INTERFACE Visual;

(* Optical properties of materials *)

IMPORT LR3;

TYPE
  T = RECORD
      name: Name;
      color: LR3.T;
    END; 

  List = ARRAY OF T;
  Num = CARDINAL;     (* Index in a "List" *)
  Name = TEXT;
  
CONST None = LAST(CARDINAL); (* A NIL value for "Num" *)

PROCEDURE Find(READONLY vis: List; name: Name): Num;
  (*
    Looks for "name" in the given list. If it doesn't
    occur, returns "None" *)

END Visual.