[RFA] Removing const from std::swap

[Gabriel Dos Reis]

Joe Buck <Joe.Buck@synopsys.COM> writes:

| On Thu, May 19, 2005 at 08:09:29PM +0200, Gabriel Dos Reis wrote:
| > I guess, the question is whether the proper assumption (concept) for
| > swap() is Assignable.  I think no (even though the standard says yes.
| > Now, I see what you mean.) 
| 
| Maybe the answer should be that either the arguments are Assignable or
| a specialization is provided that can do the swap, and that all standard
| library classes that are, in principle, swap-able should supply
| specializations if needed (e.g. auto_ptr).  Then there's the small
| matter of swap versus iter_swap, and which is used by sorting algorithms.
| 
| Certainly Assignable is needed if the three-assignment implementation (or
| copy ctor + two assignment) is to work ( T t(a); a = b; b = t).

I think the point was that Assignable was too strong and too fuzzy
assumption for the three-assignment implementation to work.
Can the implementation use const?  If yes, must it?  I think that is a
recipe for non-portability.

-- Gaby