Yes, you're right. Sorry for that confusion. I don't have that confusion with positive? and +0.0, after all!
Robby On Fri, Mar 1, 2013 at 10:50 AM, Eric Dobson <[email protected]>wrote: > Why is Nonnegative-Real not suggestive of the right thing? To me that > means (and/c real? (not/c (lambda (x) (< x 0)))) which is exactly what > it is. > > I think the confusing part is that -0.0 has a minus sign in front > which means that you think it is negative, but this isn't true. > > On Fri, Mar 1, 2013 at 8:31 AM, Robby Findler > <[email protected]> wrote: > > Is there perhaps a more suggestive name? (Not that I'm coming up with > > one...) > > > > Robby > > > > > > On Fri, Mar 1, 2013 at 10:22 AM, Vincent St-Amour <[email protected]> > > wrote: > >> > >> At Fri, 01 Mar 2013 09:05:21 +0100, > >> Marijn wrote: > >> > On 27-02-13 21:51, Neil Toronto wrote: > >> > > >> > > (An example that came up in the implementation of matrix norms: the > >> > > type of (sqrt (/ 1 x)) isn't Nonnegative-Real if x : > >> > > Nonnegative-Real, but Complex. Consider x = -0.0. Without TR's > >> > > complaints, `matrix-norm' would have contained a time bomb.) > >> > > >> > Should -0.0 really be a Nonnegative-Real? > >> > >> That's by design. > >> > >> Including both floating-point zeroes in both non-negative and > >> non-positive types is necessary to make occurrence typing useful for > >> comparisons between floating-point numbers and zero (see PR12706 for > >> more details). It also simplifies parts of the numeric base environment > >> significantly. > >> > >> Vincent > >> > >> _________________________ > >> Racket Developers list: > >> http://lists.racket-lang.org/dev > > > > > > > > _________________________ > > Racket Developers list: > > http://lists.racket-lang.org/dev > > > _________________________ > Racket Developers list: > http://lists.racket-lang.org/dev >
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