pascal.cpp

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/****************************************************/
/*              pascal.cpp							*/
/*          高级语言到四元式						*/
/***************************************************/
#include	<STDIO.H>
#include    <STRING.H>
#include	<STDLIB.H>
#include	<conio.h>

#define	ACC		-2
/****************************************/
#define sy_if			0
#define sy_then			1
#define sy_else			2
#define sy_while		3
#define sy_begin		4
#define sy_do			5
#define sy_end			6
#define a				7
#define semicolon		8
#define e				9
#define sharp			10
#define S				11
#define L				12

#define tempsy 			15
#define EA				18 /*E and*/
#define EO				19 /*E or*/

#define plus			34

#define times			36

#define becomes			38

#define op_and			39
#define op_or			40
#define op_not			41
#define rop				42

#define lparent			48
#define rparent			49
#define ident       	56
#define intconst    	57

/******************************************/
char	ch='\0' ; 							/*当前字符*/
int     count=0;
static	char	spelling[10]={ ""} ; 		/*存放识别的字*/
static	char	line[81]={ ""}	 ; 			/*一行字符缓冲区*/
char	*pline	 ; 							/*字符缓冲区指针*/
static	char	varnametable[100][10];

struct	ntab
{
	int tc;
	int fc;
}ntab2[200];
int label=0;
/*存放临时变量的表的定义 */
struct	KEYWORD{
	char	spell[10];
	int		type;
};
/*存放文件的结构*/
KEYWORD keyword[10]={{ "if",sy_if},
{"do",sy_do},
{"else",sy_else},
{"while",sy_while},
{"then",sy_then},
{"begin",sy_begin},
{"end",sy_end},
{"and",op_and},
{"or",op_or},
{"not",op_not}};
struct  aa{
	int type;
	int pos;
}buf[1000],		/*词法分析结果缓冲区*/
g_nCurChar,		/*当前字符*/
g_nExpCurChar,	/*当前表达式中的字符*/
E,				/*非终结符*/
sstack[100],	/*符号栈*/
ibuf[100],
stack[1000];
struct  aa oth;
struct  fourexp{
	char op[10];
	struct aa arg1;
	struct aa arg2;
	int	result;
}fexp[200];
/*四元式的结构*/
int ssp=0;		/*指向sstack[100]*/
struct aa	*pbuf=buf;	/*指向词法分析缓冲区*/
int		nlength=0;
int		lnum=0;	/*源程序长度*/
int		tt1=0;
FILE   	*cfile;
FILE   	*mfile;
/*********************************************************/
int newt=0;
/*临时变量*/
int nxq=100;
/*nxq指向下一个形成的四元式的地址*/
int lr;
int lr1;
int sp=0;
/* 状态栈定义*/
int stack1[100];
int sp1=0;
/*状态栈1的定义*/
int num=0;
struct ll{
	int nxq1;
	int tc1;
	int fc1;
}labelmark[10];
int labeltemp[10];
int pointmark=-1,pointtemp=-1;
int sign=0;
/*sign＝1，表达式为赋值语句；sign＝2，表达式为布尔表达式。*/
/***********************************************/
static int		action[19][13]=
/*0*/		{{2,-1,-1,3,4,-1,-1,5,-1,-1,-1,1,-1},
/*1*/		{-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,ACC,-1,-1},
/*2*/		{-1,-1,-1,-1,-1,-1,-1,-1,-1,6,-1,-1,-1},
/*3*/	 {-1,-1,-1,-1,-1,-1,-1,-1,-1,7,-1,-1,-1},
/*4*/	 {2,-1,-1,3,4,-1,-1,5,-1,-1,-1,9,8},
/*5*/	 {-1,-1,104,-1,-1,-1,104,-1,104,-1,104,-1,-1},
