(* buffer.sig *)

(* CML buffers of fixed maximum length *)

signature BUFFER =
sig

(* a buffer with fixed maximum length whose elements have type 'a *)

type 'a buffer

(* exception raised by make *)

exception Size

(* create a buffer with a given maximum length; raises Size if
   the length is not positive *)

val make : int -> 'a buffer

(* add(buf, x) adds x to the end of buf, and then returns (); it
   blocks until the addition is possible *)

val add : 'a buffer * 'a -> unit

(* del buf deletes the first element of buf, and returns the deleted
   element; it blocks until the deletion is possible *)

val del : 'a buffer -> 'a

end;