On Sat, Dec 11, 2010 at 9:47 PM, Robby Findler <ro...@eecs.northwestern.edu> wrote: > This seems like an unfortunate naming discrepancy.
I agree. I think the solution is to change Racket, however. From the perspective of the type system, inexact integers are useless - they have no closure properties, don't obey various laws we'd like the integers to obey, etc. Changing Racket is tricky, but I think using the `Integer' type for something useless (it's not even currently represented in the TR type system) would be a mistake. > > Robby > > On Sat, Dec 11, 2010 at 7:52 PM, Vincent St-Amour <stamo...@ccs.neu.edu> > wrote: >> At Sat, 11 Dec 2010 18:35:17 -0700, >> Petey Aldous wrote: >>> I've discovered what may be a bug in the type system of Typed Racket. The >>> functions that round - (round), (truncate), (ceiling), etc. are typed as >>> Real, not Integer; however, the result of (integer? (round (* 10e15 >>> (random)))) is consistently true - and the same holds for the other rounding >>> functions. >> >> Typed Racket's Integer type corresponds to racket's exact integers >> (exact-integer?, not integer?). >> >> integer? can return true for floating point numbers: >> (integer? 1.0) -> #t >> but exact-integer? cannot. >> >> The types for round, truncate, etc. take this into account. For >> instance, if you round an exact rational, the type of the result will >> be Integer, whereas if you round a floating point number, you get a >> Float back. >> >>> Is this intentional? If so, why? If it is (or even if it isn't), how can I >>> transform the result of (random) to an Integer? >> >> You can use inexact->exact on the result of round. >> >> Vincent >> _________________________________________________ >> For list-related administrative tasks: >> http://lists.racket-lang.org/listinfo/dev >> > _________________________________________________ > For list-related administrative tasks: > http://lists.racket-lang.org/listinfo/dev -- sam th sa...@ccs.neu.edu _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/dev
