What sane defaults are will change over the years. Perl kept amazing backwards compatibility by adding extra statements to modify how it worked. So "use strict

What sane defaults are will change over the years. Perl kept amazing backwards compatibility by adding extra statements to modify how it worked. So "use strict;", "use warnings;" and "use <other_newer_perl_features>;". Both new code -- using the best OO system of the scripting languages, extendable syntax, etc, etc -- will run at the same time as most of the old and crufty stuff from before testing took over after the Millennium.