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<p><font class="example">例4.17  </font>设文法G的产生式为：<br>   
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(1)S→L=R <br>    
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(2)S→R <br>   
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(3)L→*R&nbsp;&nbsp;&nbsp;&nbsp;(4.17)  <br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(4)L→id <br>   
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(5)R→L  <br>   
</p>   
<p>这个文法的拓广文法G'的LR(0)项目集规范族为：<br>   
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I<sub>0</sub> = {S'→·S, S→·L=R,S→·R,L→·*R,<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;L→·id, R→·L} <br>   
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I<sub>1</sub> = {S'→S·} <br>   
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I<sub>2</sub> = {S→L·＝R，R→L·} <br>   
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I<sub>3</sub> = {S→R·}<br>   
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I<sub>4</sub> = {L→*·R，R→·L，L→·*R，L→·id}<br>   
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I<sub>5</sub> = {L→id·} <br>   
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I<sub>6</sub> = {S→LR，R→·L，L→·*R，L→·id}<br>   
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I<sub>7</sub> = {L→*R·}<br>   
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I<sub>8</sub> = {R→L·}<br>   
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;I<sub>9</sub> = {S→L=R·}   
</p>   
<p>识别这个文法的所有活前缀的DFA如图4.21所示。图中用双圆圈表示句柄识别态。 </p>   
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<center><img src="images/4_21.gif" ></center><br>   
<center class="content">图4.21 识别文法(4.17)活前缀的DFA</center></p>    
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