sub __handle_key {
		my ( $s, $key_event, $key_code) = @_[1..3];
		my $image_win = $s->image_win;
	#	use Readonly;
	
		Readonly my $single_key_commands => "\003\015\033 +-0123456789RWbnpq";
		
		Readonly my	@single_key_functions => ( 
						\&_abort, \&next_rand_or_recorded_entry, 
						\&_abort, \&_space, 
						\&inc_cur_rating, \&dec_cur_rating,
						\&_set_rating, \&_set_rating, \&_set_rating,
						\&_set_rating, \&_set_rating, \&_set_rating,
						\&_set_rating, \&_set_rating, \&_set_rating,
						\&_set_rating,
						\&_reset_to_beginning_entry, \&write_db,
						\&backup_entry, \&next_rand_or_recorded_entry, 
						\&_pause, \&_quit
					);
		Readonly my @key_code_commands => qw( Left Up Right Down Home KP_Home);
		Readonly my @key_code_functions => (
						\&backup_entry,\&backup_entry,
						\&next_rand_or_recorded_entry, \&next_rand_or_recorded_entry,
						\&_set_to_beginning_entry,
						\&_set_to_beginning_entry,
				);
	  KEY_SWITCH:
		{	
			if ($key_event ne '') {
				my $active_key=index $single_key_commands, $key_event;
				if ($active_key >=  0 ) {
					$single_key_functions[$active_key] -> 
												($s, $key_event, $key_code);
					last KEY_SWITCH;
				}
			} else {	# ($key_event eq '') 
				# ignore modkeys
				return if ($key_code =~ /^(?:Shift|Control|Alt)_[RL]$/ ||
					$key_code =~ /^(:Shift|Num|Scroll)_Lock$/); 
				($key_code eq '') && do { # null event
					carp("key handler called with no key data\n");
					error_beep(); 
					return;
				};
				my $active_key_code=_str_index @key_code_commands, $key_code;
				if ($active_key_code >= 0) {
					$key_code_functions[$active_key_code] -> 
												($s, $key_event, $key_code);
					last KEY_SWITCH;
				}
			}
			{    # default (unhandled/unexpected key)
				printf "Unrecognized key \'%s\', code \'%s\'\n", $key_event,
				  $key_code;
				error_beep(); return;
			};
	
		}	# end KEY_SWITCH;
	
		if ($s->disable_auto_advance()) {
			alarm 0;
			$s->timer_enabled(0);
		} else {
			$s->timer_ticked(0);
			alarm $s->auto_advance_time;
			$s->timer_enabled(1);
		}
	
		$s->show_cur_entry_in_imgwin();
	  
	}