text: #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <ctype.h>
  #include <errno.h>
  #include "pic.h"
  #include "y.tab.h"
  
  Infile	infile[10];
  Infile	*curfile = infile;
  
  #define	MAXSRC	50
  Src	src[MAXSRC];	/* input source stack */
  Src	*srcp	= src;
  
  void	do_thru(void);
  int	nextchar(void);
  int	getarg(char *);
  void	freedef(char *);
  int	baldelim(int, char *);
  
  void pushsrc(int type, char *ptr)	/* new input source */
  {
  	if (++srcp >= src + MAXSRC)
  		ERROR "inputs nested too deep" FATAL;
  	srcp->type = type;
  	srcp->sp = ptr;
  	if (dbg > 1) {
  		printf("\n%3d ", (int)(srcp - src));
  		switch (srcp->type) {
  		case File:
  			printf("push file %s\n", ((Infile *)ptr)->fname);
  			break;
  		case Macro:
  			printf("push macro <%s>\n", ptr);
  			break;
  		case Char:
  			printf("push char <%c>\n", *ptr);
  			break;
  		case Thru:
  			printf("push thru\n");
  			break;
  		case String:
  			printf("push string <%s>\n", ptr);
  			break;
  		case Free:
  			printf("push free <%s>\n", ptr);
  			break;
  		default:
  			ERROR "pushed bad type %d", srcp->type FATAL;
  		}
  	}
  }
  
  void popsrc(void)	/* restore an old one */
  {
  	if (srcp <= src)
  		ERROR "too many inputs popped" FATAL;
  	if (dbg > 1) {
  		printf("%3d ", (int) (srcp - src));
  		switch (srcp->type) {
  		case File:
  			printf("pop file\n");
  			break;
  		case Macro:
  			printf("pop macro\n");
  			break;
  		case Char:
  			printf("pop char <%c>\n", *srcp->sp);
  			break;
  		case Thru:
  			printf("pop thru\n");
  			break;
  		case String:
  			printf("pop string\n");
  			break;
  		case Free:
  			printf("pop free\n");
  			break;
  		default:
  			ERROR "pop weird input %d", srcp->type FATAL;
  		}
  	}
  	srcp--;
  }
  
  void definition(char *s)	/* collect definition for s and install */
  				/* definitions picked up lexically */
  {
  	char *p;
  	struct symtab *stp;
  
  	p = delimstr("definition");
  	stp = lookup(s);
  	if (stp != NULL) {	/* it's there before */
  		if (stp->s_type != DEFNAME) {
  			ERROR "%s used as variable and definition", s WARNING;
  			return;
  		}
  		free(stp->s_val.p);
  		stp->s_val.p = p;
  	} else {
  		YYSTYPE u;
  		u.p = p;
  		makevar(tostring(s), DEFNAME, u);
  	}
  	dprintf("installing %s as `%s'\n", s, p);
  }
  
  char *delimstr(char *s)	/* get body of X ... X */
  				/* message if too big */
  {
  	int c, delim, rdelim, n, deep;
  	static char *buf = NULL;
  	static int nbuf = 0;
  	char *p;
  
  	if (buf == NULL)
  		buf = grow(buf, "buf", nbuf += 1000, sizeof(buf[0]));
  	while ((delim = input()) == ' ' || delim == '\t' || delim == '\n')
  		;
  	rdelim = baldelim(delim, "{}");		/* could be "(){}[]`'" */
  	deep = 1;
  	for (p = buf; ; ) {
  		c = input();
  		if (c == rdelim)
  			if (--deep == 0)
  				break;
  		if (c == delim)
  			deep++;
  		if (p >= buf + nbuf) {
  			n = p - buf;
  			buf = grow(buf, "buf", nbuf += 1000, sizeof(buf[0]));
  			p = buf + n;
  		}
  		if (c == EOF)
  			ERROR "end of file in %s %c %.20s... %c", s, delim, buf, delim FATAL;
  		*p++ = c;
  	}
  	*p = '\0';
  	dprintf("delimstr %s %c <%s> %c\n", s, delim, buf, delim);
  	return tostring(buf);
  }
  
  int
  baldelim(int c, char *s)	/* replace c by balancing entry in s */
  {
  	for ( ; *s; s += 2)
  		if (*s == c)
  			return s[1];
  	return c;
  }
  
  void undefine(char *s)	/* undefine macro */
  {
  	while (*s != ' ' && *s != '\t')		/* skip "undef..." */
  		s++;
  	while (*s == ' ' || *s == '\t')
  		s++;
  	freedef(s);
  }
  
