an class="special">&lt;&lt;</span> <span class="identifier">double_</span> <span class="special">&lt;&lt;</span> <span class="char">')'</span>
        <span class="special">|</span>   <span class="identifier">omit</span><span class="special">[</span><span class="identifier">bool_</span><span class="special">]</span>  <span class="special">&lt;&lt;</span> <span class="identifier">double_</span>
        <span class="special">),</span>
        <span class="comment">//  End grammar</span>

        <span class="