xref: /netbsd-src/bin/sh/parser.c (revision b1c86f5f087524e68db12794ee9c3e3da1ab17a0)
1 /*	$NetBSD: parser.c,v 1.74 2009/01/18 00:30:54 lukem Exp $	*/
2 
3 /*-
4  * Copyright (c) 1991, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Kenneth Almquist.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #include <sys/cdefs.h>
36 #ifndef lint
37 #if 0
38 static char sccsid[] = "@(#)parser.c	8.7 (Berkeley) 5/16/95";
39 #else
40 __RCSID("$NetBSD: parser.c,v 1.74 2009/01/18 00:30:54 lukem Exp $");
41 #endif
42 #endif /* not lint */
43 
44 #include <stdlib.h>
45 
46 #include "shell.h"
47 #include "parser.h"
48 #include "nodes.h"
49 #include "expand.h"	/* defines rmescapes() */
50 #include "eval.h"	/* defines commandname */
51 #include "redir.h"	/* defines copyfd() */
52 #include "syntax.h"
53 #include "options.h"
54 #include "input.h"
55 #include "output.h"
56 #include "var.h"
57 #include "error.h"
58 #include "memalloc.h"
59 #include "mystring.h"
60 #include "alias.h"
61 #include "show.h"
62 #ifndef SMALL
63 #include "myhistedit.h"
64 #endif
65 
66 /*
67  * Shell command parser.
68  */
69 
70 #define EOFMARKLEN 79
71 
72 /* values returned by readtoken */
73 #include "token.h"
74 
75 #define OPENBRACE '{'
76 #define CLOSEBRACE '}'
77 
78 
79 struct heredoc {
80 	struct heredoc *next;	/* next here document in list */
81 	union node *here;		/* redirection node */
82 	char *eofmark;		/* string indicating end of input */
83 	int striptabs;		/* if set, strip leading tabs */
84 };
85 
86 
87 
88 static int noalias = 0;		/* when set, don't handle aliases */
89 struct heredoc *heredoclist;	/* list of here documents to read */
90 int parsebackquote;		/* nonzero if we are inside backquotes */
91 int doprompt;			/* if set, prompt the user */
92 int needprompt;			/* true if interactive and at start of line */
93 int lasttoken;			/* last token read */
94 MKINIT int tokpushback;		/* last token pushed back */
95 char *wordtext;			/* text of last word returned by readtoken */
96 MKINIT int checkkwd;		/* 1 == check for kwds, 2 == also eat newlines */
97 struct nodelist *backquotelist;
98 union node *redirnode;
99 struct heredoc *heredoc;
100 int quoteflag;			/* set if (part of) last token was quoted */
101 int startlinno;			/* line # where last token started */
102 
103 
104 STATIC union node *list(int, int);
105 STATIC union node *andor(void);
106 STATIC union node *pipeline(void);
107 STATIC union node *command(void);
108 STATIC union node *simplecmd(union node **, union node *);
109 STATIC union node *makename(void);
110 STATIC void parsefname(void);
111 STATIC void parseheredoc(void);
112 STATIC int peektoken(void);
113 STATIC int readtoken(void);
114 STATIC int xxreadtoken(void);
115 STATIC int readtoken1(int, char const *, char *, int);
116 STATIC int noexpand(char *);
117 STATIC void synexpect(int) __dead;
118 STATIC void synerror(const char *) __dead;
119 STATIC void setprompt(int);
120 
121 
122 /*
123  * Read and parse a command.  Returns NEOF on end of file.  (NULL is a
124  * valid parse tree indicating a blank line.)
125  */
126 
127 union node *
128 parsecmd(int interact)
129 {
130 	int t;
131 
132 	tokpushback = 0;
133 	doprompt = interact;
134 	if (doprompt)
135 		setprompt(1);
136 	else
137 		setprompt(0);
138 	needprompt = 0;
139 	t = readtoken();
140 	if (t == TEOF)
141 		return NEOF;
142 	if (t == TNL)
143 		return NULL;
144 	tokpushback++;
145 	return list(1, 0);
146 }
147 
148 
149 STATIC union node *
150 list(int nlflag, int erflag)
151 {
152 	union node *n1, *n2, *n3;
153 	int tok;
154 	TRACE(("list: entered\n"));
155 
156 	checkkwd = 2;
157 	if (nlflag == 0 && tokendlist[peektoken()])
158 		return NULL;
159 	n1 = NULL;
160 	for (;;) {
161 		n2 = andor();
162 		tok = readtoken();
163 		if (tok == TBACKGND) {
164 			if (n2->type == NCMD || n2->type == NPIPE) {
165 				n2->ncmd.backgnd = 1;
166 			} else if (n2->type == NREDIR) {
167 				n2->type = NBACKGND;
168 			} else {
169 				n3 = (union node *)stalloc(sizeof (struct nredir));
170 				n3->type = NBACKGND;
171 				n3->nredir.n = n2;
172 				n3->nredir.redirect = NULL;
