 one <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></code> instance is created per input file and all parser functions
      involved in parsing elements of the same file are passed the same <code class="fsharp"><a href="../reference/charstream.html#CharStream"><span
      class="ci">CharStream</span></a></code> instance. Since calling the methods of a <code