</a></code> number and the index
      of the first char in the line, the <code class="fsharp"><a href="../reference/charstream.html#CharStream.members.LineBegin"><span
      class="ci">LineBegin</span></a></code>. By combining the <code class="fsharp"><a
      href="../reference/charstream.html#CharStream.members.Index"><span class="ci">Index</span></a></code> and <code class="fsharp"><a
      href="../reference/charstream.html#CharStream.members.LineBegin"><span class="ci">LineBegin</span></a></code> we c