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

[Regan Heath]

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.

If you mean to check arr.length, then code that explicitly.  Coding if  
(arr) and having it check arr.length hides details which really should be  
visible for the programmer to see.

R

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