inverted "when" statement

Never.pm6

use nqp;
use QAST:from<NQP>;
sub EXPORT(|) {
    role Control::Never {
        rule statement_control:sym<never> {
            <sym><.kok> <xblock>
        }
    }
    role Control::Never::Actions {
        method statement_control:sym<never>(|c) {
            $/ := c[0];
            my $when = self.'statement_control:sym<when>'($/);
            $when.op('unless');
        }
    }
    nqp::bindkey(%*LANG, 'MAIN', %*LANG<MAIN>.HOW.mixin(%*LANG<MAIN>, Control::Never));
    nqp::bindkey(%*LANG, 'MAIN-actions', %*LANG<MAIN-actions>.HOW.mixin(%*LANG<MAIN-actions>, Control::Never::Actions));
    {}
}