[norswap]

The biggest improvement from this (besides maybe performance) is that it should enable much better manually programmed syntax error messages. Those generated by yacc were pretty shit.

This is generally my #1 reason for using a manual parser — nobody has yet made a pretty good syntax error handling / reporting for parser generators or parser combinators.

It's genuinely very complex — I read the whole literature on that as of 2019 (there's surprisingly little). You basically have to inject custom logic, though there are a few heuristics that you can prepackage and can be useful in a lot of places. But the custom aspect of it means this doesn't play nice with traditional LL/LR parser generators. It could be done for parser combinators (PEG etc) however. Didn't have enough time in my PhD thesis to play with this, and I moved on to other things, but I'm hoping someone will make this eventually.