added the boost::range::separated function for range output streaming.

include/boost/range/separated.hpp

@@ -0,0 +1,94 @@
+// Boost.Range library
+//
+//  Copyright Neil Groves 2014.
+//  Use, modification and distribution is subject to the Boost Software
+//  License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+//  http://www.boost.org/LICENSE_1_0.txt)
+//
+// For more information, see http://www.boost.org/libs/range/
+//
+#ifndef BOOST_RANGE_SEPARATED_HPP_INCLUDED
+#define BOOST_RANGE_SEPARATED_HPP_INCLUDED
+
+#include <boost/config.hpp>
+#include <boost/range/concepts.hpp>
+#include <boost/range/begin.hpp>
+#include <boost/range/end.hpp>
+#include <boost/range/iterator.hpp>
+#include <ostream>
+
+namespace boost
+{
+    namespace range_detail
+    {
+
+template<typename Iter, typename Separator>
+class output_stream_writer
+{
+public:
+    output_stream_writer(Iter first, Iter last, Separator separator)
+        : m_first(first)
+        , m_last(last)
+        , m_separator(separator)
+    {
+    }
+
+    template<typename OStream>
+    void write(OStream& out) const
+    {
+        write_impl(out, m_first, m_last, m_separator);
+    }
+
+private:
+    template<typename OStream>
+    static void write_impl(
+            OStream& out, Iter first, Iter last, Separator separator)
+    {
+        if (first != last)
+        {
+            out << *first;
+            for (++first; first != last; ++first)
+            {
+                out << separator << *first;
+            }
+        }
+    }
+
+    Iter m_first;
+    Iter m_last;
+    Separator m_separator;
+};
+
+template<typename Char, typename Traits, typename Iter, typename Separator>
+std::basic_ostream<Char, Traits>&
+operator<<(
+        std::basic_ostream<Char, Traits>& out,
+        const output_stream_writer<Iter, Separator>& writer)
+{
+    writer.write(out);
+    return out;
+}
+
+    } // namespace range_detail
+
+    namespace range
+    {
+
+template<typename Range, typename Separator>
+inline range_detail::output_stream_writer<
+    typename range_iterator<const Range>::type,
+    Separator
+>
+separated(const Range& rng, Separator separator)
+{
+    BOOST_RANGE_CONCEPT_ASSERT((SinglePassRangeConcept<const Range>));
+    return range_detail::output_stream_writer<
+            typename range_iterator<const Range>::type,
+            Separator
+    >(boost::begin(rng), boost::end(rng), separator);
+}
+
+    } // namespace range
+} // namespace boost
+
+#endif // include guard