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/*
* Modification History
*
* 2003-April-29 Jason Rohrer
* Created.
*
* 2003-May-9 Jason Rohrer
* Added support for replacing a variable.
*/
#ifndef VARIABLE_EXPRESSION_INCLUDED
#define VARIABLE_EXPRESSION_INCLUDED
#include "Expression.h"
#include "Variable.h"
/**
* Expression that contains a single variable.
*
* @author Jason Rohrer
*/
class VariableExpression : public Expression {
public:
/**
* Constructs a variable expression.
*
* @param inVariable the variable.
* Must be destroyed by caller after this class is destroyed.
*/
VariableExpression( Variable *inVariable );
/**
* Gets this expression's variable.
*
* @return the variable.
* Must not be destroyed by caller.
*/
Variable *getVariable();
/**
* A static version of getID().
*/
static long staticGetID();
// implements the Expression interface
virtual double evaluate();
virtual long getID();
virtual void print();
virtual Expression *copy();
virtual long getNumArguments();
virtual Expression *getArgument( long inArgumentNumber );
virtual void setArgument( long inArgumentNumber,
Expression *inArgument );
virtual Expression *extractArgument( long inArgumentNumber );
// overrides the default implementation
virtual void replaceVariable( Variable *inTarget,
Variable *inReplacement );
protected:
static long mID;
Variable *mVariable;
};
// static init
long VariableExpression::mID = 14;
inline VariableExpression::VariableExpression( Variable *inVariable )
: mVariable( inVariable ) {
}
inline Variable *VariableExpression::getVariable() {
return mVariable;
}
inline double VariableExpression::evaluate() {
return mVariable->getValue();
}
inline long VariableExpression::getID() {
return mID;
}
inline long VariableExpression::staticGetID() {
return mID;
}
inline void VariableExpression::print() {
char *varName = mVariable->getName();
printf( " %s ", varName );
delete [] varName;
}
inline Expression *VariableExpression::copy() {
// don't copy our variable
VariableExpression *copy =
new VariableExpression( mVariable );
return copy;
}
long VariableExpression::getNumArguments() {
return 0;
}
inline Expression *VariableExpression::getArgument(
long inArgumentNumber ) {
return NULL;
}
inline void VariableExpression::setArgument( long inArgumentNumber,
Expression *inArgument ) {
// do nothing
return;
}
inline Expression *VariableExpression::extractArgument(
long inArgumentNumber ) {
return NULL;
}
inline void VariableExpression::replaceVariable( Variable *inTarget,
Variable *inReplacement ) {
if( mVariable == inTarget ) {
mVariable = inReplacement;
}
}
#endif
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