(*
 * Illustration of an apparently polymorphic function, effected via generic
 * instantiation.
 *)

obj MList =  MObj*		(* A generic list of multipliable objects *)
    ops: LG2(l:MList)->MObj;	(*  This explicit op decl enables apparent *)
end;				(*   polymorphism of the function LG2. *)

obj MObj			(* A generic multipliable object *)
    ops:			(*  This op decl constrains the possbile *)
	"_*_"(ListElem,ListElem)->ListElem;  (* instances (including where *)
end;					     (* substitutions) of MObj. *)

op LG2(l:MList)->MObj		(* A generic (apparently polymorphic) *)
begin				(*  function on the generic MList object *)
    foreach (i in l)
	suspend i*2;
    end;
end;

obj MIntList extends MList	(* An integer extends MList, which *)
    where: MObj = integer;	(*  effects creation of the instance fcn *)
end;				(*    LG2(l:MIntList)->integer *)


op Test
begin
    var l: MIntList;

    set l = [1,2,3];
    print(LG2(l));		(* This calls the instance function, *)
    print(LG2(([1,2,3])));	(*  as does this. *)
end;


(*
 * The remainder of the file is just a bit more fiddling around. 
 *)
obj intlist =  integer*;

op F()->()
begin
    var i:integer;
    var l:intlist;

    foreach (i in [1..10])
	print(i);
    end;

    foreach (item in l)
	print(item);
    end;

    set l = [1,2,3];
end;