RhodeCode

namespace lemon {

  namespace concepts {

    /// \addtogroup concept

    /// @{

    /// Readable map concept

    /// Readable map concept.

    ///

    template<typename K, typename T>

    class ReadMap

    {

    public:

      typedef K Key;    

      typedef T Value;

      /// Returns the value associated with a key.

      /// \bug Value shouldn't need to be default constructible.

      ///

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

      template<typename _ReadMap>

      struct Constraints {

	void constraints() {

	  Value val = m[key];

	  val = m[key];

	  typename _ReadMap::Value own_val = m[own_key]; 

	  own_val = m[own_key]; 

	Key& key;

	typename _ReadMap::Key& own_key;

	_ReadMap& m;

      };

    };

    /// Writable map concept

    /// Writable map concept.

    ///

    template<typename K, typename T>

    class WriteMap

    {

    public:

      typedef K Key;    

      typedef T Value;

      /// Sets the value associated with a key.

      void set(const Key &,const Value &) {}

      ///Default constructor

      WriteMap() {}

      template <typename _WriteMap>

      struct Constraints {

	void constraints() {

	  // No constraints for constructor.

	  m.set(key, val);

	  m.set(own_key, own_val);

	  ignore_unused_variable_warning(key);

	  ignore_unused_variable_warning(val);

	Value& val;

	typename _WriteMap::Value own_val;

	Key& key;

	typename _WriteMap::Key& own_key;

	_WriteMap& m;

      };

    };

    /// Read/Writable map concept

    /// Read/writable map concept.

    ///

    template<typename K, typename T>

    class ReadWriteMap : public ReadMap<K,T>,

    {

    public:

      typedef K Key;    

      typedef T Value;

      /// Returns the value associated with a key.

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

      /// Sets the value associated with a key.

      void set(const Key & ,const Value &) {}

      template<typename _ReadWriteMap>

      struct Constraints {

	void constraints() {

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

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

	}

      };

    };

    /// Dereferable map concept

    /// Dereferable map concept.

    ///

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

    class ReferenceMap : public ReadWriteMap<K,T>

    {

    public:

      /// Tag for reference maps.

      typedef True ReferenceMapTag;

      typedef K Key;    

      typedef T Value;

      typedef R Reference;

      typedef CR ConstReference;

    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.

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

      /// Sets the value associated with a key.

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

      /// \todo Rethink this concept. 

      template<typename _ReferenceMap>

      struct ReferenceMapConcept {