Guido van Rossum | 7627c0d | 2000-03-31 14:58:54 +0000 | [diff] [blame] | 1 | # |
| 2 | # Secret Labs' Regular Expression Engine |
Guido van Rossum | 7627c0d | 2000-03-31 14:58:54 +0000 | [diff] [blame] | 3 | # |
| 4 | # re-compatible interface for the sre matching engine |
| 5 | # |
Fredrik Lundh | 770617b | 2001-01-14 15:06:11 +0000 | [diff] [blame] | 6 | # Copyright (c) 1998-2001 by Secret Labs AB. All rights reserved. |
Guido van Rossum | 7627c0d | 2000-03-31 14:58:54 +0000 | [diff] [blame] | 7 | # |
Fredrik Lundh | 29c4ba9 | 2000-08-01 18:20:07 +0000 | [diff] [blame] | 8 | # This version of the SRE library can be redistributed under CNRI's |
| 9 | # Python 1.6 license. For any other use, please contact Secret Labs |
| 10 | # AB (info@pythonware.com). |
| 11 | # |
Guido van Rossum | 7627c0d | 2000-03-31 14:58:54 +0000 | [diff] [blame] | 12 | # Portions of this engine have been developed in cooperation with |
Fredrik Lundh | 29c4ba9 | 2000-08-01 18:20:07 +0000 | [diff] [blame] | 13 | # CNRI. Hewlett-Packard provided funding for 1.6 integration and |
Guido van Rossum | 7627c0d | 2000-03-31 14:58:54 +0000 | [diff] [blame] | 14 | # other compatibility work. |
| 15 | # |
| 16 | |
Guido van Rossum | 7627c0d | 2000-03-31 14:58:54 +0000 | [diff] [blame] | 17 | import sre_compile |
Fredrik Lundh | 436c3d58 | 2000-06-29 08:58:44 +0000 | [diff] [blame] | 18 | import sre_parse |
Guido van Rossum | 7627c0d | 2000-03-31 14:58:54 +0000 | [diff] [blame] | 19 | |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 20 | # flags |
Fredrik Lundh | 770617b | 2001-01-14 15:06:11 +0000 | [diff] [blame] | 21 | I = IGNORECASE = sre_compile.SRE_FLAG_IGNORECASE # ignore case |
| 22 | L = LOCALE = sre_compile.SRE_FLAG_LOCALE # assume current 8-bit locale |
| 23 | U = UNICODE = sre_compile.SRE_FLAG_UNICODE # assume unicode locale |
| 24 | M = MULTILINE = sre_compile.SRE_FLAG_MULTILINE # make anchors look for newline |
| 25 | S = DOTALL = sre_compile.SRE_FLAG_DOTALL # make dot match newline |
| 26 | X = VERBOSE = sre_compile.SRE_FLAG_VERBOSE # ignore whitespace and comments |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 27 | |
Fredrik Lundh | 770617b | 2001-01-14 15:06:11 +0000 | [diff] [blame] | 28 | # sre extensions (experimental, don't rely on these) |
| 29 | T = TEMPLATE = sre_compile.SRE_FLAG_TEMPLATE # disable backtracking |
| 30 | DEBUG = sre_compile.SRE_FLAG_DEBUG # dump pattern after compilation |
Fredrik Lundh | 436c3d58 | 2000-06-29 08:58:44 +0000 | [diff] [blame] | 31 | |
| 32 | # sre exception |
Fredrik Lundh | be2211e | 2000-06-29 16:57:40 +0000 | [diff] [blame] | 33 | error = sre_compile.error |
Fredrik Lundh | 436c3d58 | 2000-06-29 08:58:44 +0000 | [diff] [blame] | 34 | |
Guido van Rossum | 7627c0d | 2000-03-31 14:58:54 +0000 | [diff] [blame] | 35 | # -------------------------------------------------------------------- |
| 36 | # public interface |
| 37 | |
Guido van Rossum | 7627c0d | 2000-03-31 14:58:54 +0000 | [diff] [blame] | 38 | def match(pattern, string, flags=0): |
Fredrik Lundh | 770617b | 2001-01-14 15:06:11 +0000 | [diff] [blame] | 39 | """Try to apply the pattern at the start of the string, returning |
