Defining a custom *constructor* (not initializer!)

[Jacob Carlborg]

On 2012-05-06 21:55, Mehrdad wrote:
> Is this possible in D2?
>
> i.e. I'm wondering if there is a way to do the object
> construction yourself, which would allow you to call the object's
> "constructor" (initializer) manually, and just return a pointer
> to the new object.
>
> Something along the lines of:
>
> class Window
> {
> static Window opConstruct(void* ptr)
> {
> // Assume ptr is already correctly sized and filled
> Window result = cast(Window)ptr;
> result.__ctor();
> return return result;
> }
> }
>
> It seems like overloading new() *almost* does this, but not
> quite: It only lets you allocate the memory, not call the
> constructor yourself.
>
> This would be useful, because some objects can have external
> constructors (notably when interfacing with C/C++, such as when
> using CreateWindow() in Windows), and you *cannot* call these
> constructors inside the object's "constructor" (initializer) due
> to re-entrancy issues.

You can have a look at my Orange library:

https://github.com/jacob-carlborg/orange/blob/master/orange/util/Reflection.d#L460

It's basically what TypeInfo_Class.create does but it doesn't call the 
constructor and works for LDC as well.

https://github.com/D-Programming-Language/druntime/blob/master/src/object_.d#L878

-- 
/Jacob Carlborg