On Sat, Dec 26, 2020 at 06:09:42PM -0800, Brendan Barnwell wrote:
> On 2020-12-26 18:00, Steven D'Aprano wrote:
> >I think if we were designing mapping protocols now, that would be an
> >excellent idea, but we aren't, we have decades of history from `dict`
> >behind us. And protocols from dict use `keys()` and getitem. E.g.
> >update.
>
> What do you mean by "protocols from dict"? What are these protocols?
"And protocols from dict use `keys()` and getitem. E.g. update."
The dict in-place union assignment operator also uses the same protocol:
>>> class A:
... def keys(self):
... return iter('abc')
... def __getitem__(self, key):
... return key.upper()
...
>>> d = {}
>>> d |= A()
>>> d
{'a': 'A', 'b': 'B', 'c': 'C'}
(Regular union operator does not, it requires an actual dict.)
There may be others. I know I have written code that followed the same
interface as update, although I don't have it easily at hand.
--
Steve
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