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📄 unit1.cpp

📁 PL/0语言是Pascal语言的一个子集
💻 CPP
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/*** PL0 COMPILER WITH CODE GENERATION ***/
//---------------------------------------------------------------------------
#include <vcl.h>
#pragma hdrstop
#include "Unit1.h"
#include "String.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
const  AL    =  10;  /* 地址上界*/ /* LENGTH OF IDENTIFIERS */
const  NORW  =  19;  /* # OF RESERVED WORDS */
const  TXMAX = 100;  /* LENGTH OF IDENTIFIER TABLE */
const  NMAX  =  14;  /* MAX NUMBER OF DEGITS IN NUMBERS */
const  AMAX  =2047;  /* MAXIMUM ADDRESS */
const  LEVMAX=   3;  /* MAX DEPTH OF BLOCK NESTING */
const  CXMAX = 200;  /* SIZE OF CODE ARRAY */

typedef enum  {NUL, IDENT, NUMBER, PLUS, MINUS, TIMES,
	            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, TOSYM, DOWNTOSYM,
                    PLUSEQL, MINUSEQL, PPLUS, MMINUS,
                    ARRAYSYM, LMIDPAREN,RMIDPAREN//45个关键字
        } SYMBOL;//新增保留字ELSE，FOR，TO, DOWNTO ;运算符 +=，-=，++，--
char *SYMOUT[] = {"NUL", "IDENT", "NUMBER", "PLUS", "MINUS", "TIMES",
	    "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", "DOWNTOSYM", "TOSYM",
            "PLUSEQL", "MINUSEQL", "PPLUS", "MMINUS",
            "ARRAYSYM", "LMIDPAREN","RMIDPAREN"};
typedef  int *SYMSET; // SET OF SYMBOL;
typedef  char ALFA[11];//alfa类型用于标识符
typedef  enum { CONSTANT, VARIABLE, ARRAYAL, PROCEDUR } OBJECTS ; //object1为标识符的类型
typedef  enum { LIT, OPR, LOD, STO, CAL, INI, JMP, JPC, GET} FCT;//fct类型分别标识类PCODE的各条指令
typedef struct {
	 FCT F;     /*FUNCTION CODE*/
	 int L; 	/*0..LEVMAX  LEVEL*/
	 int A;     /*0..AMAX    DISPLACEMENT ADDR*/
} INSTRUCTION;
	  /* LIT O A -- LOAD CONSTANT A             */
	  /* OPR 0 A -- EXECUTE OPR A               */
	  /* LOD L A -- LOAD VARIABLE L,A           */
	  /* STO L A -- STORE VARIABLE L,A          */
	  /* CAL L A -- CALL PROCEDURE A AT LEVEL L */
	  /* INI 0 A -- INCREMET T-REGISTER BY A    */
	  /* JMP 0 A -- JUMP TO A                   */
	  /* JPC 0 A -- JUMP CONDITIONAL TO A       */
char   CH;  /*LAST CHAR READ*/
SYMBOL SYM; /*LAST SYMBOL READ*/
ALFA   ID;  /*LAST IDENTIFIER READ*/
int    NUM; /*LAST NUMBER READ*/
int    CC;  /*CHARACTER COUNT*/
int    LL;  /*LINE LENGTH*/
int    CX;  /*CODE ALLOCATION INDEX*/
char   LINE[81];
INSTRUCTION  CODE[CXMAX];
ALFA    KWORD[NORW+1];
SYMBOL  WSYM[NORW+1];
SYMBOL  SSYM['^'+1];//95个地址
ALFA    MNEMONIC[9];
SYMSET  DECLBEGSYS, STATBEGSYS, FACBEGSYS; // 开始符号集

struct {
  ALFA NAME;
  OBJECTS KIND;
  union {
    int VAL;   /*CONSTANT*/
    struct { int LEVEL,ADR,SIZE; } vp;
  };
  struct { int LOWB,UPB;}bound;   //数组的内情向量,数组的上下界
} TABLE[TXMAX]; //名字表

