IMO truthifying and falsifying non-truth-values at all is a Bad Idea: ugly and wrong in principle and mother to a hundred million if-statement bugs in practise.

IMO truthifying and falsifying non-truth-values at all is a Bad Idea: ugly and wrong in principle and mother to a hundred million if-statement bugs in practise. If you really can't stand making explicit comparisons to nil or whatever then employ some kind of syntactic sugaring as necessary.