AMDG On 02/18/2013 10:15 AM, Jonathan Wakely wrote:
On 18 February 2013 18:04, Dave Abrahams wrote:
However, if detecting whether "r.size()" is a valid expression cannot be done reliably (for example, if we determine that for iterator_range<I> where I is not random-access it is a valid expression, but then that static-asserts on us), then we can't use this approach.
Then you can't use this approach (in general).
Why? What other range-like types provide an size() member that appears to be callable but must not be called?
That's irrelevant. The point is that the range concepts provide no such requirement. It is unsafe to rely on any behavior which is not intentional and explicitly documented, /especially/ with generic code. In Christ, Steven Watanabe