Toolkit to produce and manipulate various types CFG graphs. The CFG
graphs can have as nodes any implementation of Directed; typically,
Unit elements or Block elements. The latter corresponds to
BasicBlocks of Units. Some of the classes produce UnitGraphs where
the control flow for exceptions is taken into account, while others
produce graphs abstracting away extra exception-related edges.
All classes in this package should now be thread safe. (Thu Feb 10 00:03:48 EST 2000)