On Oct 7, 2010, at 8:40 AM, Stewart, Robert wrote:
vicente.botet wrote:
From: "Stewart, Robert" <Robert.Stewart@sig.com>
The use of enable_if to control the contexts in which the copy constructor and copy assignment operator apply goes beyond the standard's specification. That means boost::ratio behaves differently than will std::ratio. I think this will lead to surprising results when one transitions from one to the other.
I 've made a request to add these constructors and this request has not ben decided yet. I thinh the best for Bost could be a flagf that intruduce this feature or not. So i prupose that Boost.Ration includes thes constructors and assignemes conditionally.
As I read the LGW issue, there was no support for adding that behavior.
This is correct. However this is a good place to add that "no consensus" in the LWG issues list notes does not mean "no one in favor". I argued in favor of this change as did Walter Brown. As I recall people were mainly nervous about the timing of this change. It was discussed post FCD. I would be tempted to consider this extension to the standard semantics based on its technical merits alone, motivated by Beman's more general policy statement: On Oct 2, 2010, at 8:11 AM, Beman Dawes wrote:
One of the advantages of Boost is that we can add extensions and get user experience before something gets standardized. That's very helpful to the C++ committee.
-Howard