SLib.S : ('a -> 'b -> 'c) -> ('a -> 'b) -> 'a -> 'c
Generalized function composition: S f g x equals
f x (g x).
S f never fails and S f g never fails, but
S f g x fails if g x fails or
f x (g x) fails.
Lib, Lib.##, Lib.C, Lib.I, Lib.K, Lib.W