(*
CSE 341, Marty Stepp
A signature represents a set of public members a structure can expose.
It is similar to an interface in Java, combined with Java's "private" keyword.
*)

signature RATIONAL =
sig
	(* abstract type declaration; says that there is a rational type,
	   but doesn't describe how it is implemented                     *)
	type rational;
	
	exception TheRoof;
	
	(* function declarations (no bodies) *)
	val compare: rational * rational -> order;
	val new: int * int -> rational;
	val add: rational * rational -> rational;
	val toString: rational -> string;
end;