编译原理实验报告--PL-0编译程序的修改.docx

实验报告课程名称_编译原理题目名称PL/O编译程序的修改一学牛学院一计算机学院.专'W班级一J2级软件4班一、基本内容(成绩范围：“中”、“及格”或“不及格”)对PL/O作以下修改扩充：(1)增力口单词：保留字ELSE,FOR,STEP,UNTIL,DO,RETURN运算符*=,/=,&,9!(2)修改单词：不等号#改为<>(3)增加条件语句的ELSE子句，要求：写出相关文法，语法图，语义规则。二、设计思路1.扩充单词1）修改变量定义a）先修改保留字的个数ConStNORW=19;b）修改枚举变量SYMBOL的个数为43typedefenumNUL,IDENT,NUMBER,PLUS,MINUS,TIMES,Timesequal,slashequal,SLASH,ODDSYM,EQL,NEQ,LSS,LEQ,GTR,GEQ,LPAREN,RPAREN,COMMA,SEMICOLON,PERIOD,BECOMES,BEGINSYM,ENDSYM,IFSYM,THENSYM,WHILESYM,WRITESYM,READSYM,DOSYM,CALLSYM,CONSTSYM,VARSYM,PROCSYM,PROGSYM,ELSESYM,FORSYM,STEPSYM,UNTILSYM,RETURNSYM,AND,OR,NOTSYMBOL;c）修改SYMoUT数组的个数为43char*SYMOUT=nNUL","1DENT",nNUMBERn,"PLUSu,MINUS"；TIMESVtTIMESEQUAL,nSLASHEQUALn,nSLASH","ODDSYM,"EQL,uNEQ,nLSS",LEQ,GTR,hGEQm,nLPARENn,'RPAREN,nC0MMA,',SEMICOLONm,"PER10Dh,“BECOMES“，"BEGlNSYM“，"ENDSYM“，"IFSYMTTHENSYM”，nWHILESYMu,WRITESYM",nREADSYMn,DOSYM,nCALLSYM",CONSTSYMh,mVARSYMm,"PROCSYM11,mPROGSYM11,elsesymhmFORSYMh,"STEPSYM,mUNTILSYMm,mRETURNSYMm,andm,11orm,notm1;d)增加关键字和保留字strcpy(KWORDll,"BEGlN);strcpy(KWORD2,"CALL")；strcpy(KWORD3,“CONST");strcpy(KWORD4,"DO");strcpy(KWORD5,ELSE");strcpy(KWORD6J,END);StrCPy(KWoRD7JFOR")；strcpy(KWORD8,IF);StrcPy(KWoRD9,“ODD”);strcpy(KWORDl0,"PROCEDURE");strcpy(KWORD11,PR0GRAMu);StrCPy(KWORDH2,“READ”);StrCPy(KWORD13JRETURN');strcpy(KWORD14,'STEP");strcpy(KWORD15,THENu);StrCPy(KWoRD16JUNTlL");strcpy(KWORD17,"VAR);strcpy(KWORD18,"WHILE");strcpy(KWORD19,"WRITE");WSYM1=BEGINSYM;WSYM2=CALLSYM;WSYM3=C0NSTSYM;WSYM4=D0SYM;WSYM5=ELSESYM;WSYM6=ENDSYM;WSYM7=FORSYM;WSYM8=IFSYM;WSYM9=ODDSYM;WSYM10=PROCSYM;WSYM11=PROGSYM;WSYM12=READSYM;WSYM13J=RETURNSYM;WSYM14=STEPSYM;WSYM15=THENSYM;WSYM16=UNTILSYM;WSYM17=VARSYM;WSYM18=WHILESYM;WSYM19=WRITESYM;e.在STATEMENT方法中添加caseELSESYM:FOrml>printfs("读取到ELSE*);break;caseFORSYM:FOrmI>printfsr读取到FOR,);break;caseSTEPSYM:FQrml>printfs(”读取到STEPh);break;caseUNTILSYM:FormI>pring("读取到UNTILm);break;caseRETURNSYM:FOrml>pri11fs("读取到RETURN”)；break;caseTIMESEQUAL:FormL>printfs("读取到*=”)；break;caseSLASHEQUAL:Forml>printfs读取到/=")；break;caseAND:FormI>printfs(“读取到&”)；break;caseOR:FOrml>printfsC'读取到r);break;caseNOT:FOrml>printfsC'读取到NOT");break;2)修改GetSym()方法voidGetSym()inti,J,K;ALFAA;while(