ext</span>, <span class="type-var">'f_in</span>, <span class="type-var">'f_out</span>, <span class="type-var">'arg_payload</span>)</span> <a href="../index.html#type-name_matcher">name_matcher</a></span> <span class="arrow">&#45;&gt;</span></span>
  <span>string <span class="arrow">&#45;&gt;</span></span>
  <span><span>(<span class="type-var">'context</span>, <span class="type-var">'f_in</span>, <span class="type-var">'f_out</span>, <span class="type-var">'arg_payload</span>)</span> <a href="../index.html#t