Why will the delete keyword be removed?

[Andrei Alexandrescu]

On 07/14/2010 02:38 PM, Max Samukha wrote:
> On 07/14/2010 12:50 AM, Andrei Alexandrescu wrote:
>> On 07/13/2010 03:51 PM, Trass3r wrote:
>>> Does it really add so much complexity to the compiler that it's worth
>>> removing?
>>
>> It adds misconception and confusion. delete must disappear from D.
>>
>> Andrei
>
> FWIW, the current implementation of clear() has at least one problem
> that guarantees my not using it: the default constructor may be
> arbitrarily complex (for example, it may allocate an expensive
> resource), so running it on the dead object is not acceptable.

You mean class objects, right? I agree. I think it's okay to fill the 
object with its stateless .init members, which would assuage the issue.

> Also, as other people mentioned, resurrecting the dead object prevents
> the program from failing early in case a dangling pointer to that object
> gets dereferenced.

There is no early failure with dangling pointers.

> I'd probably want clear() to run the destructor and zero the object's
> memory.

No, because:

class A
{
     int x = -1;
     float y = 0;
     ...
}

You'd want that guy to be obliterated with the proper initializers for x 
and y.

> This way the objects the dead object may reference can be GCed
> even in the presence of dangling pointers the dead object. Additionally,
> the probability of the program failing early on a dangling pointer
> dereference is high because the vtable pointer is null (any virtual call
> is bound to fail).
>
> Or something like that.

I think the vtable could remain valid.


Andrei