/Lib/lib2to3/fixes/fix_filter.py
http://unladen-swallow.googlecode.com/ · Python · 75 lines · 52 code · 1 blank · 22 comment · 0 complexity · 0879d4b1af4eeb93b1a8baff1fd298c1 MD5 · raw file
- # Copyright 2007 Google, Inc. All Rights Reserved.
- # Licensed to PSF under a Contributor Agreement.
- """Fixer that changes filter(F, X) into list(filter(F, X)).
- We avoid the transformation if the filter() call is directly contained
- in iter(<>), list(<>), tuple(<>), sorted(<>), ...join(<>), or
- for V in <>:.
- NOTE: This is still not correct if the original code was depending on
- filter(F, X) to return a string if X is a string and a tuple if X is a
- tuple. That would require type inference, which we don't do. Let
- Python 2.6 figure it out.
- """
- # Local imports
- from ..pgen2 import token
- from .. import fixer_base
- from ..fixer_util import Name, Call, ListComp, in_special_context
- class FixFilter(fixer_base.ConditionalFix):
- PATTERN = """
- filter_lambda=power<
- 'filter'
- trailer<
- '('
- arglist<
- lambdef< 'lambda'
- (fp=NAME | vfpdef< '(' fp=NAME ')'> ) ':' xp=any
- >
- ','
- it=any
- >
- ')'
- >
- >
- |
- power<
- 'filter'
- trailer< '(' arglist< none='None' ',' seq=any > ')' >
- >
- |
- power<
- 'filter'
- args=trailer< '(' [any] ')' >
- >
- """
- skip_on = "future_builtins.filter"
- def transform(self, node, results):
- if self.should_skip(node):
- return
- if "filter_lambda" in results:
- new = ListComp(results.get("fp").clone(),
- results.get("fp").clone(),
- results.get("it").clone(),
- results.get("xp").clone())
- elif "none" in results:
- new = ListComp(Name("_f"),
- Name("_f"),
- results["seq"].clone(),
- Name("_f"))
- else:
- if in_special_context(node):
- return None
- new = node.clone()
- new.set_prefix("")
- new = Call(Name("list"), [new])
- new.set_prefix(node.get_prefix())
- return new