// In header: <boost/log/expressions/predicates/channel_severity_filter.hpp>
template<typename ChannelT, typename SeverityT, 
         typename ChannelFallbackT = fallback_to_none, 
         typename SeverityFallbackT = fallback_to_none, 
         typename ChannelOrderT = less, 
         typename SeverityCompareT = greater_equal, 
         typename AllocatorT = std::allocator< void >, 
         template< typename > class ActorT = phoenix::actor> 
class channel_severity_filter_actor : public ActorT< channel_severity_filter_terminal< ChannelT, SeverityT, ChannelFallbackT, SeverityFallbackT, ChannelOrderT, SeverityCompareT, AllocatorT > >
{
public:
  // types
  typedef channel_severity_filter_terminal< ChannelT, SeverityT, ChannelFallbackT, SeverityFallbackT, ChannelOrderT, SeverityCompareT, AllocatorT > terminal_type;             // Terminal type. 
  typedef ActorT< terminal_type >                                                                                                                   base_type;                 // Base actor type. 
  typedef terminal_type::channel_value_type                                                                                                         channel_value_type;        // Channel attribute value type. 
  typedef terminal_type::channel_fallback_policy                                                                                                    channel_fallback_policy;   // Channel fallback policy. 
  typedef terminal_type::severity_value_type                                                                                                        severity_value_type;       // Severity level attribute value type. 
  typedef terminal_type::severity_fallback_policy                                                                                                   severity_fallback_policy;  // Severity level fallback policy. 
  // member classes/structs/unions
  // An auxiliary pseudo-reference to implement insertion through subscript
  // operator.
  class subscript_result {
  public:
    // construct/copy/destruct
    subscript_result(channel_severity_filter_actor &, 
                     channel_value_type const &);
    void operator=(severity_value_type const &);
  };
  // construct/copy/destruct
  explicit channel_severity_filter_actor(base_type const &);
  channel_severity_filter_actor(channel_severity_filter_actor const &);
  // public member functions
  this_type & set_default(bool);
  this_type & add(channel_value_type const &, severity_value_type const &);
  subscript_result operator[](channel_value_type const &);
};