173 				n2 = n3;
174 			}
175 		}
176 		if (n1 == NULL) {
177 			n1 = n2;
178 		}
179 		else {
180 			n3 = (union node *)stalloc(sizeof (struct nbinary));
181 			n3->type = NSEMI;
182 			n3->nbinary.ch1 = n1;
183 			n3->nbinary.ch2 = n2;
184 			n1 = n3;
185 		}
186 		switch (tok) {
187 		case TBACKGND:
188 		case TSEMI:
189 			tok = readtoken();
190 			/* fall through */
191 		case TNL:
192 			if (tok == TNL) {
193 				parseheredoc();
194 				if (nlflag)
195 					return n1;
196 			} else {
197 				tokpushback++;
198 			}
199 			checkkwd = 2;
200 			if (tokendlist[peektoken()])
201 				return n1;
202 			break;
203 		case TEOF:
204 			if (heredoclist)
205 				parseheredoc();
206 			else
207 				pungetc();		/* push back EOF on input */
208 			return n1;
209 		default:
210 			if (nlflag || erflag)
211 				synexpect(-1);
212 			tokpushback++;
213 			return n1;
214 		}
215 	}
216 }
217 
218 
219 
220 STATIC union node *
221 andor(void)
222 {
223 	union node *n1, *n2, *n3;
224 	int t;
225 
226 	TRACE(("andor: entered\n"));
227 	n1 = pipeline();
228 	for (;;) {
229 		if ((t = readtoken()) == TAND) {
230 			t = NAND;
231 		} else if (t == TOR) {
232 			t = NOR;
233 		} else {
234 			tokpushback++;
235 			return n1;
236 		}
237 		n2 = pipeline();
238 		n3 = (union node *)stalloc(sizeof (struct nbinary));
239 		n3->type = t;
240 		n3->nbinary.ch1 = n1;
241 		n3->nbinary.ch2 = n2;
242 		n1 = n3;
243 	}
244 }
245 
246 
247 
248 STATIC union node *
249 pipeline(void)
250 {
251 	union node *n1, *n2, *pipenode;
252 	struct nodelist *lp, *prev;
253 	int negate;
254 
255 	TRACE(("pipeline: entered\n"));
256 
257 	negate = 0;
258 	checkkwd = 2;
259 	while (readtoken() == TNOT) {
260 		TRACE(("pipeline: TNOT recognized\n"));
261 		negate = !negate;
262 	}
263 	tokpushback++;
264 	n1 = command();
265 	if (readtoken() == TPIPE) {
266 		pipenode = (union node *)stalloc(sizeof (struct npipe));
267 		pipenode->type = NPIPE;
268 		pipenode->npipe.backgnd = 0;
269 		lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
270 		pipenode->npipe.cmdlist = lp;
271 		lp->n = n1;
272 		do {
273 			prev = lp;
274 			lp = (struct nodelist *)stalloc(sizeof (struct nodelist));
275 			lp->n = command();
276 			prev->next = lp;
277 		} while (readtoken() == TPIPE);
278 		lp->next = NULL;
279 		n1 = pipenode;
280 	}
281 	tokpushback++;
282 	if (negate) {
283 		TRACE(("negate pipeline\n"));
284 		n2 = (union node *)stalloc(sizeof (struct nnot));
285 		n2->type = NNOT;
286 		n2->nnot.com = n1;
287 		return n2;
288 	} else
289 		return n1;
290 }
291 
292 
293 
294 STATIC union node *
295 command(void)
296 {
297 	union node *n1, *n2;
298 	union node *ap, **app;
299 	union node *cp, **cpp;
300 	union node *redir, **rpp;
301 	int t, negate = 0;
302 
303 	TRACE(("command: entered\n"));
304 
305 	checkkwd = 2;
306 	redir = NULL;
307 	n1 = NULL;
308 	rpp = &redir;
309 
310 	/* Check for redirection which may precede command */
311 	while (readtoken() == TREDIR) {
312 		*rpp = n2 = redirnode;
313 		rpp = &n2->nfile.next;
314 		parsefname();
315 	}
316 	tokpushback++;
317 
318 	while (readtoken() == TNOT) {
319 		TRACE(("command: TNOT recognized\n"));
320 		negate = !negate;
321 	}
322 	tokpushback++;
323 
324 	switch (readtoken()) {
325 	case TIF:
326 		n1 = (union node *)stalloc(sizeof (struct nif));
327 		n1->type = NIF;
328 		n1->nif.test = list(0, 0);
329 		if (readtoken() != TTHEN)
330 			synexpect(TTHEN);
331 		n1->nif.ifpart = list(0, 0);
332 		n2 = n1;
333 		while (readtoken() == TELIF) {
334 			n2->nif.elsepart = (union node *)stalloc(sizeof (struct nif));
335 			n2 = n2->nif.elsepart;
336 			n2->type = NIF;
337 			n2->nif.test = list(0, 0);
338 			if (readtoken() != TTHEN)
339 				synexpect(TTHEN);
340 			n2->nif.ifpart = list(0, 0);
341 		}
342 		if (lasttoken == TELSE)
343 			n2->nif.elsepart = list(0, 0);
344 		else {
345 			n2->nif.elsepart = NULL;
346 			tokpushback++;
347 		}
348 		if (readtoken() != TFI)
349 			synexpect(TFI);
350 		checkkwd = 1;
351 		break;
352 	case TWHILE:
353 	case TUNTIL: {
354 		int got;
355 		n1 = (union node *)stalloc(sizeof (struct nbinary));
