[Python-Dev] PEP 0424: A method for exposing a length hint (original) (raw)

Mark Dickinson dickinsm at gmail.com
Tue Jul 17 09:49:26 CEST 2012

On Sun, Jul 15, 2012 at 1:36 PM, Antoine Pitrou <solipsis at pitrou.net> wrote:

On Sun, 15 Jul 2012 18:47:38 +1000 Nick Coghlan <ncoghlan at gmail.com> wrote:

I'm not seeing the value in returning None over 0 for the don't know case - it just makes the API harder to use. The point is that 0 is a legitimate value for a length hint. Simple implementations of lengthhint will start returning 0 as a legitimate value and you will wrongly interpret that as "don't know", which kinds of defeat the purpose of length-hint ;)

I agree with this: giving special meaning to what's already a valid length value seems wrong.

Mark

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