Empty.h

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/* Copyright (C) 2006 - 2009, Bernd Speiser */

/* This file is part of GeneralQuantities.

GeneralQuantities is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

GeneralQuantities is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
  
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA.
*/

#ifndef _Empty_h
#define _Empty_h

// Quantity includes
#include "Quantity/Variable.h"
#include "Quantity/Constant.h"
#include "Quantity/QuantityCluster.h"

namespace quantity {
  namespace empty {

class Class;

class Unit;

/* declaration of Empty units */
class EmptyUnit;

typedef unit::NonPrefixable<Unit, EmptyUnit> Unity;

typedef LOKI_TYPELIST_1(Unity) Units;

/* Empty quantity */

typedef Quantity<Class> Quantity;

class DerivedEmpty;

} // end namespace empty



  template<typename ST>
    struct Standard<empty::Unity, ST>
    {
      static const ST ratio;
      static const bool exact;
    };

template<typename ST> const ST Standard<empty::Unity, ST>::ratio = 1.0;

template<typename ST> const bool Standard<empty::Unity, ST>::exact = true;

template<>
  struct QuantityTraits<empty::Class>
  {
    typedef
      dimension::Dimension<BSUtilities::Rational<0>,
        BSUtilities::Rational<0>, BSUtilities::Rational<0>,
          BSUtilities::Rational<0>, BSUtilities::Rational<0>,
            BSUtilities::Rational<0>, BSUtilities::Rational<0> > Dimension;
    typedef empty::Unit UnitType;
    typedef empty::Units UnitList;
    typedef empty::Unity DefaultUnit;

    typedef empty::DerivedEmpty DefaultDerivedQuantityType;

    static const std::string NameString;
    static const std::string SymbolString;

  };

// the derived quantity traits template for derived Empty
template<>
  struct DerivedQuantityTraits<empty::Class, empty::DerivedEmpty>
  {
    static const bool OverwriteName = false;
    static const bool OverwriteSymbol = false;

    static const std::string NameString;
    static const std::string SymbolString;

  };

typedef Variable<empty::Quantity> Empty;

typedef Constant<empty::Quantity> EmptyConstant;

typedef QuantityVector<Variable, empty::Quantity> EmptyVector;

  } // end namespace quantity

#endif /* _Empty_h */

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