...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
template< class T> std::enable_if< std::is_convertible< T const &, string_view_type >::value &&!std::is_convertible< T const &, CharT const * >::value, static_string & >::type append( T const& t, size_type pos, size_type count = npos);