📄 unit1.cpp
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GetSym();
STATEMENT(SymSetUnion(SymSetNew(SEMICOLON,ENDSYM),FSYS),LEV,TX);
while (SymIn(SYM, SymSetAdd(SEMICOLON,STATBEGSYS))) {
if (SYM==SEMICOLON) GetSym();
else Error(10);
STATEMENT(SymSetUnion(SymSetNew(SEMICOLON,ENDSYM),FSYS),LEV,TX);
}
if (SYM==ENDSYM) GetSym();
else Error(17);
break;
case WHILESYM:
CX1=CX; GetSym(); CONDITION(SymSetAdd(DOSYM,FSYS),LEV,TX);
CX2=CX; GEN(JPC,0,0);
if (SYM==DOSYM) GetSym();
else Error(18);
STATEMENT(FSYS,LEV,TX);
GEN(JMP,0,CX1);
CODE[CX2].A=CX;
break;
case FORSYM:
GetSym();
if(SYM==IDENT){//FOR后跟变量
i=POSITION(ID,TX); //在符号表中查到该标识符所在位置
if (i==0) Error(11); //不在名字表中，报错
else
if (TABLE[i].KIND!=VARIABLE&&TABLE[i].KIND!=ARRAYAL) { /*ASSIGNMENT TO NON-VARIABLE*/
Error(12); i=0;//不是变量，报错
}
GetSym();
if(SYM==BECOMES){ //
GetSym();
EXPRESSION(SymSetUnion(SymSetNew(TOSYM,DOWNTOSYM),FSYS),LEV,TX);
//调用expression过程分析表达式，用于出错恢复的集合中加上TOSYM和DOWNTOSYM
}
if(SYM==TOSYM)//循环变量的步长为1
{
GetSym();
CX1=CX;
GEN(STO,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);//把栈顶值存入变量
GEN(LOD,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);//把变量值放到栈顶
EXPRESSION(SymSetAdd(DOSYM,FSYS),LEV,TX);//处理表达式,DOSYM出错恢复集合
GEN(OPR,0,13);//当前变量(次栈顶)小于等于栈顶
CX2=CX;
GEN(JPC,0,0);
if (SYM==DOSYM) GetSym();
else Error(18);
GEN(LIT,0,1);//将1取到栈顶
GEN(LOD,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR); //取当前变量的值到栈顶
GEN(OPR,0,2);//当前变量(次栈顶)与栈顶相加,结果放在栈顶
}
else if(SYM==DOWNTOSYM)//循环变量的步长为-1
{
GetSym();
CX1=CX;
GEN(STO,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);//把栈顶值存入变量
GEN(LOD,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR);//把变量值放到栈顶
EXPRESSION(SymSetAdd(DOSYM,FSYS),LEV,TX);//处理表达式,DOSYM出错恢复集合
GEN(OPR,0,11);//当前变量(次栈顶)大于等于栈顶
CX2=CX;
GEN(JPC,0,0);
if (SYM==DOSYM) GetSym();
else Error(18);
GEN(LOD,LEV-TABLE[i].vp.LEVEL,TABLE[i].vp.ADR); //取当前变量的值到栈顶
GEN(LIT,0,1);//将1取到栈顶
GEN(OPR,0,3);//当前变量(次栈顶)与栈顶相减
}
else Error(19);
STATEMENT(FSYS,LEV,TX);
GEN(JMP,0,CX1);//跳往TOSYM或DOWNTOSYM之后
CODE[CX2].A=CX;
}
else Error(19);
break;
}
TEST(FSYS,SymSetNULL(),19);
} /*STATEMENT*/
//---------------------------------------------------------------------------
void Block(int LEV, int TX, SYMSET FSYS) { //程序主体部分
int DX=3; /*DATA ALLOCATION INDEX*/
int TX0=TX; /*INITIAL TABLE INDEX*/
int CX0=CX; /*INITIAL CODE INDEX*/
TABLE[TX].vp.ADR=CX; GEN(JMP,0,0);
if (LEV>LEVMAX) Error(32);
do {
if (SYM==CONSTSYM) {
GetSym();
do {
ConstDeclaration(LEV,TX,DX);
while (SYM==COMMA) {
GetSym(); ConstDeclaration(LEV,TX,DX);
}
if (SYM==SEMICOLON) GetSym();
else Error(5);
}while(SYM==IDENT);
}
if (SYM==VARSYM) {
GetSym();
do {
