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1# Copyright 2006 Google, Inc. All Rights Reserved.
2# Licensed to PSF under a Contributor Agreement.
3
4"""Fixer for apply().
5
6This converts apply(func, v, k) into (func)(*v, **k)."""
7
8# Local imports
9from .. import pytree
10from ..pgen2 import token
11from .. import fixer_base
12from ..fixer_util import Call, Comma, parenthesize
13
14class FixApply(fixer_base.BaseFix):
15    BM_compatible = True
16
17    PATTERN = """
18    power< 'apply'
19        trailer<
20            '('
21            arglist<
22                (not argument<NAME '=' any>) func=any ','
23                (not argument<NAME '=' any>) args=any [','
24                (not argument<NAME '=' any>) kwds=any] [',']
25            >
26            ')'
27        >
28    >
29    """
30
31    def transform(self, node, results):
32        syms = self.syms
33        assert results
34        func = results["func"]
35        args = results["args"]
36        kwds = results.get("kwds")
37        # I feel like we should be able to express this logic in the
38        # PATTERN above but I don't know how to do it so...
39        if args:
40            if (args.type == self.syms.argument and
41                args.children[0].value in {'**', '*'}):
42                return  # Make no change.
43        if kwds and (kwds.type == self.syms.argument and
44                     kwds.children[0].value == '**'):
45            return  # Make no change.
46        prefix = node.prefix
47        func = func.clone()
48        if (func.type not in (token.NAME, syms.atom) and
49            (func.type != syms.power or
50             func.children[-2].type == token.DOUBLESTAR)):
51            # Need to parenthesize
52            func = parenthesize(func)
53        func.prefix = ""
54        args = args.clone()
55        args.prefix = ""
56        if kwds is not None:
57            kwds = kwds.clone()
58            kwds.prefix = ""
59        l_newargs = [pytree.Leaf(token.STAR, "*"), args]
60        if kwds is not None:
61            l_newargs.extend([Comma(),
62                              pytree.Leaf(token.DOUBLESTAR, "**"),
63                              kwds])
64            l_newargs[-2].prefix = " " # that's the ** token
65        # XXX Sometimes we could be cleverer, e.g. apply(f, (x, y) + t)
66        # can be translated into f(x, y, *t) instead of f(*(x, y) + t)
67        #new = pytree.Node(syms.power, (func, ArgList(l_newargs)))
68        return Call(func, l_newargs, prefix=prefix)
69