Message 170946 - Python tracker

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Author	loewis
Recipients	Arfrever, docs@python, loewis, max, r.david.murray, terry.reedy
Date	2012-09-22.01:12:04
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1348276325.37.0.0215154698817.issue15997@psf.upfronthosting.co.za>
In-reply-to

Content
Terry: can you propose an alternative wording? I don't think that the discussion of TypeError belongs into the description of NotImplemented, though. IIUC, NotImplemented was added for performance reasons; returning a value is much faster than raising an exception. The return only requires an INCREF/DECREF pair, and a pointer identity test. The exception requires to create a new object, possibly a traceback, and a subclass check on exception matching.

Terry: can you propose an alternative wording? I don't think that the discussion of TypeError belongs into the description of NotImplemented, though.

IIUC, NotImplemented was added for performance reasons; returning a value is much faster than raising an exception. The return only requires an INCREF/DECREF pair, and a pointer identity test. The exception requires to create a new object, possibly a traceback, and a subclass check on exception matching.

History
Date	User	Action	Args
2012-09-22 01:12:05	loewis	set	recipients: + loewis, terry.reedy, Arfrever, r.david.murray, docs@python, max
2012-09-22 01:12:05	loewis	set	messageid: <1348276325.37.0.0215154698817.issue15997@psf.upfronthosting.co.za>
2012-09-22 01:12:04	loewis	link	issue15997 messages
2012-09-22 01:12:04	loewis	create