAR, chr(12), index + 1
+    
+    elif pattern[index] == 'a':
+       return CHAR, chr(7), index + 1
+    
+    elif pattern[index] == 'x':
+       # CAUTION: this is the Python rule, not the Perl rule!
+       end = index + 1  # Skip over the 'x' character
+       while (end < len(pattern)) and (pattern[end] in string.hexdigits):
+           end = end + 1
+       if end == index:
+           raise error, "\\x must be followed by hex digit(s)"
+       # let Python evaluate it, so we don't incorrectly 2nd-guess
+       # what it's doing (and Python in turn passes it on to sscanf,
+       # so that *it* doesn't incorrectly 2nd-guess what C does!)
+       char = eval ('"' + pattern[index-1:end] + '"')
+       assert len(char) == 1
+       return CHAR, char, end
+
+    elif pattern[index] == 'b':
+       if context != NORMAL:
+           return CHAR, chr(8), index + 1
+       else:
+           return WORD_BOUNDARY, '', index + 1
+           
+    elif pattern[index] == 'B':
+       if context != NORMAL:
+           return CHAR, 'B', index + 1
+       else:
+           return NOT_WORD_BOUNDARY, '', index + 1
+           
+    elif pattern[index] == 'A':
+       if context != NORMAL:
+           return CHAR, 'A', index + 1
+       else:
+           return BEGINNING_OF_BUFFER, '', index + 1
+           
+    elif pattern[index] == 'Z':
+       if context != NORMAL:
+           return CHAR, 'Z', index + 1
+       else:
+           return END_OF_BUFFER, '', index + 1
+           
+    elif pattern[index] in 'GluLUQE':
+       raise error, ('\\' + pattern[index] + ' is not allowed')
+    
+    elif pattern[index] == 'w':
+       if context == NORMAL:
+           return SYNTAX, reop.word, index + 1
+       elif context == CHARCLASS:
+           set = []
+           for char in reop.syntax_table.keys():
+               if reop.syntax_table[char] & reop.word:
+                   set.append(char)
+           return SET, set, index + 1
+       else:
+           return CHAR, 'w', index + 1
+       
+    elif pattern[index] == 'W':
+       if context == NORMAL:
+           return NOT_SYNTAX, reop.word, index + 1
+       elif context == CHARCLASS:
+           set = []
+           for char in reop.syntax_table.keys():
+               if not reop.syntax_table[char] & reop.word:
+                   set.append(char)
+           return SET, set, index + 1
+       else:
+           return CHAR, 'W', index + 1
+       
+    elif pattern[index] == 's':
+       if context == NORMAL:
+           return SYNTAX, reop.whitespace, index + 1
+       elif context == CHARCLASS:
+           set = []
+           for char in reop.syntax_table.keys():
+               if reop.syntax_table[char] & reop.whitespace:
+                   set.append(char)
+           return SET, set, index + 1
+       else:
+           return CHAR, 's', index + 1
+       
+    elif pattern[index] == 'S':
+       if context == NORMAL:
+           return NOT_SYNTAX, reop.whitespace, index + 1
+       elif context == CHARCLASS:
+           set = []
+           for char in reop.syntax_table.keys():
+               if not reop.syntax_table[char] & reop.whitespace:
+                   set.append(char)
+           return SET, set, index + 1
+       else:
+           return CHAR, 'S', index + 1
+       
+    elif pattern[index] == 'd':
+       if context == NORMAL:
+           return SYNTAX, reop.digit, index + 1
+       elif context == CHARCLASS:
+           set = []
+           for char in reop.syntax_table.keys():
+               if reop.syntax_table[char] & reop.digit:
+                   set.append(char)
+           return SET, set, index + 1
+       else:
+           return CHAR, 'd', index + 1
+       
+    elif pattern[index] == 'D':
+       if context == NORMAL:
+           return NOT_SYNTAX, reop.digit, index + 1
+       elif context == CHARCLASS:
+           set = []
+           for char in reop.syntax_table.keys():
+               if not reop.syntax_table[char] & reop.digit:
+                   set.append(char)
+           return SET, set, index + 1
+       else:
+           return CHAR, 'D', index + 1
+
+    elif pattern[index] in '0123456789':
+
+       if pattern[index] == '0':
+           if (index + 1 < len(pattern)) and \
+              (pattern[index + 1] in string.octdigits):
+               if (index + 2 < len(pattern)) and \
+                  (pattern[index + 2] in string.octdigits):
+                   value = string.atoi(pattern[index:index + 3], 8)
+                   index = index + 3
+
+               else:
+                   value = string.atoi(pattern[index:index + 2], 8)
+                   index = index + 2
+
+           else:
+               value = 0
