Both parsers that were presented at the hackathon did clever tricks to be able to do
context-dependent parsing, by enabling and disabling rules on the fly. Andreas and I
discussed building a formalism out of this. Turns out that someone already did this, for
his PhD thesis:
http://www.complang.org/colm/thurston-phdthesis.pdf
Using something like this could eliminate much of the informal descriptions as suggested
at the hackathon.
Cheers, Jan Paul