(<span class="keywordtype">size_t</span> i) <span class="keyword">const</span> = 0;
<a name="l00220"></a>00220 
<a name="l00221"></a>00221   <span class="comment">// return output tag of i-th token as string</span>
<a name="l00222"></a>00222   <span class="keyword">virtual</span> <span class="keyword">const</span> <span class="keywordtype">char</span>*   y2(<span class="keywordtype">size_t</span> i) <span class="keyword">const</span> = 0;
<a name="l00223"></a>00223 
<a name="l00224"></a>00224   <span class=