| 40 | a match object, or None if no match was found.""" |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 41 | return _compile(pattern, flags).match(string) |
Guido van Rossum | 7627c0d | 2000-03-31 14:58:54 +0000 | [diff] [blame] | 42 | |
| 43 | def search(pattern, string, flags=0): |
Fredrik Lundh | 770617b | 2001-01-14 15:06:11 +0000 | [diff] [blame] | 44 | """Scan through string looking for a match to the pattern, returning |
| 45 | a match object, or None if no match was found.""" |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 46 | return _compile(pattern, flags).search(string) |
Guido van Rossum | 7627c0d | 2000-03-31 14:58:54 +0000 | [diff] [blame] | 47 | |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 48 | def sub(pattern, repl, string, count=0): |
Fredrik Lundh | 770617b | 2001-01-14 15:06:11 +0000 | [diff] [blame] | 49 | """Return the string obtained by replacing the leftmost |
| 50 | non-overlapping occurrences of the pattern in string by the |
| 51 | replacement repl""" |
Fredrik Lundh | 7898c3e | 2000-08-07 20:59:04 +0000 | [diff] [blame] | 52 | return _compile(pattern, 0).sub(repl, string, count) |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 53 | |
| 54 | def subn(pattern, repl, string, count=0): |
Fredrik Lundh | 770617b | 2001-01-14 15:06:11 +0000 | [diff] [blame] | 55 | """Return a 2-tuple containing (new_string, number). |
| 56 | new_string is the string obtained by replacing the leftmost |
| 57 | non-overlapping occurrences of the pattern in the source |
| 58 | string by the replacement repl. number is the number of |
| 59 | substitutions that were made.""" |
Fredrik Lundh | 7898c3e | 2000-08-07 20:59:04 +0000 | [diff] [blame] | 60 | return _compile(pattern, 0).subn(repl, string, count) |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 61 | |
| 62 | def split(pattern, string, maxsplit=0): |
Fredrik Lundh | 770617b | 2001-01-14 15:06:11 +0000 | [diff] [blame] | 63 | """Split the source string by the occurrences of the pattern, |
| 64 | returning a list containing the resulting substrings.""" |
Fredrik Lundh | 7898c3e | 2000-08-07 20:59:04 +0000 | [diff] [blame] | 65 | return _compile(pattern, 0).split(string, maxsplit) |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 66 | |
| 67 | def findall(pattern, string, maxsplit=0): |
Fredrik Lundh | 770617b | 2001-01-14 15:06:11 +0000 | [diff] [blame] | 68 | """Return a list of all non-overlapping matches in the string. |
| 69 | |
| 70 | If one or more groups are present in the pattern, return a |
| 71 | list of groups; this will be a list of tuples if the pattern |
| 72 | has more than one group. |
| 73 | |
| 74 | Empty matches are included in the result.""" |
Fredrik Lundh | 7898c3e | 2000-08-07 20:59:04 +0000 | [diff] [blame] | 75 | return _compile(pattern, 0).findall(string, maxsplit) |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 76 | |
| 77 | def compile(pattern, flags=0): |
Fredrik Lundh | 770617b | 2001-01-14 15:06:11 +0000 | [diff] [blame] | 78 | "Compile a regular expression pattern, returning a pattern object." |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 79 | return _compile(pattern, flags) |
