At Sun, 16 Sep 2012 17:10:01 -0500, Matthias Felleisen wrote: > Suppose we had started Racket long ago and maintained it until > now. Then we'd be looking at 8bit, 16, 32, and 64 precision. In some N > years from now, we may need 128. (Actually there were machines in the > past that did, but never mind.) > > Could we separate precision and type into separate dimensions so that > we could state types like this: > > ∀ p : precision. FP[p] -> FP[p] > > where we see FP as a type constructor that consumes a precision value > to generate the right kind of type. This might be a dependent type but > it could be a useful one. Of course, it isn't really a parametric form > of polymorphism as Neil's functions show (and better still Vincent's > rewrites).
I think row types can give us that, and clean up other parts of the numeric tower, too. That's something we've been thinking about for some time. Vincent _________________________ Racket Developers list: http://lists.racket-lang.org/dev