VarDeclaration(LEV,TX,DX);
while (SYM==COMMA) { GetSym(); VarDeclaration(LEV,TX,DX); }
if (SYM==SEMICOLON) GetSym();
else Error(5);
}while(SYM==IDENT);
}
if(SYM==ARRAYSYM){//数组类型
GetSym();
do {
ArrayDeclaration(LEV,TX,DX);
while (SYM==COMMA) { GetSym(); ArrayDeclaration(LEV,TX,DX); }
if (SYM==SEMICOLON) GetSym();
else Error(5);
}while(SYM==IDENT);
}
while ( SYM==PROCSYM) {
GetSym();
if (SYM==IDENT) { ENTER(PROCEDUR,LEV,TX,DX); GetSym(); }
else Error(4);
if (SYM==SEMICOLON) GetSym();
else Error(5);
Block(LEV+1,TX,SymSetAdd(SEMICOLON,FSYS));
if (SYM==SEMICOLON) {
GetSym();
TEST(SymSetUnion(SymSetNew(IDENT,PROCSYM),STATBEGSYS),FSYS,6);
}
else Error(5);
}
TEST(SymSetAdd(IDENT,STATBEGSYS), DECLBEGSYS,7);
}while(SymIn(SYM,DECLBEGSYS));
CODE[TABLE[TX0].vp.ADR].A=CX;
TABLE[TX0].vp.ADR=CX; /*START ADDR OF CODE*/
TABLE[TX0].vp.SIZE=DX; /*SIZE OF DATA SEGMENT*/
GEN(INI,0,DX);
STATEMENT(SymSetUnion(SymSetNew(SEMICOLON,ENDSYM),FSYS),LEV,TX);
GEN(OPR,0,0); /*RETURN*/
TEST(FSYS,SymSetNULL(),8);
ListCode(CX0);
} /*Block*/
//---------------------------------------------------------------------------
int BASE(int L,int B,int S[]) { //通过基址求上一层的基址
int B1=B; /*FIND BASE L LEVELS DOWN*/
while (L>0) { B1=S[B1]; L=L-1; }
return B1;
} /*BASE*/
//---------------------------------------------------------------------------
void Interpret() { //解释程序
const STACKSIZE = 500;
int P,B,T; /*PROGRAM BASE TOPSTACK REGISTERS*/
INSTRUCTION I;
int S[STACKSIZE]; /*DATASTORE*/
Form1->printfs("~~~ RUN PL0 ~~~");
fprintf(FOUT,"~~~ RUN PL0 ~~~\n");
T=0; B=1; P=0;
S[1]=0; S[2]=0; S[3]=0;
do {
I=CODE[P]; P=P+1;
switch (I.F) {
case LIT: T++; S[T]=I.A; break;
case OPR:
switch (I.A) { /*OPERATOR*/
case 0: /*RETURN*/ T=B-1; P=S[T+3]; B=S[T+2]; break;
case 1: S[T]=-S[T]; break;
case 2: T--; S[T]=S[T]+S[T+1]; break;
case 3: T--; S[T]=S[T]-S[T+1]; break;
case 4: T--; S[T]=S[T]*S[T+1]; break;
case 5: T--; S[T]=S[T] % S[T+1]; break;
case 6: S[T]=(S[T]%2!=0); break;
case 8: T--; S[T]=S[T]==S[T+1]; break;
case 9: T--; S[T]=S[T]!=S[T+1]; break;
case 10: T--; S[T]=S[T]<S[T+1]; break;
case 11: T--; S[T]=S[T]>=S[T+1]; break;
case 12: T--; S[T]=S[T]>S[T+1]; break;
case 13: T--; S[T]=S[T]<=S[T+1]; break;
case 14: Form1->printls("",S[T]); fprintf(FOUT,"%d\n",S[T]); T--;
break;
case 15: /*Form1->printfs(""); fprintf(FOUT,"\n");*/ break;
case 16: T++; S[T]=InputBox("输入","请键盘输入：", 0).ToInt();
Form1->printls("? ",S[T]); fprintf(FOUT,"? %d\n",S[T]);
break;
}
break;
case LOD: T++; S[T]=S[BASE(I.L,B,S)+I.A]; break;
case STO: S[BASE(I.L,B,S)+I.A]=S[T]; T--; break;
case CAL: /*GENERAT NEW Block MARK*/
S[T+1]=BASE(I.L,B,S); S[T+2]=B; S[T+3]=P;
