Use wasm-{bindgen,pack} to make a steppable "debugger" for a generated parser.

[eddyb]

I imagine we could very easily support both single-stepping (as a GLL parser already kind of works like that) and "breakpoints" (by stopping when parsing reaches a certain, or when one of the named rules is entered).

Ideally, we could even allow inputting a grammar, but while we can run the code generator, the resulting Rust needs a Rust compiler, so we would instead need to have an interpreter.

We'd need some sort of HTML+JS dynamic graph viewer (for visualizing SPPF/GSS), but I believe D3, at least, has something like this.

Bonus for integrating this into a VS Code extension for testing grammars.