Merge trunk up to 43069, putting re.py back and hopefully making the branch

usable again.

1 files changed, 315 insertions, 0 deletions

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+#
+# Secret Labs' Regular Expression Engine
+#
+# re-compatible interface for the sre matching engine
+#
+# Copyright (c) 1998-2001 by Secret Labs AB.  All rights reserved.
+#
+# This version of the SRE library can be redistributed under CNRI's
+# Python 1.6 license.  For any other use, please contact Secret Labs
+# AB (info@pythonware.com).
+#
+# Portions of this engine have been developed in cooperation with
+# CNRI.  Hewlett-Packard provided funding for 1.6 integration and
+# other compatibility work.
+#
+
+r"""Support for regular expressions (RE).
+
+This module provides regular expression matching operations similar to
+those found in Perl.  It supports both 8-bit and Unicode strings; both
+the pattern and the strings being processed can contain null bytes and
+characters outside the US ASCII range.
+
+Regular expressions can contain both special and ordinary characters.
+Most ordinary characters, like "A", "a", or "0", are the simplest
+regular expressions; they simply match themselves.  You can
+concatenate ordinary characters, so last matches the string 'last'.
+
+The special characters are:
+    "."      Matches any character except a newline.
+    "^"      Matches the start of the string.
+    "$"      Matches the end of the string.
+    "*"      Matches 0 or more (greedy) repetitions of the preceding RE.
+             Greedy means that it will match as many repetitions as possible.
+    "+"      Matches 1 or more (greedy) repetitions of the preceding RE.
+    "?"      Matches 0 or 1 (greedy) of the preceding RE.
+    *?,+?,?? Non-greedy versions of the previous three special characters.
+    {m,n}    Matches from m to n repetitions of the preceding RE.
+    {m,n}?   Non-greedy version of the above.
+    "\\"      Either escapes special characters or signals a special sequence.
+    []       Indicates a set of characters.
+             A "^" as the first character indicates a complementing set.
+    "|"      A|B, creates an RE that will match either A or B.
+    (...)    Matches the RE inside the parentheses.
+             The contents can be retrieved or matched later in the string.
+    (?iLmsux) Set the I, L, M, S, U, or X flag for the RE (see below).
+    (?:...)  Non-grouping version of regular parentheses.
+    (?P<name>...) The substring matched by the group is accessible by name.
+    (?P=name)     Matches the text matched earlier by the group named name.
+    (?#...)  A comment; ignored.
+    (?=...)  Matches if ... matches next, but doesn't consume the string.
+    (?!...)  Matches if ... doesn't match next.
+
+The special sequences consist of "\\" and a character from the list
+below.  If the ordinary character is not on the list, then the
+resulting RE will match the second character.
+    \number  Matches the contents of the group of the same number.
+    \A       Matches only at the start of the string.
+    \Z       Matches only at the end of the string.
+    \b       Matches the empty string, but only at the start or end of a word.
+    \B       Matches the empty string, but not at the start or end of a word.
+    \d       Matches any decimal digit; equivalent to the set [0-9].
+    \D       Matches any non-digit character; equivalent to the set [^0-9].
+    \s       Matches any whitespace character; equivalent to [ \t\n\r\f\v].
+    \S       Matches any non-whitespace character; equiv. to [^ \t\n\r\f\v].
+    \w       Matches any alphanumeric character; equivalent to [a-zA-Z0-9_].
+             With LOCALE, it will match the set [0-9_] plus characters defined
+             as letters for the current locale.
+    \W       Matches the complement of \w.
+    \\       Matches a literal backslash.
+
+This module exports the following functions:
+    match    Match a regular expression pattern to the beginning of a string.
+    search   Search a string for the presence of a pattern.
+    sub      Substitute occurrences of a pattern found in a string.
+    subn     Same as sub, but also return the number of substitutions made.
+    split    Split a string by the occurrences of a pattern.
+    findall  Find all occurrences of a pattern in a string.
+    compile  Compile a pattern into a RegexObject.
+    purge    Clear the regular expression cache.
+    escape   Backslash all non-alphanumerics in a string.