356 		n1->type = (lasttoken == TWHILE)? NWHILE : NUNTIL;
357 		n1->nbinary.ch1 = list(0, 0);
358 		if ((got=readtoken()) != TDO) {
359 TRACE(("expecting DO got %s %s\n", tokname[got], got == TWORD ? wordtext : ""));
360 			synexpect(TDO);
361 		}
362 		n1->nbinary.ch2 = list(0, 0);
363 		if (readtoken() != TDONE)
364 			synexpect(TDONE);
365 		checkkwd = 1;
366 		break;
367 	}
368 	case TFOR:
369 		if (readtoken() != TWORD || quoteflag || ! goodname(wordtext))
370 			synerror("Bad for loop variable");
371 		n1 = (union node *)stalloc(sizeof (struct nfor));
372 		n1->type = NFOR;
373 		n1->nfor.var = wordtext;
374 		if (readtoken() == TWORD && ! quoteflag && equal(wordtext, "in")) {
375 			app = &ap;
376 			while (readtoken() == TWORD) {
377 				n2 = (union node *)stalloc(sizeof (struct narg));
378 				n2->type = NARG;
379 				n2->narg.text = wordtext;
380 				n2->narg.backquote = backquotelist;
381 				*app = n2;
382 				app = &n2->narg.next;
383 			}
384 			*app = NULL;
385 			n1->nfor.args = ap;
386 			if (lasttoken != TNL && lasttoken != TSEMI)
387 				synexpect(-1);
388 		} else {
389 			static char argvars[5] = {CTLVAR, VSNORMAL|VSQUOTE,
390 								   '@', '=', '\0'};
391 			n2 = (union node *)stalloc(sizeof (struct narg));
392 			n2->type = NARG;
393 			n2->narg.text = argvars;
394 			n2->narg.backquote = NULL;
395 			n2->narg.next = NULL;
396 			n1->nfor.args = n2;
397 			/*
398 			 * Newline or semicolon here is optional (but note
399 			 * that the original Bourne shell only allowed NL).
400 			 */
401 			if (lasttoken != TNL && lasttoken != TSEMI)
402 				tokpushback++;
403 		}
404 		checkkwd = 2;
405 		if ((t = readtoken()) == TDO)
406 			t = TDONE;
407 		else if (t == TBEGIN)
408 			t = TEND;
409 		else
410 			synexpect(-1);
411 		n1->nfor.body = list(0, 0);
412 		if (readtoken() != t)
413 			synexpect(t);
414 		checkkwd = 1;
415 		break;
416 	case TCASE:
417 		n1 = (union node *)stalloc(sizeof (struct ncase));
418 		n1->type = NCASE;
419 		if (readtoken() != TWORD)
420 			synexpect(TWORD);
421 		n1->ncase.expr = n2 = (union node *)stalloc(sizeof (struct narg));
422 		n2->type = NARG;
423 		n2->narg.text = wordtext;
424 		n2->narg.backquote = backquotelist;
425 		n2->narg.next = NULL;
426 		while (readtoken() == TNL);
427 		if (lasttoken != TWORD || ! equal(wordtext, "in"))
428 			synerror("expecting \"in\"");
429 		cpp = &n1->ncase.cases;
430 		noalias = 1;
431 		checkkwd = 2, readtoken();
432 		do {
433 			*cpp = cp = (union node *)stalloc(sizeof (struct nclist));
434 			if (lasttoken == TLP)
435 				readtoken();
436 			cp->type = NCLIST;
437 			app = &cp->nclist.pattern;
438 			for (;;) {
439 				*app = ap = (union node *)stalloc(sizeof (struct narg));
440 				ap->type = NARG;
441 				ap->narg.text = wordtext;
442 				ap->narg.backquote = backquotelist;
443 				if (checkkwd = 2, readtoken() != TPIPE)
444 					break;
445 				app = &ap->narg.next;
446 				readtoken();
447 			}
448 			ap->narg.next = NULL;
449 			noalias = 0;
450 			if (lasttoken != TRP) {
451 				synexpect(TRP);
452 			}
453 			cp->nclist.body = list(0, 0);
454 
455 			checkkwd = 2;
456 			if ((t = readtoken()) != TESAC) {
457 				if (t != TENDCASE) {
458 					noalias = 0;
459 					synexpect(TENDCASE);
460 				} else {
461 					noalias = 1;
462 					checkkwd = 2;
463 					readtoken();
464 				}
465 			}
466 			cpp = &cp->nclist.next;
467 		} while(lasttoken != TESAC);
468 		noalias = 0;
469 		*cpp = NULL;
470 		checkkwd = 1;
471 		break;
472 	case TLP:
473 		n1 = (union node *)stalloc(sizeof (struct nredir));
474 		n1->type = NSUBSHELL;
475 		n1->nredir.n = list(0, 0);
476 		n1->nredir.redirect = NULL;
477 		if (readtoken() != TRP)
478 			synexpect(TRP);
479 		checkkwd = 1;
480 		break;
481 	case TBEGIN:
482 		n1 = list(0, 0);
483 		if (readtoken() != TEND)
484 			synexpect(TEND);
485 		checkkwd = 1;
486 		break;
487 	/* Handle an empty command like other simple commands.  */
488 	case TSEMI:
489 		/*
490 		 * An empty command before a ; doesn't make much sense, and
491 		 * should certainly be disallowed in the case of `if ;'.
