rot13 in a more Pythonic style?

[Andy Dingley]

On 14 Feb, 21:59, Paul Rubin <http://phr...@NOSPAM.invalid> wrote:

> Why don't you describe the actual problem instead of the rot13 analogy.

I don't know what the actual problem is! I need to perform a complex
mapping between "old style" structured identifiers and "new style"
structured identifers. As the original specification was never thought
through or written down anywhere, I'm now having to try and reverse-
engineer from 5 years of collected inconsistent practice. So far I
have about four pages of BNF to describe things and I'm still not sure
what's accurate, what's inaccurate spec and what's merely an error in
practice. Hopefully there's a neat little structure underlying it all
and a few typos I can merely ignore, but probably it really is just an
inconsistent structure that needs a lot of explicit tests around the
corner-cases to make sense of.

rot13 isn't the issue here, and I already know how to use .translate()
What I'm after is a tutorial of my Python coding style for an example
that's quite similar to the rot13 case.  Your previous posting was
very helpful here.