class inheritance

[Dave Angel]

Carl Banks wrote:
> On Mar 15, 4:34 pm, JLundell <jlund... at pobox.com> wrote:
>   
>> It's also unfortunate that Python doesn't have an approximately-equal
>> operator; it'd come in handy for floating-point applications while
>> preserving hash. If only there were a ~=r ≈ operator I could
>> overload. And ~ is unary, so no joy.
>>     
>
> One problem with it is that there's no way to make it universal;
> different appiplications have different ideas of close.  Conceivably
> it could be usefully defined for a user type though..
>
> Bacause of this problem almost no languages have an almost equal
> operator.  I'm curious what languages do, of if there are any with a
> trinary operator that also takes a threshold.
>
> Carl Banks
>
>   
If I recall correctly, APL has a *fuzz* value, which is used in all(?) 
comparisons. But I do not recall anything about how it was defined. I do 
recall that you could change the threshold, and suspect it was relative 
to the operands. For symmetry, it would probably have to be relative to 
the average of the two values, or some such.