You would probably get reasonable results from simply feeding the POSIX grammar to lrparsing[1], but unfortunately it doesn’t look like there’s much support in

You would probably get reasonable results from simply feeding the POSIX grammar to lrparsing[1], but unfortunately it doesn’t look like there’s much support in it for lexer feedback (aka the “lexer hack”), which you’ll need for the regular expression syntax. It’s likely possible to hack that in, but I don’t know how much work it’d be. [1] https://lrparsing.sourceforge.net/ https://lrparsing.sourceforge.net/