wasm-wrapper-gen

JavaScript wrapper generation for rust code targeting wasm32-unknown-unknown.

This repository is currently very WIP, but there's a full working example Cargo project in examples/simple_summation/.

General overview:

wasm-wrapper-gen is composed of two interlocking parts:

• wasm-wrapper-gen provides the js_fn!() macro which generates extern "C" functions
• wasm-wrapper-gen-build is a build-script utility which scrapes the source for usages of js_fn!() and generates a JavaScript file which binds to those exported functions.

Note: this assumes little-endian hardware (the majority of modern hardware).

Currently supported:

• Argument types:
  • bool, u8, u16, u32, usize, i8, i16, i32, isize, f32, f64
  • &[_], &mut [_], Vec<_> where _ is any of the above
• Return types:
  • bool, u8, u16, u32, usize, i8, i16, i32, isize, f32, f64
  • Vec<_> where _ is any of the above
• Full automatic memory management and freeing unless rust function panics
• Configuration to use either a single DataView or a TypedArray instance per argument to access arrays
• Configurable output JS indentation

Unimplemented:

• Next to do:

  • Add support for making an async constructor rather than sync one.
  • Add support for impl blocks with self arguments and creating wrapper JS types which manage allocation sanely.

• Further future:

  • Make real tests and figure out how to do a build.rs script which only runs for tests
  • Arbitrary argument types implementing some serialization trait
  • Macro to wrap individual structs in separate JavaScript classes which all reference the same WebAssembly.Instance

Links:

• Full example of usage
• Full example of generated code