📄 4.10.12.htm
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<title>4.12的解答</title>
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<center><font class="title2"><b>练习4.12</b></font></center><br>
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解：<br>
该文法的拓广文法G'为
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<tr><td>(0) E' → E</td><td>(1) E → E+T</td></tr>
<tr><td>(2) E → T</td><td>(3) T → TF</td></tr>
<tr><td>(4) T → F</td><td>(5) F → F*</td></tr>
<tr><td>(6) F → a</td><td>(7) F → b</td></tr>
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其LR(0)项目集规范族和goto函数(识别活前缀的DFA)如下:<br>
I<sub>0 </sub> = {E'→·E, E→·E+T, E→·T, T→·TF, T→·F, F→·F*,<br>
<b> <b> F→·a, F→·b}<br>
I<sub>1</sub> = {E'→E·, E→E·+T}<br>
I<sub>2</sub> = {E→T·, T→T·F, F→·F*, F→·a, F→·b}<br>
I<sub>3</sub> = {T→F·, F→F·*}<br>
I<sub>4</sub> = {F→a·}<br>
I<sub>5</sub> = {F→b·}<br>
I<sub>6</sub> = {E→E+·T, T→·TF, T→·F, F→·F*, F→·a, F→·b}<br>
I<sub>7 </sub> = {T→TF·, F→F·*}<br>
I<sub>8 </sub> = {F→F*·}<br>
I<sub>9</sub> = {E→E+T·, T→T·F, F→·F*, F→·a, F→·b}<br>
<center><img src="images/ex4.121.gif"></center><br>
求<b>FOLLOW</b>集：<br>
<b> FOLLOW</b>(E)={＋, ＄}<br>
<b>FOLLOW(</b>T)={＋, ＄, a, b}<br>
<b> FOLLOW</b>(F)={＋, ＄, a, b, *}<br>
构造的SLR分析表如下：
<center><img src="images/ex4.122.gif" width="553" height="274"></center><br>
显然，此分析表无多重定义入口，所以此文法是SLR文法。<br>
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