hgraph

hgraph is a Haskell library for heterogeneous, fully statically typed graphs whose nodes can perform computations on the node data of their predecessors.

Installation

    git clone git://github.com/peddie/hgraph.git
    cd hgraph
    cabal install

Features

a heterogeneously typed HList akin to Oleg's one, but this one uses associated type families rather than functional dependencies and undecideable instances. These have a convenient type operator syntax.
an HGraph class for heterogenous, statically typed directed graphs, and an HGraphApply subclass for acyclic HGraphs whose nodes perform computations on the node data of their predecessors.
two example HGraphApply instances, one built directly on HLists and the other built on a new HNode data type.
Data and Typeable instances for everything, so you can scrap your boilerplate and your zippers.

Misfeatures and Bugs

No graph algorithms yet; all you can do is build and inspect graphs and apply graph nodes. You can't apply entire graphs yet either.
No unit tests yet.
Type errors are, for the most part, intimidating and inscrutable.
The library doesn't implement everything in Oleg's HList yet, although most of it should be straightforward.
The typechecker gets upset about ambiguity, so you have to tell it the types of literals and of some polymorphic functions. I expect this to be less of a problem when the graph has all your own types.