-----Original Message----- From: boost-bounces@lists.boost.org [mailto:boost-bounces@lists.boost.org] On Behalf Of Steven Watanabe Sent: Wednesday, August 08, 2012 3:29 PM To: boost@lists.boost.org Subject: Re: [boost] [type_erasure] Review started (July 18-27, 2012)
AMDG
namespace boost { namespace type_erasure { template <typename T1, typename T2> std::ostream& operator<< (std::ostream& os, const std::pair<T1, T2>& p) { /*! Output a pair of values with space as delimiter. \details For example: "1.23 3.45". */ os << p.first << " " << p.second; return os; } // std::ostream& operator<< (std::ostream& os, const std::pair<T1, T2>& p) // Partial specialization of struct ostreamable for pair<T1, T2>: template<class Os, typename T1, typename T2> struct ostreamable<Os, std::pair<T1, T2> > { static void apply(Os& out, const std::pair<T1, T2>& arg) { out << arg; } }; } // namespace type_erasure } // namespace boost Works nicely for anything needing std::pair like map. Followers of this thread may also be amused to see my fumblings with type_erasure (attached) adding a few more bells and whistles and using with lots of types of things (including User defined types) in various containers. I can see lots of neat applications just printing things in containers. Paul PS I note in fiddling with cosmetic details that boost::tuple only provides a char option for std::cout << set_open('[') << set_delimiter('_') << set_close(']') << std::endl; this prevents, for example ", " (comma and space) as a delimiter. Can anyone remember a good reason why a std::string is not also provided?