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/*
* Modification History
*
* 2003-May-2 Jason Rohrer
* Created.
*/
#ifndef COMPARISON_EXPRESSION_INCLUDED
#define COMPARISON_EXPRESSION_INCLUDED
#include "Expression.h"
#include "BinaryOperationExpression.h"
/**
* Expression implementation of a binary comparison operation.
*
* Evaluating this expression returns 1 if the comparisson is true
* and 0 if it is false.
*
* @author Jason Rohrer
*/
class ComparisonExpression : public BinaryOperationExpression {
public:
static const int GREATER_THAN = 0;
static const int LESS_THAN = 1;
static const int GREATER_THAN_OR_EQUAL_TO = 2;
static const int LESS_THAN_OR_EQUAL_TO = 3;
static const int EQUAL_TO = 4;
static const int NOT_EQUAL_TO = 5;
/**
* Constructs a binary comparison operation expression.
*
* Both arguments are destroyed when the class is destroyed.
*
* @param inComparison the comparison to make, one of
* GREATER_THAN, LESS_THAN, GREATER_THAN_OR_EQUAL_TO,
* LESS_THAN_OR_EQUAL_TO, EQUAL_TO, NOT_EQUAL_TO.
* @param inArgumentA the first argument.
* @param inArgumentB the second argument.
*/
ComparisonExpression( int inComparison,
Expression *inArgumentA,
Expression *inArgumentB );
/**
* Gets the comparison being made.
*
* @return one of GREATER_THAN, LESS_THAN, GREATER_THAN_OR_EQUAL_TO,
* LESS_THAN_OR_EQUAL_TO, EQUAL_TO, NOT_EQUAL_TO.
*/
int getComparison();
/**
* Sets the comparison to make.
*
* @param inComparison the comparison to make, one of
* GREATER_THAN, LESS_THAN, GREATER_THAN_OR_EQUAL_TO,
* LESS_THAN_OR_EQUAL_TO, EQUAL_TO, NOT_EQUAL_TO.
*/
void setComparison( int inComparison );
/**
* A static version of getID().
*/
static long staticGetID();
// implements the Expression interface
virtual double evaluate();
virtual long getID();
virtual void print();
virtual Expression *copy();
protected:
static long mID;
int mComparison;
};
// static init
long ComparisonExpression::mID = 15;
inline ComparisonExpression::ComparisonExpression(
int inComparison,
Expression *inArgumentA,
Expression *inArgumentB )
: BinaryOperationExpression( inArgumentA, inArgumentB ),
mComparison( inComparison ) {
}
inline int ComparisonExpression::getComparison() {
return mComparison;
}
inline void ComparisonExpression::setComparison( int inComparison ) {
mComparison = inComparison;
}
inline double ComparisonExpression::evaluate() {
if( mComparison == GREATER_THAN ) {
if( mArgumentA->evaluate() > mArgumentB->evaluate() ) {
return 1;
}
else {
return 0;
}
}
else if( mComparison == LESS_THAN ) {
if( mArgumentA->evaluate() < mArgumentB->evaluate() ) {
return 1;
}
else {
return 0;
}
}
else if( mComparison == GREATER_THAN_OR_EQUAL_TO ) {
if( mArgumentA->evaluate() >= mArgumentB->evaluate() ) {
return 1;
}
else {
return 0;
}
}
else if( mComparison == LESS_THAN_OR_EQUAL_TO ) {
if( mArgumentA->evaluate() <= mArgumentB->evaluate() ) {
return 1;
}
else {
return 0;
}
}
else if( mComparison == EQUAL_TO ) {
if( mArgumentA->evaluate() == mArgumentB->evaluate() ) {
return 1;
}
else {
return 0;
}
}
else if( mComparison == NOT_EQUAL_TO ) {
if( mArgumentA->evaluate() != mArgumentB->evaluate() ) {
return 1;
}
else {
return 0;
}
}
else {
// unknown comparison type
// default to false
return 0;
}
}
inline long ComparisonExpression::getID() {
return mID;
}
inline long ComparisonExpression::staticGetID() {
return mID;
}
inline void ComparisonExpression::print() {
printf( "( " );
mArgumentA->print();
if( mComparison == GREATER_THAN ) {
printf( " > " );
}
else if( mComparison == LESS_THAN ) {
printf( " < " );
}
else if( mComparison == GREATER_THAN_OR_EQUAL_TO ) {
printf( " >= " );
}
else if( mComparison == LESS_THAN_OR_EQUAL_TO ) {
printf( " <= " );
}
else if( mComparison == EQUAL_TO ) {
printf( " == " );
}
else if( mComparison == NOT_EQUAL_TO ) {
printf( " != " );
}
else {
printf( " UNKNOWN_COMPARISON " );
}
mArgumentB->print();
printf( " )" );
}
inline Expression *ComparisonExpression::copy() {
ComparisonExpression *copy =
new ComparisonExpression( mComparison,
mArgumentA->copy(),
mArgumentB->copy() );
return copy;
}
#endif
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