| # 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 = u"" |
| new = Call(Name(u"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 = u"" |
| new = Call(Name(u"list"), [new]) |
| new.prefix = node.prefix |
| return new |
