let f1 = \(x, y).         x + y in f1 (1, 2)
let f2 = \(x:N, y:N).     x + y in f2 (1, 2)
let f3 = \((x, y) : N*N). x + y in f3 (1, 2)
let h = \left (x, y). x in h (left (10, -10))
let fwop = \((x1, y1), (x2, y2)). ((x1, x2), (y1, y2)) in fwop((1, 2), (3, 4))
let uncurry = \f. \(a, b). f a b in uncurry (\a. \b. a + b) (40, 2)
:type         \f. \(a, b). f a b