(* Copyright (C) 1990, Digital Equipment Corporation.         *)
(* All rights reserved.                                       *)
(* See the file COPYRIGHT for a full description.             *)

(* Last modified on Tue Mar 20 23:58:30 1990 by muller        *)


INTERFACE M3Value;

(* A Value.T is a representation for a Modula-3 value; it is intended 
   to be used in conjunction with the typed Abstract Syntax Tree 
   interface, TypedAST.  A Value.T only contains enough information 
   to determine the value if you already know the value's type; 
   therefore Value.T's should generally be paired with Type.T's. 
   
   For good measue, this interface also defines types to represent 
   procedures and exceptions. *)

TYPE 
  T <: ROOT;
  (* Ordinal | Float | LongFloat | Array | Set | Record | Text | Null *)

    Ordinal = T OBJECT ord: INTEGER END;
    (* ORD(the value) *)

    Float = T OBJECT val: REAL END;

    LongFloat = T OBJECT val: LONGREAL END;

    Array = T OBJECT elements: REF ARRAY OF T END;

    Set = T OBJECT elements: REF ARRAY OF BOOLEAN END;

    Record = T OBJECT elements: REF ARRAY OF T END;
    (* The field values in the order the fields are declared. *)

    Text = T OBJECT val: TEXT END;

    Null = T OBJECT END;
    (* The value NIL. *)

    Procedure <: ROOT;

    Exception  <: ROOT;

END M3Value.