Proof of concept of type hints for the Micropython RP2 PIO assembler

This is a PoC for adding type hints for the PIO assembler. It is not a full implementation, but it shows the idea.

This concept is being integrated into the MicroPython-stubs via the Micropython-reference stubs

the goal is to allow have the simular benefits in code PIO code , as there is for MicroPython code.

Regular	With pio_asm_types

I have not found a way to automatically load the type hints when the @rp2.asm_pio decorator is used. So the type hints have to be loaded manually. to to this add the following lines to the top of the file with the PIO assembler code:

# -----------------------------------------------
# add type hints for the rp2.PIO Instructions
try: 
    from typing_extensions import TYPE_CHECKING # type: ignore
except ImportError:
    TYPE_CHECKING = False
if TYPE_CHECKING:
    from rp2.asm_pio import *
# -----------------------------------------------

To allow both typechecking and running the code on the RP2, then you will also need th add an additional file typing_extensions.py to your scripts or lib with the following content:

# typing_extensions.py
TYPE_CHECKING = False

This allows the typechecking to run without errors, but the if TYPE_CHECKING: block will not be executed when the code is run on the RP2.

For the current implementation see the typings/rp2/rp2.pyi file.

Try it out in 2 minutes

How to use for your own project

I have not packaged or published this, so for now you will will need to copy some files into your typings folder.

copy to typings/rp2:

• https://github.com/Josverl/PIO_ASM_typing/tree/main/typings/rp2

include in your source ( and also sync to the rp2040 board):

• https://github.com/Josverl/PIO_ASM_typing/blob/main/src/typing_extensions.py

Feedback, improvements, corrections.

I assembled this from different sources, approx 50% automated and a lot of manual edits and additions. So there will be errors, If you find any please raise an issue an error or a snippet to improve, or better yet share the update in a PR.

Open items

• Does the manner and name for importing the type hints make sense?

• Is there a way in which the type hints can be loaded automatically by type-checkers such as pylance and mypy?

• The decorator has limited type information, to improve this it may be needed to depend on Pyton 3.10 or later to allow for a better support for type hints

• The type hints are not complete, also some of the methods currently need to be duplicated to allow for the fluent style of programming. e.g. out().side(0)

• The text for the docstrings originates from multiple locations, and is not always consistent. - Micropython RP2 Documentation - not fully complete on all methods and classes - RP2 python and C datasheets - sometime the language does not make sense in a python context.

• The defined methods and functions are also avaiable to the type checkers after/outside the scope where the @rp2.asm_pio decorator is used, this is not needed and should be removed. This can/will be confusing when the same names are used in the PIO assembler code and in the python code.

• The type hints should be included with the micropython-rp2[-*]-stub packages, for this the generation of the stubs is preferred to be mostly automated.

Please feel free to comment and suggest improvements.