At Tue, 28 Sep 2010 08:39:23 -0500, Andrew Sutton wrote:
Having done the exercise, I'm satisfied with my results (which agree with Mathias').
Great; let's see your work!
I think your "left to the reader as an exercise" approach doesn't seem to be getting the point across. Perhaps you could provide a more concrete argument?
It's hard to provide an argument more concrete than an example that doesn't work. But in fairness I guess it's also easy to overlook non-workingness when you don't have a computer doing the checking for you, or the STL wouldn't have been designed with the "valid expression" approach... OK, I found a good explanation. See ยง3.2.3 of http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1758.pdf HTH, -- Dave Abrahams BoostPro Computing http://www.boostpro.com