Re: [Boost-users] any_range vs. “canonical form” - what is the latter?

Den 09-04-2011 18:45, Neil Groves skrev:

On Sat, Apr 9, 2011 at 4:36 PM, Steven Watanabe

For example, copying the range into a vector.

Yes, this is exactly the alternative design that I had in mind when writing the documentation. The overhead of iterating over an any_range is quite considerable, and often compares poorly with copying a concrete result-type into a container such as a vector. However, this is not always the case and some of the users of Boost.Range have desired the ability to implement algorithms that operate upon any_range instances. This is sometimes desirable to allow, for example, exposure of algorithms from a shared library that supports various containers.

Two questions: A. would it not be more efficient to store only a range object instead of two iterators as this leads to each iterator begin potentially heap-allocated. (e.g. use boost::iterator_range<I> internally) B. would it not make sense to remove a whole bunch of those template arguments to any_range? Why can't I just say void foo( const any_range<int>& rng ) { switch( rng.category() ) { case boost::ranges::consequtive: ...; break; case boost::ranges::randome_access: ...; break; // etc } } -Thorsten