on Fri Oct 07 2011, "Peter Dimov" <pdimov-AT-pdimov.com> wrote:
Dave Abrahams wrote:
Bottom line, you'll add a conversion and a bunch of unnecessary
requirements and end up with the exact same specification as before, namely, returns the first i for which *i == value.
I claim that "finds the first element in [first, last) that equals value" is a better way to say it.
I know, and I question this claim. Why is it better, when it says the exact same thing, while needing to impose unnecessary requirements to arrive at it?
The current specification (ignoring the conversion issue for now, as it's separate) says:
- when T is EqualityComparable, returns the first element that equals value; - otherwise, returns the first element *i for which *i == value.
Your preferred replacement says:
- when T is EqualityComparable, returns the first element that equals value; - otherwise, the behavior is undefined.
Do tell me why it's better.
Here's another reason why the first formulation might not be such a hot idea: it rules out some obvious implementations that really ought to be OK. For example, template <class InputIterator, class T> InputIterator find(InputIterator i, InputIterator j, T value) { while (i != j && !(*i == value)) ++i; return i; } (this is essentially equivalent to the implementation of find in the original STL). -- Dave Abrahams BoostPro Computing http://www.boostpro.com