Neil Groves wrote: I think that empty() is not beneficial as part of the Range concept. It adds nothing in features or performance. On Wed, Dec 3, 2008 at 7:50 PM, Michael Marcin <mike.marcin@gmail.com>wrote:
David Abrahams wrote:
Seems to me, requiring empty() in ranges is sort of equivalent to requiring iterators to support distance.
Does removing empty from the range concept prevent the empty algorithm from being specialized for ranges with a more efficient way to determine calculate empty?
For instance a vector-like range might store a pointer to the first element and a element count in this case empty is
bool empty() const { return !count; }
where as the default range empty is equivalent to writing empty as
bool empty() const { return p != p+count; }
perhaps there is a range refinement which can support ranges which have a more efficient empty?
We could use adl to find a boost_range_empty() function from boost::empty(). This could be implemented by comparing iterators by default, and specialised as desired for optimisation purposes.
-- Michael Marcin
Neil Groves
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