I certainly like text manipulation (well string manipulation at least) in python much more than other languages I use (C, C++, Matlab). It might just be the case that python is the best tool in the authors tool belt for this sort of work.
I'm curious what language you would consider optimal for writing a parser in?
I've written a couple parsers in D using https://github.com/PhilippeSigaud/Pegged and they seem pretty fast and easy to verify. Of course since it generates a lot of code at compile time, you can end up with somewhat slow builds.
I'm curious what language you would consider optimal for writing a parser in?