CH<='')GetCh();if(CH>=,A'&&CH<=,Z,)*IDORRESERVEDWORD*/K=O;doif(K<AL)AK+=CH;GetCh();while(CH>=,A,&&CH<=,Z')(CH>=,O'&&CH<='9');AK=,O,;strcpy(ID,A);i=l;J=NORW;doK=(i+J)/2;if(strcmp(ID,KWORDK)<=0)J=K-I;if(strcmp(ID,KWORDK)>=0)i=K+1;while(i<=J);if,(i-l>J)SYM=WSYMK;if(SYM=ELSESYM)Forml->printfs(,ELSEM);If(SYM=FORSYM)Forml->printfs(,FORM);If(SYM=STEPSYM)Forml->printfs(MSTEPM);If(SYM=UNTILSYM)Forml->printfs(MUNTILM);if(SYM=RETURNSYM)FOnnl>priItfSrRETURN'');)elseSYM=IDENT;elseif(CH>=,O,&&CH<='9')*NUMBER*/K=O;NUM=O;SYM=NUMBER;doNUM=10*NUM+(CH-O);K+;GetCh();while(CH>=,O'&&CH<=,9');if(K>NMAX)Error(30);elseif(CH=':')GetCh();if(CH='=')SYM=BECOMES;GetCh();elseSYM=NUL;)else*THEFOLLOWINGTWOCHECKWEREADDEDBECAUSEASCIIDOESNOTHAVEASINGLECHARACTERFOR<=OR>=*/if(CH=,<,)GetCh();if(CH=*=r)SYM=LEQ;GetCh();elseif(CH='>')SYM=NEQ;GetCh();elseSYM=LSS;elseif(CH='>,)GetCh();if(CH='=1)SYM=GEQ;GetCh();elseSYM=GTR;if(CH=,*,)添加运算符*=GetCh();if(CH=,=t)SYM=TIMESEQUAL;GetCh();elseSYM=TIMES;if(CH=7,)GetCh();添加运算符/=if(CH=,=t)SYM=SLASHEQUAL,GetCh();)elseSYM=SLASH;if(CH=,)SYM=AND,GetCh();添加运算符&if(CH=T)GetCh();if(CH=T)SYM=OR,GetCh();添加运算符elseSYM=NUL;添加运算符!if(CH=,!t)SYM=NOT,GetCh();elseSYM=SSYMCH;GetCh();/*GetSym()*/2 .修改单词：不等号#改为<>a.在文件中的设置单字符符号的部分，将SSym=NEQ删除。b.在GetSym()方法中elseif(CH=':')GetCh();if(CH=,三,)(SYM=BECOMES;GetCh();JelseSYM=NUL;1else*THEFOLLOWINGTWOCHECKWEREADDEDBECAUSEASCIIDOESNOTHAVEASINGLECHARACTERFOR<=OR>=if(CH=,<,)GetCh();if(CH=,三,)SYM=LEQ;GetCh();elseif(CH=,>>)SYM=NEQ;GetCh();elseSYM=LSS;)elseif(CH='>')GetCh();if(CH=,=)SYM=GEQ;GetCh();)elseSYM=GTR;3 .增加条件语句的ELSE子句1)语法图2)修改STATEMENTO方法caseIFSYM:GetSyniO;CoNDmoN(SymSetUni。Il(SymSetNeW(THENSYM,DOSYM),FSYS),LEVTX);If(SYM=THENSYM)GetSym();elseError(16);CXl=CX;GEN(JPC,0,0);STATEMENT(SymSetUni。II(SymSetNeW(ELSESYM),FSYS),LEV,TX);if(SYM!=ELSESYM)COI)ECX1J.A=CX;e!se!GetSym();CX2=CX;GEN(JMH0,0);CODECX1.A=CX;STATEMENT(SymSetlJnion(SymSetNew(ELSESYM),FSYS),LEV,TX);CODECX2.A=CX;)/STATEMENT(FSYS,LEV,TX);COI)ECX1J.A=CX;break;三、运行测试1.扩充单词的测试(贴运行结果截图)PROGRAMEXOlBEGINELSE;FOR;STEP;UNTIL;RETURN;*h/=;&II;END.=COMPILEPLO=0PROGRAMEXOl;0BEGIN2ELSE；ELSE读取到ELSEl192FOR;FOR读取到FoR人192STEP;STEP读取到STEP2UNTIL；UNTIL读取到UNT工La192RETURN；RETURN读取到RETURN