#include <stdio.h>
#include <string.h>
#include "pl0.h"

int getch()
{
	if(cc==ll)                          //如果一行緩存取完
	{
		if(feof(fin))
		{
			printf("Program incomplete!");
			return -1;
		}
		cc=0;                           //當(dāng)前行取詞位置初始化
		ll=0;                           //當(dāng)前行取詞總數(shù)初始化
		ch=' ';
		while(ch!=10&&ll<=81)
		{
			ch=fgetc(fin);
			if(feof(fin))
			{
				ch=0;
				break;
			}
			line[ll]=ch;
			printf("%c",ch);
			fprintf(fa1,"%c",ch);
			ll++;
		}
	}
	ch=line[cc];
	cc++;
	return 0;
}
	
int getsym()
{
	while(ch==10||ch==32||ch==9)
	{
		if(getch()==-1)
			return -1;
	}
	if(ch>='a'&&ch<='z')                //字母開頭可能是標(biāo)識(shí)符或關(guān)鍵字
	{
		int k=0;
		do{
			if(k<WMAX)                  //最多讀入WMAX個(gè)字符
				tmp[k]=ch;
			if(getch()==-1)
				return -1;
			k++;
		}while(ch>='a'&&ch<='z'||ch>='0'&&ch<='9');
		tmp[k]=0;
		strcpy(id,tmp);
		for(k=0;k<NKEY;k++)
		{
			if(strcmp(id,word[k])==0)
			{
				sym=wsym[k];
				break;
			}
		}
		if(k>=NKEY)
			sym=ident;
	}
	else if(ch>='0'&&ch<='9')            //開頭為數(shù)字，當(dāng)作常數(shù)
	{
		int k=0;
		num=0;
		sym=number;
		do{
			num=num*10+ch-'0';
			k++;
			if(getch()==-1)
				return -1;
		}while(ch>='0'&&ch<='9');
		if(k>NMAX)
			error(0);
	}
	else                                 //剩下的是單雙字符符號(hào)
	{
		if(ch==':')
		{
			if(getch()==-1)
				return -1;
			if(ch=='=')
			{
				sym=becomes;
				if(getch()==-1)
					return -1;
			}
			else
				sym=nul;
		}
		else if(ch=='>')
		{
			if(getch()==-1)
				return -1;
			if(ch=='=')
			{
				sym=geq;
				if(getch()==-1)
					return -1;
			}
			else
				sym=gtr;
		}
		else if(ch=='<')
		{
			if(getch()==-1)
				return -1;
			if(ch=='=')
			{
				sym=leq;
				if(getch()==-1)
					return -1;
			}
			else
				sym=lss;
		}
		else
		{
			sym=ssym[ch];
			if(sym!=period)              //當(dāng)且僅當(dāng)當(dāng)前符號(hào)是句號(hào)時(shí)，
			{                            //不再讀入一個(gè)符號(hào)
				if(getch()==-1)
					return -1;
			}
		}
	}
	return 0;
}

int inset(int e,int *s)
{
	return s[e];
}

int addset(int *sr,int *s1,int *s2,int n)
{
	int i;
	for(i=0;i<n;i++)
		sr[i]=s1[i]||s2[i];
	return 0;
}

int subset(int *sr,int *s1,int *s2,int n)
{
	int i;
	for(i=0;i<n;i++)
		sr[i]=s1[i]&&(!s2[i]);
		return 0;
}

int mulset(int *sr,int *s1,int *s2,int n)
{
	int i;
	for(i=0;i<n;i++)
		sr[i]=s1[i]&&s2[i];
	return 0;
}
	