492 		 */
493 		if (!redir)
494 			synexpect(-1);
495 	case TAND:
496 	case TOR:
497 	case TNL:
498 	case TEOF:
499 	case TWORD:
500 	case TRP:
501 		tokpushback++;
502 		n1 = simplecmd(rpp, redir);
503 		goto checkneg;
504 	default:
505 		synexpect(-1);
506 		/* NOTREACHED */
507 	}
508 
509 	/* Now check for redirection which may follow command */
510 	while (readtoken() == TREDIR) {
511 		*rpp = n2 = redirnode;
512 		rpp = &n2->nfile.next;
513 		parsefname();
514 	}
515 	tokpushback++;
516 	*rpp = NULL;
517 	if (redir) {
518 		if (n1->type != NSUBSHELL) {
519 			n2 = (union node *)stalloc(sizeof (struct nredir));
520 			n2->type = NREDIR;
521 			n2->nredir.n = n1;
522 			n1 = n2;
523 		}
524 		n1->nredir.redirect = redir;
525 	}
526 
527 checkneg:
528 	if (negate) {
529 		TRACE(("negate command\n"));
530 		n2 = (union node *)stalloc(sizeof (struct nnot));
531 		n2->type = NNOT;
532 		n2->nnot.com = n1;
533 		return n2;
534 	}
535 	else
536 		return n1;
537 }
538 
539 
540 STATIC union node *
541 simplecmd(union node **rpp, union node *redir)
542 {
543 	union node *args, **app;
544 	union node **orig_rpp = rpp;
545 	union node *n = NULL, *n2;
546 	int negate = 0;
547 
548 	/* If we don't have any redirections already, then we must reset */
549 	/* rpp to be the address of the local redir variable.  */
550 	if (redir == 0)
551 		rpp = &redir;
552 
553 	args = NULL;
554 	app = &args;
555 	/*
556 	 * We save the incoming value, because we need this for shell
557 	 * functions.  There can not be a redirect or an argument between
558 	 * the function name and the open parenthesis.
559 	 */
560 	orig_rpp = rpp;
561 
562 	while (readtoken() == TNOT) {
563 		TRACE(("simplcmd: TNOT recognized\n"));
564 		negate = !negate;
565 	}
566 	tokpushback++;
567 
568 	for (;;) {
569 		if (readtoken() == TWORD) {
570 			n = (union node *)stalloc(sizeof (struct narg));
571 			n->type = NARG;
572 			n->narg.text = wordtext;
573 			n->narg.backquote = backquotelist;
574 			*app = n;
575 			app = &n->narg.next;
576 		} else if (lasttoken == TREDIR) {
577 			*rpp = n = redirnode;
578 			rpp = &n->nfile.next;
579 			parsefname();	/* read name of redirection file */
580 		} else if (lasttoken == TLP && app == &args->narg.next
581 					    && rpp == orig_rpp) {
582 			/* We have a function */
583 			if (readtoken() != TRP)
584 				synexpect(TRP);
585 			rmescapes(n->narg.text);
586 			if (!goodname(n->narg.text))
587 				synerror("Bad function name");
588 			n->type = NDEFUN;
589 			n->narg.next = command();
590 			goto checkneg;
591 		} else {
592 			tokpushback++;
593 			break;
594 		}
595 	}
596 	*app = NULL;
597 	*rpp = NULL;
598 	n = (union node *)stalloc(sizeof (struct ncmd));
599 	n->type = NCMD;
600 	n->ncmd.backgnd = 0;
601 	n->ncmd.args = args;
602 	n->ncmd.redirect = redir;
603 
604 checkneg:
605 	if (negate) {
606 		TRACE(("negate simplecmd\n"));
607 		n2 = (union node *)stalloc(sizeof (struct nnot));
608 		n2->type = NNOT;
609 		n2->nnot.com = n;
610 		return n2;
611 	}
612 	else
613 		return n;
614 }
615 
616 STATIC union node *
617 makename(void)
618 {
619 	union node *n;
620 
621 	n = (union node *)stalloc(sizeof (struct narg));
622 	n->type = NARG;
623 	n->narg.next = NULL;
624 	n->narg.text = wordtext;
625 	n->narg.backquote = backquotelist;
626 	return n;
627 }
628 
629 void fixredir(union node *n, const char *text, int err)
630 	{
631 	TRACE(("Fix redir %s %d\n", text, err));
632 	if (!err)
633 		n->ndup.vname = NULL;
634 
635 	if (is_digit(text[0]) && text[1] == '\0')
636 		n->ndup.dupfd = digit_val(text[0]);
637 	else if (text[0] == '-' && text[1] == '\0')
638 		n->ndup.dupfd = -1;
639 	else {
640 
641 		if (err)
642 			synerror("Bad fd number");
643 		else
644 			n->ndup.vname = makename();
645 	}
646 }
647 
648 
649 STATIC void
650 parsefname(void)
651 {
652 	union node *n = redirnode;
653 
654 	if (readtoken() != TWORD)
655 		synexpect(-1);
656 	if (n->type == NHERE) {
657 		struct heredoc *here = heredoc;
658 		struct heredoc *p;
659 		int i;
660 
661 		if (quoteflag == 0)
662 			n->type = NXHERE;
663 		TRACE(("Here document %d\n", n->type));
664 		if (here->striptabs) {
665 			while (*wordtext == '\t')
666 				wordtext++;
667 		}
668 		if (! noexpand(wordtext) || (i = strlen(wordtext)) == 0 || i > EOFMARKLEN)
669 			synerror("Illegal eof marker for << redirection");
670 		rmescapes(wordtext);
671 		here->eofmark = wordtext;
672 		here->next = NULL;
673 		if (heredoclist == NULL)
674 			heredoclist = here;
675 		else {
676 			for (p = heredoclist ; p->next ; p = p->next);
677 			p->next = here;
678 		}
679 	} else if (n->type == NTOFD || n->type == NFROMFD) {
680 		fixredir(n, wordtext, 0);
681 	} else {
682 		n->nfile.fname = makename();
683 	}
684 }
685 
686 
687 /*
688  * Input any here documents.
