unionfs VS JSage

I am using the Python ecosystem (with full support for dynamic loading of C extension modules) as an initial motivating project. Also, the Python test suite is extremely useful to root out problems. I certainly hope that this can provide a more complete alternative to Emscripten to the community eventually. That said, Emscripten is huge, and the problems involved in creating a more maintainable modular WASM build tool are subtle. For example, when implementing a custom module loader for Python-wasm last week, I discovered several bugs in the memfs and unionfs Javascript libraries (https://github.com/streamich/memfs/pulls?q=is%3Apr+author%3A... and https://github.com/streamich/unionfs/pulls?q=is%3Apr+author%...). I had to learn the code sufficiently to fix all these bugs, submit PR's, etc. Emscripten has its own analogue of memfs, which is optimized specifically for WebAssembly in the browser, where memfs is a more general widely used library (with 10M+ downloads/week).

CoWasm has no support for asyncify. Where I've run into setjmp/longjmp so far, I've been rewriting the code instead. E.g., the dash shell uses setjmp/longjmp, and I'm rewriting that to use return error codes instead (see, e.g., https://github.com/sagemathinc/dash/commit/7117e1f6496728af0...).

> how would I go about porting a simple C->WASM w/ Typescript library project to CoWasm?

That's a great question, which I'm not sure how to quickly answer, so I've created a discussion item here https://github.com/sagemathinc/cowasm/discussions/40

Yes, porting https://SageMath.org to the browser is part of the plan, and this is a key foundation for that. I ported some of the components of Sage (e.g., https://libntl.org/) already as part of https://github.com/sagemathinc/jsage, and I don't see any fundamental obstruction to porting all of Sage, except time. It would be great if once CoWasm is more stable, I can get some help porting some components to WASM.

And here is the more lightweight and flexible (in some ways) one from Wasmer, before they completely rewrote it in Rust:

https://github.com/sagemathinc/JSage/tree/main/packages/wasi

It took me some work to track down the old version, fix some bugs in it, and keep it going. But I personally find the old version very useful too, and if you can see from the comments that it has an interesting history.

Here's a third called "JPython", which I've been writing lately for fun:

https://github.com/sagemathinc/JSage/tree/main/packages/jpyt...