This graph structure is based on Data.Map
and allows any Ord type for nodes
and allows directed, undirected and more edge types.
There is no need to map nodes to integer numbers.
This makes handling in applications much more comfortable,
thus the package name.

Currently the package does not contain any advanced algorithm,
just the data structure and some manipulation functions.

The edge type can be freely chosen.
This allows great flexibility
but it is a bit more cumbersome to do in Haskell 98.
Examples of edge types:

DirEdge: Edges in a directed graph

UndirEdge: Edges in an undirected graph

EitherEdge: For graphs containing both directed and undirected edges

You may define an edge type with an additional identifier
in order to support multiple edges between the same pair of nodes.

Using type functions on the node type
you may even define an edge type for nodes from a Cartesian product,
where only "horizontal" and "vertical" edges are allowed.

For examples see the linear-circuit package and its tests.
The ResistorCube test demonstrates non-integer node types
and the Tree test demonstrates multigraphs.

The package is plain Haskell 98.

Related packages:

fgl:
standard package for graph processing with many graph algorithms
but cumbersome data structure with Int numbered nodes