[ANN] Wasicaml - code emitter for WebAssembly

Ecosystem
1

Hello,

just want to repeat here what I already wrote in caml-list ([Caml-list] [ANN] wasicaml - a code emitter for OCaml targeting WebAssembly) - there is now a code generator for WebAssembly at

which is highly experimental. Any feedback welcome.

Gerd

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This looks extremely cool. Does this support (or plan to support) calling into the generated module from js, or calling external functions from OCaml?

I went ahead and made a minimal demo for browsers (copy-pasting the JavaScript from the repository plus a small wasi shim): GitHub - copy/wasicaml-demo

You can see it in action here: https://copy.sh/wasicaml-demo/

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For interfacing with JS (or the host environment in general) it is best to have some minimal C wrapper, e.g. put this into mylib.c:

__attribute__((import_module("env")))
__attribute__((import_name("myFunction")))
value myFunction(value arg1);

and then declare on the OCaml side as usual, e.g. external myFunction : int -> int = "myFunction".

You can link mylib.o into the final executable, e.g. wasicaml ... -cclib mylib.o.

If you want to call OCaml from JS, you’d have to register callbacks.

Hope this helps (I can make a bigger and more complete example if needed).

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Nice demo - but it took a while until I understood that the only effect is that it writes something into the console.

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@gstolpmann Thanks. I got both OCaml-to-JS and JS-to-OCaml calls working now. Code is in the repo if anybody is interested.

I’ve pushed a simple canvas demo (a naive implementation of conway’s game of life): https://copy.sh/wasicaml-demo/ (code).

And also a jsoo version for comparison: https://copy.sh/wasicaml-demo/jsoo.html

At the moment the jsoo version seems to be a bit faster and significantly smaller (not surprising considering this is still experimental). Still quite impressive, especially the fact that C code can be linked and works as expected.

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