[wrs]

I think the argument here is that you don’t need a full N:1:M mapping of data types to make this work. Transparency is a myth. If you try it (as in Sun RPC, DCE, CORBA, COM, etc.) you end up just writing wrappers anyway as you hit some edge case that the universal type system doesn’t support. E.g., look at the clunky IDL interfaces COM had to invent to get interop with JavaScript objects because IDL had baked-in assumptions about how records work.

Since the point is to enable component-level interop, not fine-grained function interop, you can instead define a simple interchange format (more JSONish than IDLish) and write the library interfaces accordingly. More of a microservice approach than a linker approach.

[Arnavion]

Counter-point: I happen to be working at $dayjob on things related to Components (both on the host side and the module side), including using some "WIP" things like the "resource" feature (opaque handles with methods), and haven't hit any edge cases.

[wrs]

Sure, it’s expected that you won’t hit problems if you’re using the paradigms that existed when the IDL was defined. On the other hand, trying to apply Sun RPC after everything became object-oriented…well, that’s when we blew it up and invented CORBA. So I’m just saying the cycle is likely to continue with this approach. In other words, come back in ten years and see how it aged.

The alternative is to use something so simple it can’t become outdated. Dumb down the interface rather than making the interop omniscient. (Kind of like the dumb network principle.)

[wrs]

I just realized: The very fact that WASI isn’t using any of the previous N attempts at a supposedly universal IDL, but instead inventing yet another one, itself demonstrates the problem with this approach.

[torginus]

It's entirely reasonable for WASM to use its own IDL. Afaik Chrome already uses an IDL to describe the interaction between native C++ classes and their Javascript bindings.

Integrating WASM modules with each other, WASM with JS, and WASM with native functionality seamlessly is a huge and unsolved challenge.

[p_l]

Or it just points towards NIH syndrome, combined with hype and anti-hype driven mentality of programmers, and general forgetting of previous technologies. Or even when the differences are close to 0, doing a new not exactly same implementation for ... whatever reason.

[pjmlp]

Or COM's evolution, WinRT, where the .NET metadata also doesn't really map to JavaScript or C++, without some additional kludges with metadata as workaround.