Paste: multiple dispatch

record Human {
}

record Dog {
}

variant Animal = Human | Dog;

procedure what;
overload what(x:Human) = "Human";
overload what(x:Dog) = "Dog";

procedure printPair;
overload printPair(a:Human, b:Human) { println(what(a), ", ", what(b)); }
overload printPair(a:Human, b:Dog) { println(what(a), ", ", what(b)); }
overload printPair(a:Dog, b:Human) { println(what(a), ", ", what(b)); }
overload printPair(a:Dog, b:Dog) { println(what(a), ", ", what(b)); }

main() {
    var v = Vector[Animal]();
    push(v, Animal(Human()));
    push(v, Animal(Dog()));
 
    for (a in v)
        for (b in v)
            printPair(*a, *b);
}