[Python-Dev] Re: Keeping Python a Duck Typed Language.

2021年4月22日 18:23:29 -0700

On 4/20/21 10:03 AM, Mark Shannon wrote:
If you guarded your code with `isinstance(foo, Sequence)` then I could not use it with my `Foo` even if my `Foo` quacked like a sequence. I was forced to use nominal typing; inheriting from Sequence, or explicitly registering as a Sequence.
If I'm reading the library correctly, this is correct--but, perhaps, it could be remedied by adding a __subclasshook__ to Sequence that looked for an __iter__ attribute. That technique might also apply to other ABCs in collections.abc, Mapping for example. Would that work, or am I missing an critical detail?
Cheers,
//arry/
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