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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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    &nbsp;&nbsp;&nbsp; 4． E→L <br>
    &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;｛<b>if</b> L.offset＝<b>null then</b> 
    &nbsp;&nbsp;&nbsp;&nbsp;／* L is a simple <b>id</b> */ <br>
    &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.place:＝L.place 
    <br>
    &nbsp;&nbsp;&nbsp; <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;else begin</b> <br>
    &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;E.place:=newtemp; 
    <br>
    &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;emit(E.place':='L.place'['L.offset']') 
    <br>
    &nbsp;&nbsp;&nbsp; <b>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;end</b>} <br>
    L.offset是一个新的临时变量，存放着w与Elist.place 值的乘积。因此L.offset等价于（7.5）式的第一项: 
    <br>
    &nbsp;&nbsp;&nbsp; 5． L→Elist] <br>
    &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;｛L.place:=newtemp; <br>
    &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;emit（L.place':='Elist.array'－' 
    <br>
    &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;（（…（（low<span
    class="down"><sub>1</sub></span> n<span class="down"><sub>2</sub></span>＋low<span
    class="down"><sub>2</sub></span>）n<span class="down"><sub>3</sub></span>＋low<span
    class="down"><sub>3</sub></span>）…）n<span class="down"><sub>k</sub></span> ＋low<span
    class="down"><sub>k</sub></span>） * w ））； <br>
    &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;L.offset:=newtemp; <br>
    &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;emit（L.offset':='w'*'Elist.place)} 
    <br>
    一个空的offset表示一个简单的名字： <br>
    &nbsp;&nbsp;&nbsp; 6． L→<b>id</b> <br>
    &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;（L.place:=<b>id</b>.place;L.offset:=＝<b>null</b>} 
    <br>
    每当扫描到下一个下标表达式时，我们应用递归公式（7.7）。在下列语义动作中，Elist.place与（7.7）式中的e<span
    class="down"><sub>m-1</sub></span>对应，Elist.place与(7.7)式中的e<span class="down"><sub>m</sub></span>对应。注意若Elist有m一1个元素，则产生式左部的Elist有m个元素。 
    <br>
    &nbsp;&nbsp;&nbsp; 7．Elist→Elist<span class="down"><sub>1</sub></span>,E <br>
    &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;{t：＝newtemp; <br>
    &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;m： ＝Elist<span class="down"><sub>1</sub></span>．ndim＋1； 
    <br>
    &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;emit（t'：= ' Elist<span class="down"><sub>1</sub></span>.place'*'limit（Elist<span
    class="down"><sub>1</sub></span>.array,m））； <br>
    &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;emit（t'：= ' t '＋'E.place）； <br>
    &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;Elist.array：＝Elist<span class="down"><sub>1</sub></span>．array; 
    <br>
    &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;Elist.place：=t; <br>
    &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;Elist.ndim：＝m｝ <br>
    E.place保存表达式E的值，即先后用来存放下标表达式i<span class="down"><sub>1</sub></span>，i<span
    class="down"><sub>2</sub></span>,...i<span class="down"><sub>m</sub></span>之值，特别当m= 
    1时为i<span class="down"><sub>1</sub></span>之值，即为（7.6）式之值。 <br>
    &nbsp;&nbsp;&nbsp; 8． Elist→<b>id</b>[E <br>
    &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;｛Elist.place:=E.place; <br>
    &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Elist.ndim:=1： <br>
    &nbsp;&nbsp;&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Elist.array：＝<b>id</b>.place} 
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