#ifndef SUM_H
#define SUM_H

#include "Expression.h"

template<class T>
struct Sum : public Expression<T> {
  Sum(Expression<T>* left, Expression<T>* right)
    : _left(left), _right(right) { }

  T eval(const std::map<std::string, T>& mappings) const {
    T left = _left->eval(mappings);
    T right = _right->eval(mappings);
    return left + right;
  }
  
  private:
  Expression<T>* _left;
  Expression<T>* _right;
};

#endif