struct vs. class, int vs. char.

[Denis Koroskin]

On Tue, 28 Apr 2009 22:13:50 +0400, Tomas Lindquist Olsen <tomas.l.olsen at gmail.com> wrote:

> On Tue, Apr 28, 2009 at 6:07 PM, MLT <none at anon.com> wrote:
>> 2. char[] vs. int[]
>> I think it is strange that
>> char[] x = "1234" ;
>> x[0] = '4' ;
>>
>> Produces a run time error, but
>> int[] x = [1,2,3,4] ;
>> x[0] = 4 ;
>> Doesn't. I think that they both should, or both shouldn't - to be  
>> consistent (and it would be better if they both didn't). Best would be  
>> again, to allow the programmer to specify where the array (or other  
>> stuff) should be stored.
>>
>
> It pretty much boils down to this (mostly said in other replies)
>
> * string literals are special, they are allocated in a static data
> segment, readonly if the platform allows it.
>
> * arrayliterals as non-static expressions are always heap allocated.
> even when there's absolute no need for it... (see
> http://d.puremagic.com/issues/show_bug.cgi?id=2356 )
>
> -Tomas

Someone ought to post a feature request to make arrayliterals immutable by default (D2 only, I don't think this change will go to D1 anyway) and don't heap-allocate them every time they're used:

int[] x1 = [1,2,3,4]; // error: can't assign immutable(int)[] to int[]

int[] x2 = [1,2,3,4].dup; // okay, allocates

int[4] x3 = [1,2,3,4]; // okay, doesn't allocate

foreach (int i; [1,2,3,4]) { // okay, doesn't allocate
    // ...
}