Thorsten Ottosen wrote:
Sylvain Pion <Sylvain.Pion <at> sophia.inria.fr> writes:
Jeff Flinn wrote:
Would not the boost.assign library work here?
class A { boost::array<int, 3> a; A() : a(boost::assign::list_of(1)(2)(3)(4)) {} };
I don't think I've tried it this way yet.
It works, but it's not efficient. It is even incredibly worse that doing the assignments by hand (boost 1.33.1 is better than 1.32 though). See my attached test program. Here is what I get (with g++ 4.1):
Try throwing this into the mix:
a(boost::assign::cref_list_of<3>(1)(2)(3))
It gives the same result as the "assignment by hand", so it's still not optimal.
It would be nice to see what other compiler give back. Also, do you have full optimization turned on?
Optimizing or not does not change anything for the g++ I tested.
That said, list_of() is never going to compete with direct aggregrate initialization.
My point about introducing make_array() was also about syntax. The various Boost.Assign variants have poor syntax, imho, even if they could be optimized (I haven't looked at their implementation). I agree that the best thing would be to have a change in the language. But in the mean time, I think introducing make_array() in Boost.Array would be nice. I did not get feedback on that. -- Sylvain