Re: [boost] Graph stuff

From: jeremy siek (jsiek_at_[hidden])
Date: 2000-09-19 16:15:07

David Abrahams writes:
 > Do you think we could have one of these instead?
 > 
 > 
 >   edge_property<Graph, edge_capacity>::type capacity
 >     = edge_property(G, edge_capacity());
 >   edge_property<Graph, edge_flow>::type flow
 >     = edge_property(G, edge_flow());

As one of the reviewers mentioned, this could be confusing because it
sounds like you are accessing a property value instead of a property
accessor.

 > or better yet:
 > 
 >   // using static template member functions
 >   edge_capacity_type<Graph>::type capacity = edge_capacity::get(G);
 >   edge_flow_type<Graph>::type flow = edge_flow::get(G);
 >
 > or maybe:
 > 
 >   property_traits<Graph, edge_capacity>::type capacity =
 > edge_capacity::get(G);
 >   property_traits<Graph, edge_flow>::type flow = edge_flow::get(G);

Since 'property_traits' is already taken, how about:

property_accessor<Graph, edge_capacity>::type
  capacity = accessor(G, edge_capacity());

or if you prefer using a static member function:

property_accessor<Graph, edge_capacity>::type
  capacity = edge_capacity::accessor(G);

One caveat to this is that implementing this will require a little
meta-programming to distinguish beteen edge and vertex property tags.

 > And then some convenience functions:
 > 
 >   edge_capacity::get(G, edge_descriptor) // to get an edge_capacity
 >   edge_capacity::set(G, edge_descriptor, value) // to set an edge capacity
 > 
 > If you want to call it put(), that's OK too I guess.

I'm not sure why you'd ever want these. The property accessor
interface already handles this:

property_accessor<Graph, edge_capacity>::type
  capacity = edge_capacity::accessor(G);

get(capacity, e)
set(capacity, e, c);

Cheers,

Jeremy