parser.y

unix v7是最后一个广泛发布的研究型UNIX版本

						error("Premature eof");
					case 's': case 'S':		/* start conditions */
						lgate();
						while(*p && index(*p," \t,") < 0) p++;
						n = TRUE;
						while(n){
							while(*p && index(*p," \t,") >= 0) p++;
							t = p;
							while(*p && index(*p," \t,") < 0)p++;
							if(!*p) n = FALSE;
							*p++ = 0;
							if (*t == 0) continue;
							i = sptr*2;
							if(!ratfor)fprintf(fout,"# ");
							fprintf(fout,"define %s %d\n",t,i);
							scopy(t,sp);
							sname[sptr++] = sp;
							sname[sptr] = 0;	/* required by lookup */
							if(sptr >= STARTSIZE)
								error("Too many start conditions");
							sp =+ slength(sp) + 1;
							if(sp >= schar+STARTCHAR)
								error("Start conditions too long");
							}
						continue;
					default:
						warning("Invalid request %s",p);
						continue;
						}	/* end of switch after seeing '%' */
				case ' ': case '\t':		/* must be code */
					lgate();
					fprintf(fout, "%s\n",p);
					continue;
				default:		/* definition */
					while(*p && !space(*p)) p++;
					if(*p == 0)
						continue;
					prev = *p;
					*p = 0;
					bptr = p+1;
					yylval = buf;
					if(digit(buf[0]))
						warning("Substitution strings may not begin with digits");
					return(freturn(STR));
					}
				}
			/* still sect 1, but prev != '\n' */
			else {
				p = bptr;
				while(*p && space(*p)) p++;
				if(*p == 0)
					warning("No translation given - null string assumed");
				scopy(p,token);
				yylval = token;
				prev = '\n';
				return(freturn(STR));
				}
			}
		/* end of section one processing */
		}
	else if(sect == RULESECTION){		/* rules and actions */
		while(!eof){
			switch(c=gch()){
			case '\0':
				return(freturn(0));
			case '\n':
				if(prev == '\n') continue;
				x = NEWE;
				break;
			case ' ':
			case '\t':
				if(sectbegin == TRUE){
					cpyact();
					while((c=gch()) && c != '\n');
					continue;
					}
				if(!funcflag)phead2();
				funcflag = TRUE;
				if(ratfor)fprintf(fout,"%d\n",30000+casecount);
				else fprintf(fout,"case %d:\n",casecount);
				if(cpyact()){
					if(ratfor)fprintf(fout,"goto 30997\n");
					else fprintf(fout,"break;\n");
					}
				while((c=gch()) && c != '\n');
				if(peek == ' ' || peek == '\t' || sectbegin == TRUE){
					warning("Executable statements should occur right after %%");
					continue;
					}
				x = NEWE;
				break;
			case '%':
				if(prev != '\n') goto character;
				if(peek == '{'){	/* included code */
					getl(buf);
					while(!eof && getl(buf) && scomp("%}",buf) != 0)
						fprintf(fout,"%s\n",buf);
					continue;
					}
				if(peek == '%'){
					c = gch();
					c = gch();
					x = DELIM;
					break;
					}
				goto character;
			case '|':
				if(peek == ' ' || peek == '\t' || peek == '\n'){
					if(ratfor)fprintf(fout,"%d\n",30000+casecount++);
					else fprintf(fout,"case %d:\n",casecount++);
					continue;
					}
				x = '|';
				break;
			case '$':
				if(peek == '\n' || peek == ' ' || peek == '\t' || peek == '|' || peek == '/'){
					x = c;
					break;
					}
				goto character;
			case '^':
				if(prev != '\n' && scon != TRUE) goto character;	/* valid only at line begin */
				x = c;
				break;
			case '?':
			case '+':
			case '.':
			case '*':
			case '(':
			case ')':
			case ',':
			case '/':
				x = c;
				break;
			case '}':
				iter = FALSE;
				x = c;
				break;
			case '{':	/* either iteration or definition */
				if(digit(c=gch())){	/* iteration */
					iter = TRUE;
				ieval:
					i = 0;
					while(digit(c)){
						token[i++] = c;
						c = gch();
						}
					token[i] = 0;
					yylval = siconv(token);
					munput('c',c);
					x = ITER;
					break;
					}
				else {		/* definition */
					i = 0;
					while(c && c!='}'){
						token[i++] = c;
						c = gch();
						}
					token[i] = 0;
					i = lookup(token,def);
					if(i < 0)
						warning("Definition %s not found",token);
