Re: [Boost-users] [BGL] adding behaviour to nodes and edges

On Jun 14, 2005, at 9:44 AM, martin f krafft wrote:

also sprach Doug Gregor [2005.06.14.1558 +0200]:

...

...

g[*ei].fn() g[*vi].fn()

This is rather awkward. Is there a better way?

Not really. If you can come up with a more natural syntax to express what you'd like to do, we can try to incorporate it into the BGL.

I'll think about it. One trivial way would be to store properties in the descriptors, rather than keeping a list of properties indexed by descriptor in the graph instance. Has this been considered?

Yes. When bundled properties were originally added, we talked about allowing property access through "->" on vertex and edge descriptors, because it would be convenient. Unfortunately it becomes a const-qualification nightmare. In the BGL now, descriptors just abstractly name a vertex or edge. To get to a property, you need to go through the graph (or, more commonly, a property map). If you have a const graph or property map, you get const property values; non-const graphs and property maps give non-const property values. If we put the properties in the descriptors, we need to have const and non-const descriptors, which then implies const and non-const versions of vertex_iterator, edge_iterator, out_edge_iterator, in_edge_iterator, and adjacency_iterator. The const_iterator/iterator difference in STL containers can get really annoying; this would be much worse. Doug