> PEG is not unambiguous in any helpful sense of that word. BNF allows you to specify ambiguous grammars, and that feature is tied to its power and flexibility and often useful in itself. PEG will only deliver one of those parses. But without an easy way of knowing which parse, the underlying ambiguity is not addressed -- it is just ignored.
I frequently hear this mentioned ("PEGs don't have ambiguity"). It is literally true, but I don't think it's true in the sense that actually matters.
I've blogged about this in the past (https://blog.reverberate.org/2013/09/ll-and-lr-in-context-wh...), but I'm not the only person saying this:
> PEG is not unambiguous in any helpful sense of that word. BNF allows you to specify ambiguous grammars, and that feature is tied to its power and flexibility and often useful in itself. PEG will only deliver one of those parses. But without an easy way of knowing which parse, the underlying ambiguity is not addressed -- it is just ignored.
https://jeffreykegler.github.io/Ocean-of-Awareness-blog/indi...