I still don't know that I've seen anything more impressive for this sort of thing than the Rebol parser.

http://www.rebol.net/cookbook/recipes/0042.html

Red also has this capability, and it is quite expressive and natural.

https://www.red-lang.org/2013/11/041-introducing-parse.html

Prior work: https://metacpan.org/dist/Lingua-Romana-Perligata/view/lib/L...