I alluded to that in my last note. :) If you properly define the functions (`c`, `f`, `g`, `t`), you can get the semantics of halted computation on failure. Th

I alluded to that in my last note. :) If you properly define the functions (`c`, `f`, `g`, `t`), you can get the semantics of halted computation on failure. That is essentially what Haskell's `do` notation does.