--- a/mercurial/match.py	Sat May 16 15:45:46 2015 -0700
+++ b/mercurial/match.py	Sat May 16 15:46:54 2015 -0700
@@ -498,3 +498,49 @@
     for kind, pat in kindpats:
         if kind in ('glob', 're', 'relglob', 'relre', 'set'):
             return True
+
+_commentre = None
+
+def readpatternfile(filepath, warn):
+    '''parse a pattern file, returning a list of
+    patterns. These patterns should be given to compile()
+    to be validated and converted into a match function.'''
+    syntaxes = {'re': 'relre:', 'regexp': 'relre:', 'glob': 'relglob:'}
+    syntax = 'relre:'
+    patterns = []
+
+    fp = open(filepath)
+    for line in fp:
+        if "#" in line:
+            global _commentre
+            if not _commentre:
+                _commentre = re.compile(r'((^|[^\\])(\\\\)*)#.*')
+            # remove comments prefixed by an even number of escapes
+            line = _commentre.sub(r'\1', line)
+            # fixup properly escaped comments that survived the above
+            line = line.replace("\\#", "#")
+        line = line.rstrip()
+        if not line:
+            continue
+
+        if line.startswith('syntax:'):
+            s = line[7:].strip()
+            try:
+                syntax = syntaxes[s]
+            except KeyError:
+                warn(_("%s: ignoring invalid syntax '%s'\n") % (filepath, s))
+            continue
+
+        linesyntax = syntax
+        for s, rels in syntaxes.iteritems():
+            if line.startswith(rels):
+                linesyntax = rels
+                line = line[len(rels):]
+                break
+            elif line.startswith(s+':'):
+                linesyntax = rels
+                line = line[len(s) + 1:]
+                break
+        patterns.append(linesyntax + line)
+    fp.close()
+    return patterns