Stream: wit-bindgen

Topic: Generating code for a component to be wrapped with a library

i509VCB (Oct 11 2023 at 21:40):

At the moment I can't use wit-bindgen to generate types and traits for a library and then provide a more ergonomic wrapper for Rust at least.

The goal is to provide a library api like this:

pub trait Library {
    fn new() -> Result<Self>;
}

// This type is effectively thunks which may manage some internal state and call into the trait implementation of T.
struct LibraryImpl<T> { ... }
impl<T: Library> GuestWhatever for LibraryImpl<T> { ... }

And the user would implement the trait and use a macro to generate the component entrypoints, delegating the implementation to LibraryImpl.

pub struct Implementation {}

impl Library for Implementation { ... }

// This macro effectively would tell wit-bindgen to generate entrypoints targeting LibraryImpl<Implementation>.
library_crate::implement!(Implementation);

At the moment this type of API would be blocked on two things:

1. The generate macro needs to allow generics
2. The generate macro needs to split generation of types and entrypoints.

Any other thoughts on what might be needed for this?

i509VCB (Oct 11 2023 at 21:42):

For use case, I plan to provide a wgpu context implementation that you can ask for that is constructed for you and delegates via the component model to the runtime. (Instead of using the raw wit-bindgen generated types which won't work with the wgpu ecosystem)

Last updated: Dec 23 2024 at 12:05 UTC