DMD 0.173 release

[Bill Baxter]

Ivan Senji wrote:
> Bruno Medeiros wrote:
> 
>> Ok, so this one is about a feature of some releases ago, but you're 
>> releasing new features faster than what we can keep up and look at :P
> 
> 
> Aint that the truth. :)
> 
>>
>> Regarding array literals, it concerns me that each new literal 
>> "evaluation" will create a new instance. For example a literal inside 
>> a function will allocate a new instance every time the function is 
>> called. Likewise a literal inside a loop will allocate a new instance 
>> for every cycle of the loop!
>> This strikes me as both inefficient (as there is no simple way to use 
>> the opposite behavior: static/global instances) and inconsistent: 
>> other kinds of literals, like string literals, are not instanced per 
>> "evaluation" but instead are single/global/static instances.
>> Is there any particular reason for this behavior? Because if not I'm 
>> inclined to think it would be better that array literals work as 
>> string literals (global/static instances). If the new'ed-instance 
>> behavior is needed it could be easily emulated with dup'ing:
>>   ar = [1, 4, 9].dup;
>>
> 
> I'm afraid that things have to be that way. It would make sense for 
> array literals to be allocated only once if they were made of only 
> constant values, but in cases like:
> 
> for(int i=0; i<100; i++)
> {
>    f( [i, i*i] );
> }
> 
> I would expect a new instance to be created at each step in the loop.
> 

It doesn't even need to be dynamic values.  Given

for(int i=0; i<100; i++)
{
    f( [1, 42] );
}

You might have f modifying the array since D doesn't have good support 
for const:

void f(int[2] v) {
       v[0]++;
}

And then f([1,42]) after the first call becomes equivalent to f([2,42]) 
which would be bad.

--bb