Movatterモバイル変換
[0]ホーム
[Python-Dev] Explicit Lexical Scoping (pre-PEP?)
Boris Borcicbborcic at gmail.com
Tue Jul 11 18:21:20 CEST 2006
Fredrik Lundh wrote:> Just van Rossum wrote:>>> Why couldn't at least augmented assignment be implicitly rebinding? It>> has been suggested before (in the context of a rebinding operator), but>> I'm wondering, is this also off the table?>>>> def counter(num):>> def inc():>> num += 1>> return num>> return inc>>>> Reads very natural to me. It's likely the most frequent example of what>> people try before they learn that rebinding to outer scopes isn't>> allowed. It could Just Work.>> note that most examples of this type already work, if the target type is> mutable, and implement the right operations:>> def counter(num):> num = mutable_int(num)> def inc():> num += 1> return num> return incI agree with you (and argued it in "scopes vs augmented assignment vs sets" recently) that mutating would be sufficient /if/ the compiler would view augmented assignment as mutations operators : which it doesn't as far as concerns scopes where a variable appears as target only of /augmented/ assignments.Currently, the code you propose above will not work, and whatever your mutable_int() it will result inUnboundLocalError: local variable 'num' referenced before assignmentWhat probably trips you is that the compiler thus makes a choice of interpretation that has no use cases.Cheers, BB
More information about the Python-Devmailing list
[8]ページ先頭