RGL is a framework for graph data structures and algorithms.  The
design of the library is much influenced by the Boost Graph Library
(BGL) which is written in C++ heavily using its template mechanism.
RGL provides some general purpose graph classes that conform to the
interface for how the structure of a graph can be accessed using a
generic interface that hides the details of the graph data structure
implementation, but they are not meant to be the only graph classes.
As in BGL, the main contribution of the RGL is the formulation of this
interface.