+               index = index + 1
+
+           if value > 255:
+               raise error, 'octal value out of range'
+
+           return CHAR, chr(value), index
+       
+       else:
+           if (index + 1 < len(pattern)) and \
+              (pattern[index + 1] in string.digits):
+               if (index + 2 < len(pattern)) and \
+                  (pattern[index + 2] in string.octdigits) and \
+                  (pattern[index + 1] in string.octdigits) and \
+                  (pattern[index] in string.octdigits):
+                   value = string.atoi(pattern[index:index + 3], 8)
+                   if value > 255:
+                       raise error, 'octal value out of range'
+
+                   return CHAR, chr(value), index + 3
+
+               else:
+                   value = string.atoi(pattern[index:index + 2])
+                   if (value < 1) or (value > 99):
+                       raise error, 'memory reference out of range'
+
+                   if context == CHARCLASS:
+                       raise error, ('cannot reference a register from '
+                                     'inside a character class')
+                   return MEMORY_REFERENCE, value, index + 2
+
+           else:
+               if context == CHARCLASS:
+                   raise error, ('cannot reference a register from '
+                                 'inside a character class')
+
+               value = string.atoi(pattern[index])
+               return MEMORY_REFERENCE, value, index + 1
+           
+    elif pattern[index] == 'g':
+       if context != REPLACEMENT:
+           return CHAR, 'g', index + 1
+
+       index = index + 1
+       if index >= len(pattern):
+           raise error, 'unfinished symbolic reference'
+       if pattern[index] != '<':
+           raise error, 'missing < in symbolic reference'
+
+       index = index + 1
+       end = string.find(pattern, '>', index)
+       if end == -1:
+           raise error, 'unfinished symbolic reference'
+       value = pattern[index:end]
+       if not valid_identifier(value):
+           raise error, 'illegal symbolic reference'
+       return MEMORY_REFERENCE, value, end + 1
+    
+    else:
+       return CHAR, pattern[index], index + 1
+
+def compile(pattern, flags=0):
+    stack = []
+    label = 0
+    register = 1
+    groupindex = {}
+    lastop = ''
+
+    # look for embedded pattern modifiers at the beginning of the pattern
+
+    index = 0
+
+    if len(pattern) >= 3 and \
+       (pattern[:2] == '(?') and \
+       (pattern[2] in 'iImMsSxX'):
+       index = 2
+       while (index < len(pattern)) and (pattern[index] != ')'):
+           if pattern[index] in 'iI':
+               flags = flags | IGNORECASE
+           elif pattern[index] in 'mM':
+               flags = flags | MULTILINE
+           elif pattern[index] in 'sS':
+               flags = flags | DOTALL
+           elif pattern[index] in 'xX':
+               flags = flags | VERBOSE
+           else:
+               raise error, 'unknown modifier'
+           index = index + 1
+       index = index + 1
+
+    # compile the rest of the pattern
+    
+    while (index < len(pattern)):
+       char = pattern[index]
+       index = index + 1
+       if char == '\\':
+           escape_type, value, index = expand_escape(pattern, index)
+
+           if escape_type == CHAR:
+               stack.append([Exact(value, flags)])
+               lastop = '\\' + value
+               
+           elif escape_type == MEMORY_REFERENCE:
+               if value >= register:
+                   raise error, ('cannot reference a register '
+                                 'not yet used')
+               stack.append([MatchMemory(value)])
+               lastop = '\\1'
+               
+           elif escape_type == BEGINNING_OF_BUFFER:
+               stack.append([BegBuf()])
+               lastop = '\\A'
+               
+           elif escape_type == END_OF_BUFFER:
+               stack.append([EndBuf()])
+               lastop = '\\Z'
+               
+           elif escape_type == WORD_BOUNDARY:
+               stack.append([WordBound()])
+               lastop = '\\b'
+               
+           elif escape_type == NOT_WORD_BOUNDARY:
+               stack.append([NotWordBound()])
+               lastop = '\\B'
+               
+           elif escape_type == SYNTAX:
+               stack.append([SyntaxSpec(value)])
+               if value == reop.word:
+                   lastop = '\\w'
+               elif value == reop.whitespace:
+                   lastop = '\\s'
+               elif value == reop.digit:
+                   lastop = '\\d'
+               else:
+                   lastop = '\\?'
