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

[Regan Heath]

On Fri, 05 Jul 2013 10:17:02 +0100, Jonathan M Davis <jmdavisProg at gmx.com>  
wrote:

> On Friday, July 05, 2013 11:01:17 TommiT wrote:
>> On Thursday, 4 July 2013 at 19:15:09 UTC, Dmitry Olshansky 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.
>>
>> What do you mean by D's dynamic arrays being half-reference
>> types? And what kind of "schizophrenia" do exhibit?
>
> Okay. Take this function.
>
> void foo(T)(T bar)
> {
>     bar.mutateMe();
> }
>
> If T is a reference type, then the argument passed to foo will be  
> mutated. If
> T is a value type, it won't be. But with arrays, it depends. If you alter
> bar's length in any way, it won't have any effect on the array that you  
> passed
> to foo. However, if you alter any of bar's elements, then it _will_  
> alter the
> array that was passed in. So, arrays are sort of a half-reference type  
> rather
> than a reference type or a value type.

I think it is simpler to think of arrays as a struct with 2 members (ptr  
and length) and this struct is/as a value type.  Then it all simply makes  
sense.

R

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