message: Add range class
diff: @@ -150,4 +150,42 @@ namespace RINGMesh {
  protected:
  std::string category_;
  };
  +
  + class RINGMESH_API range {
  + public:
  + range( index_t begin, index_t end )
  + : iter_( begin ), last_( end )
  + {
  + }
  + range( index_t end )
  + : last_( end )
  + {
  + }
  + // Iterable functions
  + const range& begin() const
  + {
  + return *this;
  + }
  + const range& end() const
  + {
  + return *this;
  + }
  + // Iterator functions
  + bool operator!=( const range& ) const
  + {
  + return iter_ < last_;
  + }
  + void operator++()
  + {
  + ++iter_;
  + }
  + index_t operator*() const
  + {
  + return iter_;
  + }
  +
  + private:
  + index_t iter_ { 0 };
  + index_t last_ { 0 };
  + };
  }
  