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
      22  
      23  
      24  parend_expr = patcomp.compile_pattern(
      25                """atom< '(' [atom|STRING|NAME] ')' >"""
      26                )
      27  
      28  
      29  class ESC[4;38;5;81mFixPrint(ESC[4;38;5;149mfixer_baseESC[4;38;5;149m.ESC[4;38;5;149mBaseFix):
      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)