BGL: Custom Property Writer for Bundled Properties and listS as VertexList/EdgeList

Question

I take the the following code from this post and changed the VertexList and the EdgeList to listS instead of vecS.

I found out that because of the missing index make_label_writer(get(&VertexProps::name, g)) doesn't work. Could someone tell me how I should change the code to get it work. I would prefer a solution with a custom property writer.

Thank you very much.

#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/graphviz.hpp>

struct VertexProps { std::string name; };
struct EdgeProps   { std::string name; };
typedef boost::adjacency_list<boost::listS, boost::listS, boost::directedS, VertexProps, EdgeProps> Graph;

int main() {
    Graph g(3);
    g[0].name = "one";
    g[1].name = "two";
    g[2].name = "three";
    add_edge(1, 0, {"e1"}, g);
    add_edge(2, 1, {"e2"}, g);
    add_edge(1, 2, {"e3"}, g);
    add_edge(2, 0, {"e4"}, g);

write_graphviz(std::cout, g,
        make_label_writer(get(&VertexProps::name, g)),
        make_label_writer(get(&EdgeProps::name, g)));

}

---

For the sake of completeness, here is a modification of the solution by sehe with a custom property writer. Please don't forget to upvote the original answer.

Wandbox

#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/graphviz.hpp>

struct VertexProps { std::string name; };
struct EdgeProps   { std::string name; };
typedef boost::adjacency_list<boost::listS, boost::listS, boost::directedS, VertexProps, EdgeProps> Graph;

template <class Name>
class my_label_writer {
public:
    my_label_writer(Name _name) : name(_name) {}
    template <class VertexOrEdge>
    void operator()(std::ostream& out, const VertexOrEdge& v) const {
        out << "[label=\"" << name[v].name << "\"]";
    }
private:
    Name name;
};


int main() {
    Graph g;
    Graph::vertex_descriptor v0 = add_vertex({"one"}, g);
    Graph::vertex_descriptor v1 = add_vertex({"two"}, g);
    Graph::vertex_descriptor v2 = add_vertex({"three"}, g);
    add_edge(v1, v0, {"e1"}, g);
    add_edge(v2, v1, {"e2"}, g);
    add_edge(v1, v2, {"e3"}, g);
    add_edge(v2, v0, {"e4"}, g);

    std::map<Graph::vertex_descriptor, int> vertex_index;
    for (auto vd : boost::make_iterator_range(vertices(g)))
        vertex_index[vd] = vertex_index.size();

    my_label_writer<Graph> w(g);

    write_graphviz(std::cout, g,
        w,
        make_label_writer(get(&EdgeProps::name, g)),
        boost::default_writer{}, // graph_property_writer
        boost::make_assoc_property_map(vertex_index));
}

Answer 1

With listS the vertex descriptor type is not integral, and therefore not suitable as a vertex index.

You need to use the actual descriptors now:

Graph g;
Graph::vertex_descriptor v0 = add_vertex({"one"}, g);
Graph::vertex_descriptor v1 = add_vertex({"two"}, g);
Graph::vertex_descriptor v2 = add_vertex({"three"}, g);
add_edge(v1, v0, {"e1"}, g);
add_edge(v2, v1, {"e2"}, g);
add_edge(v1, v2, {"e3"}, g);
add_edge(v2, v0, {"e4"}, g);

Also, when writing, you'll have to supply a vertex_index property map. This incidentally requires you to pass a graph_property_writer pro forma:

std::map<Graph::vertex_descriptor, int> vertex_index;
for (auto vd : boost::make_iterator_range(vertices(g)))
    vertex_index[vd] = vertex_index.size();

write_graphviz(std::cout, g,
    make_label_writer(get(&VertexProps::name, g)),
    make_label_writer(get(&EdgeProps::name, g)),
    boost::default_writer{}, // graph_property_writer
    boost::make_assoc_property_map(vertex_index));

DEMO

Live On Wandbox

#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/adjacency_list.hpp>
#include <boost/graph/graphviz.hpp>

struct VertexProps { std::string name; };
struct EdgeProps   { std::string name; };
typedef boost::adjacency_list<boost::listS, boost::listS, boost::directedS, VertexProps, EdgeProps> Graph;

int main() {
    Graph g;
    Graph::vertex_descriptor v0 = add_vertex({"one"}, g);
    Graph::vertex_descriptor v1 = add_vertex({"two"}, g);
    Graph::vertex_descriptor v2 = add_vertex({"three"}, g);
    add_edge(v1, v0, {"e1"}, g);
    add_edge(v2, v1, {"e2"}, g);
    add_edge(v1, v2, {"e3"}, g);
    add_edge(v2, v0, {"e4"}, g);

    std::map<Graph::vertex_descriptor, int> vertex_index;
    for (auto vd : boost::make_iterator_range(vertices(g)))
        vertex_index[vd] = vertex_index.size();

    write_graphviz(std::cout, g,
        make_label_writer(get(&VertexProps::name, g)),
        make_label_writer(get(&EdgeProps::name, g)),
        boost::default_writer{}, // graph_property_writer
        boost::make_assoc_property_map(vertex_index));
}

Prints

digraph G {
0[label=one];
1[label=two];
2[label=three];
1->0 [label=e1];
1->2 [label=e3];
2->1 [label=e2];
2->0 [label=e4];
}