[boost] [bimap][multi_index][range] sub_range vs std::pair<iter, iter>

From: Matias Capeletto (matias.capeletto_at_[hidden])
Date: 2007-05-23 17:19:33

Hi,

Boost.MultiIndex and Boost.Bimap implements a function named range. It
is designed to integrate well with the new Boost.Range framework.

The actual signature is:

template< class LowerBound, class UpperBound >
std::pair<iterator,iterator> range(LowerBound lower, UpperBound upper);

template< class LowerBound, class UpperBound >
std::pair<const_iterator, const_iterator> range(LowerBound lower,
UpperBound upper) const;

In bimap docs it is stated that the way to use it is:

typedef bimap<string,int> bm_type;
bm_type bm;
//...
std::pair<bm_type::left_iterator, bm_type::left_iterator>r =
bm.left.range(...,...);

I want to know if this is the best approach.
Boost.Range defines two range classes (iterator_range and sub_range)
http://www.boost.org/libs/range/doc/utility_class.html
It is said that they are better abstraction for ranges that std::pair<iter,iter>

1) Do you think that the range functions should return a sub_range<map_type>
instead of a std::pair<iter,iter>?
The signature will be:

template< class LowerBound, class UpperBound >
sub_range<map_type> range(LowerBound lower, UpperBound upper);

template< class LowerBound, class UpperBound >
const sub_range<map_type> range(LowerBound lower, UpperBound upper) const;

2) In any case do you think that including typedef for the returned
range type will make code more readable?
The idea is to define:

typedef -range_type- sub_range; // the name can be different
typedef -const_range_type- const_sub_range;

So the user code will look like this:

typedef bimap<string,int> bm_type;
bm_type bm;
//...
bm_type::left_sub_range r = bm.left.range(...,...);

Best regards
Matias