#include <boost/hana/core/when.hpp>
-BOOST_HANA_NAMESPACE_BEGIN
+namespace boost { namespace hana {
//! @ingroup group-concepts
//! @defgroup group-Sequence Sequence
//! The `Sequence` concept represents generic index-based sequences.
template <typename S, typename = void>
struct Sequence : Sequence<S, when<true>> { };
#endif
-BOOST_HANA_NAMESPACE_END
+}} // end namespace boost::hana
#endif // !BOOST_HANA_FWD_CONCEPT_SEQUENCE_HPP