FILE *FIN,*FOUT;
int ERR;

void EXPRESSION(SYMSET FSYS, int LEV, int &TX);
void TERM(SYMSET FSYS, int LEV, int &TX);
//---------------------------------------------------------------------------
int SymIn(SYMBOL SYM, SYMSET S1) {//新的符号进入符号表
  return S1[SYM];
}
//---------------------------------------------------------------------------
SYMSET SymSetUnion(SYMSET S1, SYMSET S2) {//为符号开空间
  SYMSET S=(SYMSET)malloc(sizeof(int)*44);
  for (int i=0; i<44; i++)
	if (S1[i] || S2[i]) S[i]=1;
	else S[i]=0;
  return S;
}
//---------------------------------------------------------------------------
SYMSET SymSetAdd(SYMBOL SY, SYMSET S) {
  SYMSET S1;
  S1=(SYMSET)malloc(sizeof(int)*44);
  for (int i=0; i<44; i++) S1[i]=S[i];
  S1[SY]=1;
  return S1;
}
//---------------------------------------------------------------------------
SYMSET SymSetNew(SYMBOL a) {
  SYMSET S; int i,k;
  S=(SYMSET)malloc(sizeof(int)*44);
  for (i=0; i<44; i++) S[i]=0;
  S[a]=1;
  return S;
}
//---------------------------------------------------------------------------
SYMSET SymSetNew(SYMBOL a, SYMBOL b) {
  SYMSET S; int i,k;
  S=(SYMSET)malloc(sizeof(int)*44);
  for (i=0; i<44; i++) S[i]=0;
  S[a]=1;  S[b]=1;
  return S;
}
//---------------------------------------------------------------------------
SYMSET SymSetNew(SYMBOL a, SYMBOL b, SYMBOL c) {
  SYMSET S; int i,k;
  S=(SYMSET)malloc(sizeof(int)*44);
  for (i=0; i<44; i++) S[i]=0;
  S[a]=1;  S[b]=1; S[c]=1;
  return S;
}
//---------------------------------------------------------------------------
SYMSET SymSetNew(SYMBOL a, SYMBOL b, SYMBOL c, SYMBOL d) {
  SYMSET S; int i,k;
  S=(SYMSET)malloc(sizeof(int)*44);
  for (i=0; i<44; i++) S[i]=0;
  S[a]=1;  S[b]=1; S[c]=1; S[d]=1;
  return S;
}
//---------------------------------------------------------------------------
SYMSET SymSetNew(SYMBOL a, SYMBOL b, SYMBOL c, SYMBOL d,SYMBOL e) {
  SYMSET S; int i,k;
  S=(SYMSET)malloc(sizeof(int)*44);
  for (i=0; i<44; i++) S[i]=0;
  S[a]=1;  S[b]=1; S[c]=1; S[d]=1; S[e]=1;
  return S;
}
//---------------------------------------------------------------------------
SYMSET SymSetNew(SYMBOL a, SYMBOL b, SYMBOL c, SYMBOL d,SYMBOL e, SYMBOL f) {
  SYMSET S; int i,k;
  S=(SYMSET)malloc(sizeof(int)*44);
  for (i=0; i<44; i++) S[i]=0;
  S[a]=1;  S[b]=1; S[c]=1; S[d]=1; S[e]=1; S[f]=1;
  return S;
}
//---------------------------------------------------------------------------
SYMSET SymSetNULL() {
  SYMSET S; int i,n,k;
  S=(SYMSET)malloc(sizeof(int)*44);
  for (i=0; i<44; i++) S[i]=0;
  return S;
}
//---------------------------------------------------------------------------
void Error(int n) { //出错分析,识别代码正常的出错
  String s = "***"+AnsiString::StringOfChar(' ', CC-1)+"^";
  Form1->printls(s.c_str(),n);
  fprintf(FOUT,"%s%d--", s.c_str(), n);
  ERR++;
  switch(n)
  {
  case 0: Form1->printfs("标识符错误");
	  fprintf(FOUT,"标识符错误\n");
          break;
  case 1: Form1->printfs("把=写成了:=");
	  fprintf(FOUT,"把=写成了:=\n");
          break;
  case 2: Form1->printfs("常量说明=后应是数字");
	  fprintf(FOUT,"常量说明=后应是数字\n");
          break;
  case 3: Form1->printfs("常量说明标识后应是=");
	  fprintf(FOUT,"常量说明标识后应是=\n");
          break;
  case 4: Form1->printfs("const后应是标识");
	  fprintf(FOUT,"const后应是标识\n");
          break;
  case 5: Form1->printfs("漏掉了分号");
	  fprintf(FOUT,"漏掉了分号\n");
          break;