+                   
+           elif escape_type == NOT_SYNTAX:
+               stack.append([NotSyntaxSpec(value)])
+               if value == reop.word:
+                   lastop = '\\W'
+               elif value == reop.whitespace:
+                   lastop = '\\S'
+               elif value == reop.digit:
+                   lastop = '\\D'
+               else:
+                   lastop = '\\?'
+               
+           elif escape_type == SET:
+               raise error, 'cannot use set escape type here'
+           
+           else:
+               raise error, 'unknown escape type'
+
+       elif char == '|':
+           expr = []
+           
+           while (len(stack) != 0) and \
+                 (stack[-1][0].name != '(') and \
+                 (stack[-1][0].name != '|'):
+               expr = stack[-1] + expr
+               del stack[-1]
+           stack.append([FailureJump(label)] + \
+                        expr + \
+                        [Jump(-1),
+                         Label(label)])
+           stack.append([Alternation()])
+           label = label + 1
+           lastop = '|'
+           
+       elif char == '(':
+           if index >= len(pattern):
+               raise error, 'no matching close paren'
+
+           elif pattern[index] == '?':
+               # Perl style (?...) extensions
+               index = index + 1
+               if index >= len(pattern):
+                   raise error, 'extension ends prematurely'
+
+               elif pattern[index] == 'P':
+                   # Python extensions
+                   index = index + 1
+                   if index >= len(pattern):
+                       raise error, 'extension ends prematurely'
+
+                   elif pattern[index] == '<':
+                       # Handle Python symbolic group names (?P<...>...)
+                       index = index + 1
+                       end = string.find(pattern, '>', index)
+                       if end == -1:
+                           raise error, 'no end to symbolic group name'
+                       name = pattern[index:end]
+                       if not valid_identifier(name):
+                           raise error, ('symbolic group name must be a '
+                                         'valid identifier')
+                       index = end + 1
+                       groupindex[name] = register
+                       stack.append([OpenParen(register)])
+                       register = register + 1
+                       lastop = '('
+
+                   elif pattern[index] == '=':
+                       # backreference to symbolic group name
+                       if index >= len(pattern):
+                           raise error, '(?P= at the end of the pattern'
+                       start = index + 1
+                       end = string.find(pattern, ')', start)
+                       if end == -1:
+                           raise error, 'no ) to end symbolic group name'
+                       name = pattern[start:end]
+                       if name not in groupindex.keys():
+                           raise error, ('symbolic group name ' + name + \
+                                         ' has not been used yet')
+                       stack.append([MatchMemory(groupindex[name])])
+                       index = end + 1
+                       lastop = '(?P=)'
+                       
+                   else:
+                       raise error, ('unknown Python extension: ' + \
+                                     pattern[index])
+                   
+               elif pattern[index] == ':':
+                   # grouping, but no registers
+                   index = index + 1
+                   stack.append([OpenParen(-1)])
+                   lastop = '('
+                   
+               elif pattern[index] == '#':
+                   # comment
+                   index = index + 1
+                   end = string.find(pattern, ')', index)
+                   if end == -1:
+                       raise error, 'no end to comment'
+                   index = end + 1
+                   # do not change lastop
+                   
+               elif pattern[index] == '=':
+                   raise error, ('zero-width positive lookahead '
+                                 'assertion is unsupported')
+
+               elif pattern[index] == '!':
+                   raise error, ('zero-width negative lookahead '
+                                 'assertion is unsupported')
+
+               elif pattern[index] in 'iImMsSxX':
+                   raise error, ('embedded pattern modifiers are only '
+                                 'allowed at the beginning of the pattern')
+
+               else:
+                   raise error, 'unknown extension'
+
+           else:
+               stack.append([OpenParen(register)])
+               register = register + 1
+               lastop = '('
+
+       elif char == ')':
+           # make one expression out of everything on the stack up to
+           # the marker left by the last parenthesis
+           expr = []
+           while (len(stack) > 0) and (stack[-1][0].name != '('):
+               expr = stack[-1] + expr
+               del stack[-1]
+
+           if len(stack) == 0:
+               raise error, 'too many close parens'
+           
