Re: [Boost-users] Completely Perplexed Noob to BGL: Reachability Question

Subject: Re: [Boost-users] Completely Perplexed Noob to BGL: Reachability Question
From: Jens Weller (JensWeller_at_[hidden])
Date: 2009-03-26 13:09:11

> In this case, you probably need to write your own visitor.
> 
> struct found_vertex {};
> 
> template<class Graph, class Vertex>
> struct reachable_visitor : boost::bfs_visitor<> {
> public:
>     reachable_visitor(const Vertex& v) : vertex(v) {}
>     void discover_vertex(const Vertex& v, const Graph&) const {
>         if(v == vertex) throw found_vertex();
>     }
> private:
>     Vertex vertex;
> };
> 
> template<class Graph, class Vertex>
> bool reachable(const Graph& g, const Vertex& start, const Vertex& end) {
>     try {
>         boost::breadth_first_search(g, start, 
> boost::visitor(reachable_visitor<Graph, Vertex>(end)));
>     } catch(found_vertex&) {
>         return true;
>     }
>     return false;
> }

Nice, but is throw-to-return-type-idiom really the best to be used here?
Isn't there a "better" way to do this?

regards

Jens Weller
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