1# Copyright 2007 Google, Inc. All Rights Reserved.
2# Licensed to PSF under a Contributor Agreement.
3
4"""Fixer that changes xrange(...) into range(...)."""
5
6# Local imports
7from .. import fixer_base
8from ..fixer_util import Name, Call, consuming_calls
9from .. import patcomp
10
11
12class FixXrange(fixer_base.BaseFix):
13    BM_compatible = True
14    PATTERN = """
15              power<
16                 (name='range'|name='xrange') trailer< '(' args=any ')' >
17              rest=any* >
18              """
19
20    def start_tree(self, tree, filename):
21        super(FixXrange, self).start_tree(tree, filename)
22        self.transformed_xranges = set()
23
24    def finish_tree(self, tree, filename):
25        self.transformed_xranges = None
26
27    def transform(self, node, results):
28        name = results["name"]
29        if name.value == u"xrange":
30            return self.transform_xrange(node, results)
31        elif name.value == u"range":
32            return self.transform_range(node, results)
33        else:
34            raise ValueError(repr(name))
35
36    def transform_xrange(self, node, results):
37        name = results["name"]
38        name.replace(Name(u"range", prefix=name.prefix))
39        # This prevents the new range call from being wrapped in a list later.
40        self.transformed_xranges.add(id(node))
41
42    def transform_range(self, node, results):
43        if (id(node) not in self.transformed_xranges and
44            not self.in_special_context(node)):
45            range_call = Call(Name(u"range"), [results["args"].clone()])
46            # Encase the range call in list().
47            list_call = Call(Name(u"list"), [range_call],
48                             prefix=node.prefix)
49            # Put things that were after the range() call after the list call.
50            for n in results["rest"]:
51                list_call.append_child(n)
52            return list_call
53
54    P1 = "power< func=NAME trailer< '(' node=any ')' > any* >"
55    p1 = patcomp.compile_pattern(P1)
56
57    P2 = """for_stmt< 'for' any 'in' node=any ':' any* >
58            | comp_for< 'for' any 'in' node=any any* >
59            | comparison< any 'in' node=any any*>
60         """
61    p2 = patcomp.compile_pattern(P2)
62
63    def in_special_context(self, node):
64        if node.parent is None:
65            return False
66        results = {}
67        if (node.parent.parent is not None and
68               self.p1.match(node.parent.parent, results) and
69               results["node"] is node):
70            # list(d.keys()) -> list(d.keys()), etc.
71            return results["func"].value in consuming_calls
72        # for ... in d.iterkeys() -> for ... in d.keys(), etc.
73        return self.p2.match(node.parent, results) and results["node"] is node
74