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RE: duck typing assert

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There is sense for #2. Let me explain. There is basic IFoo implementation and improved Foo. While I switched to Foo, I still want to be as close to IFoo as possible, since there might be sense to switch to Foo2 later, which conform to IFoo.

Here is the problem: if I will not assert #2 potentially I will use some `features` that are not in IFoo, thus that breaks my code switching to Foo2 later.

That might not apply for 100% usability cases, just wanted to point that out as reasonable thing.

Thanks.

Andriy Kornatskyy


----------------------------------------
> Date: Sat, 10 Nov 2012 01:15:36 +1100
> Subject: Re: duck typing assert
> From: rosuav@gmail.com
> To: python-list@python.org
>
> On Sat, Nov 10, 2012 at 1:01 AM, Andriy Kornatskyy
> <andriy.kornatskyy@live.com> wrote:
> >
> > 1. In looks-like we check features of Foo (that may be superset) of what IFoo offers.
> >
> > assert looks(Foo).like(IFoo)
> >
> > 2. We can check if Foo is limited to IFoo only:
> >
> > assert looks(IFoo).like(Foo)
> >
> > So it valid to have both asserts.
>
> You'll almost never need #2, but since there's no difference between a
> "class" and an "interface", it's perfectly legal to switch them
> around.
>
> But I would generally expect that unrecognized methods are never a
> problem (assuming they don't collide with anything) - that, as in
> Steven's example, it's fine to have an actor who can sing when you
> don't need her to. When you post job openings, you don't normally ask
> for someone with "5+ years Python experience and unable to program in
> REXX" [1]. You're checking for a minimum set of requirements.
>
> [1] Though I suppose you might ask for someone who's unable to program
> in Pascal. Might save you some hassle.
>
> ChrisA
> --
> http://mail.python.org/mailman/listinfo/python-list
 		 	   		  

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duck typing assert‏ Andriy Kornatskyy <andriy.kornatskyy@live.com> - 2012-11-08 20:34 +0300
  Re: duck typing assert‏ Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-11-08 23:33 +0000
    Re: duck typing assert Ian Kelly <ian.g.kelly@gmail.com> - 2012-11-08 18:00 -0700
      Re: duck typing assert Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-11-09 13:36 +0000
        RE: duck typing assert Andriy Kornatskyy <andriy.kornatskyy@live.com> - 2012-11-09 17:01 +0300
        Re: duck typing assert Chris Angelico <rosuav@gmail.com> - 2012-11-10 01:15 +1100
        RE: duck typing assert Andriy Kornatskyy <andriy.kornatskyy@live.com> - 2012-11-09 17:37 +0300
    Re: duck typing assert Chris Angelico <rosuav@gmail.com> - 2012-11-09 17:14 +1100
    RE: duck typing assert Andriy Kornatskyy <andriy.kornatskyy@live.com> - 2012-11-09 13:26 +0300
    RE: duck typing assert "Prasad, Ramit" <ramit.prasad@jpmorgan.com> - 2012-11-09 17:37 +0000
    RE: duck typing assert Andriy Kornatskyy <andriy.kornatskyy@live.com> - 2012-11-09 20:55 +0300

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