  case 10: Form1->printfs("缺少分号");
	  fprintf(FOUT,"缺少分号\n");
          break;
  case 11: Form1->printfs("变量未找到");
	   fprintf(FOUT,"变量未找到\n");
           break;
  case 12: Form1->printfs("赋值语句格式错误");
	   fprintf(FOUT,"赋值语句格式错误\n");
           break;
   case 13: Form1->printfs("没有检测到赋值语句");
	    fprintf(FOUT,"没有检测到赋值语句\n");
            break;
   case 14: Form1->printfs("call后应为标识符");
	    fprintf(FOUT,"call后应为标识符\n");
            break;
   case 15: Form1->printfs("call后标识符应为过程");
	    fprintf(FOUT,"call后标识符应为过程\n");
            break;
   case 16: Form1->printfs("缺少then");
	  fprintf(FOUT,"缺少then\n");
          break;
  case 17: Form1->printfs("缺少end或分号");
	  fprintf(FOUT,"缺少end或分号\n");
          break;
  case 18: Form1->printfs("缺少do");
	  fprintf(FOUT,"缺少do\n");
          break;
  case 19: Form1->printfs("标识?");
	  fprintf(FOUT,"标识?\n");
          break;
  case 20: Form1->printfs("非比较的操作符");
	  fprintf(FOUT,"非比较的操作符\n");
          break;
  case 21: Form1->printfs("不能为过程");
	  fprintf(FOUT,"不能为过程\n");
          break;
  case 22: Form1->printfs("缺少右括号");
	  fprintf(FOUT,"缺少右括号\n");
          break;
   case 23: Form1->printfs("因子后非法符号");
	  fprintf(FOUT,"因子后非法符号\n");
          break;
   case 31: Form1->printfs("数越界");
	   fprintf(FOUT,"数越界\n");
           break;
   case 32: Form1->printfs("不能使用保留字");
	   fprintf(FOUT,"不能使用保留字\n");
           break;
   case 33: Form1->printfs("格式应是右括号");
	    fprintf(FOUT,"格式应是右括号\n");
            break;