689  */
690 
691 STATIC void
692 parseheredoc(void)
693 {
694 	struct heredoc *here;
695 	union node *n;
696 
697 	while (heredoclist) {
698 		here = heredoclist;
699 		heredoclist = here->next;
700 		if (needprompt) {
701 			setprompt(2);
702 			needprompt = 0;
703 		}
704 		readtoken1(pgetc(), here->here->type == NHERE? SQSYNTAX : DQSYNTAX,
705 				here->eofmark, here->striptabs);
706 		n = (union node *)stalloc(sizeof (struct narg));
707 		n->narg.type = NARG;
708 		n->narg.next = NULL;
709 		n->narg.text = wordtext;
710 		n->narg.backquote = backquotelist;
711 		here->here->nhere.doc = n;
712 	}
713 }
714 
715 STATIC int
716 peektoken(void)
717 {
718 	int t;
719 
720 	t = readtoken();
721 	tokpushback++;
722 	return (t);
723 }
724 
725 STATIC int
726 readtoken(void)
727 {
728 	int t;
729 	int savecheckkwd = checkkwd;
730 #ifdef DEBUG
731 	int alreadyseen = tokpushback;
732 #endif
733 	struct alias *ap;
734 
735 	top:
736 	t = xxreadtoken();
737 
738 	if (checkkwd) {
739 		/*
740 		 * eat newlines
741 		 */
742 		if (checkkwd == 2) {
743 			checkkwd = 0;
744 			while (t == TNL) {
745 				parseheredoc();
746 				t = xxreadtoken();
747 			}
748 		} else
749 			checkkwd = 0;
750 		/*
751 		 * check for keywords and aliases
752 		 */
753 		if (t == TWORD && !quoteflag)
754 		{
755 			const char *const *pp;
756 
757 			for (pp = parsekwd; *pp; pp++) {
758 				if (**pp == *wordtext && equal(*pp, wordtext))
759 				{
760 					lasttoken = t = pp -
761 					    parsekwd + KWDOFFSET;
762 					TRACE(("keyword %s recognized\n", tokname[t]));
763 					goto out;
764 				}
765 			}
766 			if(!noalias &&
767 			    (ap = lookupalias(wordtext, 1)) != NULL) {
768 				pushstring(ap->val, strlen(ap->val), ap);
769 				checkkwd = savecheckkwd;
770 				goto top;
771 			}
772 		}
773 out:
774 		checkkwd = (t == TNOT) ? savecheckkwd : 0;
775 	}
776 	TRACE(("%stoken %s %s\n", alreadyseen ? "reread " : "", tokname[t], t == TWORD ? wordtext : ""));
777 	return (t);
778 }
779 
780 
781 /*
782  * Read the next input token.
783  * If the token is a word, we set backquotelist to the list of cmds in
784  *	backquotes.  We set quoteflag to true if any part of the word was
785  *	quoted.
786  * If the token is TREDIR, then we set redirnode to a structure containing
787  *	the redirection.
788  * In all cases, the variable startlinno is set to the number of the line
789  *	on which the token starts.
790  *
791  * [Change comment:  here documents and internal procedures]
792  * [Readtoken shouldn't have any arguments.  Perhaps we should make the
793  *  word parsing code into a separate routine.  In this case, readtoken
794  *  doesn't need to have any internal procedures, but parseword does.
795  *  We could also make parseoperator in essence the main routine, and
796  *  have parseword (readtoken1?) handle both words and redirection.]
797  */
798 
799 #define RETURN(token)	return lasttoken = token
800 
801 STATIC int
802 xxreadtoken(void)
803 {
804 	int c;
805 
806 	if (tokpushback) {
807 		tokpushback = 0;
808 		return lasttoken;
809 	}
810 	if (needprompt) {
811 		setprompt(2);
812 		needprompt = 0;
813 	}
814 	startlinno = plinno;
815 	for (;;) {	/* until token or start of word found */
816 		c = pgetc_macro();
817 		if (c == ' ' || c == '\t')
818 			continue;		/* quick check for white space first */
819 		switch (c) {
820 		case ' ': case '\t':
821 			continue;
822 		case '#':
823 			while ((c = pgetc()) != '\n' && c != PEOF);
824 			pungetc();
825 			continue;
826 		case '\\':
827 			if (pgetc() == '\n') {
828 				startlinno = ++plinno;
829 				if (doprompt)
830 					setprompt(2);
831 				else
832 					setprompt(0);
833 				continue;
834 			}
835 			pungetc();
836 			goto breakloop;
837 		case '\n':
838 			plinno++;
839 			needprompt = doprompt;
840 			RETURN(TNL);
841 		case PEOF:
842 			RETURN(TEOF);
843 		case '&':
844 			if (pgetc() == '&')
845 				RETURN(TAND);
846 			pungetc();
847 			RETURN(TBACKGND);
848 		case '|':
849 			if (pgetc() == '|')
850 				RETURN(TOR);
851 			pungetc();
852 			RETURN(TPIPE);
853 		case ';':
854 			if (pgetc() == ';')
855 				RETURN(TENDCASE);
856 			pungetc();
857 			RETURN(TSEMI);
858 		case '(':
859 			RETURN(TLP);
860 		case ')':
861 			RETURN(TRP);
862 		default:
863 			goto breakloop;
864 		}
865 	}
866 breakloop:
867 	return readtoken1(c, BASESYNTAX, (char *)NULL, 0);
868 #undef RETURN
869 }
870 
871 
872 
873 /*
874  * If eofmark is NULL, read a word or a redirection symbol.  If eofmark
875  * is not NULL, read a here document.  In the latter case, eofmark is the
876  * word which marks the end of the document and striptabs is true if
877  * leading tabs should be stripped from the document.  The argument firstc
878  * is the first character of the input token or document.