+           # remove markers left by alternation
+           expr = filter(lambda x: x.name != '|', expr)
+
+           # clean up jumps inserted by alternation
+           need_label = 0
+           for i in range(len(expr)):
+               if (expr[i].name == 'jump') and (expr[i].label == -1):
+                   expr[i] = Jump(label)
+                   need_label = 1
+           if need_label:
+               expr.append(Label(label))
+               label = label + 1
+
+           if stack[-1][0].register > 0:
+               expr = [StartMemory(stack[-1][0].register)] + \
+                      expr + \
+                      [EndMemory(stack[-1][0].register)]
+           del stack[-1]
+           stack.append(expr)
+           lastop = ')'
+
+       elif char == '{':
+           if len(stack) == 0:
+               raise error, 'no expression to repeat'
+           end = string.find(pattern, '}', index)
+           if end == -1:
+               raise error, ('no close curly bracket to match'
+                             ' open curly bracket')
+
+           fields = map(string.strip,
+                        string.split(pattern[index:end], ','))
+           index = end + 1
+
+           minimal = 0
+           if (index < len(pattern)) and (pattern[index] == '?'):
+               minimal = 1
+               index = index + 1
+
+           if len(fields) == 1:
+               # {n} or {n}? (there's really no difference)
+               try:
+                   count = string.atoi(fields[0])
+               except ValueError:
+                   raise error, ('count must be an integer '
+                                 'inside curly braces')
+               if count > 65535:
+                   raise error, 'repeat count out of range'
+               expr = []
+               while count > 0:
+                   expr = expr + stack[-1]
+                   count = count - 1
+               del stack[-1]
+               stack.append(expr)
+               if minimal:
+                   lastop = '{n}?'
+               else:
+                   lastop = '{n}'
+
+           elif len(fields) == 2:
+               # {n,} or {n,m}
+               if fields[1] == '':
+                   # {n,}
+                   try:
+                       min = string.atoi(fields[0])
+                   except ValueError:
+                       raise error, ('minimum must be an integer '
+                                     'inside curly braces')
+                   if min > 65535:
+                       raise error, 'minimum repeat count out of range'
+
+                   expr = []
+                   while min > 0:
+                       expr = expr + stack[-1]
+                       min = min - 1
+                   if minimal:
+                       expr = expr + \
+                              ([Jump(label + 1),
+                                Label(label)] + \
+                               stack[-1] + \
+                               [Label(label + 1),
+                                FailureJump(label)])
+                       lastop = '{n,}?'
+                   else:
+                       expr = expr + \
+                              ([Label(label),
+                                FailureJump(label + 1)] +
+                               stack[-1] +
+                               [StarJump(label),
+                                Label(label + 1)])
+                       lastop = '{n,}'
+
+                   del stack[-1]
+                   stack.append(expr)
+                   label = label + 2
+
+               else:
+                   # {n,m}
+                   try:
+                       min = string.atoi(fields[0])
+                   except ValueError:
+                       raise error, ('minimum must be an integer '
+                                     'inside curly braces')
+                   try:
+                       max = string.atoi(fields[1])
+                   except ValueError:
+                       raise error, ('maximum must be an integer '
+                                     'inside curly braces')
+                   if min > 65535:
+                       raise error, ('minumim repeat count out '
+                                     'of range')
+                   if max > 65535:
+                       raise error, ('maximum repeat count out '
+                                     'of range')
+                   if min > max:
+                       raise error, ('minimum repeat count must be '
+                                     'less than the maximum '
+                                     'repeat count')
+                   expr = []
+                   while min > 0:
+                       expr = expr + stack[-1]
+                       min = min - 1
+                       max = max - 1
+                   if minimal:
+                       while max > 0:
+                           expr = expr + \
+                                  [FailureJump(label),
+                                   Jump(label + 1),
+                                   Label(label)] + \
+                                  stack[-1] + \
+                                  [Label(label + 1)]
+                           max = max - 1
+                           label = label + 2
+                       del stack[-1]
+                       stack.append(expr)
+                       lastop = '{n,m}?'
