On 07/04/2013 08:03 PM, Andrei Alexandrescu wrote:
On 7/4/13 10:58 AM, TommiT wrote:
On Thursday, 4 July 2013 at 17:32:29 UTC, Andrei Alexandrescu wrote:
[..] Maybe someone returned [] thinking it will be a null array. [..]
I wouldn't think that [] is null, and I suspect neither would very many
other newcomers to the language. To me, the only problem with [] being
null is that it doesn't look like null. It looks like an empty array.
A null array _is_ an empty array.
Whether null is [] is the subject of this discussion.
There are multiple possibilities, such as:
1. null !is [], but [] is []
2. null !is [], and not even [] is []
3. !is(typeof(null is [])) // also, !is(typeof(null == []))
4. null is []
1 is the most useful, 2 is the most wasteful, 3 is the sanest, and 4 is
what DMD/druntime implement.
The spec is loose enough to allow an implementation to behave like 1, 2
or 4 or in even other ways.
So, the problem is that [] is not what you'd intuitively expect it to be.
Is the intuition that it's an empty array that's not part of anything,
presumably obtained by forging 1 into a pointer? Didn't think so.
Why do multiple persons come up with this suggestion independently?
By the way, this must be a bug, right?
template arr(X_...)
{
int[] arr = [X_]; // [1]
}
void main()
{
auto a2 = arr!(1, 2);
auto a1 = arr!(1);
auto a0 = arr!(); // [2]
}
[1] Error: initializer must be an expression, not '()'
[2] Error: template instance main.arr!() error instantiating
...because if that's not supposed to work, then I don't see much point
in having the [] literal in the language.
I also happen to think we don't quite need [].
[1,2,3]
[1,2]
null
[1]
[]
Find Waldo.