   case 35: Form1->printfs("read()中应是声明过的变量名");
	    fprintf(FOUT,"read()中应是声明过的变量名\n");
            break;
  }
} /*Error*/
//---------------------------------------------------------------------------
void GetCh() { //读一个字符,每次读一行,存入LINE缓冲区
  if (CC==LL) {
    if (feof(FIN)) {
	  Form1->printfs("PROGRAM INCOMPLETE");
	  fprintf(FOUT,"PROGRAM INCOMPLETE\n");
	  fclose(FOUT);
	  exit(0);
	}
	LL=0; CC=0;
	CH=' ';
	while (!feof(FIN) && CH!=10)
      { CH=fgetc(FIN);  LINE[LL++]=CH; }
	LINE[LL-1]=' ';  LINE[LL]=0;
    String s=IntToStr(CX);
    while(s.Length()<3) s=" "+s;
    s=s+" "+LINE;
	Form1->printfs(s.c_str());
    fprintf(FOUT,"%s\n",s);
  }
  CH=LINE[CC++];
} /*GetCh()*/
//---------------------------------------------------------------------------
void GetSym() {//词法分析,获取一个符号,忽略大小写
  int i,J,K;   ALFA  A;
  while (CH<=' ') GetCh();
  if (CH>='a' && CH<='z'||CH>='A' && CH<='Z') { /*ID OR RESERVED WORD*/
    K=0;
	do {
	  if (K<AL) A[K++]=CH;
	  GetCh();
	}while(CH>='a' && CH<='z'||(CH>='A' && CH<='Z')||(CH>='0' && CH<='9'));
	A[K]='\0';
	strcpy(ID,A); i=1; J=NORW; //有序表的折半搜索,要求关键字从小到大排好了序
	do {
	  K=(i+J) / 2;
	  if (strcmpi(ID,KWORD[K])<=0) J=K-1;
	  if (strcmpi(ID,KWORD[K])>=0) i=K+1;
	}while(i<=J);
	if (i-1 > J) SYM=WSYM[K];
	else SYM=IDENT;
  }
  else if (CH>='0' && CH<='9') { /*NUMBER*/
      K=0; NUM=0; SYM=NUMBER;
	  do {
	    NUM=10*NUM+(CH-'0');
		K++; GetCh();
      }while(CH>='0' && CH<='9');
	  if (K>NMAX) Error(30);
    }
    else if (CH==':') {
	    GetCh();
		if (CH=='=') { SYM=BECOMES; GetCh(); }
		else SYM=NUL;
      }
    else if (CH=='<') {
    	GetCh();
        if (CH=='=') { SYM=LEQ; GetCh(); }
        else if (CH=='>') { SYM=NEQ; GetCh(); }
        else SYM=LSS;
    }
    else if (CH=='>') {
    	GetCh();
        if (CH=='=') { SYM=GEQ; GetCh(); }
        else SYM=GTR;
    }
    else if (CH=='+') {
    	GetCh();
        if (CH=='=') { SYM=PLUSEQL; GetCh(); }
        else if (CH=='+') { SYM=PPLUS; GetCh(); }
        else SYM=PLUS;
    }
    else if (CH=='-') {
    	GetCh();
        if (CH=='=') { SYM=MINUSEQL; GetCh(); }
        else if (CH=='-') { SYM=MMINUS; GetCh(); }
        else SYM=MINUS;
    }
    else { SYM=SSYM[CH]; GetCh(); }
} /*GetSym()*/
//---------------------------------------------------------------------------
void GEN(FCT X, int Y, int Z) {//生成目标代码
  if (CX>CXMAX) {
    Form1->printfs("PROGRAM TOO LONG");
	fprintf(FOUT,"PROGRAM TOO LONG\n");
	fclose(FOUT);
    exit(0);
  }
  CODE[CX].F=X; CODE[CX].L=Y; CODE[CX].A=Z;
  CX++;
} /*GEN*/
//---------------------------------------------------------------------------
void TEST(SYMSET S1, SYMSET S2, int N) { //测试,检测类型集合的匹配
  if (!SymIn(SYM,S1)) {
    Error(N);
	while (!SymIn(SYM,SymSetUnion(S1,S2))) GetSym();
  }
} /*TEST*/
//---------------------------------------------------------------------------
void ENTER(OBJECTS K, int LEV, int &TX, int &DX) { /*登录名字表ENTER OBJECT INTO TABLE*/
  TX++;
  strcpy(TABLE[TX].NAME,ID); TABLE[TX].KIND=K;
  switch (K) {
	case CONSTANT:
	       if (NUM>AMAX) { Error(31); NUM=0; }
	       TABLE[TX].VAL=NUM;
	       break;
    case VARIABLE:
	       TABLE[TX].vp.LEVEL=LEV; TABLE[TX].vp.ADR=DX; DX++;
	       break;
    case ARRAYAL:
               TABLE[TX].vp.LEVEL=LEV;
	       break;
    case PROCEDUR:
	       TABLE[TX].vp.LEVEL=LEV;
	       break;
  }
} /*ENTER*/
//---------------------------------------------------------------------------
int POSITION(ALFA ID, int TX) { /*查标识符在名字表的位置FIND IDENTIFIER IN TABLE*/
  int i=TX;
  strcpy(TABLE[0].NAME,ID);
  while (strcmp(TABLE[i].NAME,ID)!=0) i--;
  return i;
} /*POSITION*/
//---------------------------------------------------------------------------
123

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