| 80 | |
Fredrik Lundh | 8a3ebf8 | 2000-07-23 21:46:17 +0000 | [diff] [blame] | 81 | def purge(): |
Fredrik Lundh | 770617b | 2001-01-14 15:06:11 +0000 | [diff] [blame] | 82 | "Clear the regular expression cache" |
Fredrik Lundh | 8a3ebf8 | 2000-07-23 21:46:17 +0000 | [diff] [blame] | 83 | _cache.clear() |
| 84 | |
Fredrik Lundh | 436c3d58 | 2000-06-29 08:58:44 +0000 | [diff] [blame] | 85 | def template(pattern, flags=0): |
Fredrik Lundh | 770617b | 2001-01-14 15:06:11 +0000 | [diff] [blame] | 86 | "Compile a template pattern, returning a pattern object" |
| 87 | |
Fredrik Lundh | 436c3d58 | 2000-06-29 08:58:44 +0000 | [diff] [blame] | 88 | return _compile(pattern, flags|T) |
| 89 | |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 90 | def escape(pattern): |
Fredrik Lundh | 770617b | 2001-01-14 15:06:11 +0000 | [diff] [blame] | 91 | "Escape all non-alphanumeric characters in pattern." |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 92 | s = list(pattern) |
| 93 | for i in range(len(pattern)): |
| 94 | c = pattern[i] |
| 95 | if not ("a" <= c <= "z" or "A" <= c <= "Z" or "0" <= c <= "9"): |
| 96 | if c == "\000": |
| 97 | s[i] = "\\000" |
| 98 | else: |
| 99 | s[i] = "\\" + c |
Fredrik Lundh | 8a3ebf8 | 2000-07-23 21:46:17 +0000 | [diff] [blame] | 100 | return _join(s, pattern) |
Guido van Rossum | 7627c0d | 2000-03-31 14:58:54 +0000 | [diff] [blame] | 101 | |
| 102 | # -------------------------------------------------------------------- |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 103 | # internals |
Guido van Rossum | 7627c0d | 2000-03-31 14:58:54 +0000 | [diff] [blame] | 104 | |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 105 | _cache = {} |
| 106 | _MAXCACHE = 100 |
Guido van Rossum | 7627c0d | 2000-03-31 14:58:54 +0000 | [diff] [blame] | 107 | |
Fredrik Lundh | 8a3ebf8 | 2000-07-23 21:46:17 +0000 | [diff] [blame] | 108 | def _join(seq, sep): |
| 109 | # internal: join into string having the same type as sep |
Eric S. Raymond | b08b2d3 | 2001-02-09 11:10:16 +0000 | [diff] [blame] | 110 | return sep[:0].join(seq) |
Fredrik Lundh | 8a3ebf8 | 2000-07-23 21:46:17 +0000 | [diff] [blame] | 111 | |
Fredrik Lundh | 7898c3e | 2000-08-07 20:59:04 +0000 | [diff] [blame] | 112 | def _compile(*key): |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 113 | # internal: compile pattern |
Fredrik Lundh | 7898c3e | 2000-08-07 20:59:04 +0000 | [diff] [blame] | 114 | p = _cache.get(key) |
| 115 | if p is not None: |
| 116 | return p |
| 117 | pattern, flags = key |
| 118 | if type(pattern) not in sre_compile.STRING_TYPES: |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 119 | return pattern |
Fredrik Lundh | e186983 | 2000-08-01 22:47:49 +0000 | [diff] [blame] | 120 | try: |
| 121 | p = sre_compile.compile(pattern, flags) |
| 122 | except error, v: |
| 123 | raise error, v # invalid expression |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 124 | if len(_cache) >= _MAXCACHE: |
| 125 | _cache.clear() |
| 126 | _cache[key] = p |
| 127 | return p |
| 128 | |
Fredrik Lundh | 5644b7f | 2000-09-21 17:03:25 +0000 | [diff] [blame] | 129 | def _expand(pattern, match, template): |
