lift some work out so it happens earlier (and less often) in the -> contract combinators. This speeds up the running of the (new) file tut.scrbl by about 10%.
lift some work out so it happens earlier (and less often) in
the -> contract combinators. This speeds up the running of the (new)
file tut.scrbl by about 10%.

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