[plt-scheme] real but not rational?

From: Eli Barzilay (eli at barzilay.org)
Date: Wed Feb 1 16:23:31 EST 2006

On Feb  1, Greg Woodhouse wrote:
> Is it possible to (read) a value in PLT Scheme to get a value v such
> that (real? v) is true and (rational? v) is false? I suppse that with
> arbitrary precision arithmetic, this shouldn't be too surprising, but I
> was surprised to see that my evaluator always tags numeric values as
> rational, even values like 2.7e8 or 3.14159. I eventually plan to write
> my own reader, but for now, I'm just using the underlying Scheme.

All reals are rationals, even (rational? (sqrt 2))...  (Because the
actual result of (sqrt 2) is an approximation that is rational.)

> Irrelevant newbie question; What is the correct pronunciation of
> MzScheme? I kind of assumed that DrScheme was "Doctor Scheme", MrEd
> was "Mister Ed", etc. (but have been corrected on that point). I
> usually end up saying M-Z Scheme, but wondered if it should be "Miz
> Scheme" (as in "Les Mis", a colloquial reference to the musical.)

"Miz" -- it was supposed to be MsScheme, but that could be read as
"Microsoft Scheme"...

          ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
                  http://www.barzilay.org/                 Maze is Life!

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