1# Copyright 2006 Google, Inc. All Rights Reserved.
2# Licensed to PSF under a Contributor Agreement.
3
4"""Fixer for print.
5
6Change:
7    'print'          into 'print()'
8    'print ...'      into 'print(...)'
9    'print ... ,'    into 'print(..., end=" ")'
10    'print >>x, ...' into 'print(..., file=x)'
11
12No changes are applied if print_function is imported from __future__
13
14"""
15
16# Local imports
17from .. import patcomp
18from .. import pytree
19from ..pgen2 import token
20from .. import fixer_base
21from ..fixer_util import Name, Call, Comma, String
22
23
24parend_expr = patcomp.compile_pattern(
25              """atom< '(' [atom|STRING|NAME] ')' >"""
26              )
27
28
29class FixPrint(fixer_base.BaseFix):
30
31    BM_compatible = True
32
33    PATTERN = """
34              simple_stmt< any* bare='print' any* > | print_stmt
35              """
36
37    def transform(self, node, results):
38        assert results
39
40        bare_print = results.get("bare")
41
42        if bare_print:
43            # Special-case print all by itself
44            bare_print.replace(Call(Name("print"), [],
45                               prefix=bare_print.prefix))
46            return
47        assert node.children[0] == Name("print")
48        args = node.children[1:]
49        if len(args) == 1 and parend_expr.match(args[0]):
50            # We don't want to keep sticking parens around an
51            # already-parenthesised expression.
52            return
53
54        sep = end = file = None
55        if args and args[-1] == Comma():
56            args = args[:-1]
57            end = " "
58        if args and args[0] == pytree.Leaf(token.RIGHTSHIFT, ">>"):
59            assert len(args) >= 2
60            file = args[1].clone()
61            args = args[3:] # Strip a possible comma after the file expression
62        # Now synthesize a print(args, sep=..., end=..., file=...) node.
63        l_args = [arg.clone() for arg in args]
64        if l_args:
65            l_args[0].prefix = ""
66        if sep is not None or end is not None or file is not None:
67            if sep is not None:
68                self.add_kwarg(l_args, "sep", String(repr(sep)))
69            if end is not None:
70                self.add_kwarg(l_args, "end", String(repr(end)))
71            if file is not None:
72                self.add_kwarg(l_args, "file", file)
73        n_stmt = Call(Name("print"), l_args)
74        n_stmt.prefix = node.prefix
75        return n_stmt
76
77    def add_kwarg(self, l_nodes, s_kwd, n_expr):
78        # XXX All this prefix-setting may lose comments (though rarely)
79        n_expr.prefix = ""
80        n_argument = pytree.Node(self.syms.argument,
81                                 (Name(s_kwd),
82                                  pytree.Leaf(token.EQUAL, "="),
83                                  n_expr))
84        if l_nodes:
85            l_nodes.append(Comma())
86            n_argument.prefix = " "
87        l_nodes.append(n_argument)
88