ntifier">std</span><span class="special">::</span><span class="identifier">basic_string</span><span class="special">&lt;</span> <span class="identifier">CharT</span> <span class="special">&gt;</span> <span class="special">&gt;</span> <a name="boost.date_time.period_parser.collection_type"></a><span class="identifier">collection_type</span><span class="special">;</span>

  <span class="keyword">enum</span> <a name="boost.date_time.period_parser.period_range_option"></a>period_range_option <span class="specia