Fredrik Lundh: here's the 96.6% version of SRE

Lib/sre.py

@@ -1,4 +1,3 @@
-# -*- Mode: Python; tab-width: 4 -*-
 #
 # Secret Labs' Regular Expression Engine
 # $Id$
@@ -7,39 +6,127 @@
 #
 # Copyright (c) 1998-2000 by Secret Labs AB.  All rights reserved.
 #
-# This code can only be used for 1.6 alpha testing.  All other use
-# require explicit permission from Secret Labs AB.
-#
 # Portions of this engine have been developed in cooperation with
 # CNRI.  Hewlett-Packard provided funding for 1.6 integration and
 # other compatibility work.
 #
 
-"""
-this is a long string
-"""
-
 import sre_compile
 
+# flags
+I = IGNORECASE = sre_compile.SRE_FLAG_IGNORECASE
+L = LOCALE = sre_compile.SRE_FLAG_LOCALE
+M = MULTILINE = sre_compile.SRE_FLAG_MULTILINE
+S = DOTALL = sre_compile.SRE_FLAG_DOTALL
+X = VERBOSE = sre_compile.SRE_FLAG_VERBOSE
+
 # --------------------------------------------------------------------
 # public interface
 
-def compile(pattern, flags=0):
-    return sre_compile.compile(pattern, _fixflags(flags))
+# FIXME: add docstrings
 
 def match(pattern, string, flags=0):
-    return compile(pattern, _fixflags(flags)).match(string)
+    return _compile(pattern, flags).match(string)
 
 def search(pattern, string, flags=0):
-    return compile(pattern, _fixflags(flags)).search(string)
+    return _compile(pattern, flags).search(string)
 
-# FIXME: etc
+def sub(pattern, repl, string, count=0):
+    return _compile(pattern).sub(repl, string, count)
+
+def subn(pattern, repl, string, count=0):
+    return _compile(pattern).subn(repl, string, count)
+
+def split(pattern, string, maxsplit=0):
+    return _compile(pattern).split(string, maxsplit)
+
+def findall(pattern, string, maxsplit=0):
+    return _compile(pattern).findall(string, maxsplit)
+
+def compile(pattern, flags=0):
+    return _compile(pattern, flags)
+
+def escape(pattern):
+    s = list(pattern)
+    for i in range(len(pattern)):
+        c = pattern[i]
+        if not ("a" <= c <= "z" or "A" <= c <= "Z" or "0" <= c <= "9"):
+            if c == "\000":
+                s[i] = "\\000"
+            else:
+                s[i] = "\\" + c
+    return pattern[:0].join(s)
 
 # --------------------------------------------------------------------
-# helpers
+# internals
 
-def _fixflags(flags):
-    # convert flag bitmask to sequence
-    assert not flags
-    return ()
+_cache = {}
+_MAXCACHE = 100
 
+def _compile(pattern, flags=0):
+    # internal: compile pattern
+    tp = type(pattern)
+    if tp not in (type(""), type(u"")):
+        return pattern
+    key = (tp, pattern, flags)
+    try:
+        return _cache[key]
+    except KeyError:
+        pass
+    p = sre_compile.compile(pattern, flags)
+    if len(_cache) >= _MAXCACHE:
+        _cache.clear()
+    _cache[key] = p
+    return p
+
+def _sub(pattern, template, string, count=0):
+    # internal: pattern.sub implementation hook
+    return _subn(pattern, template, string, count)[0]
+
+def _expand(match, template):
+    # internal: expand template
+    return template # FIXME
+
+def _subn(pattern, template, string, count=0):
+    # internal: pattern.subn implementation hook
+    if callable(template):
+        filter = callable
+    else:
+        # FIXME: prepare template
+        def filter(match, template=template):
+            return _expand(match, template)
+    n = i = 0
+    s = []
+    append = s.append
+    c = pattern.cursor(string)
+    while not count or n < count:
+        m = c.search()
+        if not m:
+            break
+        j = m.start()
+        if j > i:
+            append(string[i:j])
+        append(filter(m))
+        i = m.end()
+        n = n + 1
+    if i < len(string):
+        append(string[i:])
+    return string[:0].join(s), n
+
+def _split(pattern, string, maxsplit=0):
+    # internal: pattern.split implementation hook
+    n = i = 0
+    s = []
+    append = s.append
+    c = pattern.cursor(string)
+    while not maxsplit or n < maxsplit:
+        m = c.search()
+        if not m:
+            break
+        j = m.start()
+        append(string[i:j])
+        i = m.end()
+        n = n + 1
+    if i < len(string):
+        append(string[i:])
+    return s