| 130 | # internal: match.expand implementation hook |
| 131 | template = sre_parse.parse_template(template, pattern) |
| 132 | return sre_parse.expand_template(template, match) |
| 133 | |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 134 | def _sub(pattern, template, string, count=0): |
| 135 | # internal: pattern.sub implementation hook |
| 136 | return _subn(pattern, template, string, count)[0] |
| 137 | |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 138 | def _subn(pattern, template, string, count=0): |
| 139 | # internal: pattern.subn implementation hook |
| 140 | if callable(template): |
Andrew M. Kuchling | e8d52af | 2000-06-18 20:27:10 +0000 | [diff] [blame] | 141 | filter = template |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 142 | else: |
Fredrik Lundh | 90a0791 | 2000-06-30 07:50:59 +0000 | [diff] [blame] | 143 | template = sre_parse.parse_template(template, pattern) |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 144 | def filter(match, template=template): |
Fredrik Lundh | 436c3d58 | 2000-06-29 08:58:44 +0000 | [diff] [blame] | 145 | return sre_parse.expand_template(template, match) |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 146 | n = i = 0 |
| 147 | s = [] |
| 148 | append = s.append |
Fredrik Lundh | be2211e | 2000-06-29 16:57:40 +0000 | [diff] [blame] | 149 | c = pattern.scanner(string) |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 150 | while not count or n < count: |
| 151 | m = c.search() |
| 152 | if not m: |
| 153 | break |
Fredrik Lundh | 90a0791 | 2000-06-30 07:50:59 +0000 | [diff] [blame] | 154 | b, e = m.span() |
Fredrik Lundh | 01016fe | 2000-06-30 00:27:46 +0000 | [diff] [blame] | 155 | if i < b: |
| 156 | append(string[i:b]) |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 157 | append(filter(m)) |
Fredrik Lundh | 90a0791 | 2000-06-30 07:50:59 +0000 | [diff] [blame] | 158 | i = e |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 159 | n = n + 1 |
Fredrik Lundh | 01016fe | 2000-06-30 00:27:46 +0000 | [diff] [blame] | 160 | append(string[i:]) |
Fredrik Lundh | 8a3ebf8 | 2000-07-23 21:46:17 +0000 | [diff] [blame] | 161 | return _join(s, string[:0]), n |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 162 | |
| 163 | def _split(pattern, string, maxsplit=0): |
| 164 | # internal: pattern.split implementation hook |
| 165 | n = i = 0 |
| 166 | s = [] |
| 167 | append = s.append |
Fredrik Lundh | be2211e | 2000-06-29 16:57:40 +0000 | [diff] [blame] | 168 | extend = s.extend |
| 169 | c = pattern.scanner(string) |
Fredrik Lundh | 01016fe | 2000-06-30 00:27:46 +0000 | [diff] [blame] | 170 | g = pattern.groups |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 171 | while not maxsplit or n < maxsplit: |
| 172 | m = c.search() |
| 173 | if not m: |
| 174 | break |
Fredrik Lundh | 90a0791 | 2000-06-30 07:50:59 +0000 | [diff] [blame] | 175 | b, e = m.span() |
| 176 | if b == e: |
| 177 | if i >= len(string): |
| 178 | break |
| 179 | continue |
Fredrik Lundh | be2211e | 2000-06-29 16:57:40 +0000 | [diff] [blame] | 180 | append(string[i:b]) |
Fredrik Lundh | 90a0791 | 2000-06-30 07:50:59 +0000 | [diff] [blame] | 181 | if g and b != e: |
