[Python-3000] PEP 3133: Introducing Roles (original) (raw)

Benji York benji at benjiyork.com
Wed May 16 19:41:11 CEST 2007

Guido van Rossum wrote:

On 5/14/07, Benji York <benji at benjiyork.com> wrote:

Collin Winter wrote:

PEP: 3133 Title: Introducing Roles Everything included here is included in zope.interface. See in-line comments below for the analogs. Could you look at PEP 3119 and do a similar analysis?

Sure.

I expect that the main thing missing there is that it (currently) has no way to claim that a particular object has a certain behavior.

Is "it" in that sentence the ABC PEP or zope.interface?

PEP 3119 currently also doesn't have a verification step -- but this could easily be added as an (optional) part of the registration call.

I don't care much for verification. People using zope.interface have found that writing good tests is superior to on-demand verification, and I suspect execution time verification is a non-starter because of the overhead (not to mention its actual desirability, or lack thereof).

BTW I think Collin made a mistake when he claimed that the Doglike role should throw a tantrum just because the actual bark() implementation has an optional extra argument

Agreed.

Benji York http://benjiyork.com

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