+                   else:
+                       while max > 0:
+                           expr = expr + \
+                                  [FailureJump(label)] + \
+                                  stack[-1]
+                           max = max - 1
+                       del stack[-1]
+                       stack.append(expr + [Label(label)])
+                       label = label + 1
+                       lastop = '{n,m}'
+
+           else:
+               raise error, ('there need to be one or two fields '
+                             'in a {} expression')
+
+       elif char == '}':
+           raise error, 'unbalanced close curly brace'
+
+       elif char == '*':
+           # Kleene closure
+           if len(stack) == 0:
+               raise error, '* needs something to repeat'
+
+           if lastop in ['(', '|']:
+               raise error, '* needs something to repeat'
+
+           if lastop in repetition_operators:
+               raise error, 'nested repetition operators'
+           
+           if (index < len(pattern)) and (pattern[index] == '?'):
+               # non-greedy matching
+               expr = [Jump(label + 1),
+                       Label(label)] + \
+                      stack[-1] + \
+                      [Label(label + 1),
+                       FailureJump(label)]
+               index = index + 1
+               lastop = '*?'
+           else:
+               # greedy matching
+               expr = [Label(label),
+                       FailureJump(label + 1)] + \
+                      stack[-1] + \
+                      [StarJump(label),
+                       Label(label + 1)]
+               lastop = '*'
+           del stack[-1]
+           stack.append(expr)
+           label = label + 2
+
+       elif char == '+':
+           # positive closure
+           if len(stack) == 0:
+               raise error, '+ needs something to repeat'
+           
+           if lastop in ['(', '|']:
+               raise error, '+ needs something to repeat'
+
+           if lastop in repetition_operators:
+               raise error, 'nested repetition operators'
+
+           if (index < len(pattern)) and (pattern[index] == '?'):
+               # non-greedy
+               expr = [Label(label)] + \
+                      stack[-1] + \
+                      [FailureJump(label)]
+               label = label + 1
+               index = index + 1
+               lastop = '+?'
+               
+           else:
+               # greedy
+               expr = [DummyFailureJump(label + 1),
+                       Label(label),
+                       FailureJump(label + 2),
+                       Label(label + 1)] + \
+                      stack[-1] + \
+                      [StarJump(label),
+                       Label(label + 2)]
+               label = label + 3
+               lastop = '+'
+               
+           del stack[-1]
+           stack.append(expr)
+
+       elif char == '?':
+           if len(stack) == 0:
+               raise error, 'need something to be optional'
+           
+           if len(stack) == 0:
+               raise error, '? needs something to repeat'
+           
+           if lastop in ['(', '|']:
+               raise error, '? needs something to repeat'
+
+           if lastop in repetition_operators:
+               raise error, 'nested repetition operators'
+
+           if (index < len(pattern)) and (pattern[index] == '?'):
+               # non-greedy matching
+               expr = [FailureJump(label),
+                       Jump(label + 1),
+                       Label(label)] + \
+                      stack[-1] + \
+                      [Label(label + 1)]
+               label = label + 2
+               index = index + 1
+               lastop = '??'
+               
+           else:
+               # greedy matching
+               expr = [FailureJump(label)] + \
+                      stack[-1] + \
+                      [Label(label)]
+               label = label + 1
+               lastop = '?'
+               
+           del stack[-1]
+           stack.append(expr)
+
+       elif char == '.':
+           if flags & DOTALL:
+               stack.append([Set(map(chr, range(256)), flags)])
+           else:
+               stack.append([AnyChar()])
+           lastop = '.'
