On Fri, Jun 11, 2010 at 12:29 PM, Jeremiah Willcock <jewillco@osl.iu.edu> wrote:

On Thu, 10 Jun 2010, Eric Fowler wrote:

It seems I do not have a mutable graph. This sort of raises another issue: how do I declare an object that is described by a concept?

The best you can do is apply a concept checking class. That doesn't filter the members so you can only use the MutableGraph-required functions, but it at least makes sure that the graph you have is a MutableGraph.

For example, in this case I know I need a MutableGraph, and I see from the doc (http://www.boost.org/doc/libs/1_43_0/libs/graph/doc/MutableGraph.html) that MutableGraphs
have certain properties, such as DefaultConstructible, etc.

Now, how do I declare a MutableGraph, and know I have one? I know that:

typedef adjacency_list<vecS, vecS, undirectedS, POS<position_type> LEN<position_type> > DG;

What methods are missing? Could you please try applying the MutableGraph concept checking class to the DG type and see what breaks?

Again I must ask: How? I have mined the examples and come up with:

BOOST_CONCEPT_ASSERT((MutableGraph<DG>));

and

BOOST_CONCEPT_ASSERT((MutableGraph<DG<int>));

BOOST_CONCEPT_ASSERT((BidirectionalGraph<DG<int>));

and put them the head of a .cpp file that uses DG. These have generated obscure and unhelpful error messages.

Copying this line from the examples and using it in the same place produces no errors:

BOOST_CONCEPT_ASSERT((BidirectionalIterator<std::list<int>::iterator>));

What do you mean? You want to add methods/functions to the graph type to make it model a specific concept?

No. I mean, yes. I want to know how to define my graph type so it models a specific concept.

Eric

-- Jeremiah Willcock
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