//=======================================================================

 // Copyright 2002 Indiana University.

 // Authors: Andrew Lumsdaine, Lie-Quan Lee, Jeremy G. Siek

 //

 // Distributed under the Boost Software License, Version 1.0. (See

 // accompanying file LICENSE_1_0.txt or copy at

 // http://www.boost.org/LICENSE_1_0.txt)

 //=======================================================================

 #ifndef BOOST_GRAPH_SELECTORS_HPP

 #define BOOST_GRAPH_SELECTORS_HPP

 namespace boost {

   //===========================================================================

   // Selectors for the Directed template parameter of adjacency_list

   // and adjacency_matrix.

   struct directedS { enum { is_directed = true, is_bidir = false }; 

     typedef true_type is_directed_t; 

     typedef false_type is_bidir_t;

   };

   struct undirectedS { 

     enum { is_directed = false, is_bidir = false }; 

     typedef false_type is_directed_t;

     typedef false_type is_bidir_t;

   };

   struct bidirectionalS { 

     enum { is_directed = true, is_bidir = true }; 

     typedef true_type is_directed_t;

     typedef true_type is_bidir_t;

   };

 } // namespace boost

 #endif // BOOST_GRAPH_SELECTORS_HPP