an><span class="special">::</span><span class="identifier">parse</span><span class="special">(</span><span class="identifier">begin</span><span class="special">,</span> <span class="identifier">end</span><span class="special">,</span> <span class="char">'('</span> <span class="special">&gt;&gt;</span> <span class="identifier">qi</span><span class="special">::</span><span class="identifier">double_</span> <span class="special">&gt;&gt;</span> <span class="string">", "</span> <span class="special">&gt;&gt;</s