|Maintainer||Andy Gill <email@example.com>|
This is the shared definition of a
Graph in Data.Reify.
Graph is a basic graph structure over nodes of the higher kind
e, with a single root.
There is an assumption that there is no Unique used in a node which does not have a
corresponding entry is the association list.
The idea with this structure is that it is trivial to convert into an
IntMap, or into a Martin Erwig's Functional Graph, as required.