For my work, I sometimes have to deal with logfiles from a binary protocol (the logfiles contain hexdumps of the messages). I want to write a Perl script that can interpret the binary data for me and print the contents in a more friendly format.

I have a (machine readable) description of the protocol messages in a proprietary format and I have (mostly) figured out how to parse that format (the parts I can"t fully understand are not related to my goal, so I can just ignore them), so I can convert the description into a data structure for use in my script.

Because the protocol description only rarely changes, it seems a waste to re-parse the protocol description each time I want to analyse a logfile, but on the other hand, if the description does change or if I accidentally throw away my pre-parsed form of the description, then I would like my script to automatically trigger a re-parsing of the description.  

What is the best way to realise this?