Options for shorthand for sys.platform checks

[Josverl]

This is related to a conversation on the use of sys.platform in typechecking micropython code for pyscript pyscript/pyscript#2316 (reply in thread)

Im looking for a way to use the about 12 additional sys.platform values that Micropython uses , without needing to write too long and repetitive boilerplate such as:

if sys.platform == "esp32" or sys.platform ==  "esp8266" or sys.platform ==  "mimxrt" or sys.platform ==  "nrf" or sys.platform ==  "renesas-ra" or sys.platform ==  "rp2" or sys.platform ==  "samd" or sys.platform ==  "stm32" or sys.platform ==  "unix" or sys.platform ==  "webassembly" or sys.platform ==  "windows" or sys.platform ==  "zephyr" : 
     @overload
     def sleep_ms(delay: float) -> None: ...

Is there a way to shorten this ?

for MicroPython there is a defined sys.implementation.name that that would simplify matters,
however it appears that defineConstant = { sys.implementation.name = 'micropython' } for pyright
does not work as expected, conditional branches are always processed , regardless of the value.

It would be possible to set sys.platform to micropython in the typecheckers configs, but that would mean giving up the ability for the stubs to distinguish between for instance webassembly (Pyscript) and a bare metal port such as rp2

[srittau]

Currently, platform checks are underspecified in the typing spec: https://typing.python.org/en/latest/spec/directives.html#version-and-platform-checking

From experience, currently only sys.platform is guaranteed to work for all type checkers and only with operators == and != as well as boolean operators and grouping parentheses.

[JelleZijlstra]

I think it would be useful to specify sys.platform checks in more detail and add other useful patterns. For your example, it would be nice to support if sys.platform in ('x', 'y'):. Maybe there could also be a good way to support some version of "if on pypy", "if on cpython", "if on micropython".

If you're interested in pursuing this, I'd advise you to first start a thread on discuss.python.org, with the aim of brainstorming a concrete proposal. Then turn that into a PR to the typing spec, and follow the procedure in https://github.com/python/typing-council/#decisions to get the change into the spec.

[Josverl]

Thanks, wanted first to sanity check that I had not overlooked something obvious.