[Boost-users] [BGL] Question on dijkstra-example.cpp

Hello, could you please explain what this code in the dijkstra-example (http://www.boost.org/doc/libs/1_44_0/libs/graph/example/dijkstra-example.cpp) exactly does? predecessor_map(&p[0]).distance_map(&d[0]) I understand the non-named-parameter version, but the combination of predecessor_map with distance_map is not so obvious to me. What does the "." do there? Do I get it right, that the predecessor_map or distance_map, respectively, automatically wrap the vectors p and d into iterator_property_maps? Thank you. Best regards, Cedric