Interesting to see that there is some VPRI / Smalltalk / Squeak influence with HARC/YC Research http://vpri.org/html/team_bios/yoshiki.htm aboard

There is also Moose that can create grammars quite easily.

http://www.moosetechnology.org/ https://en.wikipedia.org/wiki/Moose_(analysis)

Using PetitParser, GTInspector, and other such tooling, visual construction, debugging, and evaluation of grammars and parsers is a breeze.