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- # Copyright 2006 Google, Inc. All Rights Reserved.
- # Licensed to PSF under a Contributor Agreement.
- """Fixer for print.
- Change:
- "print" into "print()"
- "print ..." into "print(...)"
- "print(...)" not changed
- "print ... ," into "print(..., end=' ')"
- "print >>x, ..." into "print(..., file=x)"
- No changes are applied if print_function is imported from __future__
- """
- # Local imports
- from lib2to3 import patcomp, pytree, fixer_base
- from lib2to3.pgen2 import token
- from lib2to3.fixer_util import Name, Call, Comma, String
- # from libmodernize import add_future
- parend_expr = patcomp.compile_pattern(
- """atom< '(' [arith_expr|atom|power|term|STRING|NAME] ')' >"""
- )
- class FixPrint(fixer_base.BaseFix):
- BM_compatible = True
- PATTERN = """
- simple_stmt< any* bare='print' any* > | print_stmt
- """
- def transform(self, node, results):
- assert results
- bare_print = results.get("bare")
- if bare_print:
- # Special-case print all by itself.
- bare_print.replace(Call(Name(u"print"), [],
- prefix=bare_print.prefix))
- # The "from __future__ import print_function"" declaration is added
- # by the fix_print_with_import fixer, so we skip it here.
- # add_future(node, u'print_function')
- return
- assert node.children[0] == Name(u"print")
- args = node.children[1:]
- if len(args) == 1 and parend_expr.match(args[0]):
- # We don't want to keep sticking parens around an
- # already-parenthesised expression.
- return
- sep = end = file = None
- if args and args[-1] == Comma():
- args = args[:-1]
- end = " "
- # try to determine if the string ends in a non-space whitespace character, in which
- # case there should be no space at the end of the conversion
- string_leaves = [leaf for leaf in args[-1].leaves() if leaf.type == token.STRING]
- if (
- string_leaves
- and string_leaves[-1].value[0] != "r" # "raw" string
- and string_leaves[-1].value[-3:-1] in (r"\t", r"\n", r"\r")
- ):
- end = ""
- if args and args[0] == pytree.Leaf(token.RIGHTSHIFT, u">>"):
- assert len(args) >= 2
- file = args[1].clone()
- args = args[3:] # Strip a possible comma after the file expression
- # Now synthesize a print(args, sep=..., end=..., file=...) node.
- l_args = [arg.clone() for arg in args]
- if l_args:
- l_args[0].prefix = u""
- if sep is not None or end is not None or file is not None:
- if sep is not None:
- self.add_kwarg(l_args, u"sep", String(repr(sep)))
- if end is not None:
- self.add_kwarg(l_args, u"end", String(repr(end)))
- if file is not None:
- self.add_kwarg(l_args, u"file", file)
- n_stmt = Call(Name(u"print"), l_args)
- n_stmt.prefix = node.prefix
- # Note that there are corner cases where adding this future-import is
- # incorrect, for example when the file also has a 'print ()' statement
- # that was intended to print "()".
- # add_future(node, u'print_function')
- return n_stmt
- def add_kwarg(self, l_nodes, s_kwd, n_expr):
- # XXX All this prefix-setting may lose comments (though rarely)
- n_expr.prefix = u""
- n_argument = pytree.Node(self.syms.argument,
- (Name(s_kwd),
- pytree.Leaf(token.EQUAL, u"="),
- n_expr))
- if l_nodes:
- l_nodes.append(Comma())
- n_argument.prefix = u" "
- l_nodes.append(n_argument)
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