879  *
880  * Because C does not have internal subroutines, I have simulated them
881  * using goto's to implement the subroutine linkage.  The following macros
882  * will run code that appears at the end of readtoken1.
883  */
884 
885 #define CHECKEND()	{goto checkend; checkend_return:;}
886 #define PARSEREDIR()	{goto parseredir; parseredir_return:;}
887 #define PARSESUB()	{goto parsesub; parsesub_return:;}
888 #define PARSEBACKQOLD()	{oldstyle = 1; goto parsebackq; parsebackq_oldreturn:;}
889 #define PARSEBACKQNEW()	{oldstyle = 0; goto parsebackq; parsebackq_newreturn:;}
890 #define	PARSEARITH()	{goto parsearith; parsearith_return:;}
891 
892 /*
893  * Keep track of nested doublequotes in dblquote and doublequotep.
894  * We use dblquote for the first 32 levels, and we expand to a malloc'ed
895  * region for levels above that. Usually we never need to malloc.
896  * This code assumes that an int is 32 bits. We don't use uint32_t,
897  * because the rest of the code does not.
898  */
899 #define ISDBLQUOTE() ((varnest < 32) ? (dblquote & (1 << varnest)) : \
900     (dblquotep[(varnest / 32) - 1] & (1 << (varnest % 32))))
901 
902 #define SETDBLQUOTE() \
903     if (varnest < 32) \
904 	dblquote |= (1 << varnest); \
905     else \
906 	dblquotep[(varnest / 32) - 1] |= (1 << (varnest % 32))
907 
908 #define CLRDBLQUOTE() \
909     if (varnest < 32) \
910 	dblquote &= ~(1 << varnest); \
911     else \
912 	dblquotep[(varnest / 32) - 1] &= ~(1 << (varnest % 32))
913 
914 STATIC int
915 readtoken1(int firstc, char const *syn, char *eofmark, int striptabs)
916 {
917 	char const * volatile syntax = syn;
918 	int c = firstc;
919 	char * volatile out;
920 	int len;
921 	char line[EOFMARKLEN + 1];
922 	struct nodelist *bqlist;
923 	volatile int quotef;
924 	int * volatile dblquotep = NULL;
925 	volatile size_t maxnest = 32;
926 	volatile int dblquote;
927 	volatile size_t varnest;	/* levels of variables expansion */
928 	volatile int arinest;	/* levels of arithmetic expansion */
929 	volatile int parenlevel;	/* levels of parens in arithmetic */
930 	volatile int oldstyle;
931 	char const * volatile prevsyntax;	/* syntax before arithmetic */
932 #ifdef __GNUC__
933 	prevsyntax = NULL;	/* XXX gcc4 */
934 #endif
935 
936 	startlinno = plinno;
937 	dblquote = 0;
938 	varnest = 0;
939 	if (syntax == DQSYNTAX) {
940 		SETDBLQUOTE();
941 	}
942 	quotef = 0;
943 	bqlist = NULL;
944 	arinest = 0;
945 	parenlevel = 0;
946 
947 	STARTSTACKSTR(out);
948 	loop: {	/* for each line, until end of word */
949 #if ATTY
950 		if (c == '\034' && doprompt
951 		 && attyset() && ! equal(termval(), "emacs")) {
952 			attyline();
953 			if (syntax == BASESYNTAX)
954 				return readtoken();
955 			c = pgetc();
956 			goto loop;
957 		}
958 #endif
959 		CHECKEND();	/* set c to PEOF if at end of here document */
960 		for (;;) {	/* until end of line or end of word */
961 			CHECKSTRSPACE(4, out);	/* permit 4 calls to USTPUTC */
962 			switch(syntax[c]) {
963 			case CNL:	/* '\n' */
964 				if (syntax == BASESYNTAX)
965 					goto endword;	/* exit outer loop */
966 				USTPUTC(c, out);
967 				plinno++;
968 				if (doprompt)
969 					setprompt(2);
970 				else
971 					setprompt(0);
972 				c = pgetc();
973 				goto loop;		/* continue outer loop */
974 			case CWORD:
975 				USTPUTC(c, out);
976 				break;
977 			case CCTL:
978 				if (eofmark == NULL || ISDBLQUOTE())
979 					USTPUTC(CTLESC, out);
980 				USTPUTC(c, out);
981 				break;
982 			case CBACK:	/* backslash */
983 				c = pgetc();
984 				if (c == PEOF) {
985 					USTPUTC('\\', out);
986 					pungetc();
987 					break;
988 				}
989 				if (c == '\n') {
990 					if (doprompt)
991 						setprompt(2);
992 					else
993 						setprompt(0);
994 					break;
995 				}
996 				quotef = 1;
997 				if (ISDBLQUOTE() && c != '\\' &&
998 				    c != '`' && c != '$' &&
999 				    (c != '"' || eofmark != NULL))
1000 					USTPUTC('\\', out);
1001 				if (SQSYNTAX[c] == CCTL)
1002 					USTPUTC(CTLESC, out);
1003 				else if (eofmark == NULL) {
1004 					USTPUTC(CTLQUOTEMARK, out);
1005 					USTPUTC(c, out);
