Arrays are sufficient for ArrayLists? Really??

[Mehrdad]

1. Are you sure you need an array rather than a linked list?

Yes. I'm only asking about a functionality already present in every other language I know (C++'s vector.erase,
C#'s List.RemoveAt, Java's removeAt) so it's not something out of the blue. ;)

2. The garbage collector guarantees amortized constant runtime for insertion at the back of the array.

The problem is that that is _only_ true if the array is NOT a slice of another array!

As an example, let's say I define:

void removeAt(T)(ref T[] arr, size_t index)
{
    foreach (i, ref item; arr[index .. $ - 1])
        item = arr[i + 1];
    arr = arr[0 .. $ - 1];
}

and then I have:

auto arr = [1, 2, 3];
arr.removeAt(0);
arr ~= 4;

The last statement ***WILL*** cause a reallocation, so that doesn't help.