/data/refman/pasoursint/CMSSW_5_3_0/src/CommonTools/Utils/src/ExpressionSelectorSetter.h

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#ifndef CommonTools_Utils_ExpressionSelectorSetter_h
#define CommonTools_Utils_ExpressionSelectorSetter_h
/* \class reco::parser::ExpressionSelectorSetter
 *
 * Creates an implicit Binary selector setter by comparing an expression to 0
 *
 * \author original version: Chris Jones, Cornell, 
 *         adapted to Reflex by Luca Lista, INFN
 *
 * \version $Revision: 1.1 $
 *
 */
#include "CommonTools/Utils/src/SelectorStack.h"
#include "CommonTools/Utils/src/ExpressionStack.h"
#include "CommonTools/Utils/src/BinarySelector.h"
#include "CommonTools/Utils/src/ExpressionNumber.h"
#include "CommonTools/Utils/src/Comparison.h"
#include "CommonTools/Utils/interface/Exception.h"
#include <boost/shared_ptr.hpp>
#include <functional>

namespace reco {
  namespace parser {    
    class ExpressionSelectorSetter {
    public:
      ExpressionSelectorSetter(SelectorStack& selStack, ExpressionStack& expStack) : 
        selStack_(selStack), expStack_(expStack) { }
      
      void operator()(const char * begin, const char *) const {
        if(expStack_.empty())
          throw Exception(begin)
            << "Grammar error: empty expression stack. Please contact developer." << "\"";
        boost::shared_ptr<ExpressionBase> rhs = expStack_.back(); expStack_.pop_back();
        boost::shared_ptr<ExpressionBase> lhs(new ExpressionNumber(0.0));
        boost::shared_ptr<ComparisonBase> comp(new Comparison<std::not_equal_to<double> >());
#ifdef BOOST_SPIRIT_DEBUG 
        BOOST_SPIRIT_DEBUG_OUT << "pushing expression selector" << std::endl;
#endif
        selStack_.push_back(SelectorPtr(new BinarySelector(lhs, comp, rhs)));
      }
    private:
      SelectorStack & selStack_;
      ExpressionStack & expStack_;
    };
  }
}

#endif