initialization of structs

[Christian Köstlin]

On 09/26/2011 11:15 PM, Timon Gehr wrote:
> On 09/26/2011 10:55 PM, Christian Köstlin wrote:
>> Hi,
>>
>> I have the problem, that I want to always construct a struct with a
>> parameter. To make this more comfortable (e.g. provide a default
>> parameter I have a factory function to create this struct).
>>
>> struct S {
>> int i;
>> this(int i_) { i = i_; }
>> }
>>
>> S createS(int i=5) {
>> return S(i);
>> }
>>
>> My question now is:
>> Is there a way to enfore the creation of the struct with createS?
>> Or to put it in another way. Is it possible to forbid something like:
>> S s; or even auto s = S(1);? I read about the this(this) thing, but that
>> is only used when the struct is copied, as far as I understood.
>>
>>
>> (My struct has the nature to only work if it is not constructed with the
>> default struct constructor).
>>
>> thank in advance
>>
>> christian
>
> Starting with DMD 2.055, this works.
>
> struct S{
> this() @disable;
> this(int i_) { i = i_; }
> }
mhh ... strange ... i have dmd 2.055 64bit for linux and this compiles 
without error and outputs
l: 0
c: 0


import std.stdio : writeln;
struct S {
private:
   int[] data;
   @disable this(this);
   @disable this();

   this(size_t s) {
     data = new int[s];
   }
public:
   void p() {
     writeln("l: ", data.length);
     writeln("c: ", data.capacity);
   }
   static S create(size_t  s = 8) {
     return S(s);
   }
}
unittest {
   auto s = S();
   s.p();
}
int main(string[] args) {
   return 0;
}


shouldnt this lead to a compile error?


thanks in advance

christian