Hi Doug, On Mar 31, 2004, at 1:52 PM, Douglas Paul Gregor wrote:

The only thing I've ever found complex in the BGL is actually forming a graph type out of adjacency_list. Every single time I need a graph I have to read through the adjacency_list documentation to figure out what to do, although often I just copy the typedef from somewhere else. Simplified graph adaptors could really help here.

Right. In particular, the way internal properties are dealt with is rather cumbersome.

There's a lot we could do in the way of syntactic sugar. For instance, I'd love to be able to easily loop over the edges in a graph without dealing with iterators directly:

Graph g; for(Graph::vertex_descriptor u, v; (u, v) = G; ) { // do something with edge (u, v) }

The same thing can be applied to, e.g., adjacent vertices:

for(Graph::vertex_descriptor v; v = adj(u, g); ) { // v is adjacent to u }

Since vertex descriptors tend to be iterators or indices, this could be implemented just as efficiently as the corresponding iterator loop, but it's a simpler idiom.

Looks neat. How would that be implemented? I hope it doesn't require storing something in the graph object itself that keeps track of the progress of the iteration. BTW, for those who like macros, there's boost/graph/iteration_macros.hpp. Cheers, Jeremy _______________________________________________ Jeremy Siek http://www.osl.iu.edu/~jsiek Ph.D. Student, Indiana University Bloomington Graduating in August 2004 and looking for work C++ Booster (http://www.boost.org) _______________________________________________

Douglas Paul Gregor wrote:

The only thing I've ever found complex in the BGL is actually forming a graph type out of adjacency_list. Every single time I need a graph I have to read through the adjacency_list documentation to figure out what to do, although often I just copy the typedef from somewhere else. Simplified graph adaptors could really help here.

Agreed. For example, I never can remember the order of all template arguments to adjacency_list, and declaration of properties. Maybe, some combination of "named template parameters" and mpl::list would help: adjacency_list< graph_config< vertex_property_t, mpl::list, edge_property_t, mpl::list > > graph; The "associative_list" that was posted some time ago probably can be used to implement this syntax. (BTW, shouldn't we move this conversation to the main mailing list. After all, we're not talking how to use existing interface, but how it can be improved). - Volodya

Jeremy Siek wrote:

...

The "associative_list" that was posted some time ago probably can be used to implement this syntax.

Anyone volunteering to move the associative_list forward into boost?

Good question, but isn't it more the the author of associative_list? Anyway, I think it's fine to try using that class in some parts of BGL even if it's not officially accepted. We can hide it in "detail" directory ;-) - Volodya