1006 					if (varnest != 0)
1007 						USTPUTC(CTLQUOTEEND, out);
1008 					break;
1009 				}
1010 				USTPUTC(c, out);
1011 				break;
1012 			case CSQUOTE:
1013 				if (syntax != SQSYNTAX) {
1014 					if (eofmark == NULL)
1015 						USTPUTC(CTLQUOTEMARK, out);
1016 					quotef = 1;
1017 					syntax = SQSYNTAX;
1018 					break;
1019 				}
1020 				if (eofmark != NULL && arinest == 0 &&
1021 				    varnest == 0) {
1022 					/* Ignore inside quoted here document */
1023 					USTPUTC(c, out);
1024 					break;
1025 				}
1026 				/* End of single quotes... */
1027 				if (arinest)
1028 					syntax = ARISYNTAX;
1029 				else {
1030 					syntax = BASESYNTAX;
1031 					if (varnest != 0)
1032 						USTPUTC(CTLQUOTEEND, out);
1033 				}
1034 				break;
1035 			case CDQUOTE:
1036 				if (eofmark != NULL && arinest == 0 &&
1037 				    varnest == 0) {
1038 					/* Ignore inside here document */
1039 					USTPUTC(c, out);
1040 					break;
1041 				}
1042 				quotef = 1;
1043 				if (arinest) {
1044 					if (ISDBLQUOTE()) {
1045 						syntax = ARISYNTAX;
1046 						CLRDBLQUOTE();
1047 					} else {
1048 						syntax = DQSYNTAX;
1049 						SETDBLQUOTE();
1050 						USTPUTC(CTLQUOTEMARK, out);
1051 					}
1052 					break;
1053 				}
1054 				if (eofmark != NULL)
1055 					break;
1056 				if (ISDBLQUOTE()) {
1057 					if (varnest != 0)
1058 						USTPUTC(CTLQUOTEEND, out);
1059 					syntax = BASESYNTAX;
1060 					CLRDBLQUOTE();
1061 				} else {
1062 					syntax = DQSYNTAX;
1063 					SETDBLQUOTE();
1064 					USTPUTC(CTLQUOTEMARK, out);
1065 				}
1066 				break;
1067 			case CVAR:	/* '$' */
1068 				PARSESUB();		/* parse substitution */
1069 				break;
1070 			case CENDVAR:	/* CLOSEBRACE */
1071 				if (varnest > 0 && !ISDBLQUOTE()) {
1072 					varnest--;
1073 					USTPUTC(CTLENDVAR, out);
1074 				} else {
1075 					USTPUTC(c, out);
1076 				}
1077 				break;
1078 			case CLP:	/* '(' in arithmetic */
1079 				parenlevel++;
1080 				USTPUTC(c, out);
1081 				break;
1082 			case CRP:	/* ')' in arithmetic */
1083 				if (parenlevel > 0) {
1084 					USTPUTC(c, out);
1085 					--parenlevel;
1086 				} else {
1087 					if (pgetc() == ')') {
1088 						if (--arinest == 0) {
1089 							USTPUTC(CTLENDARI, out);
1090 							syntax = prevsyntax;
1091 							if (syntax == DQSYNTAX)
1092 								SETDBLQUOTE();
1093 							else
1094 								CLRDBLQUOTE();
1095 						} else
1096 							USTPUTC(')', out);
1097 					} else {
1098 						/*
1099 						 * unbalanced parens
1100 						 *  (don't 2nd guess - no error)
1101 						 */
1102 						pungetc();
1103 						USTPUTC(')', out);
1104 					}
1105 				}
1106 				break;
1107 			case CBQUOTE:	/* '`' */
1108 				PARSEBACKQOLD();
1109 				break;
1110 			case CEOF:
1111 				goto endword;		/* exit outer loop */
1112 			default:
1113 				if (varnest == 0)
1114 					goto endword;	/* exit outer loop */
1115 				USTPUTC(c, out);
1116 			}
1117 			c = pgetc_macro();
1118 		}
1119 	}
1120 endword:
1121 	if (syntax == ARISYNTAX)
1122 		synerror("Missing '))'");
1123 	if (syntax != BASESYNTAX && /* ! parsebackquote && */ eofmark == NULL)
1124 		synerror("Unterminated quoted string");
1125 	if (varnest != 0) {
1126 		startlinno = plinno;
1127 		/* { */
1128 		synerror("Missing '}'");
1129 	}
1130 	USTPUTC('\0', out);
1131 	len = out - stackblock();
1132 	out = stackblock();
1133 	if (eofmark == NULL) {
1134 		if ((c == '>' || c == '<')
1135 		 && quotef == 0
1136 		 && len <= 2
1137 		 && (*out == '\0' || is_digit(*out))) {
1138 			PARSEREDIR();
1139 			return lasttoken = TREDIR;
1140 		} else {
1141 			pungetc();
1142 		}
1143 	}
1144 	quoteflag = quotef;
1145 	backquotelist = bqlist;
1146 	grabstackblock(len);
1147 	wordtext = out;
1148 	if (dblquotep != NULL)
1149 	    ckfree(dblquotep);
1150 	return lasttoken = TWORD;
1151 /* end of readtoken routine */
1152 
1153 
1154 
1155 /*
1156  * Check to see whether we are at the end of the here document.  When this
1157  * is called, c is set to the first character of the next input line.  If
1158  * we are at the end of the here document, this routine sets the c to PEOF.
