Rule macros

[Muon]

Rule macros in the style of e.g. LALRPOP or nearley give a nice way of defining shorthands for common constructs such as repetition. Could we see a similar feature implemented for grmtools?

[ltratt]

I would like to see repetition operators, but the last time I looked at this, there are some interesting edge cases that need to be handled (I think due to conflicts). I might be wrong on that, though.

[Muon]

For what it's worth, there's this paper which claims to handle EBNF constructs correctly, but I haven't had the time to read it properly:

Borsotti, A., Breveglieri, L., Crespi Reghizzi, S. et al. Fast deterministic parsers for transition networks. Acta Informatica 55, 547–574 (2018). https://doi.org/10.1007/s00236-017-0308-3