hs-bindgen

Handy macro to generate C-FFI bindings from Rust to Haskell.

This library intended to work best in a project configured by cabal-pack.

Examples

A minimal example would be to have a function annotated like this:

```rust use hs_bindgen::*;

/// Haskell type signature are auto-magically inferred from Rust function /// type! This feature could slow down compilation and be disabled with: /// hs-bindgen = { ..., default-features = false }

[hs_bindgen]

fn greetings(name: &str) { println!("Hello, {name}!"); } ```

This will be expanded to (you can try yourself with cargo expand):

```rust use hs_bindgen::*;

fn greetings(name: &str) { println!("Hello, {name}!"); }

[no_mangle] // Mangling randomize symbols

extern "C" fn cgreetings(0: *const std::os::raw::cchar) { greetings(traits::ReprC::from(__0)) } ```

A more complete example, when we now try to pass a custom type to our interface:

```rust use hs_bindgen::{traits::ReprC, *};

/// A custom Rust data-type struct User { name: String, }

/// Declare targeted Haskell signature

[hs_bindgen(hello :: CString -> IO ())]

fn hello(user: User) { println!("Hello, {}!", user.name); }

/// Implementation of the helper trait required by hs_bindgen impl ReprC<*const i8> for User { fn from(ptr: *const i8) -> Self { User { name: >::from(ptr), } } } ```

Acknowledgments

⚠️ This is still a working experiment, not yet production ready.

hs-bindgen was heavily inspired by other interoperability initiatives, as wasm-bindgen and PyO3.

This project was part of a work assignment as an IOG contractor.