B=T+1; P=I.A; break;
case INI: T=T+I.A; break;
case JMP: P=I.A; break;
case JPC: if (S[T]==0) P=I.A; T--; break;
case GET: I.A=S[T]; T--; break;//得到栈顶值
} /*switch*/
}while(P!=0);
Form1->printfs("~~~ END PL0 ~~~");
fprintf(FOUT,"~~~ END PL0 ~~~\n");
} /*Interpret*/
//---------------------------------------------------------------------------
void Init(){
for (CH=' '; CH<='^'; CH++) SSYM[CH]=NUL;//初始化操作符符号表为nul
//关键字符号表
strcpy(KWORD[ 1],"ARRAY");
strcpy(KWORD[ 2],"BEGIN"); strcpy(KWORD[ 3],"CALL");//关键字按字母顺序排列
strcpy(KWORD[ 4],"CONST"); strcpy(KWORD[ 5],"DO");
strcpy(KWORD[ 6],"DOWNTO"); strcpy(KWORD[ 7],"ELSE");
strcpy(KWORD[ 8],"END"); strcpy(KWORD[ 9],"FOR");
strcpy(KWORD[ 10],"IF"); strcpy(KWORD[11],"ODD");
strcpy(KWORD[12],"PROCEDURE");strcpy(KWORD[13],"PROGRAM");
strcpy(KWORD[14],"READ"); strcpy(KWORD[15],"THEN");
strcpy(KWORD[16],"TO"); strcpy(KWORD[17],"VAR");
strcpy(KWORD[18],"WHILE"); strcpy(KWORD[19],"WRITE");
//关键字类型列表
WSYM[ 1]=ARRAYSYM;
WSYM[ 2]=BEGINSYM; WSYM[ 3]=CALLSYM;
WSYM[ 4]=CONSTSYM; WSYM[ 5]=DOSYM;
WSYM[ 6]=DOWNTOSYM; WSYM[ 7]=ELSESYM;
WSYM[ 8]=ENDSYM; WSYM[ 9]=FORSYM;
WSYM[ 10]=IFSYM; WSYM[11]=ODDSYM;
WSYM[12]=PROCSYM; WSYM[13]=PROGSYM;
WSYM[14]=READSYM; WSYM[15]=THENSYM;
WSYM[16]=TOSYM; WSYM[17]=VARSYM;
WSYM[18]=WHILESYM; WSYM[19]=WRITESYM;
//初始化操作符符号表，把可能出现的符号赋上相应的类型
SSYM['+']=PLUS; SSYM['-']=MINUS;
SSYM['*']=TIMES; SSYM['/']=SLASH;
SSYM['(']=LPAREN; SSYM[')']=RPAREN;
SSYM['[']=LMIDPAREN; SSYM[']']=RMIDPAREN;
SSYM['=']=EQL; SSYM[',']=COMMA;
SSYM['.']=PERIOD; SSYM['#']=NEQ;
SSYM[';']=SEMICOLON;
//目标指令的功能码列表
strcpy(MNEMONIC[LIT],"LIT"); strcpy(MNEMONIC[OPR],"OPR");
strcpy(MNEMONIC[LOD],"LOD"); strcpy(MNEMONIC[STO],"STO");
strcpy(MNEMONIC[CAL],"CAL"); strcpy(MNEMONIC[INI],"INI");
strcpy(MNEMONIC[JMP],"JMP"); strcpy(MNEMONIC[JPC],"JPC");
strcpy(MNEMONIC[GET],"GET");
//为符号集分配空间
DECLBEGSYS=(int*)malloc(sizeof(int)*44);
STATBEGSYS=(int*)malloc(sizeof(int)*44);
FACBEGSYS =(int*)malloc(sizeof(int)*44);
for(int j=0; j<44; j++) {//设置符号集
DECLBEGSYS[j]=0; STATBEGSYS[j]=0; FACBEGSYS[j] =0;
}
//设置声明开始符号集
DECLBEGSYS[CONSTSYM]=1;
DECLBEGSYS[VARSYM]=1;
DECLBEGSYS[ARRAYSYM]=1;
DECLBEGSYS[PROCSYM]=1;
//设置语句开始符号集
STATBEGSYS[BEGINSYM]=1;
STATBEGSYS[CALLSYM]=1;
STATBEGSYS[IFSYM]=1;
STATBEGSYS[WHILESYM]=1;
STATBEGSYS[WRITESYM]=1;
STATBEGSYS[FORSYM]=1; //增加FOR语句
//设置因子开始符号集
FACBEGSYS[IDENT] =1;
FACBEGSYS[NUMBER]=1;
FACBEGSYS[LPAREN]=1;
FACBEGSYS[PPLUS]=1;
FACBEGSYS[MMINUS]=1;
FACBEGSYS[LMIDPAREN]=1;
}
void __fastcall TForm1::ButtonRunClick(TObject *Sender) {
Init(); //初始化变量
//程序主体部分,读.PL0文件,输出到.COD文件和屏幕,调用编译程序主体block;
if ((FIN=fopen((Form1->EditName->Text+".PL0").c_str(),"r"))!=0) {
