pan><span class="cp">,</span><span class="ctv">'u</span><span class="cp">&gt;</span></code> is simply an abbreviation for <code
      class="fsharp"><a href="../reference/charstream.html#CharStream"><span class="ci">CharStream</span></a><span class="cp">&lt;</span><span
      class="ctv">'u</span><span class="cp">&gt;</span> <span class="cr">-&gt;</span> <a href="../reference/reply.html"><span
      class="ci">Reply</span></a><span class="cp">&lt;</span><span class="ctv">'a</span><span class="cp">&gt;</span