MOD function does not work! So be warned!

[Dar Scott]

On Friday, April 5, 2002, at 05:24 PM, Dar Scott wrote:

>> I think Xtalk should follow normal programming convent and have 
>> mod reject non-integer values.
>
> The definition from Knuth's _Fundamental Algorithms_ is this:
>
> x mod y = x - y * floor( x/y ) if y is not 0
> x mod 0 = x
> where x and y are real numbers

Of course, that is not a programming language in itself.  But these 
are...

Pascal       (Jensen & Wirth)    integer X integer --> integer
MODULA-2     (Wirth)             integer X integer --> integer
PostScript   (Adobe)             integer X integer --> integer
Common Lisp  (Steele)            number X number --> number
Tcl          (Ousterhout)        real X real --> real (fmod())
C            (Harbison & Steele) double X double --> double (fmod())
Mathematica  (Wolfram)           number X number --> number
LabView                          number X number --> number (Q&R)

(Some of these have slightly differing meanings.)

I don't think we can say there is a convention.

If the Revolution mod function works as expected for two positive 
whole numbers (less than 15 digits), what do we care if it does 
something useful for other numbers?

Dar Scott