ipper</span><span class="special">&gt;</span>
<span class="special">{</span>
    <span class="comment">// This is a simplified preprocessor grammar recognizing</span>
    <span class="comment">//</span>
    <span class="comment">//   #define MACRONAME something</span>
    <span class="comment">//   #undef MACRONAME</span>
    <span class="comment">//</span>
    <span class="comment">// Its sole purpose is to show an example how to use the </span>
    <span class="comment">// flush_multi_pass parser. At the 