Rakudo grammar versus STD.pm

Q: Why doesn't Rakudo just use STD.pm directly?

A1: STD.pm requires some features we don't have implemented yet

A2: STD.pm continues to evolve -- changes to STD.pm sometimes imply major Rakudo refactors

Rakudo's grammar follows STD.pm as closely as we can

Periodically we "re-sync" Rakudo's grammar with latest STD.pm refactors