Common Lisp has been standardized for longer than Java's life. Also in the lisp world, Clojure has a fastidious dedication to backward compatibility. Perl 5 h

Common Lisp has been standardized for longer than Java's life. Also in the lisp world, Clojure has a fastidious dedication to backward compatibility. Perl 5 has maintained backward compatibility (though I am not certain if it is 100% compatible) by putting changes behind flags.