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This looks great, I like the simple examples which show how to get a string out from the web assembly module. One thing I didn't see in the readme or examples, however, is a way to import python functions to the web assembly modules. Is it possible, and just missing from the documentation atm?

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We don't support that yet, but we are working on it. It's not that easy even if the theory is kind of simple to explain. The implementation in the different backends is mostly the challenge. The Python extension uses the Wasmer runtime (https://github.com/wasmerio/wasmer) which supports 3 backends to generate executable code: Singlepass, Cranelift, and LLVM.

Cranelift is the easiest one to embed, and it brings a great balance between compilation time and execution time. That's the one used in the Python extension right now.

The “import functions” feature is also missing in the PHP extension (https://github.com/wasmerio/php-ext-wasm), but yeah, as I said, we are working on it. It's coming soon!

understood, thanks for the explanation - keep up the great work! is there anything external contributors can do to help? :) I didn't find any issues labelled "good first issue" but I did find a related issue[0]

[0]: https://github.com/wasmerio/wasmer/issues/267

The best way to help right now is to test it, and report any issues! I've been able to try it on Windows so far for instance.

Also the API isn't complete. We need to be able to grow the memory for instance. We need to understand the community needs to define a roadmap for the community itself.

Once you allow to call Python, keeping things sandboxed becomes pretty hard, doesn't it?

That's true. However, it allows to integrate your Wasm program to your favorite framework more easily. It's likely to be a small surface of code to review carefully. It's always a balance :-).

It's often for code that is asynchronous that will not return an answer immediately... the function passing is most often used to send a callback for these situations.

A state-machine, generator or coroutine can be used instead of callbacks.

I mostly prefer only having one direction of who-calls-who when combining multiple languages. Though I understand that for a general purpose system like Wasmer it makes sense to support everything, so that users can choose the architecture.

Looks like the current code doesn't support it.

https://github.com/wasmerio/python-ext-wasm/blob/master/src/...

but in theory it shouldn't be too hard™

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