WASI platform

[maxrossi]

Hello,
any plans to introduce WASI platform (now tier 2) for greenlet builds?

[jamadden]

Contributions welcome. I would be pleasantly surprised, however, if WASI/WASM exposed the necessary stack-switching abilities.

[maxrossi]

ok so as far as I understand that would not be an easy task:

Compiling Greenlet's C code:
You can compile greenlet's C code to WASM using something like Emscripten or wasi-sdk.
However, the critical slp_switch assembly or setjmp/longjmp based parts will likely not function as intended because the underlying assumptions about stack manipulation don't hold in the WASM environment. The compiler might try its best, but the runtime behavior for stack switching would be undefined or incorrect.

This could be the problem? @jamadden

[jamadden]

Where did that come from? AI? It has some things right and some things wrong. The part it has right is exactly what I said before about stack-switching. Except there's no such thing as "not function as intended" if you can't write the assembly for it in the first place, and there's no way for the compiler to "try its best".

[jamadden]

There are apparently specs in the works that might enable this kind of thing on WASM. In the meantime, people have found other ways to implement greenlet (via pyodide/pyodide#2664 (comment)).