signature CHAR =
sig
type char
val ord : char -> int
val chr : int -> char
val (=) : char -> char -> bool
val (<>) : char -> char -> bool
val (<) : char -> char -> bool
val (<=) : char -> char -> bool
val (>) : char -> char -> bool
val (>=) : char -> char -> bool
val compare : char -> char -> order
end
structure Char : CHAR where type char = Pervasive.char