This is a good example of a theoretical problem with PEGs. It also applies (of course) to recursive descent parsers. I don't think this problem is a practical i

This is a good example of a theoretical problem with PEGs. It also applies (of course) to recursive descent parsers. I don't think this problem is a practical issue, though; I can't speak for others, but this kind of problem hasn't come up in practice for me. PEGs do cause other headaches from time to time, but are still head-and-shoulders easier to get right than other styles of working with grammars.