get address of object if opCast is overridden

[Artur Skawina]

On 12/01/12 20:26, Jonathan M Davis wrote:
> On Saturday, December 01, 2012 18:43:22 Timon Gehr wrote:
>> On 12/01/2012 06:23 PM, Jonathan M Davis wrote:
>>> On Saturday, December 01, 2012 12:05:49 Artur Skawina wrote:
>>>>> So, unless there's a way to do it without a cast, you're stuck. And I
>>>>> have
>>>>> no idea how you could possibly do it without a cast.
>>>>>
>>>>     *cast(void**)&O // assuming O is a class
>>>
>>> Are you sure? I'd be _very_ wary of that, because references aren't the
>>> same as pointers. I don't believe that there's any guarantee whatsoever
>>> that that will work, even if it happens to work now (which it may or may
>>> not).
>>>
>>> - Jonathan M Davis
>>
>> Certainly works now. Another workaround that would keep working if class
>> references were not pointers is:
>>
>> ((Object o)=>cast(void*)o)(O) // assuming O is the class object
> 
> Ah, good point. Using Object would work just fine and doesn't rely on the 
> implementation details of references.

References not appearing as if they were pointers is less likely than Object
growing an opCast...

Another workaround (for both non-empty classes and structs) would be

  cast(void*)&O.tupleof[0]-O.tupleof[0].offsetof

which will let you not worry about that kind of potential changes to the core
of the language. :) 


Seriously though, if one only needs to compare the addresses of class objects,
"is" may be a better solution.

artur