[Boost-bugs] [Boost C++ Libraries] #7107: Support property bundles as default parameter in graph algorithms

Subject: [Boost-bugs] [Boost C++ Libraries] #7107: Support property bundles as default parameter in graph algorithms
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2012-07-09 16:07:09

#7107: Support property bundles as default parameter in graph algorithms
-------------------------------------------------+--------------------------
 Reporter:  philipp.moeller@…                    |       Owner:  jewillco    
     Type:  Feature Requests                     |      Status:  new         
Milestone:  To Be Determined                     |   Component:  graph       
  Version:  Boost 1.51.0                         |    Severity:  Optimization
 Keywords:  property bundles                     |  
-------------------------------------------------+--------------------------
 Bundled properties don't support default parameters as internal properties
 do. Adding a possibility to tag members of a bundle would solve that
 issue.


 {{{
 #include <boost/graph/adjacency_list.hpp>
 #include <boost/graph/properties.hpp>
 #include <boost/graph/dijkstra_shortest_paths.hpp>
 #include <string>

 using namespace std;
 using namespace boost;

 struct City{};

 struct Highway { double weight; };

 typedef adjacency_list<
     listS, vecS, bidirectionalS,
     City, Highway>
 Map;

 typedef adjacency_list <
   listS, vecS, directedS,
   no_property, property < edge_weight_t, int > >
 Map2;

 int main()
 {
   Map m;
   Map2 m2;
   vector<double> distances(num_vertices(m2));
   dijkstra_shortest_paths(
     m2, *vertices(m2).first,
     distance_map(make_iterator_property_map(distances.begin(),
                                                    get(vertex_index,
 m2))));
   // does not work
   // dijkstra_shortest_paths(
   //   m, *vertices(m).first,
   //   boost::distance_map(make_iterator_property_map(distances.begin(),
   //                                                  get(vertex_index,
 m))));

   return 0;
 }
 }}}

 One solution could be to add an optional tags typedef that contains an
 mpl::map between member pointers and property enum types. Alternatively, a
 traits class could be specified to map to the right enum type. Maybe
 someone can also come up with a nice mechanism to transparently tag a
 member.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/7107>
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