Cheney also writes: "The lessons of Python 3 (and Perl 6) are prescient; ignore backward compatibility at your peril." I believe Perl 6 can embed and/or call P

Cheney also writes: "The lessons of Python 3 (and Perl 6) are prescient; ignore backward compatibility at your peril." I believe Perl 6 can embed and/or call Perl 5 code, similar to the proposed Go 1/Go 2, but that hasn't helped its uptake.