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

[Andrei Alexandrescu]

On 7/4/13 8:37 AM, monarch_dodra wrote:
> On Thursday, 4 July 2013 at 15:27:17 UTC, Timon Gehr wrote:
>> On 07/04/2013 04:35 PM, Andrei Alexandrescu wrote:
>>> On 7/4/13 6:32 AM, Steven Schveighoffer wrote:
>>>> I would not be opposed to a pull request that made [] be non-null, as
>>>> long as it doesn't allocate.
>>>
>>> What would be the benefits?
>>>
>>> Andrei
>>
>> - Additional sentinel values at basically no cost.
>>
>> - No accidental flawed relying on empty array is null or empty array
>> !is null.
>> (i.e. less nondeterminism.)
>>
>> - One thing less to discuss (this has come up before.)
>
> There are no benefits to making "[]" return null either. Implementation
> wise, instead of returning a void[] with "ptr == 0x0" and "length == 0",
> it could just as well return a void[] with "ptr == 0x1" and "length == 0".
>
> You'd get better behavior at no extra cost.

I'm clear on the no extra cost part, but confused about the benefits.

Andrei