More on C++ stack arrays

[dennis luehring]

Am 23.10.2013 16:41, schrieb Namespace:
> On Wednesday, 23 October 2013 at 14:35:12 UTC, dennis luehring
> wrote:
>> Am 23.10.2013 15:59, schrieb Namespace:
>>> On Sunday, 20 October 2013 at 16:33:35 UTC, Walter Bright
>>> wrote:
>>>> On 10/20/2013 7:25 AM, bearophile wrote:
>>>>> More discussions about variable-sized stack-allocated arrays
>>>>> in C++, it seems
>>>>> there is no yet a consensus:
>>>>>
>>>>> http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3810.pdf
>>>>>
>>>>> I'd like variable-sized stack-allocated arrays in D.
>>>>
>>>> They're far more trouble than they're worth.
>>>>
>>>> Just use:
>>>>
>>>>    auto a = new T[n];
>>>>
>>>> Stack allocated arrays are far more trouble than they're
>>>> worth.
>>>> But what about efficiency? Here's what I often do something
>>>> along the lines of:
>>>>
>>>>    T[10] tmp;
>>>>    T[] a;
>>>>    if (n <= 10)
>>>> 	a = tmp[0..n];
>>>>    else
>>>> 	a = new T[n];
>>>>    scope (exit) if (a != tmp) delete a;
>>>>
>>>> The size of the static array is selected so the dynamic
>>>> allocation is almost never necessary.
>>>
>>> Another idea would be to use something like this:
>>> http://dpaste.dzfl.pl/8613c9be
>>> It has a syntax similar to T[n] and is likely more efficient
>>> because the memory is freed when it is no longer needed. :)
>>>
>>
>> but it would be still nice to change the 4096 size by template
>> parameter maybe defaulted to 4096 :)
>
> That is true. ;) And can be easily done. :)
>

can't you remove the if(this.ptr is null) return; checks everywhere - 
how should that happen - without exception at creation time