negative numbers are not equal...

[ariel ledesma]

well, i'm glad i stumbled upon this detail early on (i only had to fix 
about one page of code)... i'll just stick to 'is' when it concerns 
checking if it is the *same* object (memorywise) instead of an 
*equivalent* one...
just before wrapping up, the special methods __eq__ and __ne__ are 
called upon == and !=, right? not for 'is', 'is not'...

Steven D'Aprano wrote:
>
> Mathematicians often *define* equality as identity. That certainly makes 
> sense when dealing with numbers -- what would it mean to say that there 
> are (say) three different instances of the abstract integer 42, all equal 
> yet not identical? I suggest that this simply doesn't make sense -- it is 
> "not even wrong".
>
> Equality-as-identity may not hold in all areas of mathematics, but I 
> think it is safe to say it holds for ideal (abstract) numbers, as opposed 
> to implementations of numbers as bit patterns or objects in memory.
>
> http://en.wikipedia.org/wiki/Equality_(mathematics)
>
>

but who knows? maybe abstract numbers -5 to 256 are optimized as well! :-)