quadruple
Lib.quadruple : 'a -> 'b -> 'c -> 'd -> 'a * 'b * 'c * 'd
Makes four values into a quadruple.
quadruple x1 x2 x3 x4 returns (x1, x2, x3, x4).
quadruple x1 x2 x3 x4
(x1, x2, x3, x4)
Never fails.
Lib.quadruple_of_list, Lib.pair, Lib.triple
Lib.quadruple_of_list
Lib.pair
Lib.triple