[wffurr]

Note that the high level language needs a sufficient abstraction in its own runtime to allow substituting the Wasm GC for the runtime’s own GC. Work has been done for Java and Kotlin, but Python, C#, Ruby, Go can’t yet use the Wasm GC.

[goku12]

Agreed. That's what I guessed too. WASM GC is probably a low level component which high level languages can wrap to get their native/idiomatic GC behavior.

> Work has been done for Java and Kotlin

I'm unaware of this development. What did they do? Did they create an interface to the GC specification in the draft proposal?

[wffurr]

Well, for Java it's actually a separate compiler that targets Wasm and integrates with WasmGC: https://github.com/google/j2cl The Google Sheets team used it for their calc engine: https://v8.dev/blog/wasm-gc-porting

For Kotlin it's similar but the compiler backend is from Jetbrains themselves, targets Wasm and adapts the Kotlin runtime to use WasmGC: https://kotlinlang.org/docs/wasm-overview.html. https://seb.deleuze.fr/introducing-kotlin-wasm/ has some low level detail on how Kotlin works with WasmGC.

A bit more on Kotlin/Wasm here, seems like also Dart/Flutter uses WasmGC: https://developer.chrome.com/blog/wasmgc#kotlin_wasm

https://github.com/dotnet/runtime/issues/94420 has some notes on why C# can't use WasmGC (yet?).

[goku12]

Good info! Thanks!