define-typed-syntax-class form

[Alexis King]

I’m sure this has already been considered, and I’m sure it would be a nontrivial amount of work to implement, but it would be extremely useful to have a define-typed-syntax-class form that mirrors define-syntax-class but with Turnstile’s type judgement DSL. I’ve already run into a couple different places where I would want such a thing, and while it’s not usually too complicated to find an alternate approach, syntax classes are a really nice tool to have.

[Stephen Chang]

This is a good idea and shouldn't be hard.

We already have syntax-parse/typed-syntax that is analogous to syntax-parse, though it's undocumented bc we are still debating the name. I proposed typed-syntax-parse though @AlexKnauth didnt like it (and I agreed that it's a little weird). But if there's a define- in front, then I think it's ok.

[Alex Knauth]

It will be a bit more work that syntax-parse/typed-syntax would be because with no conclusion line we can't reuse the clause syntax class, but it still shouldn't be too hard.