module type Container = 
sig
	type 'a t
	exception Empty of string
	
	val create: unit -> 'a t
	val put: 'a * 'a t -> unit
	val take: 'a t -> 'a
end;;

module ContainerList = 
struct
	type 'a t = {mutable a : 'a list }
	exception Empty of string
	
	let create() = { a = [] }


	let put (e, c) = 
		match c.a with
		| [] -> begin c.a <- [e] end
		| h::t -> begin c.a <- c.a@[e] end

	let take c = 
		match c.a with
		| [] -> raise (Empty "e")
		| h::t -> begin c.a <- t ; h end

	
end;;

let cL = ContainerList.create();;
ContainerList.put(1, cL);;
ContainerList.put(2, cL);;
ContainerList.put(3, cL);;

ContainerList.take cL;;