Re: [boost] Geometry/Vec lib swizzle syntax prototype

From: Michael Fawcett (michael.fawcett_at_[hidden])
Date: 2006-12-04 14:15:32

On 12/1/06, Michael Marcin <mmarcin_at_[hidden]> wrote:
> If I were to write:
>
> float4 red( 1, 0, 0, 1 );
> glColor4fv( (float*)&red ); // make color red
> glColor4fv( (float*)&red.xxxw() ); // make color white
>
> would this work?  I'm guessing red would and white would not.

In another posting it was pointed out that taking the address of a
function's return is generally not done for specifically this reason
(among others).  Should there be any effort to solve this or just
leave the swizzle functions as is?

We could put a static assert in the address-of operator for when the
underlying types are references...but again, I think there is
precedent in coding guidelines to not do:

&red.xxxw(); // taking the address of a temporary

int add(int lhs, int rhs)
{
   int result = lhs + rhs;
   return result;
}

int *p = &add(5, 5);

This has never been expected to work.  IMHO I don't think the swizzle
functions should be expected to behave any differently.

--Michael Fawcett