I wonder why the author decided integrating with python was a better idea than, say, lua. Seems to me that lua is winning that fight, but that's just my current impression - I don't really have any solid numbers to back that up.
* Calling out from your C program to the scripting language.
* Setting variables in the scripting language from C.
* Creating functions that can be called from the scripting language.
* Making those available by creating a loadable shared lib that the scripting language can utilize.
Stuff like that is not that different across different languages and if you've figured one out, others won't be that hard.
My take: Tcl's C API is pretty cool. I wrote about it some here: http://www.amazon.com/dp/032133633X/?tag=dedasys-20
I'm not really a Lua fan personally (the confusing indice and ordinal notation scares me), but I can see why it makes sense for integration purposes. Clean, simple, to the point.