fusion vertical loop combination <programming> A {program transformation} where a {composition} of two functions is replaced by in-lining them and combining their bodies. E.g. f x = g (h x) ==> f x = g (2 * x) g x = x + 1 f x = 2 * x + 1 h x = 2 * x This has the beneficial effect of reducing the number of function calls. It can be especially useful where the intermediate result is a large data structure which can be eliminated. See also {vertical loop combination}. (1994-12-05)