type HandlerFn = fn ()

fn new_static_router(route_not_found_handler ?fn ()) fn () {
    return route_not_found_handler or {
        fn () {}
    }
}

fn new_static_router2(route_not_found_handler ?HandlerFn) fn () {
    return route_not_found_handler or {
        fn () {}
    }
}

fn test_option_fn_alias_decl_with_none() {
    b := new_static_router2(none)
    $if b is $function {
        assert true
    } $else {
        assert false
    }
}

fn test_option_fn_decl_with_none() {
    a := new_static_router(none)
    $if a is $function {
        assert true
    } $else {
        assert false
    }
}

fn test_option_fn_passing_normal() {
    anon_1 := fn () {
        println(1)
    }
    c := new_static_router(anon_1)
    assert c == anon_1
}

fn test_option_fn_passing_to_alias() {
    anon_2 := fn () {
        println(2)
    }
    d := new_static_router(anon_2)
    assert d == anon_2
}