extism VS gc

Extism can be really useful for packaging up and running cross-language libraries!

The most clear information about it is at: https://extism.org, but its a bit focused on the primary use case for Extism, being a universal plugin system.

There is a C PDK (https://github.com/extism/c-pdk) which you'd probably want to use in a new wrapper around your library in C++, and compile it to wasm32 freestanding or WASI, but without emscripten. Extism doesn't currently have an interop layer to emscripten.

It may just be my own unique obsession to peek at the internals of .wasm, but if anyone else is curious:

https://modsurfer.dylibso.com/module?hash=ab6f4b2de9db171347...

u/nbittich - curious if you've tried to use your language as as a scripting language inside other apps? I took a peak at your browser wasm environment, and think we could hook up the `compute` entrypoint you have here[0], but I'm not certain what the `ctx` does without going super deep, and if it could be passed into an Extism function[1] (which is how I'd try to run it from within 16+ other languages).

[0]: https://github.com/nbittich/adana/blob/master/adana-script-w...

[1]: https://github.com/extism/extism

Yep, this is one of the initial motivations for creating Extism: https://github.com/extism/extism -- and it works across 16 host languages & 8 guest languages.

On the devx, there's definitely some rough edges around building and using Wasm. My company has been working on a framework to ease integrating Wasm into existing applications. One area it focuses on is providing easy data passing between the host program and the Wasm and vice versa. https://github.com/extism/extism We do not have WASI preview 2 support yet, but are interested in integrating it.

Extism handles this really well across 16 or so different languages - and you don’t need to write a whole IDL / schema.

https://github.com/extism/extism

It’s a general purpose framework for building with WebAssembly and sharing code across languages is a great way to put it to work.

It may take some time for WasmGC to be usable by .NET. Based on the discussions the first version of WasmGC does not have a good way to handle a few .NET specific scenarios, and said scenarios are "post-post-mvp". [0]

My concern, of course, is that there is not much incentive for those features to be added if .NET is the only platform that needs them... at that point having a form of 'include' (to where a specific GC version can just be cached and loaded by another WASM assembly) would be more useful, despite the pain it would create.

[0] - https://github.com/WebAssembly/gc/issues/77

Yes, that's definitely true: a single GC will not be optimal for everything, or even possible. Atm interior pointers are not supported at all, for example, but they are on the roadmap for later:

https://github.com/WebAssembly/gc/blob/main/proposals/gc/Pos...

What launched now is enough WasmGC to support a big and useful set of languages (Java, Kotlin, Dart, OCaml, Scheme), but a lot more work will be required here!

GC proposal is from 2018: https://github.com/WebAssembly/proposals/issues/16 and there’s code: https://github.com/WebAssembly/gc/blob/master/proposals/gc/O...

Seems like an awefully long time for progress to be made, given all the possibilities it would unlock.

First is the size. Writing a server-side and client-side program is possible with Rust, and the resulting WASM package will be small enough. At the same time, Microsoft Blazor converts C# code to WASM, but the client delivery has to include the reduced .NET runtime, taking several megabytes for a script. The same is true for GoLang, even with an attempt to reduce the runtime delivery in TinyGo WASM. Developers want to work with their favorite languages, whether it is Java, Kotlin, Dart, C#, F#, Swift, Ruby, Python, C, C++, GoLang, or Rust. These languages produce groups of runtimes. For example, JVM and .NET have many common parts, Ruby and Python are dynamically interpreted at runtime, and all mentioned depend on automatic garbage collection. For smaller WASM packages, browser vendors can include extended runtime implementations, for example, by delivering a general garbage collector as part of WASM. Garbage collection support by WASM is currently in progress: WASM GC, .NET WASM Notes.

My understanding is that the main limitation is technical. WASM doens't do GC or the host system calling conventions and cannot interact directly with object from Javascript because of this. However, this is being worked[0] on and will be solved eventually. Even without this the performance overhead of bridging to JS is low enough that WASM frameworks can beat out React.

0: https://github.com/WebAssembly/gc/blob/main/proposals/gc/Ove...

I’ve just watched a video on YouTube from Google I/O 2023 on Flutter for the web. Kevin Moore explains that Flutter can compile to Wasm, but now that GC support has been added to the standard and WasmGC is supported in Chromium and Firefox, I’m quite intrigued.

I have found the main thread about using WebAssembly GC in C#: https://github.com/WebAssembly/gc/issues/77. If I understand it correctly, it is not possible to use the current prototype version of GC in C#.

The .net team has given their notes on it, the concern is more on the memory layout from what I remember. Though it may be possible still. The runtime would likely still ship some gc code, but only a subset for cases not supported by the wasm gc itself and a few more for interfacing with the gc service, which overall should still result on smaller payloads compared to current sizes.

I assume that's one of the parts of the work done at https://github.com/WebAssembly/gc - not happening any soon yet, but it'll eventually be done.