RhodeCode

namespace lemon {

  namespace concepts {

    /// \addtogroup concept

    /// @{

    /// Readable map concept

    template<typename K, typename T>

    class ReadMap

    {

    public:

      /// Map's key type.

      typedef K Key;    

      /// Map's value type. (The type of objects associated with the keys).

      typedef T Value;

      /// Returns the value associated with a key.

      ///

      Value operator[](const Key &) const {return Value();}

      template<typename _ReadMap>

      struct Constraints {

	void constraints() {

	  Value val = m[key];

	typename _ReadMap::Key& own_key;

	_ReadMap& m;

      };

    };

    /// Writable map concept

    template<typename K, typename T>

    class WriteMap

    {

    public:

      /// Map's key type.

      typedef K Key;    

      /// Map's value type. (The type of objects associated with the keys).

      typedef T Value;

	typename _WriteMap::Value own_val;

	Key& key;

	typename _WriteMap::Key& own_key;

	_WriteMap& m;

      };

    };

    template<typename K, typename T>

    class ReadWriteMap : public ReadMap<K,T>,

			    public WriteMap<K,T>

    {

    public:

      /// Map's key type.

      typedef K Key;    

      /// Map's value type. (The type of objects associated with the keys).

	void constraints() {

	  checkConcept<ReadMap<K, T>, _ReadWriteMap >();

	  checkConcept<WriteMap<K, T>, _ReadWriteMap >();

	}

      };

    };

    template<typename K, typename T, typename R, typename CR>

    class ReferenceMap : public ReadWriteMap<K,T>

    {

    public:

      /// Tag for reference maps.

      typedef True ReferenceMapTag;

      /// Map's key type.

      typedef K Key;    

    protected:

      Value tmp;

    public:

      ///Returns a reference to the value associated to a key.

      Reference operator[](const Key &) { return tmp; }

      ///Returns a const reference to the value associated to a key.

      /// Sets the value associated with a key.

      void set(const Key &k,const Value &t) { operator[](k)=t; }

      template<typename _ReferenceMap>

      struct ReferenceMapConcept {

	void constraints() {

	  checkConcept<ReadWriteMap, _ReferenceMap >();

	  m[key] = val;

	  val  = m[key];

	  m[key] = ref;

	Reference& ref;

	_ReferenceMap& m;

      };

    };

    // @}

  } //namespace concepts

} //namespace lemon

#endif // LEMON_CONCEPT_MAPS_H