On Sat, Feb 23, 2008 at 8:06 AM, Guido van Rossum email@example.com wrote:
I don't think a -3 warning for oct or hex would do any good.
I do think map() and filter() should issue a warning under -3 when the first arg is None. (Or does 2to3 detect this now?)
2to3 does detect that: it will turn map(None, foo) into list(foo).
On Sat, Feb 23, 2008 at 6:06 AM, Eric Smith firstname.lastname@example.org wrote:
Georg Brandl wrote:
Eric Smith schrieb:
Guido van Rossum wrote:
I wonder if, in order to change the behavior of various built-in functions, it wouldn't be easier to be able to write
from future_builtins import oct, hex # and who knows what else
This makes sense to me, especially if we have a 2to3 fixer which removes this line. I'll work on implementing future_builtins.
Will the future map and filter also belong there (and if they are imported from future_builtins, 2to3 won't put a list() around them)?
I can certainly do the mechanics of adding the new versions of map and filter to future_builtins, if it's seen as desirable.
Maybe we could have 2to3 not put list() around map and filter, if there's been an import of future_builtins. I realize that there are pathological cases where 2to3 doesn't know that a usage of map or filter would really be the generator version from future_builtins, as opposed to the actual list-producing builtins. But would it be good enough to take an import of future_builtins as a hint that the author was aware that 2to3 wasn't going to change map and filter?
Still an open issue in my mind is adding a -3 warning to oct and hex, and now conceivably map and filter. Would that be going too far?
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