[boost] Re: passing temporaries to mutating algorithms

From: Daniel Wallin (dalwan01_at_[hidden])
Date: 2004-04-13 07:01:27

Thorsten Ottosen wrote:

> "Daniel Wallin" <dalwan01_at_[hidden]> wrote in message
> news:407BC506.6020209_at_student.umu.se...
> 
> 
>>How about this:
> 
> 
> [snip]
> 
> it's better, although I can't compile it on comeau 4.3. gcc and vc7 seems to
> like it.
> I'm know sure there can be made a normal boost-hacked implementation that
> will work nicely
> on many platforms. We just someone to do it.

OK, this works on comeau:

   template<class T> struct cant_mutate_const_values
   {
       typedef int type;
   };

   template<class T> struct cant_mutate_const_values<T const>
   {
       template<class U> struct error {};
       typedef typename error<T>::type type;
   };

   template<class T>
   T& mutate_rvalue(T const& x)
   {
       return const_cast<T&>(x);
   }

   template<class T>
   T& mutate_rvalue(T& x, typename cant_mutate_const_values<T>::type = 0)
   {
       return x;
   }

-- 
Daniel Wallin