 class="identifier">boost</span><span class="special">::</span><span class="identifier">gregorian</span><span class="special">;</span>
<span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">posix_time</span><span class="special">;</span>
<span class="keyword">typedef</span> <span class="identifier">us_dst_trait</span><span class="special">&lt;</span><span class="identifier">date</span><span class=