A possible solution for the opIndexXxxAssign morass

[Robert Jacques]

On Wed, 14 Oct 2009 10:31:06 -0400, Andrei Alexandrescu  
<SeeWebsiteForEmail at erdani.org> wrote:

> Don wrote:
>> Well timed. I just wrote this operator overloading proposal, part 1.
>> http://www.prowiki.org/wiki4d/wiki.cgi?LanguageDevel/DIPs/DIP7
>> I concentrated on getting the use cases established.
>
> I'm not sure multiplication is generally commutative (e.g. in linear  
> algebra it isn't). So why should a * x be interchangeable with x * a?
>
> Also, the much-discussed identity:
>
> x @= y	<-->	x = x @ y
>
> is difficult to enforce statically in practice. I think some types would  
> want to define both to achieve good efficiency. It would be hard for the  
> compiler to render one unnecessary or to prove that the two are  
> equivalent.
>
>
> Andrei

When a is a scaler, a * x <=> x * a generally holds. It's only when  
something isn't a scaler, i.e. x1 * x2 != x2 * x1, that community(?)  
doesn't hold.