Macro ocaml::function

macro_rules! function {
    ($x:expr, ($($argname:ident: $arg:ty),*) -> $r:ty) => { ... };
}

Convert OCaml value into a callable closure

For example, if you have an OCaml closure stored in f that accepts two int parameters, and returns a string, then you can create a Rust closure like this:

#[ocaml::func]
#[ocaml::sig("(int -> int -> string) -> int -> int -> string")]
pub fn call_function(f: ocaml::Value, a: ocaml::Int, b: ocaml::Int) -> Result<String, ocaml::Error> {
    let f = ocaml::function!(f, (a: ocaml::Int, b: ocaml::Int) -> String);
    f(gc, &a, &b)
}