I've used PEGs in the past. They're nice since they combine the mental model of LL grammars with the automation of LALR parser generators. However, it is quite easy to accidentally write rules where you never parse the second rule due to the ordering priority for rules. For instance:

    ident ::= name | name ("." name)+

Because with PEGs, the parser tries the first rule, then the second, and because whenever the second rule matches, the first one will also match, we will never parse the second rule. That's kinda annoying.

Of course with PEG tools you could probably solve this by computing the first sets for both rules and noticing that they're the same. Hopefully that's what this tool does.