What is the modern way to to do XML transforms in Python?

Question

I need to do bi-direction transforms between some significantly complex XML and flat-file formats in Python. I'm out of date and don't know how people are solving this problem in the far off future year of 2011.

I've got back up to date with the various Python XML libraries, but it's been 8 years since my last time in XSLT hell and I was amazed after googling around that that's still common.

So how do you go about doing complex XML data transforms?

I'd like to do this in Python because the documents are not direct mappings and there is some processing and calculation required. But I'd still like to pass as much off to a rule engine as possible.

Edit: To be clear I'm interested in techniques more so than specific libraries or tools, but please to post those too. I'm trying hard to avoid the word pattern here, but surely this is a common problem.

Edit 2: I still don't think there were any good answers on general techniques, but the original problem I had was solved using the Bots EDI framework for doing document translations. It is quite heavily focussed on EDI but can be used for generic translation. It was a heavy-weight solution though.

Answer 1

For python, here is a comprehensive list of available XML libs/modules:

http://wiki.python.org/moin/PythonXml

If you are looking for something simpler than XSLT, XMLStarlet is a set of command line tools which may be of interest for you:

http://xmlstar.sourceforge.net/

As any command line tool, this is not especially made for Python, but can be easily integrated into a python script.