  
  Arg	args[10];	/* argument frames */
  Arg	*argfp = args;	/* frame pointer */
  int	argcnt;		/* number of arguments seen so far */
  
  void dodef(struct symtab *stp)	/* collect args and switch input to defn */
  {
  	int i, len;
  	char *p;
  	Arg *ap;
  
  	ap = argfp+1;
  	if (ap >= args+10)
  		ERROR "arguments too deep" FATAL;
  	argcnt = 0;
  	if (input() != '(')
  		ERROR "disaster in dodef" FATAL;
  	if (ap->argval == 0)
  		ap->argval = malloc(1000);
  	for (p = ap->argval; (len = getarg(p)) != -1; p += len) {
  		ap->argstk[argcnt++] = p;
  		if (input() == ')')
  			break;
  	}
  	for (i = argcnt; i < MAXARGS; i++)
  		ap->argstk[i] = "";
  	if (dbg)
  		for (i = 0; i < argcnt; i++)
  			printf("arg %d.%d = <%s>\n", (int) (ap-args), i+1, ap->argstk[i]);
  	argfp = ap;
  	pushsrc(Macro, stp->s_val.p);
  }
  
  int
  getarg(char *p)	/* pick up single argument, store in p, return length */
  {
  	int n, c, npar;
  
  	n = npar = 0;
  	for ( ;; ) {
  		c = input();
  		if (c == EOF)
  			ERROR "end of file in getarg" FATAL;
  		if (npar == 0 && (c == ',' || c == ')'))
  			break;
  		if (c == '"')	/* copy quoted stuff intact */
  			do {
  				*p++ = c;
  				n++;
  			} while ((c = input()) != '"' && c != EOF);
  		else if (c == '(')
  			npar++;
  		else if (c == ')')
  			npar--;
  		n++;
  		*p++ = c;
  	}
  	*p = 0;
  	unput(c);
  	return(n + 1);
  }
  
  #define	PBSIZE	2000
  char	pbuf[PBSIZE];		/* pushback buffer */
  char	*pb	= pbuf-1;	/* next pushed back character */
  
  char	ebuf[200];		/* collect input here for error reporting */
  char	*ep	= ebuf;
  
  int	begin	= 0;
  extern	int	thru;
  extern	struct symtab	*thrudef;
  extern	char	*untilstr;
  
  int
  input(void)
  {
  	register int c;
  
  	if (thru && begin) {
  		do_thru();
  		begin = 0;
  	}
  	c = nextchar();
  	if (dbg > 1)
  		printf(" <%c>", c);
  	if (ep >= ebuf + sizeof ebuf)
  		ep = ebuf;
  	return *ep++ = c;
  }
  
  int
  nextchar(void)
  {
  	register int c;
  
  	c = 0; /* Botch: gcc */
  
    loop:
  	switch (srcp->type) {
  	case Free:	/* free string */
  		free(srcp->sp);
  		popsrc();
  		goto loop;
  	case Thru:	/* end of pushed back line */
  		begin = 1;
  		popsrc();
  		c = '\n';
  		break;
  	case Char:
  		if (pb >= pbuf) {
  			c = *pb--;
  			popsrc();
  			break;
  		} else {	/* can't happen? */
  			popsrc();
  			goto loop;
  		}
  	case String:
  		c = *srcp->sp++;
  		if (c == '\0') {
  			popsrc();
  			goto loop;
  		} else {
  			if (*srcp->sp == '\0')	/* empty, so pop */
  				popsrc();
  			break;
  		}
  	case Macro:
  		c = *srcp->sp++;
  		if (c == '\0') {
  			if (--argfp < args)
  				ERROR "argfp underflow" FATAL;
  			popsrc();
  			goto loop;
  		} else if (c == '$' && isdigit((unsigned char) *srcp->sp)) {
  			int n = 0;
  			while (isdigit((unsigned char) *srcp->sp))
  				n = 10 * n + *srcp->sp++ - '0';
  			if (n > 0 && n <= MAXARGS)
  				pushsrc(String, argfp->argstk[n-1]);
  			goto loop;
  		}
  		break;
  	case File:
  		c = getc(curfile->fin);
  		if (c == EOF) {
  			if (curfile == infile)
  				ERROR "end of file inside .PS/.PE" FATAL;
  			if (curfile->fin != stdin) {
  				fclose(curfile->fin);
  				free(curfile->fname);	/* assumes allocated */
  			}
  			curfile--;
  			printlf(curfile->lineno, curfile->fname);
  			popsrc();
  			thru = 0;	/* chicken out */
  			thrudef = 0;
  			if (untilstr) {
  				free(untilstr);
  				untilstr = 0;
  			}
  			goto loop;
  		}
  		if (c == '\n')
  			curfile->lineno++;
  		break;
  	}
  	return c;
  }
  
