JezK
Edit File: fix_map.py
# Copyright 2007 Google, Inc. All Rights Reserved. # Licensed to PSF under a Contributor Agreement. """Fixer that changes map(F, ...) into list(map(F, ...)) unless there exists a 'from future_builtins import map' statement in the top-level namespace. As a special case, map(None, X) is changed into list(X). (This is necessary because the semantics are changed in this case -- the new map(None, X) is equivalent to [(x,) for x in X].) We avoid the transformation (except for the special case mentioned above) if the map() 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 map(F, X, Y, ...) to go on until the longest argument is exhausted, substituting None for missing values -- like zip(), it now stops as soon as the shortest argument is exhausted. """ # Local imports from ..pgen2 import token from .. import fixer_base from ..fixer_util import Name, Call, ListComp, in_special_context from ..pygram import python_symbols as syms class FixMap(fixer_base.ConditionalFix): BM_compatible = True PATTERN = """ map_none=power< 'map' trailer< '(' arglist< 'None' ',' arg=any [','] > ')' > > | map_lambda=power< 'map' trailer< '(' arglist< lambdef< 'lambda' (fp=NAME | vfpdef< '(' fp=NAME ')'> ) ':' xp=any > ',' it=any > ')' > > | power< 'map' trailer< '(' [arglist=any] ')' > > """ skip_on = 'future_builtins.map' def transform(self, node, results): if self.should_skip(node): return if node.parent.type == syms.simple_stmt: self.warning(node, "You should use a for loop here") new = node.clone() new.prefix = "" new = Call(Name("list"), [new]) elif "map_lambda" in results: new = ListComp(results["xp"].clone(), results["fp"].clone(), results["it"].clone()) else: if "map_none" in results: new = results["arg"].clone() else: if "arglist" in results: args = results["arglist"] if args.type == syms.arglist and \ args.children[0].type == token.NAME and \ args.children[0].value == "None": self.warning(node, "cannot convert map(None, ...) " "with multiple arguments because map() " "now truncates to the shortest sequence") return if in_special_context(node): return None new = node.clone() new.prefix = "" new = Call(Name("list"), [new]) new.prefix = node.prefix return new