FOUT=fopen((Form1->EditName->Text+".COD").c_str(),"w");
Form1->printfs("=== COMPILE PL0 ===");
fprintf(FOUT,"=== COMPILE PL0 ===\n");
ERR=0;
CC=0; CX=0; LL=0; CH=' '; GetSym();
if (SYM!=PROGSYM) Error(0);
else {
GetSym();
if (SYM!=IDENT) Error(32);
else {
GetSym();
if (SYM!=SEMICOLON) Error(5);
else GetSym();
}
}
Block(0,0,SymSetAdd(PERIOD,SymSetUnion(DECLBEGSYS,STATBEGSYS))); //编译
if (SYM!=PERIOD) Error(9);
if (ERR==0) Interpret();//解释
else {
Form1->printfs("ERROR IN PL/0 PROGRAM");
fprintf(FOUT,"ERROR IN PL/0 PROGRAM");
}
fprintf(FOUT,"\n"); fclose(FOUT);
}
fclose(FIN);
}
//---------------------------------------------------------------------------
void __fastcall TForm1::ButtonClearClick(TObject *Sender)
{
Memo1->Clear();
Memo1->Lines->SetText(" ***** PL/0 编译程序 Demo *****");
}
//---------------------------------------------------------------------------
void __fastcall TForm1::ButtonLoadClick(TObject *Sender)
{
if(OpenDialog1->Execute())//首先执行打开文件对话框函数，这时，打开文件对话框才显示出来。
//如果执行成功，这个函数返回true，否则返回false
{
Memo1->Clear();//把Memo中的内容清掉
Memo1->Lines->SetText(" ***** PL/0 编译程序 Demo *****");
if(OpenDialog1->FilterIndex==1){//打开源码文件
Memo2->Lines->LoadFromFile(OpenDialog1->FileName);// 调用文本装入函数从文件中装入文本，并显示在编辑框中
SaveDialog1->FileName=OpenDialog1->FileName;
}
else if(OpenDialog1->FilterIndex==2)//打开日志文件
Memo1->Lines->LoadFromFile(OpenDialog1->FileName);
else
return;
ButtonSave->Enabled=false;
String lfilename,FileExt,FileName;
lfilename= OpenDialog1->FileName;
FileExt=ExtractFileExt(lfilename);
FileName=ExtractFileName(lfilename);
char *a=(char *) malloc( 10 ); char *b;char *c;
b=FileName.c_str(); c= FileExt.c_str();
strncpy(a,b,strlen(b)-strlen(c));
a[strlen(b)-strlen(c)]='\0';
//EditName->Clear();
EditName->Text=a;
free(a);
}
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Memo2Change(TObject *Sender)
{
ButtonSave->Enabled=true;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::ButtonSaveClick(TObject *Sender)
{
if(SaveDialog1->Execute())
{
//Memo1->Clear();//把Memo中的内容清掉
//Memo1->Lines->SetText(" ***** PL/0 编译程序 Demo *****");
Memo2->Lines->SaveToFile(SaveDialog1->FileName);
String lfilename,FileExt,FileName;
lfilename= SaveDialog1->FileName;
FileExt=ExtractFileExt(lfilename);
FileName=ExtractFileName(lfilename);
/*char *a=(char *) malloc( 1 ); char *b;char *c;
b=FileName.c_str(); c= FileExt.c_str();
strncpy(a,b,strlen(b)-strlen(c));
a[strlen(b)-strlen(c)]='\0';
EditName->Text=a;
free(a); */
ButtonSave->Enabled=false;
}
}
//---------------------------------------------------------------------------
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