infinity comparison

Bovaird, Brian Brian.Bovaird at
Fri Sep 17 16:40:04 UTC 2004

VisualWorks has a class Infinity defined in their MetaNumbers application
from my OE252 version.

-----Original Message-----
From: Jarvis, Robert P. (Bob) (Contingent)
[mailto:bob.jarvis at]
Sent: Friday, September 17, 2004 6:17 AM
To: 'The general-purpose Squeak developers list'
Subject: RE: infinity comparison

Upon some reflection

   A) I'm surprised it didn't trigger a floating point overflow caused by
trying to convert 1000! to Float.
   B) Float is probably not the best place for infinity to reside.  Perhaps
a better solution would be to have an Infinity class (subclass of Number)
with a singleton instance - this class could then define the appropriate
comparison operations and voila!  No more problem.  Better yet, have a
PositiveInfinity and NegativeInfinity class, thus leading to

	1000 factorial < PositiveInfinity value		"--> true"
	1000 factorial * -1 > NegativeInfinity value	"--> true"

That would match well with the IEEE floating-point standard's concept of
positive and negative infinities.

Bob Jarvis
Compuware @ Timken

> -----Original Message-----
> From: Lex Spoon [mailto:lex at]
> Sent: Friday, September 17, 2004 11:51 AM
> To: squeak-dev at
> Subject: infinity comparison
> Okay, here's another useless discussion, following up the recent one
> about comparison of NaN's.  Try this in Squeak:
> 1000 factorial < Float infinity    "-->  false"
> This hydra just won't stay dead!
> And if this example seems silly, just think of all the algorithms that
> insert infinity's as initial values on paper, but for which C and Java
> programmers have to use some sort of sentinel value like -1.  
> There are
> some serious cool points are at stake here, if we can make it possible
> in our language to insert a plain old infinity.
> -Lex

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