removing an item from a dynamic array

[Steven Schveighoffer]

On Tue, 25 Oct 2011 06:13:09 -0400, simendsjo <simendsjo at gmail.com> wrote:

> On 25.10.2011 11:51, bearophile wrote:
>> maarten van damme:
>>
>>> import std.algorithm;
>>> struct Loc {
>>> uint row;
>>> uint col;
>>> }
>>> void main(){
>>> Loc[] testArray;
>>> Loc a={3,2};
>>> Loc b={5,3};
>>> testArray~=a;
>>> testArray~=b;
>>> remove(testArray,a);
>>> }
>>> gives the same error
>>
>> The second argument of remove() needs to be an index, a size_t.
>>
>> This works:
>>
>> import std.stdio, std.algorithm;
>> struct Loc {
>>      uint row, col;
>> }
>> void main() {
>>      auto a = Loc(3, 2),
>>           b = Loc(5, 3);
>>      auto data = [a, b];
>>      writeln(remove(data, 0));
>>      writeln(data);
>> }
>>
>>
>> It prints:
>> [Loc(5, 3)]
>> [Loc(5, 3), Loc(5, 3)]
>>
>> So curiously remove() doesn't work in-place, I think this is a bug or a  
>> design bug.
>>
>> Bye,
>> bearophile
>
> Yes, probably a bug. This example from the documentation fails:
> import std.stdio, std.algorithm;
> void main() {
>      int[] a = [ 0, 1, 2, 3 ];
>      assert(remove!(SwapStrategy.unstable)(a, 1) == [ 0, 3, 2 ]);
> }

Most certainly this is a bug.  Here is the resulting array and final state  
of a:
import std.stdio, std.algorithm;
void main() {
     int[] a = [ 0, 1, 2, 3 ];
     writeln( remove!(SwapStrategy.unstable)(a, 1));
     writeln(a);
}

output:

[3, 1, 2]
[3, 1, 2, 3]

Clearly, index 0 was removed, not index 1.  Please file a bug.

-Steve