Graph Visualization

[yigitozkavci]

Related issue: #2

This PR adds the capability of graph visualization to the existing textual and javascript output options.

• Dot language is being used for representing graphs
• We do not provide PDF or PNG format for graphs, but instead, create the .dot file. This it because graphviz library is heavyweight for our needs.

I tried every file in examples/ directory, and all of them worked as expected. I put the output of examples/head-map-repeat.hs here for convenience:

[edsko]

Ooooh very cool! I'll try to make some time this week to look at this PR (and the other open PR that I still haven't had a time to look at 😳 ). Good stuff!

[edsko]

Sorry for the slow reply, it's been very hectic. Unfortunately I will be out of the country for a few weeks now. I will take a look at this when I get back! :)

[yigitozkavci]

No worries, in the meantime I'll try to work on other possible improvements, since I loved the project :)

[edsko]

I've squashed your commits and merged into master, will release soon. Thanks for the PR, and sorry for the very slow response time. I so rarely get a chance to work on this project :)

By the way, I'm curious, why did you introduce dotty output? Did/do you envision an evaluation function where the evaluation graph isn't linear, or do you just find the dotty output convenient for rendering?

[yigitozkavci]

No, I didn't think graphs would be non-linear, that would mean there are multiple ways of reducing an expression, I don't think that's the case with this language.

I had experience with dot language and I do find it very convenient to represent directed graphs with, even though it looks uglier than html output. This is the main reason :)