  void do_thru(void)	/* read one line, make into a macro expansion */
  {
  	int c, i;
  	char *p;
  	Arg *ap;
  
  	ap = argfp+1;
  	if (ap >= args+10)
  		ERROR "arguments too deep" FATAL;
  	if (ap->argval == NULL)
  		ap->argval = malloc(1000);
  	p = ap->argval;
  	argcnt = 0;
  	c = nextchar();
  	if (thru == 0) {	/* end of file was seen, so thru is done */
  		unput(c);
  		return;
  	}
  	for ( ; c != '\n' && c != EOF; ) {
  		if (c == ' ' || c == '\t') {
  			c = nextchar();
  			continue;
  		}
  		ap->argstk[argcnt++] = p;
  		if (c == '"') {
  			do {
  				*p++ = c;
  				if ((c = nextchar()) == '\\') {
  					*p++ = c;
  					*p++ = nextchar();
  					c = nextchar();
  				}
  			} while (c != '"' && c != '\n' && c != EOF);
  			*p++ = '"';
  			if (c == '"')
  				c = nextchar();
  		} else {
  			do {
  				*p++ = c;
  			} while ((c = nextchar())!=' ' && c!='\t' && c!='\n' && c!=',' && c!=EOF);
  			if (c == ',')
  				c = nextchar();
  		}
  		*p++ = '\0';
  	}
  	if (c == EOF)
  		ERROR "unexpected end of file in do_thru" FATAL;
  	if (argcnt == 0) {	/* ignore blank line */
  		pushsrc(Thru, (char *) 0);
  		return;
  	}
  	for (i = argcnt; i < MAXARGS; i++)
  		ap->argstk[i] = "";
  	if (dbg)
  		for (i = 0; i < argcnt; i++)
  			printf("arg %d.%d = <%s>\n", (int) (ap-args), i+1, ap->argstk[i]);
  	if (strcmp(ap->argstk[0], ".PE") == 0) {
  		thru = 0;
  		thrudef = 0;
  		pushsrc(String, "\n.PE\n");
  		return;
  	}
  	if (untilstr && strcmp(ap->argstk[0], untilstr) == 0) {
  		thru = 0;
  		thrudef = 0;
  		free(untilstr);
  		untilstr = 0;
  		return;
  	}
  	pushsrc(Thru, (char *) 0);
  	dprintf("do_thru pushing back <%s>\n", thrudef->s_val.p);
  	argfp = ap;
  	pushsrc(Macro, thrudef->s_val.p);
  }
  
  int
  unput(int c)
  {
  	if (++pb >= pbuf + sizeof pbuf)
  		ERROR "pushback overflow" FATAL;
  	if (--ep < ebuf)
  		ep = ebuf + sizeof(ebuf) - 1;
  	*pb = c;
  	pushsrc(Char, pb);
  	return c;
  }
  
  void pbstr(char *s)
  {
  	pushsrc(String, s);
  }
  
  double errcheck(double x, char  *s)
  {
  	if (errno == EDOM) {
  		errno = 0;
  		ERROR "%s argument out of domain", s WARNING;
  	} else if (errno == ERANGE) {
  		errno = 0;
  		ERROR "%s result out of range", s WARNING;
  	}
  	return x;
  }
  
  char	errbuf[200];
  
  void	eprint(void);
  
  void yyerror(char *s)
  {
  	extern char *cmdname;
  	int ern = errno;	/* cause some libraries clobber it */
  
