On Wed, Feb 19, 2020 at 7:34 AM Soni L. <fakedme...@gmail.com> wrote:
>
> On 2020-02-18 5:08 p.m., Rhodri James wrote:
> > On 18/02/2020 19:43, Soni L. wrote:
> >> It'd be nice to have a __valid_getitem_requests__ protocol that, if
> >> present, yields pairs such that:
> >>
> >> for key, value in items(obj):
> >> assert obj[key] == value
> >>
> >> for any obj.
> >
> > OK, I'll bite. What is this "items()" function you apply to the
> > arbitrary object?
> >
> Similar to len(). Just a shitty wrapper for __valid_getitem_requests__.
>
> We kinda have a requirement that __iter__ and __contains__ have to be
> related, see e.g. dict.__iter__ and dict.__contains__. In an ideal world
> dict would yield pairs by default. and dict() would just iterate
> whatever. But anyway I digress. As far as my proposal goes,
> __valid_getitem_requests__ would provide slightly different semantics
> for converting-to-dict:
>
> dict(items(['a', 'b', 'c'])) == {0: 'a', 1: 'b', 2: 'c'}
> dict(items({1: 'a', 2: 'b'})) == {1: 'a', 2: 'b'}
> # TODO find other things with __getitem__ and put them here
>
> In other words: it'd allow creating a dict whose __getitem__ behaviour
> is similar to that of the original collection, in the most
> straightforward case. (note how the first dict doesn't contain negative
> indices or the infinitely many slice objects that can be used to index a
> three-element list.)
>
Is this something you do a lot of? Can you show some real-world (or
real-world-cut-down) code that would benefit from this?
ChrisA
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