void init()
{
	int i;
	for(i=0;i<256;i++)
		ssym[i]=nul;
	ssym['=']=eql;
	ssym[',']=comma;
	ssym['.']=period;
	ssym['#']=neq;
	ssym[';']=semicolon;
	ssym['(']=lparen;
	ssym[')']=rparen;
	ssym['+']=plus;
	ssym['-']=minus;
	ssym['*']=times;
	ssym['/']=slash;
	strcpy(word[0],"begin");
	strcpy(word[1],"call");
	strcpy(word[2],"const");
	strcpy(word[3],"do");
	strcpy(word[4],"end");
	strcpy(word[5],"if");
	strcpy(word[6],"odd");
	strcpy(word[7],"procedure");
	strcpy(word[8],"read");
	strcpy(word[9],"then");
	strcpy(word[10],"var");
	strcpy(word[11],"while");
	strcpy(word[12],"write");
	strcpy(mc[0],"lit");
	strcpy(mc[1],"opr");
	strcpy(mc[2],"lod");
	strcpy(mc[3],"sto");
	strcpy(mc[4],"cal");
	strcpy(mc[5],"inte");
	strcpy(mc[6],"jmp");
	strcpy(mc[7],"jpc");
	wsym[0]=beginsym;
	wsym[1]=callsym;
	wsym[2]=constsym;
	wsym[3]=dosym;
	wsym[4]=endsym;
	wsym[5]=ifsym;
	wsym[6]=oddsym;
	wsym[7]=procsym;
	wsym[8]=readsym;
	wsym[9]=thensym;
	wsym[10]=varsym;
	wsym[11]=whilesym;
	wsym[12]=writesym;
	for(i=0;i<SYMNUM;i++)
	{
		dcbsys[i]=0;
		stbsys[i]=0;
		fcbsys[i]=0;
	}
	dcbsys[constsym]=1;
	dcbsys[varsym]=1;
	dcbsys[procsym]=1;
	stbsys[beginsym]=1;
	stbsys[callsym]=1;
	stbsys[ifsym]=1;
	stbsys[whilesym]=1;
	fcbsys[ident]=1;
	fcbsys[number]=1;
	fcbsys[lparen]=1;
}

void error(int n)
{
	char space[81];
	memset(space,32,81);
	space[cc-2]=0;
	printf("%s%c%s\n",space,24,errinfo[n]);  //24為向上箭頭符號(hào)，指使出錯(cuò)位置
	fprintf(fa1,"%s%c%s\n",space,24,errinfo[n]);
	err++;
}

int mb(int lev,int tx,int *s)
{
	int ts[SYMNUM];                   //看作布爾集合數(shù)組傳給子程序
	int tx0=tx;
	int dx=3;
	tb[tx].adr=cx;
	if(gen(jmp,0,0)==-1)
		return -1;
	if(lev>LVMAX)
		error(1);
	do                                //聲明部分
	{
		if(sym==constsym)
		{
			if(getsym()==-1)
				return -1;
			constdc(&tx,lev,&dx);
			while(sym==comma)
			{
				if(getsym()==-1)
					return -1;
				constdc(&tx,lev,&dx);
			}
			if(sym!=semicolon)
				error(2);
			else
			{
				if(getsym()==-1)
					return -1;
			}
		}
		if(sym==varsym)
		{
			if(getsym()==-1)
				return -1;
			vardc(&tx,lev,&dx);
			while(sym==comma)
			{
				if(getsym()==-1)
					return -1;
				vardc(&tx,lev,&dx);
			}
			if(sym!=semicolon)
				error(3);
			else
			{
				if(getsym()==-1)
					return -1;
			}
		}
		while(sym==procsym)
		{
			if(getsym()==-1)
				return -1;
			if(sym==ident)
			{
				record(procedure,&tx,lev,&dx);
				if(getsym()==-1)
					return -1;
				if(sym!=semicolon)
					error(4);
				else
				{
					if(getsym()==-1)
						return -1;
				}
			}
			else
				error(5);
			memcpy(ts,s,sizeof(int)*SYMNUM);
			ts[semicolon]=1;
			if(mb(lev+1,tx,ts)==-1)
				return -1;
			if(sym==semicolon)
			{
				if(getsym()==-1)
					return -1;
				memcpy(ts,stbsys,sizeof(int)*SYMNUM);
				ts[procsym]=1;
				ts[ident]=1;
				if(test(ts,s,8)==-1)
					return -1;
			}
			else
				error(6);
		}
		memcpy(ts,stbsys,sizeof(int)*SYMNUM);
		ts[period]=1;
		ts[ident]=1;
		if(test(ts,s,9)==-1)
			return -1;
	}while(inset(sym,dcbsys));
	code[tb[tx0].adr].a=cx;
	tb[tx0].size=dx;
	tb[tx0].adr=cx;

	if(gen(inte,0,dx)==-1)             //分配存儲(chǔ)語句
		return -1;
	memcpy(ts,s,sizeof(int)*SYMNUM);   //語句部分
	ts[semicolon]=1;
	ts[endsym]=1;
	if(stat(&tx,ts,lev)==-1)
		return -1;
	if(gen(opr,0,0)==-1)
		return -1;
	memset(ts,0,sizeof(int)*SYMNUM);
	if(test(s,ts,10)==-1)
		return -1;
	return 0;
}

