--- a/mercurial/parser.py Wed Feb 17 21:38:25 2016 +0900
+++ b/mercurial/parser.py Wed Feb 17 21:31:09 2016 +0900
@@ -312,6 +312,59 @@
raise error.ProgrammingError('too many replacements')
return r
+def _matchtree(pattern, tree, placeholder, incompletenodes, matches):
+ if pattern == tree:
+ return True
+ if not isinstance(pattern, tuple) or not isinstance(tree, tuple):
+ return False
+ if pattern == placeholder and tree[0] not in incompletenodes:
+ matches.append(tree)
+ return True
+ if len(pattern) != len(tree):
+ return False
+ return all(_matchtree(p, x, placeholder, incompletenodes, matches)
+ for p, x in zip(pattern, tree))
+
+def matchtree(pattern, tree, placeholder=None, incompletenodes=()):
+ """If a tree matches the pattern, return a list of the tree and nodes
+ matched with the placeholder; Otherwise None
+
+ >>> def f(pattern, tree):
+ ... m = matchtree(pattern, tree, _, {'keyvalue', 'list'})
+ ... if m:
+ ... return m[1:]
+
+ >>> _ = ('symbol', '_')
+ >>> f(('func', ('symbol', 'ancestors'), _),
+ ... ('func', ('symbol', 'ancestors'), ('symbol', '1')))
+ [('symbol', '1')]
+ >>> f(('func', ('symbol', 'ancestors'), _),
+ ... ('func', ('symbol', 'ancestors'), None))
+ >>> f(('range', ('dagrange', _, _), _),
+ ... ('range',
+ ... ('dagrange', ('symbol', '1'), ('symbol', '2')),
+ ... ('symbol', '3')))
+ [('symbol', '1'), ('symbol', '2'), ('symbol', '3')]
+
+ The placeholder does not match the specified incomplete nodes because
+ an incomplete node (e.g. argument list) cannot construct an expression.
+
+ >>> f(('func', ('symbol', 'ancestors'), _),
+ ... ('func', ('symbol', 'ancestors'),
+ ... ('list', ('symbol', '1'), ('symbol', '2'))))
+
+ The placeholder may be omitted, but which shouldn't match a None node.
+
+ >>> _ = None
+ >>> f(('func', ('symbol', 'ancestors'), None),
+ ... ('func', ('symbol', 'ancestors'), ('symbol', '0')))
+ """
+ if placeholder is not None and not isinstance(placeholder, tuple):
+ raise error.ProgrammingError('placeholder must be a node tuple')
+ matches = [tree]
+ if _matchtree(pattern, tree, placeholder, incompletenodes, matches):
+ return matches
+
def parseerrordetail(inst):
"""Compose error message from specified ParseError object
"""