Power FX Expression Grammar Technology

[orcmid]

I am delighted by the presentation of Expression Grammar. I have been cringing about ways to knit a lexical grammar and expression grammar together; I'm inspired by your approach.

I also have two questions about the .grammar format.

1. Is the format of the productions in both text format and the "reference" form with _opt and such documented anywhere.? Or is there an IETF spec. I'm missing? I'd like to be able to cite it.
2. The '.grammar' extension hints at the prospect of mechanical processing. Is that also something available or is this aspirational?

PS: You can see from the too-wordy ob-exp BNF grammar that I have taken the next step to bind semantics as well, although in my case I have the luxury of a functional semantics that fits a context-free grammar, simular to the Knuth-Wegner-Irons attribute grammar idea. (The use of Quine quotes is an additional attribution :).