parser component allowing to clear the internal
          buffer of a <code class="computeroutput"><span class="identifier">multi_pass</span></code>
          iterator. Clearing the buffer of a <code class="computeroutput"><span class="identifier">multi_pass</span></code>
          might be beneficial for grammars where it is clear that no backtracking
          can occur. The general syntax for using the <code class="computeroutput"><span class="identifier">flush_multi_pass</span></code>
          is:
    