glance

I have been working on a visual programming language for Haskell: https://github.com/rgleichman/glance Currently, it uses Diagrams and Graphviz to visualize Haskell programs. Please email me since I think there is a lot we could discuss.

Why are the nodes rotated like that? It seems very distracting, and I think that might also be partly causing your "layout is too spread out" issue? [1] It could also be exacerbating your second issue of crossing edges - you are getting crossing edges in even the simplest graphs (e.g. your "f1" function example, with 5 nodes). GraphViz's "dot" algorithm (i.e., Sugiyama-style graph drawing algorithm) [2] should give a fairly compact representation that is organized into layers, and avoids crossing edges in at least simple cases, but rotating the nodes would again "spread out" the layout by forcing increasing height of each layer. Under "Possible solutions" you mention "create a better graph layout algorithm" - that sounds quite ambitious, wouldn't this be a PhD-thesis-level research task in itself? The only graph drawing library I'm aware

Graphviz is only used to find the positions for the nodes using Graphviz's Neato algorithm. The nodes and the lines themselves are all rendered using the Haskell library Diagrams [0]. The next step for the project is to improve graph layout (see Glance issue here [1]), which likely means moving away from Graphviz. What tools to use for interactivity or an editor is still up in the air. [0] http://projects.haskell.org/diagrams/ [1] https://github.com/rgleichman/glance/issues/1