AppPkg/Applications/Python/Python-2.7.2/Lib/lib2to3/fixes/fix_print.py

   1 # Copyright 2006 Google, Inc. All Rights Reserved.
   2 # Licensed to PSF under a Contributor Agreement.
   3
   4 """Fixer for print.
   5
   6 Change:
   7     'print'          into 'print()'
   8     'print ...'      into 'print(...)'
   9     'print ... ,'    into 'print(..., end=" ")'
  10     'print >>x, ...' into 'print(..., file=x)'
  11
  12 No changes are applied if print_function is imported from __future__
  13
  14 """
  15
  16 # Local imports
  17 from .. import patcomp
  18 from .. import pytree
  19 from ..pgen2 import token
  20 from .. import fixer_base
  21 from ..fixer_util import Name, Call, Comma, String, is_tuple
  22
  23
  24 parend_expr = patcomp.compile_pattern(
  25               """atom< '(' [atom|STRING|NAME] ')' >"""
  26               )
  27
  28
  29 class 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(u"print"), [],
  45                                prefix=bare_print.prefix))
  46             return
  47         assert node.children[0] == Name(u"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, u">>"):
  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 = u""
  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, u"sep", String(repr(sep)))
  69             if end is not None:
  70                 self.add_kwarg(l_args, u"end", String(repr(end)))
  71             if file is not None:
  72                 self.add_kwarg(l_args, u"file", file)
  73         n_stmt = Call(Name(u"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 = u""
  80         n_argument = pytree.Node(self.syms.argument,
  81                                  (Name(s_kwd),
  82                                   pytree.Leaf(token.EQUAL, u"="),
  83                                   n_expr))
  84         if l_nodes:
  85             l_nodes.append(Comma())
  86             n_argument.prefix = u" "
  87         l_nodes.append(n_argument)