Dude, that totally rocks!
I'm fairly sure i know what it does:
Spoiler below:

It's a brainf*ck parser yeah? with the japh written in bf encoded into the code of the interpretter: this line: $c=~s/[^\+\-\054\056<>[\]]//sg; removes all the non bf chars ($c is by default the parser code) so you can cat in a bf string and whatever arguments you need...

Very nicely done. ++ etc
Alex

Update: Worked out how to use it (ish) and clarified my spoiler.