Why string_view constructor doesn't take a pair of iterators

Question

Both string_ref in boost and string_span in GSL doesn't define constructor that takes a pair of iterator. What is the reason of this decision ?

Usually it's not a big deal, I can just create string_ref like this :

boost::string_ref s(start, std::distance(start, finish));

but the reason I want constructor that take a pair of iterators is because I have code that look like this:

template<typename Type, typename Iterator>
void func(const Iterator& begin, const Iterator& end)
{
    Type s(begin, end);
    //do stuff with s
}

Currently, I can call it like this :

func<std::string>(start, finish)

I want to change it to :

func<boost::string_ref>(start, finish) //compile error

but that code won't compile because the lack of constructor taking a pair of iterator in string_ref

Answer 1

Looks like I make a mistake. gsl::string_span do have a constructor that takes begin and end iterator. So, there is nothing problematic with creating string_view from iterator pairs and the lack of it in boost::string_ref is probably just an oversight.

For my case, I end up inheriting from boost::string_ref and add the constructor myself.