DIP 45 - approval discussion

[deadalnix]

On Tuesday, 12 November 2013 at 05:46:19 UTC, Andrei Alexandrescu 
wrote:
> On 11/11/13 2:36 PM, Timon Gehr wrote:
>> On 11/11/2013 11:02 PM, deadalnix wrote:
>>> On Sunday, 10 November 2013 at 12:39:35 UTC, Timon Gehr wrote:
>>>> What about Object.factory?
>>>
>>> I always though of it as a misfeature.
>>
>> Me too.
>
> ... well time to substantiate.
>
> Andrei

OK, but first, it has to be noted that this is putting the burden 
of proof on the wrong side of the argument.

So I ran `grep -r * -e 'Object.factory'` on my d folder. I have 
various D project there. The only uses of Object.factory are the 
test suite of dmd, ldc and GDC.

I have bunch of D code in there, not simply mine. So first thing 
: it is unused.
Secondly, the only useful things you can do with that require to 
upcast (and break basic OOP principle, which is kind of ironic 
for a feature that produce objects). The design of the feature is 
unsound.

It is not that surprising as different possible uses case are 
better solved with compile time reflection and metaprograming.

Implementationwise, this feature require to pull into the 
application some unoptimizable bloat. It is also a tedious 
constraint for shared objects as we see in this thread.