My thoughts & experiences with D so far, as a novice D coder
deadalnix
deadalnix at gmail.com
Thu Mar 28 03:40:05 PDT 2013
On Thursday, 28 March 2013 at 10:34:35 UTC, Timon Gehr wrote:
> On 03/28/2013 04:18 AM, deadalnix wrote:
>> On Wednesday, 27 March 2013 at 18:20:49 UTC, Andrei
>> Alexandrescu wrote:
>>> On 3/27/13 1:23 PM, Timon Gehr wrote:
>>>>> - Function that never return are inferred void. I would
>>>>> have preferred
>>>>> typeof(null) as void lead to many static and repetitive
>>>>> code for
>>>>> nothing
>>>>> when doing metaprograming.
>>>>
>>>> I strongly disagree.
>>>
>>> Ideally such function should return a "none" type, the bottom
>>> of the
>>> hierarchy lattice. We don't have such, so returning
>>> typeof(null)
>>> (which we do have) is the next best choice as it's just above
>>> bottom.
>>>
>>
>> I thought that typeof(null) was that bottom type. What is the
>> difference ?
>>
>
> There is a huge difference.
>
> - typeof(null) is a subtype of all _class, interface and
> pointer_
> types because they all _include_ its value, null.
>
> - bottom is a subtype of _all_ types, because there is _no_
> value of
> type bottom.
>
OK I see the difference.
>> Anyway, void isn't the right choice here and is a pain to work
>> with.
>
> typeof(null) would be worse.
I don't see how it is worse.
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