Anomalies

[Dar Scott]

On Friday, July 11, 2003, at 08:09 AM, Shari wrote:

>> Shari wrote:
>>
>>>  I wonder if I should bombard Kevin with the anomalies I've had to
>>>  find workarounds for... such as random(0) = 1
>>
>> Under what circumstances would random(0) be expected to provide a 
>> useful
>> result?  Why not save the clock cycles by using 0 directly?
>
> From my original post when discovering this anomaly:
>
> Why would one want to get random(0), you ask?
>
> If 0 is a variable, which could be any number, and you write a 
> mathematical function, assuming that if the variable is 0, the end 
> result of the function will also be zero, the function fails.

You are quite right about using 0 directly.  You might have a variable 
or other expression that needs to work in general.  And you are right 
that functions should be generalized as they naturally might.

However, I disagree that this is an anomaly.

The random(x) function is defined to return an integer in the range 
from 1 up to round(x).  We can think of the rounding as incidental and 
think of only whole numbers.  In that case it takes whole numbers 1 and 
up.  That excludes 0 from the domain of the function.  The function is 
not defined for 0.  The function is not an anomaly, because 1 up to 0 
is not meaningful.  I think the function should not crash for numbers 
outside the domain, but I hold it to nothing else.  Well, I would be 
upset if it returned a very long string.

You can define your own function, say, rnd(), based on random() and use 
that in your scripts.  It will take less time than sending a note to 
Kevin.  You can use that everywhere.  It would be at most seven lines 
long.  If you decide you want random(x+1)-1 instead of the version with 
the _if_, then you can change it in only one place.  (And then the 
function is only three lines long.)

Many built-in functions do force parameters to the closest valid value. 
  If that was done, you still would not get zero.

I, too, am not happy with some built-in functions.  For example, I wish 
mod worked differently, but I can make my own.

I would find useful a completely different random(), perhaps with 
another name, such as rand().  One that takes a number between 0 and 1 
inclusive and returns true or false.  In this case, applying it to 0 
would always return false.  Perhaps this is the kind of thing you are 
looking for.  That can be built.  It only has to be built once whether 
scripted or built-in.

It is my opinion that this is one of those cases in which you bend to 
the product and not the other way around.

Dar Scott