oroperator.h

//          Copyright Joakim Karlsson & Kim Gräsman 2010-2013.
// Distributed under the Boost Software License, Version 1.0.
//    (See accompanying file LICENSE_1_0.txt or copy at
//          http://www.boost.org/LICENSE_1_0.txt)

#ifndef IGLOO_OROPERATOR_H
#define IGLOO_OROPERATOR_H

namespace snowhouse {
  
  struct OrOperator : public ConstraintOperator
  {
    template <typename ConstraintListType, typename ActualType>
    void Evaluate(ConstraintListType& list, ResultStack& result, OperatorStack& operators, const ActualType& actual)
    {
      EvaluateOperatorsWithLessOrEqualPrecedence(*this, operators, result);
      
      operators.push(this);
      
      EvaluateConstraintList(list.m_tail, result, operators, actual);
    }
    
    void PerformOperation(ResultStack& result)
    {
      if(result.size() < 2)
      {
        throw InvalidExpressionException("The expression contains an or operator with too few operands");
      }
      
      bool right = result.top();
      result.pop();
      bool left = result.top();
      result.pop();
      
      result.push(left || right);
    }
    
    int Precedence() const
    {
      return 4;
    }
  };
  
  template<>
  struct Stringizer<OrOperator>
  {
    static std::string ToString(const OrOperator&)
    {
      return "or";
    }
  };
}

#endif