Don wrote:
Andrei Alexandrescu wrote:Walter Bright wrote:Andrei Alexandrescu wrote:This also reminds me that the entire operator overloading feature must be thrown away and redesigned.:-(It's run its course like an old BMW. We need to do new things, and bolting them on what we have won't work.AndreiIndeed, I even think that the concept of operator overloading is wrong.In C++, operator overloading was just for syntax sugar. That's wrong: pretty much everything that you want overloaded operators for, is performance-critical. And that implies you need to deal on the level of complete expressions, not individual operations.
That is true. There is, for instance, a good reason why the basic BLAS matrix multiplication routine calculates
a A B + b C (a,b: scalars; A,B,C: matrices) instead of just AB.Would/could one could gain something, performance-wise, by having such "expression overloading" as a built-in feature of the language itself, rather than as a library?
BLADE has already shown that it is possible to do stuff like this in a library, but I think it goes without saying that if it was built into the language the syntax could be made considerably nicer. Compare:
auto m = MatrixOp!("a*A*B + b*C")(aVal, bVal, aMtrx, bMtrx, cMtrx);
auto m = a*A*B + b*C;
If D could do this, I think it would become the next FORTRAN. :)
-Lars
