Add wasi_snapshot and make it default for wasi

[MaxGraey]

No description provided.

[MaxGraey]

I preserved wasi_unstable.ts but wasi.ts now redirect to wasi_snapshot.ts. We still need backward compatibility. Also node 13.3.0 it seems implement wasi_unstable version

[dcodeIO]

Hmm, bytecodealliance/wasi references a wasi_snapshot_preview1 version. Is there a difference to wasi_snapshot?

[MaxGraey]

It's wasi_snapshot_preview0. Need check which changes introduced in snapshot1...

[MaxGraey]

Ahh, sorry it's snapshot_preview1. So actually latest stable

[dcodeIO]

I see. Now I'm wondering how we can make this pluggable with a --use option. For instance if there is a wasi program that is intended to run in engines implementing different standards.

Maybe we can do

// bindings/wasi.ts
export * as unstable from "./wasi_unstable.ts";
export * as snapshot_preview1 from "./wasi_snapshot.ts";

and then utilize --use wasi=bindings/wasi/snapshot_preview1 or something like that, with the default being the latest bindings we have?

[MaxGraey]

Or just --use wasi=wasi_snapshot or --use wasi=wasi_unstable

[dcodeIO]

Thanks! I guess it's fine to look into the mechanism mentioned above later.