scale.clef.expr
Class LessOp

java.lang.Object
  scale.common.Root
      scale.clef.Node
          scale.clef.expr.Expression
              scale.clef.expr.DyadicOp
                  scale.clef.expr.LessOp

All Implemented Interfaces:

AnnotationInterface, DisplayNode

public class LessOp
extends DyadicOp

This class represnts the test for less than.

$Id: LessOp.java,v 1.29 2005-11-29 13:38:23 burrill Exp $

Copyright 2005 by the Scale Compiler Group,
Department of Computer Science
University of Massachusetts,
Amherst MA. 01003, USA
All Rights Reserved.

Constructor Summary

LessOp(Expression e1, Expression e2)

LessOp(Type type, Expression e1, Expression e2)

Method Summary

Literal	getConstantValue() Return the constant value of the expression.
boolean	hasTrueFalseResult() Return true if the result of the expression is either true (1) or false (0).
void	visit(Predicate p) Process a node by calling its associated routine.

Methods inherited from class scale.clef.expr.DyadicOp

containsDeclaration, equivalent, getChild, getDeclList, getExpr1, getExpr2, getLhs, getRhs, isSimpleOp, numChildren, setExpr1, setExpr2, setLhs, setRhs

Methods inherited from class scale.clef.expr.Expression

canonical, getCoreType, getDisplayColorHint, getDisplayLabel, getDisplayShapeHint, getPointedToCore, getType, setType, toStringSpecial

Methods inherited from class scale.clef.Node

getDecl, getSourceLineNumber, setAnnotationLevel, setReportLevel, setSourceLineNumber, toString, toString, toStringChildren

Methods inherited from class scale.common.Root

addAnnotation, allAnnotations, allMatchingAnnotations, getAnnotation, getDisplayName, getDisplayString, getNodeCount, getNodeID, hasAnnotation, hasEqualAnnotation, hashCode, removeAnnotation, removeAnnotations, toStringAnnotations, toStringClass, trace, trace, trace

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

LessOp

public LessOp(Type type,
              Expression e1,
              Expression e2)

LessOp

public LessOp(Expression e1,
              Expression e2)

Method Detail

visit

public void visit(Predicate p)

Description copied from class: Node

Process a node by calling its associated routine. See the "visitor" design pattern in Design Patterns: Elements of Reusable Object-Oriented Software by E. Gamma, et al, Addison Wesley, ISBN 0-201-63361-2.

Each class has a visit(Predicate p) method. For example, in class ABC:

   public void visit(Predicate p)
   {
     p.visitABC(this);
   }
 

and the class that implements Predicate has a method

   public void visitABC(Node n)
   {
     ABC a = (ABC) n;
     ...
   }
 

Thus, the class that implements Predicate can call

   n.visit(this);
 

where n is a Node sub-class without determining which specific sub-class n is. The visit pattern basically avoids implementing a large switch statement or defining different methods in each class for some purpose.

Overrides:

visit in class DyadicOp

See Also:

Predicate

getConstantValue

public Literal getConstantValue()

Return the constant value of the expression.

Overrides:

getConstantValue in class Expression

See Also:

Lattice

hasTrueFalseResult

public boolean hasTrueFalseResult()

Return true if the result of the expression is either true (1) or false (0).

Overrides:

hasTrueFalseResult in class Expression