(* Copyright (C) 1989, Digital Equipment Corporation           *)
(* All rights reserved.                                        *)
(* See the file COPYRIGHT for a full description.              *)

(* File: ExprRep.i3                                            *)
(* Last Modified On Sat Feb 10 17:23:43 1990 By kalsow         *)

INTERFACE ExprRep;

IMPORT M3, Expr, Type, Wr;

REVEAL
  M3.Expr = UNTRACED BRANDED OBJECT
              origin       : INTEGER;
              type         : Type.T;
              bound        : BOOLEAN;
              inCheck      : BOOLEAN;
              checked      : BOOLEAN;
            METHODS
              bind         ()                          := NoBind;
              check        ()                          := NoCheck;
              write        (t1, t2: M3.Temp)           := NoWriter;
              isEqual      (e: M3.Expr): BOOLEAN       := NeverEq;
              evaluate     (): M3.Expr                 := NoValue;
              getBounds    (VAR min, max: INTEGER)     := NoBounds;
              isWritable   (): BOOLEAN                 := IsNever;
              isDesignator (): BOOLEAN                 := IsNever;
	      isZeroes     (): BOOLEAN                 := IsNever;
	      genLiteral   ()                          := NoLiteral;
              fprint       (map: Type.Map;  wr: Wr.T);
              compile      (): M3.Temp;
            END;

PROCEDURE Init (e: M3.Expr);
(* initializes the common part of an Expr.T *)

(* misc. useful methods *)
PROCEDURE NoBind    (e: M3.Expr);
PROCEDURE NoCheck   (e: M3.Expr);
PROCEDURE NoValue   (e: M3.Expr): M3.Expr;
PROCEDURE Self      (e: M3.Expr): M3.Expr;
PROCEDURE NoBounds  (e: M3.Expr;  VAR min, max: INTEGER);
PROCEDURE IsNever   (e: M3.Expr): BOOLEAN;
PROCEDURE IsAlways  (e: M3.Expr): BOOLEAN;
PROCEDURE NeverEq   (e: M3.Expr;  x: M3.Expr): BOOLEAN;
PROCEDURE NoWriter  (e: M3.Expr;  t1, t2: M3.Temp);
PROCEDURE NoLiteral (e: M3.Expr);

END ExprRep.