#![allow(dead_code)]

macro_rules! fun {
    (
        $fname:ident $args:tt -> $ok_ty:ty => throws $err_ty:ty
        {
            $($fbody:tt)*
        }
    ) => (
        fn $fname $args -> ::std::result::Result< $ok_ty , $err_ty >
        {
            Ok({
                $($fbody)*
            })
        }
    );
}

macro_rules! throw {
    (
        $expr:expr
    ) => (
        return Err($expr)
    );
}

fun!{ foo(b: bool) -> i32 => throws String {
    if b {
        throw!("Got true".into())
    };
    42
}}

fun!{ bar(b: bool) -> () => throws String {
    foo(b)?;
}}

#[test]
fn foo_true ()
{
    if let Err(s) = foo(true) {
        assert_eq!(s, "Got true");
    } else {
        unreachable!();
    }
}

#[test]
fn foo_false ()
{
    if let Ok(x) = foo(false) {
        assert_eq!(x, 42_i32);
    } else {
        unreachable!();
    }
}