Re: [boost] [optional] problems with swap()

From: Andrey Semashev (andysem_at_[hidden])
Date: 2008-04-11 15:14:46

Fernando Cacciola wrote:
> Hi Andrey,
> 
>> Your behavior can be implemented in a non-intrusive way something like 
>> that:
>>
>>   template< typename T >
>>   void force_koenig_swap(optional< T >& left, optional< T >& right)
>>   {
>>     bool left_empty = !left;
>>     if (left_empty) left = in_place();
>>     bool right_empty = !right;
>>     if (right_empty) right = in_place();
>>
>>     using std::swap;
>>     swap(left.get(), right.get());
>>
>>     if (left_empty) right = none;
>>     if (right_empty) left = none;
>>   }
>>
> But isn't that, syntax aside, *exactly* the same Thorsten proposed?? I can't 
> tell the difference...

The only difference is that it's not intrusive.