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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 imports17from .. import patcomp18from .. import pytree19from ..pgen2 import token20from .. import fixer_base21from ..fixer_util import Name, Call, Comma, String22 23 24parend_expr = patcomp.compile_pattern(25              """atom< '(' [atom|STRING|NAME] ')' >"""26              )27 28 29class FixPrint(fixer_base.BaseFix):30 31    BM_compatible = True32 33    PATTERN = """34              simple_stmt< any* bare='print' any* > | print_stmt35              """36 37    def transform(self, node, results):38        assert results39 40        bare_print = results.get("bare")41 42        if bare_print:43            # Special-case print all by itself44            bare_print.replace(Call(Name("print"), [],45                               prefix=bare_print.prefix))46            return47        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 an51            # already-parenthesised expression.52            return53 54        sep = end = file = None55        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) >= 260            file = args[1].clone()61            args = args[3:] # Strip a possible comma after the file expression62        # 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.prefix75        return n_stmt76 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