Steven D'Aprano writes:
> On Sun, Sep 29, 2019 at 11:27:32AM +0100, Oscar Benjamin wrote:
>
> > That's the point that I would make as well. What can you do with an
> > object that is only known to be Subscriptable?
>
> I can subscript it. What did you expect the answer to be?
Technical que
On Mon, 30 Sep 2019 at 10:02, Stephen J. Turnbull
wrote:
>
> Steven D'Aprano writes:
> > On Sun, Sep 29, 2019 at 11:27:32AM +0100, Oscar Benjamin wrote:
> >
> > > That's the point that I would make as well. What can you do with an
> > > object that is only known to be Subscriptable?
> >
> >
On Sep 30, 2019, at 02:38, Paul Moore wrote:
>
> It's (in my view) sad that the simple hasattr test is no longer
> sufficient, and in particular that if you want robustness, Python has
> changed to the point where a pseudo subclass check is the "right" way
> to check for an object that has certai
>
>
> > That applies to many interface checks. Both the built-in callable() and
> the Callable ABC don't tell you what arguments the object accepts, or
> what it does; the Sequence ABC check doesn't tell you what valid indexes
> are accepted.
Sure — and Callable is probably the closest ABC to thi
On Mon, Sep 30, 2019 at 10:08 AM Andrew Barnert via Python-ideas
wrote:
> Also, what we’re checking for really is subtyping.
Is it? Subtyping in type theory satisfies some axioms, one of which is
transitivity. The addition of the ABCs broke transitivity:
>>> issubclass(list, object)
True
