How to get the "longest possible" match with Python's RE module?

[gatti at dsdata.it]

Frederic Rentsch wrote:


>    If you need regexes, why not just reverse-sort your expressions? This
> seems a lot easier and faster than writing another regex compiler.
> Reverse-sorting places the longer ones ahead of the shorter ones.

Unfortunately, not all regular expressions have a fixed match length.
Which is the longest of, for example, /(abc)?def/ and /(def)?ghi/
depends on the input. 

Lorenzo Gatti