Fredrik Lundh | 1c5aa69 | 2001-01-16 07:37:30 +0000 | [diff] [blame] | 182 | extend(list(m.groups())) |
Fredrik Lundh | 90a0791 | 2000-06-30 07:50:59 +0000 | [diff] [blame] | 183 | i = e |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 184 | n = n + 1 |
Fredrik Lundh | 8094611 | 2000-06-29 18:03:25 +0000 | [diff] [blame] | 185 | append(string[i:]) |
Jeremy Hylton | b1aa195 | 2000-06-01 17:39:12 +0000 | [diff] [blame] | 186 | return s |
Fredrik Lundh | 0640e11 | 2000-06-30 13:55:15 +0000 | [diff] [blame] | 187 | |
| 188 | # register myself for pickling |
| 189 | |
| 190 | import copy_reg |
| 191 | |
| 192 | def _pickle(p): |
| 193 | return _compile, (p.pattern, p.flags) |
| 194 | |
Fredrik Lundh | 7898c3e | 2000-08-07 20:59:04 +0000 | [diff] [blame] | 195 | copy_reg.pickle(type(_compile("", 0)), _pickle, _compile) |
Fredrik Lundh | 7cafe4d | 2000-07-02 17:33:27 +0000 | [diff] [blame] | 196 | |
| 197 | # -------------------------------------------------------------------- |
| 198 | # experimental stuff (see python-dev discussions for details) |
| 199 | |
| 200 | class Scanner: |
| 201 | def __init__(self, lexicon): |
Fredrik Lundh | 29c4ba9 | 2000-08-01 18:20:07 +0000 | [diff] [blame] | 202 | from sre_constants import BRANCH, SUBPATTERN |
Fredrik Lundh | 7cafe4d | 2000-07-02 17:33:27 +0000 | [diff] [blame] | 203 | self.lexicon = lexicon |
Fredrik Lundh | 8a3ebf8 | 2000-07-23 21:46:17 +0000 | [diff] [blame] | 204 | # combine phrases into a compound pattern |
Fredrik Lundh | 7cafe4d | 2000-07-02 17:33:27 +0000 | [diff] [blame] | 205 | p = [] |
Fredrik Lundh | 8a3ebf8 | 2000-07-23 21:46:17 +0000 | [diff] [blame] | 206 | s = sre_parse.Pattern() |
Fredrik Lundh | 7cafe4d | 2000-07-02 17:33:27 +0000 | [diff] [blame] | 207 | for phrase, action in lexicon: |
Fredrik Lundh | 8a3ebf8 | 2000-07-23 21:46:17 +0000 | [diff] [blame] | 208 | p.append(sre_parse.SubPattern(s, [ |
Fredrik Lundh | 29c4ba9 | 2000-08-01 18:20:07 +0000 | [diff] [blame] | 209 | (SUBPATTERN, (len(p), sre_parse.parse(phrase))), |
Fredrik Lundh | 8a3ebf8 | 2000-07-23 21:46:17 +0000 | [diff] [blame] | 210 | ])) |
| 211 | p = sre_parse.SubPattern(s, [(BRANCH, (None, p))]) |
| 212 | s.groups = len(p) |
| 213 | self.scanner = sre_compile.compile(p) |
Fredrik Lundh | 7cafe4d | 2000-07-02 17:33:27 +0000 | [diff] [blame] | 214 | def scan(self, string): |
| 215 | result = [] |
| 216 | append = result.append |
| 217 | match = self.scanner.match |
| 218 | i = 0 |
| 219 | while 1: |
| 220 | m = match(string, i) |
| 221 | if not m: |
| 222 | break |
| 223 | j = m.end() |
| 224 | if i == j: |
| 225 | break |
Fredrik Lundh | 019bcb5 | 2000-07-02 22:59:57 +0000 | [diff] [blame] | 226 | action = self.lexicon[m.lastindex][1] |
Fredrik Lundh | 7cafe4d | 2000-07-02 17:33:27 +0000 | [diff] [blame] | 227 | if callable(action): |
Fredrik Lundh | 770617b | 2001-01-14 15:06:11 +0000 | [diff] [blame] | 228 | self.match = m |
Fredrik Lundh | 7cafe4d | 2000-07-02 17:33:27 +0000 | [diff] [blame] | 229 | action = action(self, m.group()) |
| 230 | if action is not None: |
| 231 | append(action) |
| 232 | i = j |
| 233 | return result, string[i:] |