erg 0.6.53

add x, y =
    x + y

print! add(1, 1)
print! add(1.0, 1)
print! add("a", "b")

close_add|A <: Add(A)| x: A, y: A =
    x + y

print! close_add 1, 1
print! close_add 1.0, 1
print! close_add "a", "b"