[IgorPartola]

Agreed with the OP. The following is a shameless plug:

Python's ConfigParser module is a pain to use. It provides no validation, only supports a limited number of types of data you can retrieve, etc. Similarly, getopt vs optparse vs argparse is a mess. getopt is universal: not only is it going to be in all versions of Python, but it is also the same library available in virtually every other language. The problem with it is that it is not declarative, so you will typically see a giant if/elif statement that goes with it. argparse/optparse are better, but aren't universal even between versions of Python, though argparse has been backported and is available via pypi.

To unify all this into one convenient module, I ended up writing http://ipartola.github.com/groper/. groper lets you specify your parameters declaratively, and if you specify defaults, use them right away without having to create/modify a config file. It automatically figures out the priority of arguments: cmd > config > defaults. It also has some niceties such as the ability to automatically generate usage strings, give the user intelligent error messages, generate sample config files, etc.

[slurgfest]

I don't understand why I shouldn't be using argparse. Just using argparse means no mess of 'getopt vs optparse vs argparse' because I am not using all those other libraries. I don't see anything seriously wrong for argparse. How does it help me to use a third party module rather than argparse?

[IgorPartola]

Using argparse is probably the safest approach. However, argparse does not work with config files; groper does. So if you have more than a half-dozen options, you should use groper (or something similar).