/*6*/	 {-1,10,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1},
/*7*/	 {-1,-1,-1,-1,-1,11,-1,-1,-1,-1,-1,-1,-1},
/*8*/	 {-1,-1,-1,-1,-1,-1,12,-1,-1,-1,-1,-1,-1},
/*9*/	 {-1,-1,-1,-1,-1,-1,105,-1,13,-1,-1,-1,-1},
/*10*/	 {2,-1,-1,3,4,-1,-1,5,-1,-1,-1,14,-1},
/*11*/	 {2,-1,-1,3,4,-1,-1,5,-1,-1,-1,15,-1},
/*12*/	 {-1,-1,103,-1,-1,-1,103,-1,103,-1,103,-1,-1},
/*13*/	 {2,-1,-1,3,4,-1,-1,5,-1,-1,-1,9,16},
/*14*/	 {-1,-1,17,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1},
/*15*/	 {-1,-1,102,-1,-1,-1,102,-1,102,-1,102,-1,-1},
/*16*/	 {-1,-1,-1,-1,-1,-1,106,-1,-1,-1,-1,-1,-1},
/*17*/	 {2,-1,-1,3,4,-1,-1,5,-1,-1,-1,18,-1},
/*18*/	 {-1,-1,101,-1,-1,-1,101,-1,101,-1,101,-1,-1}};
static int action1[10][7]=
/*0*/	 {{3,-1,-1,2,-1,-1,1},
/*1*/	 {-1,4,5,-1,-1,ACC,-1},
/*2*/	 {3,-1,-1,2,-1,-1,6},
/*3*/	 {104,104,104,104,104,104,-1},
/*4*/	 {3,-1,-1,2,-1,-1,7},
/*5*/	 {3,-1,-1,2,-1,-1,8},
/*6*/	 {-1,4,5,-1,9,-1,-1},
/*7*/	 {101,101,5,101,101,101,-1},
/*8*/	 {102,102,102,102,102,102,-1},
/*9*/	 {103,103,103,103,103,103,-1}};
static int action2[16][11]=
/*0*/	 {{1,-1,4,-1,5,-1,-1,-1,13,7,8},
/*1*/	 {-1,2,-1,101,-1,101,101,101,-1,-1,-1},
/*2*/	 {3,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1},
/*3*/	 {-1,-1,-1,102,-1,102,102,102,-1,-1,-1},
/*4*/	 {1,-1,4,-1,5,-1,-1,-1,11,7,8},
/*5*/		{1,-1,4,-1,5,-1,-1,-1,6,7,8},
/*6*/		{-1,-1,-1,104,-1,9,10,104,-1,-1,-1},
/*7*/		{1,-1,4,-1,5,-1,-1,-1,14,7,8},
/*8*/		{1,-1,4,-1,5,-1,-1,-1,15,7,8},
/*9*/		{105,-1,105,-1,105,-1,-1,105,-1,-1,-1},
/*10*/		{107,-1,107,-1,107,-1,-1,107,-1,-1,-1},
/*11*/		{-1,-1,-1,12,-1,9,10,-1,-1,-1,-1},
/*12*/		{-1,103,-1,103,-1,103,103,103,-1,-1,-1},
/*13*/		{-1,-1,-1,-1,-1,9,10,ACC,-1,-1,-1},
/*14*/		{-1,-1,-1,106,-1,9,10,106,-1,-1,-1},
/*15*/		{-1,-1,-1,108,-1,9,10,108,-1,-1,-1}};
/****************从文件读一行到缓冲区***********************************/
void readline( )
{
	char ch1;
	pline=line;
	ch1=getc(cfile);
	while (ch1!= '\n')
	{
		*pline=ch1;
		pline++;
		ch1=getc(cfile);
	}
	*pline='\0';
	pline=line;
}
/*****************************从缓冲区读一个字符**********************/
void readch( )
{
	if (ch=='\0') 
	{
		readline( );
		lnum++;
	}
	ch=*pline;
	pline++;
}
/****************标志符和关键字的识别************************************/
int find(char spel[ ])	//检查变量表中是否已存在该变量名
{
	int ss1=0;
	int ii=0;
	while((ss1==0)&&(ii<nlength))
	{
		if (!strcmp(spel,varnametable[ii])) ss1=1;
		ii++;
	}
	if (ss1==1) return ii-1;
	else return -1;
}

void identifier( )
{
	int iii=0,j,k;
	int ss=0;
	k=0;
	do
	{
		spelling[k]=ch;
		k++;
		readch( );
	}while(((ch>='a')&&(ch<='z'))||((ch>='0')&&(ch<='9')));
	pline--;
	spelling[k]= '\0';
	while((ss==0)&&(iii<10))
	{
		if (!strcmp(spelling,keyword[iii].spell)) ss=1;
		iii++;
	}
	
