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.
This is especially useful for applications
where there is no simple mapping of your node identifiers to integers
or where the set of nodes is extended or reduced frequently.
However, this flexibility comes with some costs.
Since the structure is based on `Data.Map.Map`

s,
for efficient computing the node type should support fast comparison.

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 with the node type as parameter
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.
Another application is `cabal-sort`

.

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

The package is plain Haskell 98.

Related packages: