[:] as empty associative array literal, plus warning for null

[Dmitry Olshansky]

05-Jul-2013 12:55, Regan Heath пишет:
> On Thu, 04 Jul 2013 20:15:08 +0100, Dmitry Olshansky
> <dmitry.olsh at gmail.com> wrote:
>
>> 04-Jul-2013 19:00, Regan Heath пишет:
>>> In fact, you can generalise further.
>>>
>>> The meaning of if(x) is "compare the value of x with 0" (in C, C++,
>>> .. ).
>>>
>>> The value of x for a pointer is the address to which it points.
>>> The value of x for a class reference is the address of the class to
>>> which it refers.
>>>
>>> If D's arrays are reference types,
>>
>> They are not. It's a half-reference no wonder it has a bit of
>> schizophrenia now and then.
>
> True.  The struct which contains the ptr and length is actually a value
> type.  I think conceptually however we should be thinking of them as
> reference types, because.. the array struct is effectively a lightweight
> wrapper (adding length) around a reference type (ptr).
>
>>   then IMO they should exhibit the same
>>> behaviour.
>>>
>>
>> The behavior should be the most useful and since arr.length != 0 is
>> what 99% of time a programmer wants to check.
>
> IMO, the behaviour should be consistent.  If you code if (x) then the
> compiler will compare 'x' (not a property of x) to 0.  Doing anything
> else would be inconsistent and unexpected to anyone from a C background.

Then since slices compared to null by your logic means both ptr and 
length equal 0. Completely broken idea hence I'd simply propose to 
disable it.


-- 
Dmitry Olshansky