--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/django/utils/simplejson/scanner.py	Fri Jul 18 18:22:23 2008 +0000
@@ -0,0 +1,63 @@
+"""
+Iterator based sre token scanner
+"""
+import sre_parse, sre_compile, sre_constants
+from sre_constants import BRANCH, SUBPATTERN
+from re import VERBOSE, MULTILINE, DOTALL
+import re
+
+__all__ = ['Scanner', 'pattern']
+
+FLAGS = (VERBOSE | MULTILINE | DOTALL)
+class Scanner(object):
+    def __init__(self, lexicon, flags=FLAGS):
+        self.actions = [None]
+        # combine phrases into a compound pattern
+        s = sre_parse.Pattern()
+        s.flags = flags
+        p = []
+        for idx, token in enumerate(lexicon):
+            phrase = token.pattern
+            try:
+                subpattern = sre_parse.SubPattern(s,
+                    [(SUBPATTERN, (idx + 1, sre_parse.parse(phrase, flags)))])
+            except sre_constants.error:
+                raise
+            p.append(subpattern)
+            self.actions.append(token)
+
+        p = sre_parse.SubPattern(s, [(BRANCH, (None, p))])
+        self.scanner = sre_compile.compile(p)
+
+
+    def iterscan(self, string, idx=0, context=None):
+        """
+        Yield match, end_idx for each match
+        """
+        match = self.scanner.scanner(string, idx).match
+        actions = self.actions
+        lastend = idx
+        end = len(string)
+        while True:
+            m = match()
+            if m is None:
+                break
+            matchbegin, matchend = m.span()
+            if lastend == matchend:
+                break
+            action = actions[m.lastindex]
+            if action is not None:
+                rval, next_pos = action(m, context)
+                if next_pos is not None and next_pos != matchend:
+                    # "fast forward" the scanner
+                    matchend = next_pos
+                    match = self.scanner.scanner(string, matchend).match
+                yield rval, matchend
+            lastend = matchend
+            
+def pattern(pattern, flags=FLAGS):
+    def decorator(fn):
+        fn.pattern = pattern
+        fn.regex = re.compile(pattern, flags)
+        return fn
+    return decorator