[boost] Ranges [was: Layered Iterator concept]

From: jsiek_at_[hidden]
Date: 2000-09-13 14:57:36

Another approach is the begin(container), end(container) interface
that is in array_traits. Then you don't really need the Range
class... just use std::pair and have a range() function that returns a
pair.

template <class Iter>
Iter begin(std::pair<Iter,Iter>& r) { return r.first; }

template <class Iter>
Iter end(std::pair<Iter,Iter>& r) { return r.second; }

template <class Iter>
std::pair<Iter,Iter> range(Iter first, Iter last) {
  return std::make_pair(first, last);
}

David Abrahams writes:
 > That (layerd iterator) is interesting. I wonder how that might interact with
 > iterator_adaptor?
 > 
 > Also, I've been thinking how unweildy it is to write std::pair<T, T> for
 > ranges, and how much expressive power is lost by writing "pair" instead of
 > "range". Instead, I've been using the appended Range<> template (not
 > boost-ified), which I derived from std::pair for some compatibility with
 > existing uses of pair as a range. What's really missing from this class are
 > all the operations for union, intersection, containment, etc. I've
 > implemented these before, but that code is owned by a previous employer ;(.
 > 
 > Does anyone else think this would be really useful? It might be worth
 > fleshing out, if so.
 > 
 > -Dave
 > 
 > template <class T>
 > class Range : public std::pair<T, T>
 > {
 >     typedef std::pair<T, T> Base;
 >  public:
 >     Range() {}
 > 
 >     explicit Range(const T& x)
 >         : Base(x, x) {}
 > 
 >     Range(const T& start, const T& finish)
 >         : Base(start, finish) {}
 > 
 >     T begin() const;
 >     T end() const;
 > };
 > 
 > template <class T>
 > inline T Range<T>::begin() const
 > {
 >     return this->first;
 > }
 > 
 > template <class T>
 > inline T Range<T>::end() const
 > {
 >     return this->second;
 > }
 > 
 > template <class T>
 > inline Range<T> make_range(const T& start, const T& finish)
 > {
 >     return Range<T>(start, finish);
 > }
 > 
 > 
 > 
 > 
 > 
 >