Add a SLIP client for OSC over serial ports.

[MartijnBraam]

The OSC specification lets you send messages over any framed data channel and using the framing part of SLIP seems to be the most popular solution for devices allowing OSC control over USB.

[attwad]

Seems like tests are unhappy with the serial import, I don't think this is part of the standard library right? You could add the necessary dependency to https://github.com/attwad/python-osc/blob/master/.github/workflows/python-test.yml to make them pass.

[MartijnBraam]

Fixed up the receive method and added pyserial as dependency.

I wonder if it's better to return an exception instead of None when the serial port dissapears. The upside of None is that it follows the socket API a bit more closely.

[attwad]

Fixed up the receive method and added pyserial as dependency.

I wonder if it's better to return an exception instead of None when the serial port dissapears. The upside of None is that it follows the socket API a bit more closely.

Fine as is imo, thanks.

Tests are still failing but I don't think you want to write a whole set of stub types for the pyserial package... fine to suppress with # type: ignore imo. Cf. https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports

[MartijnBraam]

Seems like there are also errors in files I haven't touched and some tests complaining about the removed None (on 3.7)

[attwad]

Seems like there are also errors in files I haven't touched and some tests complaining about the removed None (on 3.7)

feel free to revert to return None then, I didn't know 3.7 was picky about it :( sorry for the back and forth