Clarify what `memoryview` is generic in

[jonathandung]

Documentation

The current documentation page for memoryview includes a version-changed directive telling readers that the class started supporting subscripting in python 3.14. However, there is no mention as to what it is generic in. Maybe the answer was too obvious for the writer of the documentation, but it certainly isn't for a layman like me.

[sobolevn]

It is generic on the __getitem__ result:

>>> memoryview(b'123')[0]
49
>>> memoryview(b'123').cast('c')[0]
b'1'

See https://github.com/python/typeshed/blob/d541d5a20cb7533c6eaba1430b5004f9b0e504ec/stdlib/builtins.pyi#L891

We generally don't specify what the type is generic on, I am not sure that this is really needed? 🤔

[JelleZijlstra]

We generally don't specify what the type is generic on, I am not sure that this is really needed?

It ought to be documented somewhere. Currently when a type is generic, the only way to figure out what the generic parameter represents is to read the typeshed stubs. That's not something we should expect users to do.

Documenting this in CPython is perhaps not ideal either, but I don't see a better place.

[ZeroIntensity]

Maybe somewhere on typing.python.org?

[picnixz]

I implemented the PEP-695 syntax in Sphinx because of Jelle wanted to document some generic classes (see sphinx-doc/sphinx#11438 and #104642) but not everything was included at that time (0511b6a). I think there was a discussion about adding the type parameters to the docs and we eventually decided not to. But I can't remember whether it was again decided differently or if we did something else