Hemera depends on the following libraries:

• ply 2.3 (or superior)
• pygraphviz (or superior)

Ply: this library is easy to install, the library can be founded in lib subdirectory.

Pygraphviz: in the past, it was a little bit more complicated!! But it seems that from now on we just need to run:

easy_install pygraphviz

In the past, for Mac OS system we have followed the procedure discribed in: http://groups.google.com/group/pygraphviz-discuss/browse_thread/thread/f3b385409bb66420?pli=1

The pygraphviz library in lib directory was downloaded from http://networkx.lanl.gov/download/pygraphviz/

And the graphviz package from: http://graphviz.org/pub/graphviz/development/macos/leopard/

Finnaly, we edited the setup.py from the pygraphviz adding the correct location of libraries (in the beggining of the file):

library_path=’/usr/local/lib’ include_path=’/usr/local/include/graphviz’

1. The initial sequent should be listed before cleaning the goals.
2. Improve the parser to consider cases like “a –> a –> a”.

python setup.py sdist