+
+       elif char == '^':
+           if flags & MULTILINE:
+               stack.append([Bol()])
+           else:
+               stack.append([BegBuf()])
+           lastop = '^'
+
+       elif char == '$':
+           if flags & MULTILINE:
+               stack.append([Eol()])
+           else:
+               stack.append([EndBuf()])
+           lastop = '$'
+
+       elif char == '#':
+           if flags & VERBOSE:
+               # comment
+               index = index + 1
+               end = string.find(pattern, '\n', index)
+               if end == -1:
+                   index = len(pattern)
+               else:
+                   index = end + 1
+               # do not change lastop
+           else:
+               stack.append([Exact(char, flags)])
+               lastop = '#'
+
+       elif char in string.whitespace:
+           if not (flags & VERBOSE):
+               stack.append([Exact(char, flags)])
+               lastop = char
+
+       elif char == '[':
+           # compile character class
+           
+           if index >= len(pattern):
+               raise error, 'unclosed character class'
+           
+           negate = 0
+           last = ''
+           set = []
+
+           if pattern[index] == '^':
+               negate = 1
+               index = index + 1
+               if index >= len(pattern):
+                   raise error, 'unclosed character class'
+
+           if pattern[index] == ']':
+               set.append(']')
+               index = index + 1
+               if index >= len(pattern):
+                   raise error, 'unclosed character class'
+               
+           elif pattern[index] == '-':
+               set.append('-')
+               index = index + 1
+               if index >= len(pattern):
+                   raise error, 'unclosed character class'
+               
+           while (index < len(pattern)) and (pattern[index] != ']'):
+               next = pattern[index]
+               index = index + 1
+               if next == '-':
+                   if index >= len(pattern):
+                       raise error, 'incomplete range in character class'
+
+                   elif pattern[index] == ']':
+                       set.append('-')
+                       
+                   else:
+                       if last == '':
+                           raise error, ('improper use of range in '
+                                         'character class')
+
+                       start = last
+                       
+                       if pattern[index] == '\\':
+                           escape_type,
+                           value,
+                           index = expand_escape(pattern,
+                                                 index + 1,
+                                                 CHARCLASS)
+
+                           if escape_type == CHAR:
+                               end = value
+                               
+                           else:
+                               raise error, ('illegal escape in character '
+                                             'class range')
+                       else:
+                           end = pattern[index]
+                           index = index + 1
+
+                       if start > end:
+                           raise error, ('range arguments out of order '
+                                         'in character class')
+                       
+                       for char in map(chr, range(ord(start), ord(end) + 1)):
+                           if char not in set:
+                               set.append(char)
+                           
+                       last = ''
+
+               elif next == '\\':
+                   # expand syntax meta-characters and add to set
+                   if index >= len(pattern):
+                       raise error, 'incomplete set'
+
+                   escape_type, value, index = expand_escape(pattern,
+                                                             index,
+                                                             CHARCLASS)
+
+                   if escape_type == CHAR:
+                       set.append(value)
+                       last = value
+
+                   elif escape_type == SET:
+                       for char in value:
+                           if char not in set:
+                               set.append(char)
+                       last = ''
+
+                   else:
+                       raise error, 'illegal escape type in character class'
+
+               else:
+                   if next not in set:
+                       set.append(next)
+                   last = next
+                   
+           if (index >= len(pattern)) or ( pattern[index] != ']'):
+               raise error, 'incomplete set'
+
+           index = index + 1
+
+           if negate:
+               # If case is being ignored, then both upper- and lowercase
+               # versions of the letters must be excluded.
+               if flags & IGNORECASE: set=set+map(string.upper, set)
+               notset = []
+               for char in map(chr, range(256)):
+                   if char not in set:
+                       notset.append(char)
+               if len(notset) == 0:
+                   raise error, 'empty negated set'
+               stack.append([Set(notset, flags)])
+           else:
+               if len(set) == 0:
+                   raise error, 'empty set'
+               stack.append([Set(set, flags)])
+
+           lastop = '[]'
+
+       else:
+           stack.append([Exact(char, flags)])
+           lastop = char
+
+    code = []
+    while len(stack) > 0:
+       if stack[-1][0].name == '(':
+           raise error, 'too many open parens'
+       code = stack[-1] + code
+       del stack[-1]
+    if len(code) == 0:
+       raise error, 'no code generated'
+    code = filter(lambda x: x.name != '|', code)
+    need_label = 0
+    for i in range(len(code)):
+       if (code[i].name == 'jump') and (code[i].label == -1):
+           code[i] = Jump(label)
+           need_label = 1
+    if need_label:
+       code.append(Label(label))
+       label = label + 1
+    code.append(End())
+#    print code
+    return RegexObject(pattern, flags, code, register, groupindex)
+
+# Replace expand_escape and _expand functions with their C equivalents.
+# If you suspect bugs in the C versions, comment out the next two lines
+expand_escape = reop.expand_escape
+_expand  = reop._expand