Re: [Boost-users] Extend boost::adjacency_list

On Mon, 3 Oct 2011, Jupp Tscheak wrote:

Dear users of boost graph library, I would like to extend boost::adjacency_list like this

code: class MyGraph:     public boost::adjacency_list<boost::multisetS,                                  boost::vecS,                                  boost::bidirectionalS,                                  boost::property<boost::some_vertex_property, SomeVertexProperty*>,                                  boost::property<boost::some_edge_property, SomeEdgeProperty*> {}

This works as expected.

Is it possible to extend class "MyGraph" with additional vertex and/or edge properties defined?

My first approach was like this

code: template <class AdditionalVertexProperty = boost::no_property, class AdditionalEdgeProperty = boost::no_property> class MyGraph:     public boost::adjacency_list<boost::multisetS,                                  boost::vecS,                                  boost::bidirectionalS,                                  boost::property<boost::some_vertex_property, SomeVertexProperty*, AdditionalVertexProperty>,                                  boost::property<boost::some_edge_property, SomeEdgeProperty*, AdditionalEdgeProperty> {}

class ExtendedMyGraph: public MyGraph<boost::property<boost::some_add_vertex_property, SomeAddVertexProperty*> > {}

This, however, led into multiple compiler errors. Does anyone know how to achieve the wanted behavior?

It is unsafe to subclass BGL graph types. However, you can define a metafunction that does what you want: template <typename VP = boost::no_property, typename EP = boost::no_property> struct gen_MyGraph { typedef <your big adjacency_list type> type; }; and then use gen_MyGraph<boost::property<...> >::type as your graph type. -- Jeremiah Willcock