module Close:This module can be used to "close" a series of functors to produce a module with a parameterized type. For example,sig
..end
module CC = ComposeComparable
module L = CC(CC(List)(Option))(Close)
creates a module with type
type 'a t = 'a list option
type'a
t ='a
val to_string : ('a -> 'b) -> 'a -> 'b
val compare : ('a -> 'b -> 'c) -> 'a -> 'b -> 'c