					else
						munput('s',subs[i]);
					continue;
					}
			case '<':		/* start condition ? */
				if(prev != '\n')		/* not at line begin, not start */
					goto character;
				t = slptr;
				do {
					i = 0;
					c = gch();
					while(c != ',' && c && c != '>'){
						token[i++] = c;
						c = gch();
						}
					token[i] = 0;
					if(i == 0)
						goto character;
					i = lookup(token,sname);
					if(i < 0) {
						warning("Undefined start condition %s",token);
						continue;
						}
					*slptr++ = i+1;
					} while(c && c != '>');
				*slptr++ = 0;
				/* check if previous value re-usable */
				for (xp=slist; xp<t; )
					{
					if (strcmp(xp, t)==0)
						break;
					while (*xp++);
					}
				if (xp<t)
					{
					/* re-use previous pointer to string */
					slptr=t;
					t=xp;
					}
				if(slptr > slist+STARTSIZE)		/* note not packed ! */
					error("Too many start conditions used");
				yylval = t;
				x = SCON;
				break;
			case '"':
				i = 0;
				while((c=gch()) && c != '"' && c != '\n'){
					if(c == '\\') c = usescape(c=gch());
					token[i++] = c;
					if(i > TOKENSIZE){
						warning("String too long");
						i = TOKENSIZE-1;
						break;
						}
					}
				if(c == '\n') {
					yyline--;
					warning("Non-terminated string");
					yyline++;
					}
				token[i] = 0;
				if(i == 0)x = NULLS;
				else if(i == 1){
					yylval = token[0];
					x = CHAR;
					}
				else {
					yylval = token;
					x = STR;
					}
				break;
			case '[':
				for(i=1;i<NCH;i++) symbol[i] = 0;
				x = CCL;
				if((c = gch()) == '^'){
					x = NCCL;
					c = gch();
					}
				while(c != ']' && c){
					if(c == '\\') c = usescape(c=gch());
					symbol[c] = 1;
					j = c;
					if((c=gch()) == '-' && peek != ']'){		/* range specified */
						c = gch();
						if(c == '\\') c = usescape(c=gch());
						k = c;
						if(j > k) {
							n = j;
							j = k;
							k = n;
							}
						if(!(('A' <= j && k <= 'Z') ||
						     ('a' <= j && k <= 'z') ||
						     ('0' <= j && k <= '9')))
							warning("Non-portable Character Class");
						for(n=j+1;n<=k;n++)
							symbol[n] = 1;		/* implementation dependent */
						c = gch();
						}
					}
				/* try to pack ccl's */
				i = 0;
				for(j=0;j<NCH;j++)
					if(symbol[j])token[i++] = j;
				token[i] = 0;
				p = ccptr;
				if(optim){
					p = ccl;
					while(p <ccptr && scomp(token,p) != 0)p++;
					}
				if(p < ccptr)	/* found it */
					yylval = p;
				else {
					yylval = ccptr;
					scopy(token,ccptr);
					ccptr =+ slength(token) + 1;
					if(ccptr >= ccl+CCLSIZE)
						error("Too many large character classes");
					}
				cclinter(x==CCL);
				break;
			case '\\':
				c = usescape(c=gch());
			default:
			character:
				if(iter){	/* second part of an iteration */
					iter = FALSE;
					if('0' <= c && c <= '9')
						goto ieval;
					}
				if(alpha(peek)){
					i = 0;
					yylval = token;
					token[i++] = c;
					while(alpha(peek))
						token[i++] = gch();
					if(peek == '?' || peek == '*' || peek == '+')
						munput('c',token[--i]);
					token[i] = 0;
					if(i == 1){
						yylval = token[0];
						x = CHAR;
						}
					else x = STR;
					}
				else {
					yylval = c;
					x = CHAR;
					}
				}
			scon = FALSE;
			if(x == SCON)scon = TRUE;
			sectbegin = FALSE;
			return(freturn(x));
			}
		}
	/* section three */
	ptail();
# ifdef DEBUG
	if(debug)
		fprintf(fout,"\n/*this comes from section three - debug */\n");
# endif
	while(getl(buf) && !eof)
		fprintf(fout,"%s\n",buf);
	return(freturn(0));
	}
/* end of yylex */
# ifdef DEBUG
freturn(i)
  int i; {
	if(yydebug) {
		printf("now return ");
		if(i < NCH) allprint(i);
		else printf("%d",i);
		printf("   yylval = ");
		switch(i){
			case STR: case CCL: case NCCL:
				strpt(yylval);
				break;
			case CHAR:
				allprint(yylval);
				break;
			default:
				printf("%d",yylval);
				break;
			}
		putchar('\n');
		}
	return(i);
	}
# endif