  	if (synerr)
  		return;
  	fflush(stdout);
  	fprintf(stderr, "%s: %s", cmdname, s);
  	if (ern > 0) {
  		errno = ern;
  		perror("???");
  	}
  	fprintf(stderr, " near %s:%d\n",
  		curfile->fname, curfile->lineno+1);
  	eprint();
  	synerr = 1;
  	errno = 0;
  }
  
  void eprint(void)	/* try to print context around error */
  {
  	char *p, *q;
  
  	p = ep - 1;
  	if (p > ebuf && *p == '\n')
  		p--;
  	for ( ; p >= ebuf && *p != '\n'; p--)
  		;
  	while (*p == '\n')
  		p++;
  	fprintf(stderr, " context is\n\t");
  	for (q=ep-1; q>=p && *q!=' ' && *q!='\t' && *q!='\n'; q--)
  		;
  	while (p < q)
  		putc(*p++, stderr);
  	fprintf(stderr, " >>> ");
  	while (p < ep)
  		putc(*p++, stderr);
  	fprintf(stderr, " <<< ");
  	while (pb >= pbuf)
  		putc(*pb--, stderr);
  	fgets(ebuf, sizeof ebuf, curfile->fin);
  	fprintf(stderr, "%s", ebuf);
  	pbstr("\n.PE\n");	/* safety first */
  	ep = ebuf;
  }
  
  void yywrap(void) {}
  
  char	*newfile = 0;		/* filename for file copy */
  char	*untilstr = 0;		/* string that terminates a thru */
  int	thru	= 0;		/* 1 if copying thru macro */
  struct symtab	*thrudef = 0;		/* macro being used */
  
  void copyfile(char *s)	/* remember file to start reading from */
  {
  	newfile = s;
  }
  
  void copydef(struct symtab *p)	/* remember macro symtab ptr */
  {
  	thrudef = p;
  }
  
  struct symtab *copythru(char *s)	/* collect the macro name or body for thru */
  {
  	struct symtab *p;
  	char *q, *addnewline(char *);
  
  	p = lookup(s);
  	if (p != NULL) {
  		if (p->s_type == DEFNAME) {
  			p->s_val.p = addnewline(p->s_val.p);
  			return p;
  		} else
  			ERROR "%s used as define and name", s FATAL;
  	}
  	/* have to collect the definition */
  	pbstr(s);	/* first char is the delimiter */
  	q = delimstr("thru body");
  	s = "nameless";
  	p = lookup(s);
  	if (p != NULL) {
  		if (p->s_val.p)
  			free(p->s_val.p);
  		p->s_val.p = q;
  	} else {
  		YYSTYPE u;
  		u.p = q;
  		p = makevar(tostring(s), DEFNAME, u);
  	}
  	p->s_val.p = addnewline(p->s_val.p);
  	dprintf("installing %s as `%s'\n", s, p->s_val.p);
  	return p;
  }
  
  char *addnewline(char *p)	/* add newline to end of p */
  {
  	int n;
  
  	n = strlen(p);
  	if (p[n-1] != '\n') {
  		p = realloc(p, n+2);
  		p[n] = '\n';
  		p[n+1] = '\0';
  	}
  	return p;
  }
  
  void copyuntil(char *s)	/* string that terminates a thru */
  {
  	untilstr = s;
  }
  
  void copy(void)	/* begin input from file, etc. */
  {
  	FILE *fin;
  
  	if (newfile) {
  		if ((fin = fopen(newfile, "r")) == NULL)
  			ERROR "can't open file %s", newfile FATAL;
  		curfile++;
  		curfile->fin = fin;
  		curfile->fname = newfile;
  		curfile->lineno = 0;
  		printlf(1, curfile->fname);
  		pushsrc(File, curfile->fname);
  		newfile = 0;
  	}
  	if (thrudef) {
  		thru = 1;
  		begin = 1;	/* wrong place */
  	}
  }
  
  char	shellbuf[1000], *shellp;
  
  void shell_init(void)	/* set up to interpret a shell command */
  {
  	sprintf(shellbuf, "rc -c '");
  	shellp = shellbuf + strlen(shellbuf);
  }
  
  void shell_text(char *s)	/* add string to command being collected */
  {
  	while ((*shellp++ = *s++))
  		;
  	shellp--;
  }
  
  void shell_exec(void)	/* do it */
  {
  	*shellp++ = '\'';
  	*shellp = '\0';
  	system(shellbuf);
  }
  