//# publish

// example using generics in a few common/interesting/non-trivial ways
module 0x42.Option {
    import 0x1.vector;

    struct T<E> has copy, drop, store {
        v: vector<E>
    }

    public none<E: store>(): Self.T<E> {
    label b0:
        return T<E> { v: vector.empty<E>() };
    }

    public some<E: store>(e: E): Self.T<E> {
        let v: vector<E>;
    label b0:
        v = vector.empty<E>();
        vector.push_back<E>(&mut v, move(e));
        return T<E> { v: move(v) };
    }

    public unwrap_or<E: copy + drop + store>(x: Self.T<E>, e: E): E {
        let v: vector<E>;
    label b0:
        T<E> { v: v } = move(x);
        jump_if (vector.is_empty<E>(&v)) b2;
    label b1:
        return vector.pop_back<E>(&mut v);
    label b2:
        return move(e);
    }

    public really_none<E: copy + drop + store>(): Self.T<E> {
    label b0:
        return Self.unwrap_or<Self.T<E>>(Self.none<Self.T<E>>(), Self.none<E>());
    }
}