Yes, its great to see progress in the tooling [1] so that the component building is easier. Although I do like to think of the component model as the "ABI linking model". You can only bind one implementation to an interface import.
You still need to cross the JS FFI boundary for wasm, I don't think WebAssembly has a specification for cross language FFI directly between WebAssembly languages.
One of the biggest goals of the component model is that it doesn't matter what language your component is written in. Composition can happen anytime one component exports an interface and another component imports it. https://component-model.bytecodealliance.org/creating-and-co...
WASM is basically similar to JVM bytecode. So the comparison would be like using compiled code from Java, Scala and/or Kotlin for example.
The source language only determines how the code is expressed in WASM and whether or not it also needs to bundle / compile-in some runtime code baggage for it to work.
I develop the Scala-to-Wasm compiler, and also maintain the JVM backend of Scala. I can tell you that Wasm is very different from JVM bytecode.
The fundamental difference is that the JVM bytecode has an object model. When they talk to each other, Java, Scala and Kotlin do so at the abstraction level of the JVM object model. You can directly call methods between them because virtual dispatch of methods is a concept with semantics in the bytecode.
There's no such thing in Wasm, even with the GC extension. You get structs and arrays, but nothing like methods. If you want virtual dispatch, you encode it yourself using your own design of virtual method tables. That means Java, Scala and Kotlin, despite all having their Wasm GC backend at this point, cannot call each other's methods in Wasm.
Yes, in retrospect I should have mentioned "Components" in my comment and just compared it to "Java" in general instead. I felt that was implied due to the thread and topic of discussion.
From a pragmatic end-user point-of-view explanation, I would still stand by saying WASM Component Model may be similar to working within the JVM multi-language ecosystem. One can work with code compiled from multiple different languages, but the generated code may be different because of the different compilers.
I am confused. You are referring to wasm modules here? And Component Model / WASI / WIT will give us polyglot interface-based programming then, right? Call each other's methods through the WIT interface between components.
[1] https://developer.fermyon.com/spin/v3/writing-apps#declaring...