[racket-dev] nan?, infinite? and regular-real? [Was: Latest Plot Package]

From: Doug Williams (m.douglas.williams at gmail.com)
Date: Sat Nov 19 12:50:40 EST 2011

The mathematical abstraction of irrational. That is, when I think of a real
number abstractly, it includes irrationals. The fact that I have to use a
representation that doesn't include irrationals doesn't mean I give up the
abstract idea of reals.

On Sat, Nov 19, 2011 at 10:27 AM, Robby Findler <robby at eecs.northwestern.edu
> wrote:

> On Sat, Nov 19, 2011 at 9:54 AM, Doug Williams
> <m.douglas.williams at gmail.com> wrote:
> > I would keep finite? for the semantics associated with the name even if
> it
> > is just a renaming of rational?. Particularly since you can't just use
> (not
> > (infinite? x)) when NaNs are a possibility. [I personally don't like
> using
> > rational? for an abstraction that includes irrational numbers.]
>
> Forgive me for being dense, but IIUC, aren't there no irrational
> numbers in Racket? Or, put another way, which class of numbers do you
> find useful to single out using rational??
>
> Robby
>
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