gistfile1.txt

enum deser = uint;

iface reader {
    fn read_vec_elt<T:copy>(f: fn() -> T) -> T;
}

impl of reader for deser {
    fn read_vec_elt<T:copy>(f: fn() -> T) -> T {
        f()
    }
}

fn read_to_vec<D:reader, T:copy>(self: D, f: fn() -> T) -> [T] {
    let v = [];
    self.read_vec_elt() {|| v += [f()] }
    v
}

fn main() {
    let x = deser(1u);
    assert [22u] == read_to_vec(x) {|| 22u };
}