I don't know if I've made this clear, but over the last few years I've been treating "but True" and "but False" as design smells. They're fine as a workaround for dire circumstances and uncooperative types, but you'll not find me designing very many of the core interfaces to use them, or other run-time mixins, for that matter. Solutions involving "but" will generally be rejected, in other words.
Larry
