FFI support for Intuicio scripting platform

0_test_library.rs

let registry = Registry::default().with_basic_types();
let mut context = Context::new(10240, 10240);
let mut lib = FfiLibrary::new("../../target/debug/ffi").unwrap();
let ffi_add = lib
    .function(function_signature!(&registry => fn add(a: i32, b: i32) -> (result: i32)))
    .unwrap();
let ffi_ensure = lib
    .function(function_signature!(&registry => fn ensure_42(v: i32) -> ()))
    .unwrap();
context.stack().push(2i32);
context.stack().push(40i32);
unsafe {
    ffi_add.call(&mut context).unwrap();
    ffi_ensure.call(&mut context).unwrap();
}

1_test_function.rs

extern "C" fn add(a: i32, b: i32) -> i32 {
    a + b
}

extern "C" fn ensure_42(v: i32) {
    assert_eq!(v, 42);
}

let registry = Registry::default().with_basic_types();
let mut context = Context::new(10240, 10240);

let i32_type = registry.find_type(TypeQuery::of::<i32>()).unwrap();
let ffi_add = Ffi::new(FfiCodePtr(add as *mut _))
    .with_argument(i32_type.clone())
    .with_argument(i32_type.clone())
    .with_result(i32_type.clone());
let ffi_ensure = Ffi::new(FfiCodePtr(ensure_42 as *mut _)).with_argument(i32_type.clone());
context.stack().push(2i32);
context.stack().push(40i32);
unsafe {
    ffi_add.call(&mut context).unwrap();
    ffi_ensure.call(&mut context).unwrap();
}

let ffi_add = Ffi::from_function_signature(
    FfiCodePtr(add as *mut _),
    &function_signature!(&registry => fn add(a: i32, b: i32) -> (result: i32)),
);
let ffi_ensure = Ffi::from_function_signature(
    FfiCodePtr(ensure_42 as *mut _),
    &function_signature!(&registry => fn ensure_42(v: i32) -> ()),
);
context.stack().push(2i32);
context.stack().push(40i32);
unsafe {
    ffi_add.call(&mut context).unwrap();
    ffi_ensure.call(&mut context).unwrap();
}

let ffi_add = Ffi::build_function(
    FfiCodePtr(add as *mut _),
    function_signature!(&registry => fn add(a: i32, b: i32) -> (result: i32)),
);
let ffi_ensure = Ffi::build_function(
    FfiCodePtr(ensure_42 as *mut _),
    function_signature!(&registry => fn ensure_42(v: i32) -> ()),
);
context.stack().push(2i32);
context.stack().push(40i32);
ffi_add.invoke(&mut context, &registry);
ffi_ensure.invoke(&mut context, &registry);