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[Python-Dev] PEP 0424: A method for exposing a length hint

Steven D'Aprano steve at pearwood.info
Sun Jul 15 18:39:01 CEST 2012 
Steven D'Aprano wrote:

> With a length hint, we could strengthen that promise:
> 
> "if __length_hint__ returns a negative number, list, tuple and set will 
> fail immediately with MemoryError"
> 
> which I think is a good safety feature for some things which cannot 
> possibly succeed, but risk DOSing your system. Does it prevent every 
> possible failure mode? No, of course not. But just because you can't 
> prevent *every* problem doesn't mean you should prevent the ones which 
> you can.

Gah, I messed that last sentence up. It should read:

just because you can't prevent *every* problem doesn't mean you SHOULDN'T 
prevent the ones which you can.


-- 
Steven
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