Can't wait to have a play with this (once I dig up my windows laptop...). I have such amazing respect for the amazing products from jetbrains; having toys to play with like this is just fantastic. I'm particularly interested in the component based grammars; I'd don't quite understand how you can get away with not breaking the 'parent' grammar when you drop an arbitrary child grammar inside of it, but quite looking fo…
Rakudo, which is built on NQP, is one of the largest of modern langs, but it's technically built out of a series of sub-languages ("slangs") that recursively reference each other. Thus there's a language for grammars, another for strings, another for closures, and all of these work seamlessly together.