                                <a name="boost.log.expressions.format_named_scope_actor.value_type"></a><span class="identifier">value_type</span><span class="special">;</span>               <span class="comment">// Attribute value type. </span>
  <span class="keyword">typedef</span> <span class="identifier">terminal_type</span><span class="special">::</span><span class="identifier">formatter_function_type</span>                    <a name="boost.log.expressions.format_named_scope_actor.formatter_function_t