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## Re: [Chicken-hackers] CR: expt should signal error on domain error

 From: John Cowan Subject: Re: [Chicken-hackers] CR: expt should signal error on domain error Date: Mon, 4 Jul 2011 15:12:13 -0400 User-agent: Mutt/1.5.18 (2008-05-17)

Felix scripsit:

> Is this intuition, or are you simply being used to it? I learned in
> School that division by zero is invalid.

I'm sure you also learned such rules as:

0.10000000000000001 /= 0.10000000000000000
x < x + 1
x - x = 0
x + y = y + x
(x + y) + z = x + (y + z)
Exactly one of x < y, x = y, or x > y is true.

But none of these are (reliably) true of flonums.

> Nobody told me about nonsense like positive or negative zero, or
> numbers that aren't. That is unintuitive.  Unfortunately we take
> conventions born out of technical peculiarities or peformance hacks
> for granted.

Flonums have a perfectly coherent mathematical theory; it just isn't the
one associated with ordinary numbers, but a sort of specialized algebra
of intervals.

> This deeply disappoints me. You all are a bunch of robots.

Not at all!

A little Learning is a dang'rous Thing;
Drink deep, or taste not the Pierian Spring:
There shallow Draughts intoxicate the Brain,
And drinking largely sobers us again.
--Alexander Pope, "An Essay upon Criticism" (1711)

The Pierian spring in Macedonia was sacred to the Muses; "largely" here
means "in large quantity".

--
Mos Eisley spaceport.  You will never           John Cowan
see a more wretched hive of scum and            address@hidden
villainy --unless you watch the                http://www.ccil.org/~cowan
Jerry Springer Show.   --georgettesworld.com