Procedural macros that turn safe, annotated Rust into the WeaveFFI C ABI.

A producer annotates an ordinary Rust module with #[weaveffi::module] and tags the items it wants to export. The macro lowers the module to the WeaveFFI IR (through [weaveffi_bridge]), builds the canonical BindingModel, and emits the #[no_mangle] extern "C" thunks every generated language binding calls. All of the unsafe marshalling lives in the weaveffi-abi runtime, so the producer writes only safe Rust.

#[weaveffi::module]
pub mod calculator {
    /// Add two integers.
    #[weaveffi::export]
    pub fn add(a: i32, b: i32) -> i32 {
        a + b
    }
}

weaveffi::export_runtime!();

The same IR the macro lowers is what weaveffi generate path/to/lib.rs reads, so the generated bindings and the producer cannot drift.

Attributes

[macro@module] marks an exported namespace (the driver attribute).
[macro@export] exports a function; [macro@record] a by-value struct; [macro@enumeration] a #[repr(i32)] C-style enum.
[macro@callback] / [macro@listener] declare a callback and an event listener; [macro@cancellable] marks an async function as cancellable.

The item-level attributes are inert markers that [macro@module] reads; on their own they expand to the item unchanged.

weaveffi-macros 0.13.1

Attributes