On Wed, Dec 11, 2013 at 5:17 PM, bearophile <bearophileHUGS@lycos.com> wrote:

Namespace:

Your gig: https://github.com/D-Programming-Language/dmd/pull/2952#discussion_r8288045

My enhancement request was for the array[$] syntax. The idea of []s was invented by someone else (Timothee Cour?).

I like the practical comments by Hara. If Kenji thinks the []s is not useful for efficiency (because the efficiency can be obtained with just improvements of the compiler), then the []s syntax becomes less necessary.

On the other hand this is an interesting use case that compiler improvements alone could not be enough to allow:

void fun(int[3]) {}
void main() {
int[3] x = [1, 2, 3];
fun(x); // OK
fun([1, 2, 3]); // error
fun([1, 2, 3]s); // OK
}

yes, that was the prime motivation for DIP34, being able to pass un-ambiguously a static array to a function without having to declare an intermediate variable first.

when fun() has overloads for both static and non-static arrays (or is just declared as fun(T)(T a) ), the compiler cannot guess whether fun([1,2,3]) asks for static or dynamic array, and probably has to assume dynamic array. And int[$] would require declaring a variable before passing it, eg: int[$]x=[1,2,3].

With [1,2,3]s, there is no ambiguity.

Are vector ops supported?

int[6] a;
a = [1,2,3]s[] + [4,5,6]s[];

DIP34 is still a draft, and it shows, some corner cases are missing in that document and need to be found, fleshed out and added to the DIP34.

Bye,
bearophile