eighty-twenty

On this page about syntactic closures, we see the definition of an anaphoric-if macro that doesn’t transmit the “it” binding to the alternative clause — just to the consequent. This is pretty sophisticated. I immediately began to think about how you could do the same with syntax-case (as clearly others had before me) and it turns out to actually be easier. The only real downside is the introduction of another binding — but of course the mythical Sufficiently Smart Compiler will optimise that away immediately anyway.