It's getting harder and harder to think out loud. One of these days someone's gonna go off and kill Thomas a'Becket for me... - Larry Wall

I was trying not to mention backtracking. Which, of course, means that yours is 'righter' than mine, in a theoretical sense.

Part of language design is perturbing the proposed feature in various directions to see how it might generalize in the future.

...this does not mean that some of us should not want, in a rather dispassionate sort of way, to put a bullet through csh's head.