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📁 建立《编译原理网络课程》的目的不仅使学生掌握构造编译程序的原理和技术
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<p><b>例5.16 </b>图5.17中的文法是LL（1）文法，因此它适于自顶向下的分析。从文法中非终结符号的属性，我们可以得到函数E,R和T的自变量和结果的如下的类型。由于E和T没有继承属性，所以它们不含有自变量： 
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<p><b>&nbsp;&nbsp; function</b> E:↑syntax-tree-node；<br> 
&nbsp;&nbsp;&nbsp; <b>&nbsp;&nbsp;&nbsp;functlon</b> R（in:↑syntax-tree-node）<br>
&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp&nbsp:↑syntax-tree-node；<br> 
&nbsp;&nbsp;&nbsp; <b>&nbsp;&nbsp;&nbsp;function</b> T：↑syntax-tree-node；  
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<p>我们把图5.17的两个R产生式结合起来使翻译程序更小，新的产生式用符号<b>addop</b>代表＋和－：  
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<p>&nbsp;&nbsp;&nbsp;&nbsp; R→<b>addop</b><br> 
&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;T｛R<span class="down"><sub>1</sub></span>．i:=mknode（addop.lexeme，R.i，T.nptr）｝<br> 
&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;R<span class="down"><sub>1</sub></span>｛R.s:=R<span class="down"><sub>1</sub></span>.s}<br> 
&nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;R→ε｛R.s:=R.i}<br> 
&nbsp;&nbsp;&nbsp;  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;（5．5） 
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