On Thu, 31 Jan 2013, The Maschine wrote:

Hi all,

Can someone explain me why I get an error with the first one and not the second?

1) (error) boost::dijkstra_shortest_paths(m_ugraph,*vertex_iterator_begin,                                       boost::distance_map(boost::make_iterator_property_map(dist_map.begin(), boost::get(boost::vertex_index, m_ugraph))),

boost::visitor(dijkstra_vis( *vertex_iterator_begin, superStorage ) ));

The syntax for named parameters in Boost.Graph requires periods, so all named arguments show up as a single argument to C++.

2) (good) boost::dijkstra_shortest_paths(m_ugraph,*vertex_iterator_begin,                                       boost::distance_map(boost::make_iterator_property_map(dist_map.begin(), boost::get(boost::vertex_index, m_ugraph))).visitor(dijkstra_vis( *vertex_iterator_begin, superStorage )) );

Why I need to "." the visitor on the distance_map?

That's how it was implemented (before Boost.Parameter or variadic templates existed).

BFS is ok with it:

(good) boost::breadth_first_search(m_ugraph, *vertex_iterator_begin , boost::visitor(bfs_vis( *vertex_iterator_begin, superStorage ) ));

You only have one named argument there; if you had more, you would need to use a period between those as well. -- Jeremiah Willcock