[Python-Dev] concerns regarding callable() method (original) (raw)

Guido van Rossum guido at python.org
Sun Apr 8 17:55:26 CEST 2007

On 4/8/07, Paul Pogonyshev <pogonyshev at gmx.net> wrote:

Guido van Rossum wrote: > What if someone passes a callable that doesn't have the expected signature?

Well, I don't know a way to catch such situations now, so removing callable() will not make it worse (even if you don't know about hasattr trick above.)

My point is that it's futile to use callable() -- even if it passes, you have no assurance that you actually have a valid callback. So why bother with it at all? It's counter to the spirit of Python. If someone passes you a bad callback, they will see a traceback when you call it. Then they fix their program. That's how it's supposed to work.

-- --Guido van Rossum (home page: http://www.python.org/~guido/)

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