tml#idp36253856-bb"><span class="identifier">flat_map</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">context</span> <span class="special">&amp;</span> <span class="special">=</span> <span class="identifier">system</span><span class="special">::</span><span class="identifier">default_context</span><span class="special">(</span><span class="special">)</span><span class="special">)</span><span class="special">;</span>
  <a class="link" href="flat_map.html#id