Okay, after some deep thought, I think I finally have a mental model for exactly what unit/c is doing here that's appropriate for fixing this section of code.  ASCII art diagrams for the win!
Okay, after some deep thought, I think I finally have a mental model for
exactly what unit/c is doing here that's appropriate for fixing this
section of code.  ASCII art diagrams for the win!

This also shows how a unit/c contract addition differs from the use
of unit/new-import-export to switch sigs, which means that I'll likely
not be able to unify as much of the guts of the two as I'd like.  Schade.

svn: r13605

mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket,mafagafogigante/racket