	/*关键字匹配*/
	if(ss==1)
	{
		buf[count].type=keyword[iii-1].type;
	}
	else
	{
		buf[count].type=ident;
		j=find(spelling);
		if (j==-1)
		{
			buf[count].pos=tt1;
			strcpy(varnametable[tt1],spelling);
			tt1++;
			nlength++;
		}
		else buf[count].pos=j;
	}
	count++;
	for(k=0;k<10;k++) spelling[k]= ' ';
}
/*****************数字的识别***********************************/
void number( )
{
	int ivalue=0;
	int digit;
	do
	{
		digit=ch-'0';
		ivalue=ivalue*10+digit;
		readch( );
	}while((ch>='0')&&(ch<='9'));
	buf[count].type=intconst;
	buf[count].pos=ivalue;
	count++;
	pline--;
}
/**************扫描主函数*************************************/
void scan( )
{
	//	int i;
	while(ch!= '~')
	{
		switch (ch)
		{
		case ' ':
			break;
		case 'a':
		case 'b':
		case 'c':
		case 'd':
		case 'e':
		case 'f':
		case 'g':
		case 'h':
		case 'i':
		case 'j':
		case 'k':
		case 'l':
		case 'm':
		case 'n':
		case 'o':
		case 'p':
		case 'q':
		case 'r':
		case 's':
		case 't':
		case 'u':
		case 'v':
		case 'w':
		case 'x':
		case 'y':
		case 'z':
			identifier( );
			break;
		case '0':
		case '1':
		case '2':
		case '3':
		case '4':
		case '5':
		case '6':
		case '7':
		case '8':
		case '9':
			number( );
			break;
		case '<':
			readch( );
			if(ch=='=')
			{
				buf[count].pos=0;
			}
			else
				
			{
				if(ch=='>') buf[count].pos=4;
				else
				{
					buf[count].pos=1;
					pline--;
				}
			}
			buf[count].type=rop;
			count++;
			break;
		case '>':
			readch( );
			if(ch=='=')
			{
				buf[count].pos=2;
			}
			else
			{
				buf[count].pos=3;
				pline--;
			}
			
			buf[count].type=rop;
			count++;
			break;
		case '(':
			buf[count].type=lparent;
			count++;
			break;
		case ') ':
			buf[count].type=rparent;
			count++;
			break;
			
		case '#':
			buf[count].type=sharp;
			count++;
			break;
		case '+':
			buf[count].type=plus;
			count++;
			break;
		case '*':
			buf[count].type=times;
			count++;
			break;
		case ': ':
			readch( );
			if (ch=='=')
				buf[count].type=becomes;
			count++;
			break;
			
		case '=':
			buf[count].type=rop;
			buf[count].pos=5;
			count++;
			break;
		case '; ':
			buf[count].type=semicolon;
			count++;
			break;
		}
		
		readch( );
	}
	buf[count].type=-1;
}
/******************************************************************/

void readnu( )
{
	if (pbuf->type>=0)
	{
		g_nCurChar.type=pbuf->type;
		g_nCurChar.pos=pbuf->pos;
		pbuf++;
	}
}
/******************中间变量的生成**************************/
int newtemp( )
{
	newt++;
	return newt;
}
/**************************生成四元式****************/
int gen(char op1[ ],struct aa arg11,struct aa arg22,int result1)
{
	strcpy(fexp[nxq].op,op1);
	fexp[nxq].arg1.type=arg11.type;
	fexp[nxq].arg1.pos=arg11.pos;
	fexp[nxq].arg2.type=arg22.type;
	fexp[nxq].arg2.pos=arg22.pos;
	fexp[nxq].result=result1;
	nxq++;
	return nxq-1;
}
/**********布尔表达式的匹配****************/
int merg(int p1,int p2)
{
	int p;
	if(p2==0) return p1;
	else
	{
		p=p2;
		while(fexp[p].result!=0) p=fexp[p].result;
		fexp[p].result=p1;
		return p2;
	}
}
void backpatch(int p,int t)
{
	int tempq;
	int q;
	q=p;
	while(q!=0)
	{
		tempq=fexp[q].result;
		fexp[q].result=t;
		q=tempq;
	}
}
/*******************************************/
int change1(int chan)
{
	switch (chan)
	{
	case ident:
	case intconst:
		return 0;
	case plus:
		return 1;
	case times:
		return 2;
	case lparent:
		return 3;
	case rparent:
		return 4;
	case sharp:
		return 5;
	case tempsy:
		return 6;
	default:
		return -1;
	}
}
int change2(int chan)
{
	switch (chan)
	{
	case ident:
	case intconst:
		return 0;
	case rop:
		return 1;
	case lparent:
		return 2;
	case rparent:
		return 3;
	case op_not:
		return 4;
	case op_and:
		return 5;
	case op_or:
		return 6;
	case sharp:
		return 7;
	case tempsy:
		return 8;
	case EA:
		return 9;
	case EO:
		return 10;
	default:
		return -1;
	}
}
/************赋值语句的分析***************************/
void lrparse1(int num)
{
	lr1=action1[stack1[sp1]][change1(g_nExpCurChar.type)];
	if (lr1==-1)
	{
		printf("\n算术表达式或赋值语句出错！\n");
		getch();
		exit(0);
	}
	if ((lr1<10)&&(lr1>=0))
	{
		sp1++;
		stack1[sp1]=lr1;