MOD function does not work! So be warned!

Dar Scott dsc at swcp.com
Fri Apr 5 23:48:01 EST 2002


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







More information about the use-livecode mailing list