+
+Some of the functions in this module takes flags as optional parameters:
+    I  IGNORECASE  Perform case-insensitive matching.
+    L  LOCALE      Make \w, \W, \b, \B, dependent on the current locale.
+    M  MULTILINE   "^" matches the beginning of lines as well as the string.
+                   "$" matches the end of lines as well as the string.
+    S  DOTALL      "." matches any character at all, including the newline.
+    X  VERBOSE     Ignore whitespace and comments for nicer looking RE's.
+    U  UNICODE     Make \w, \W, \b, \B, dependent on the Unicode locale.
+
+This module also defines an exception 'error'.
+
+"""
+
+import sys
+import sre_compile
+import sre_parse
+
+# public symbols
+__all__ = [ "match", "search", "sub", "subn", "split", "findall",
+    "compile", "purge", "template", "escape", "I", "L", "M", "S", "X",
+    "U", "IGNORECASE", "LOCALE", "MULTILINE", "DOTALL", "VERBOSE",
+    "UNICODE", "error" ]
+
+__version__ = "2.2.1"
+
+# flags
+I = IGNORECASE = sre_compile.SRE_FLAG_IGNORECASE # ignore case
+L = LOCALE = sre_compile.SRE_FLAG_LOCALE # assume current 8-bit locale
+U = UNICODE = sre_compile.SRE_FLAG_UNICODE # assume unicode locale
+M = MULTILINE = sre_compile.SRE_FLAG_MULTILINE # make anchors look for newline
+S = DOTALL = sre_compile.SRE_FLAG_DOTALL # make dot match newline
+X = VERBOSE = sre_compile.SRE_FLAG_VERBOSE # ignore whitespace and comments
+
+# sre extensions (experimental, don't rely on these)
+T = TEMPLATE = sre_compile.SRE_FLAG_TEMPLATE # disable backtracking
+DEBUG = sre_compile.SRE_FLAG_DEBUG # dump pattern after compilation
+
+# sre exception
+error = sre_compile.error
+
+# --------------------------------------------------------------------
+# public interface
+
+def match(pattern, string, flags=0):
+    """Try to apply the pattern at the start of the string, returning
+    a match object, or None if no match was found."""
+    return _compile(pattern, flags).match(string)
+
+def search(pattern, string, flags=0):
+    """Scan through string looking for a match to the pattern, returning
+    a match object, or None if no match was found."""
+    return _compile(pattern, flags).search(string)
+
+def sub(pattern, repl, string, count=0):
+    """Return the string obtained by replacing the leftmost
+    non-overlapping occurrences of the pattern in string by the
+    replacement repl.  repl can be either a string or a callable;
+    if a callable, it's passed the match object and must return
+    a replacement string to be used."""
+    return _compile(pattern, 0).sub(repl, string, count)
+
+def subn(pattern, repl, string, count=0):
+    """Return a 2-tuple containing (new_string, number).
+    new_string is the string obtained by replacing the leftmost
+    non-overlapping occurrences of the pattern in the source
+    string by the replacement repl.  number is the number of
+    substitutions that were made. repl can be either a string or a
+    callable; if a callable, it's passed the match object and must
+    return a replacement string to be used."""
+    return _compile(pattern, 0).subn(repl, string, count)
+
+def split(pattern, string, maxsplit=0):
+    """Split the source string by the occurrences of the pattern,
+    returning a list containing the resulting substrings."""
+    return _compile(pattern, 0).split(string, maxsplit)
+
+def findall(pattern, string, flags=0):
+    """Return a list of all non-overlapping matches in the string.
+
+    If one or more groups are present in the pattern, return a
+    list of groups; this will be a list of tuples if the pattern
+    has more than one group.
+
+    Empty matches are included in the result."""
+    return _compile(pattern, flags).findall(string)
+
+if sys.hexversion >= 0x02020000:
+    __all__.append("finditer")
+    def finditer(pattern, string, flags=0):
+        """Return an iterator over all non-overlapping matches in the
+        string.  For each match, the iterator returns a match object.
+
+        Empty matches are included in the result."""
