Re: [Boost-users] interal properites with boost.graph question

From: Doug Gregor (dgregor_at_[hidden])
Date: 2004-08-31 13:34:09

On Aug 31, 2004, at 1:13 PM, Jeffrey Holle wrote:
>   // Graph Data accessor methods
>   typedef boost::property_map<GraphT, vertex_Datum_t>::type VertexData;
>   typedef boost::property_map<GraphT, edge_Datum_t>::type EdgeData;
>   const VertexData& getVertexData(void) const {return vertexData_;}
> ...

FWIW, this type of thing will get easier in 1.32.0 because we'll 
actually support dropping user-defined classes into  adjacency_list, 
adjacency_matrix, etc. for vertex and edge properties; but this is the 
currently the best solution.

>
> I guess my biggest concern is initializing vertexData_ once, before 
> the graph has any data, and keeping it around though the life of the 
> graph.
> Is this safe?

It's safe.

> Also, I expect clients of this class to be able to use the operator[] 
> method via getVertexData().  Will this work?

Yes, to an extent. The only issue is that const/non-const access to 
properties won't be correct, because the types of property_map<GraphT, 
foo>::type and property_map<const GraphT, foo>::type are different.

You really don't need to store VertexData in your graph; it should be 
very efficient to construct.

        Doug