On 02/24/2011 10:28 AM, spir wrote:
> On 02/24/2011 07:08 PM, Ali Çehreli wrote:
>> Implicit conversions to immutable in the following two functions feel
>> harmless.
>> Has this been discussed before?
>>
>> string foo()
>> {
>> char[] s;
>> return s; // Error: cannot implicitly convert expression
>> // (s) of type char[] to string
>> }
>>
>> string bar()
>> {
>> char[] s;
>> return s ~ s; // Error: cannot implicitly convert expression
>> // (s ~ s) of type char[] to string
>> }
>>
>> Is there a reason why that's not possible? I am sure there must be
>> other cases
>> that at least I would find harmless. :)
>>
>> Ali
>
> I'm all for that. Can hardly how auto conversion in the sense mutable
> --> immutable could be harmful, but may miss a meaningful point.
It shouldn't be allowed if a reference to that char[] is left behind.
Otherwise although the receiver would think that the data wouldn't
change; it could be changed by that other reference.
struct S
{
char[] s;
string foo()
{
return s; // <-- Must not be allowed
}
}
But when the object in question is about to go out of scope? I don't
know. On the other hand, reducing some implicit behavior is also good.
> This
> would esp be nice for strings, since we regularly need to use char
> arrays to construct textual content.
>
> Denis
I have another question: Does calling .idup copy any data below?
string foo()
{
char[] s;
return s.idup; // Is the content copied?
}
Ali
