[Python-ideas] ABC: what about the method arguments ?

Tarek Ziadé ziade.tarek at gmail.com
Thu Sep 23 17:08:03 CEST 2010

On Thu, Sep 23, 2010 at 4:54 PM, Daniel Stutzbach
<daniel at stutzbachenterprises.com> wrote:
> On Thu, Sep 23, 2010 at 9:37 AM, Tarek Ziadé <ziade.tarek at gmail.com> wrote:
>> The problem is that the implemented method could have a different list
>> of arguments and will eventually fail.
> A slightly different argument list is okay if it is more permissive.  For
> example, the collections.Sequence ABC defines a count method with one
> parameter.  However, the list implementation's count method takes one
> mandatory parameter plus two optional parameters.  I'm not sure how easy it
> would be to detect a valid but more general signature.

Well, with inspect it's possible to see if the extra parameters have
defaults values, thus making calls without them still working.

> You might be interested in the related Issue 9731 ("Add ABCMeta.has_methods
> and tests that use it").

Ah... interesting.. has_methods could possibly have an option to check
for the signature

--will hack on that when I find some time--

> --
> Daniel Stutzbach, Ph.D.
> President, Stutzbach Enterprises, LLC

Tarek Ziadé | http://ziade.org

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