+        return _compile(pattern, flags).finditer(string)
+
+def compile(pattern, flags=0):
+    "Compile a regular expression pattern, returning a pattern object."
+    return _compile(pattern, flags)
+
+def purge():
+    "Clear the regular expression cache"
+    _cache.clear()
+    _cache_repl.clear()
+
+def template(pattern, flags=0):
+    "Compile a template pattern, returning a pattern object"
+    return _compile(pattern, flags|T)
+
+_alphanum = {}
+for c in 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ01234567890':
+    _alphanum[c] = 1
+del c
+
+def escape(pattern):
+    "Escape all non-alphanumeric characters in pattern."
+    s = list(pattern)
+    alphanum = _alphanum
+    for i in range(len(pattern)):
+        c = pattern[i]
+        if c not in alphanum:
+            if c == "\000":
+                s[i] = "\\000"
+            else:
+                s[i] = "\\" + c
+    return pattern[:0].join(s)
+
+# --------------------------------------------------------------------
+# internals
+
+_cache = {}
+_cache_repl = {}
+
+_pattern_type = type(sre_compile.compile("", 0))
+
+_MAXCACHE = 100
+
+def _compile(*key):
+    # internal: compile pattern
+    cachekey = (type(key[0]),) + key
+    p = _cache.get(cachekey)
+    if p is not None:
+        return p
+    pattern, flags = key
+    if isinstance(pattern, _pattern_type):
+        return pattern
+    if not sre_compile.isstring(pattern):
+        raise TypeError, "first argument must be string or compiled pattern"
+    try:
+        p = sre_compile.compile(pattern, flags)
+    except error, v:
+        raise error, v # invalid expression
+    if len(_cache) >= _MAXCACHE:
+        _cache.clear()
+    _cache[cachekey] = p
+    return p
+
+def _compile_repl(*key):
+    # internal: compile replacement pattern
+    p = _cache_repl.get(key)
+    if p is not None:
+        return p
+    repl, pattern = key
+    try:
+        p = sre_parse.parse_template(repl, pattern)
+    except error, v:
+        raise error, v # invalid expression
+    if len(_cache_repl) >= _MAXCACHE:
+        _cache_repl.clear()
+    _cache_repl[key] = p
+    return p
+
+def _expand(pattern, match, template):
+    # internal: match.expand implementation hook
+    template = sre_parse.parse_template(template, pattern)
+    return sre_parse.expand_template(template, match)
+
+def _subx(pattern, template):
+    # internal: pattern.sub/subn implementation helper
+    template = _compile_repl(template, pattern)
+    if not template[0] and len(template[1]) == 1:
+        # literal replacement
+        return template[1][0]
+    def filter(match, template=template):
+        return sre_parse.expand_template(template, match)
+    return filter
+
+# register myself for pickling
+
+import copy_reg
+
+def _pickle(p):
+    return _compile, (p.pattern, p.flags)
+
+copy_reg.pickle(_pattern_type, _pickle, _compile)
+
+# --------------------------------------------------------------------
+# experimental stuff (see python-dev discussions for details)
+
+class Scanner:
+    def __init__(self, lexicon, flags=0):
+        from sre_constants import BRANCH, SUBPATTERN
+        self.lexicon = lexicon
+        # combine phrases into a compound pattern
+        p = []
+        s = sre_parse.Pattern()
+        s.flags = flags
+        for phrase, action in lexicon:
+            p.append(sre_parse.SubPattern(s, [
+                (SUBPATTERN, (len(p)+1, sre_parse.parse(phrase, flags))),
+                ]))
+        p = sre_parse.SubPattern(s, [(BRANCH, (None, p))])
+        s.groups = len(p)
+        self.scanner = sre_compile.compile(p)
+    def scan(self, string):
+        result = []
+        append = result.append
+        match = self.scanner.scanner(string).match
+        i = 0
+        while 1:
+            m = match()
+            if not m:
+                break
+            j = m.end()
+            if i == j:
+                break
+            action = self.lexicon[m.lastindex-1][1]
+            if callable(action):
+                self.match = m
+                action = action(self, m.group())
+            if action is not None:
+                append(action)
+            i = j
+        return result, string[i:]