int test(int *s1,int *s2,int n)
{
	if(!inset(sym,s1))
	{
		error(n);
		while(!inset(sym,s1)&&!inset(sym,s2))
		{
			if(getsym()==-1)
				return -1;
		}
	}
	return 0;
}

int constdc(int *ptx,int lev,int *pdx)
{
	if(sym==ident)
	{
		if(getsym()==-1)
			return -1;
		if(sym==becomes)
			error(11);
		else if(sym==eql)
		{
			if(getsym()==-1)
				return -1;
			if(sym==number)
			{
				record(constant,ptx,lev,pdx);
				if(getsym()==-1)
					return -1;
			}
			else
				error(12);
		}
		else
			error(13);
	}
	else
		error(14);
	return 0;
}

int vardc(int *ptx,int lev,int *pdx)
{
	if(sym==ident)
	{
		record(variable,ptx,lev,pdx);
		if(getsym()==-1)
			return -1;
	}
	else
		error(15);
	return 0;
}

void record(enum obj k,int *ptx,int lv,int *pdx)
{
	(*ptx)++;
	tb[*ptx].kind=k;
	strcpy(tb[*ptx].name,id);
	if(k==constant)
	{
		if(num>AMAX)
		{
			error(7);           //數(shù)越界
			num=0;
		}
		tb[*ptx].val=num;	
	}
	else if(k==variable)
	{
		tb[*ptx].adr=*pdx;
		tb[*ptx].lev=lv;
		(*pdx)++;
	}
	else if(k==procedure)
		tb[*ptx].lev=lv;
}

int gen(enum fct x,int y,int z)
{
	if(cx==1000)
		printf("%s",id);
	if(cx>CXMAX)
	{
		printf("Program too long!\n");
		return -1;
	}
	code[cx].f=x;
	code[cx].l=y;
	code[cx].a=z;
	cx++;
	return 0;
}

int extable(char *idt,int tx)
{
	int j;
	for(j=tx;j>0;j--)
	{
		if(strcmp(tb[j].name,idt)==0)
			return j;
	}
	return 0;
}

int stat(int *ptx,int *s,int lev)
{
	int p;
	int ts[SYMNUM];
	if(sym==ident)
	{
		p=extable(id,*ptx);
		if(p==0)
			error(16);
		else
		{
			if(tb[p].kind!=variable)
			{
				error(17);
				p=0;
			}
			else
			{
				if(getsym()==-1)
					return -1;
				if(sym==becomes)
				{
					if(getsym()==-1)
						return -1;
					memcpy(ts,s,sizeof(int)*SYMNUM);
					if(exp(ptx,ts,lev)==-1)
						return -1;
				}
				else
				{
					error(18);
					p=0;
				}
			}
		}
		if(p!=0)
		{
			if(gen(sto,lev-tb[p].lev,tb[p].adr)==-1)
				return -1;
		}
	}
	else if(sym==callsym)
	{
		if(getsym()==-1)
			return -1;
		if(sym==ident)
		{
			p=extable(id,*ptx);
			if(p==0)
				error(25);
			else
			{
				if(tb[p].kind!=procedure)
				{
					error(26);
					p=0;
				}
				else
				{
					if(getsym()==-1)
						return -1;
				}
			}
		}
		else
		{
			error(27);
			p=0;
		}
		if(p!=0)
		{
			if(gen(cal,lev-tb[p].lev,tb[p].adr)==-1)
				return -1;
		}
	}
	else if(sym==beginsym)
	{
		if(getsym()==-1)
			return -1;
		memcpy(ts,s,sizeof(int)*SYMNUM);
		ts[semicolon]=1;
		ts[endsym]=1;
		if(stat(ptx,ts,lev)==-1)
			return -1;
		while(inset(sym,stbsys)||sym==semicolon)
		{
			if(sym==semicolon)
			{
				if(getsym()==-1)
					return -1;
			}
			else
				error(29);
			if(stat(ptx,ts,lev)==-1)
				return -1;
		}
		if(sym!=endsym)
			error(30);
		else
		{
			if(getsym()==-1)
				return -1;
		}
	}
	else if(sym==ifsym)
	{
		int cx1;
		if(getsym()==-1)
			return -1;
		memcpy(ts,s,sizeof(int)*SYMNUM);
		ts[thensym]=1;
		ts[dosym]=1;
		if(con(ptx,ts,lev)==-1)
			return -1;
		cx1=cx;
		if(gen(jpc,0,0)==-1)
			return -1;
		if(sym!=thensym)
			error(28);
		else
		{