enable_if<!has_ostream_operator< Type >::value, const char * >::type wrap_unprintable(Type, const char *instead="<unprintable>")
SFINAE magic to return "<unprintable>" instead if the value HAS NO ostream operator << available.
enable_if<!has_ostream_operator< Type >::value, const char * >::type wrap_unp(Type, const char *instead="<unprintable>")
SFINAE magic to return "<unprintable>" instead if the value HAS NO ostream operator << available.