This is a tool to generate nice sequence (flow) diagrams from textual descriptions, written in Haskell.

This tool generates a diagram description, which could be made into a nice picture with help of Graphviz (www.graphviz.org)

To try it out, run: runhaskell flow2dot.hs sample.flow | dot -T png -o sample.png and view "sample.png" with your favorite picture viewer. If you dont get a nice picture and get something else (for example, ugly segfault from dot), try upgrading to latest Graphviz (2.12 or later)

If you want to use national alphabets, make sure that your .flow files are encoded in UTF-8. If you want to tweak the output - read Dot manual and use it for scaling, colors, pagination etc.

Latest version could be obtained via: darcs pull http://adept.linux.kiev.ua:8080/repos/flow2dot/

License : BSD-style (see the file LICENSE) Send patches to dastapov@gmail.com (using "darcs send")

Thanks to Cale, quicksilver and roconnor from #haskell for suggestions on how to modularize this. Thanks to Dema from haskell@conference.jabber.ru for win32 testing. Gwern0 helped to adapt this to GHC 6.8.2

Known issues

• Dot < 2.12 will most likely segfault on files generated by flow2dot

• If your version of dot complains about "Error: lost n1 n2 edge", try using flow2dot-fix-dot-lost-edges in place of dot:

  runhaskell flow2dot your.flow | flow2dot-fix-dot-lost-edges -T png -o your.png

Trick is to remove 'constraint="false"' from all edges that dot reports as lost.