> there are things you can parse with a CFG which cannot be parsed with PEG
This is not known. It is conjectured to be true because if all context-free languages could be parsed with a PEG grammar it would imply you'd have a linear-time boolean matrix multiplication algorithm, but no one has ever constructed a concrete example of a language which is context-free but not parsable with a PEG.
This is not known. It is conjectured to be true because if all context-free languages could be parsed with a PEG grammar it would imply you'd have a linear-time boolean matrix multiplication algorithm, but no one has ever constructed a concrete example of a language which is context-free but not parsable with a PEG.