Operator overloading -- lets collect some use cases

[Stewart Gordon]

Don wrote:
> There's been some interesting discussion about operator overloading over 
> the past six months, but to take the next step, I think we need to 
> ground it in reality. What are the use cases?
> 
> I think that D's existing opCmp() takes care of the plethora of trivial 
> cases where <, >= etc are overloaded. It's the cases where the 
> arithmetic and logical operations are overloaded that are particularly 
> interesting to me.
> 
> The following mathematical cases immediately spring to mind:
> * complex numbers
> * quaternions (interesting since * is anti-commutative, a*b = -b*a)

Not true.  Quaternion multiplication does have the distinction of being 
non-commutative in the general case, but anti-commutativity occurs in 
only some special cases.

If you really want anti-commutativity, look at vectors under cross 
multiplication.

Other unusual number systems: hypercomplex, biquaternions, octonions, 
p-adic numbers

> * vectors
> * matrices
> * tensors
> * bigint operations (including bigint, bigfloat,...)
<snip>

And possibly rational and Euclidean number types.

Stewart.