1159  */
1160 
1161 checkend: {
1162 	if (eofmark) {
1163 		if (striptabs) {
1164 			while (c == '\t')
1165 				c = pgetc();
1166 		}
1167 		if (c == *eofmark) {
1168 			if (pfgets(line, sizeof line) != NULL) {
1169 				char *p, *q;
1170 
1171 				p = line;
1172 				for (q = eofmark + 1 ; *q && *p == *q ; p++, q++);
1173 				if ((*p == '\0' || *p == '\n') && *q == '\0') {
1174 					c = PEOF;
1175 					plinno++;
1176 					needprompt = doprompt;
1177 				} else {
1178 					pushstring(line, strlen(line), NULL);
1179 				}
1180 			}
1181 		}
1182 	}
1183 	goto checkend_return;
1184 }
1185 
1186 
1187 /*
1188  * Parse a redirection operator.  The variable "out" points to a string
1189  * specifying the fd to be redirected.  The variable "c" contains the
1190  * first character of the redirection operator.
1191  */
1192 
1193 parseredir: {
1194 	char fd = *out;
1195 	union node *np;
1196 
1197 	np = (union node *)stalloc(sizeof (struct nfile));
1198 	if (c == '>') {
1199 		np->nfile.fd = 1;
1200 		c = pgetc();
1201 		if (c == '>')
1202 			np->type = NAPPEND;
1203 		else if (c == '|')
1204 			np->type = NCLOBBER;
1205 		else if (c == '&')
1206 			np->type = NTOFD;
1207 		else {
1208 			np->type = NTO;
1209 			pungetc();
1210 		}
1211 	} else {	/* c == '<' */
1212 		np->nfile.fd = 0;
1213 		switch (c = pgetc()) {
1214 		case '<':
1215 			if (sizeof (struct nfile) != sizeof (struct nhere)) {
1216 				np = (union node *)stalloc(sizeof (struct nhere));
1217 				np->nfile.fd = 0;
1218 			}
1219 			np->type = NHERE;
1220 			heredoc = (struct heredoc *)stalloc(sizeof (struct heredoc));
1221 			heredoc->here = np;
1222 			if ((c = pgetc()) == '-') {
1223 				heredoc->striptabs = 1;
1224 			} else {
1225 				heredoc->striptabs = 0;
1226 				pungetc();
1227 			}
1228 			break;
1229 
1230 		case '&':
1231 			np->type = NFROMFD;
1232 			break;
1233 
1234 		case '>':
1235 			np->type = NFROMTO;
1236 			break;
1237 
1238 		default:
1239 			np->type = NFROM;
1240 			pungetc();
1241 			break;
1242 		}
1243 	}
1244 	if (fd != '\0')
1245 		np->nfile.fd = digit_val(fd);
1246 	redirnode = np;
1247 	goto parseredir_return;
1248 }
1249 
1250 
1251 /*
1252  * Parse a substitution.  At this point, we have read the dollar sign
1253  * and nothing else.
1254  */
1255 
1256 parsesub: {
1257 	int subtype;
1258 	int typeloc;
1259 	int flags;
1260 	char *p;
1261 	static const char types[] = "}-+?=";
1262 
1263 	c = pgetc();
1264 	if (c != '(' && c != OPENBRACE && !is_name(c) && !is_special(c)) {
1265 		USTPUTC('$', out);
1266 		pungetc();
1267 	} else if (c == '(') {	/* $(command) or $((arith)) */
1268 		if (pgetc() == '(') {
1269 			PARSEARITH();
1270 		} else {
1271 			pungetc();
1272 			PARSEBACKQNEW();
1273 		}
1274 	} else {
1275 		USTPUTC(CTLVAR, out);
1276 		typeloc = out - stackblock();
1277 		USTPUTC(VSNORMAL, out);
1278 		subtype = VSNORMAL;
1279 		if (c == OPENBRACE) {
1280 			c = pgetc();
1281 			if (c == '#') {
1282 				if ((c = pgetc()) == CLOSEBRACE)
1283 					c = '#';
1284 				else
1285 					subtype = VSLENGTH;
1286 			}
1287 			else
1288 				subtype = 0;
1289 		}
1290 		if (is_name(c)) {
1291 			do {
1292 				STPUTC(c, out);
1293 				c = pgetc();
1294 			} while (is_in_name(c));
1295 		} else if (is_digit(c)) {
1296 			do {
1297 				USTPUTC(c, out);
1298 				c = pgetc();
1299 			} while (is_digit(c));
1300 		}
1301 		else if (is_special(c)) {
1302 			USTPUTC(c, out);
1303 			c = pgetc();
1304 		}
1305 		else
1306 badsub:			synerror("Bad substitution");
1307 
1308 		STPUTC('=', out);
1309 		flags = 0;
1310 		if (subtype == 0) {
1311 			switch (c) {
1312 			case ':':
1313 				flags = VSNUL;
1314 				c = pgetc();
1315 				/*FALLTHROUGH*/
1316 			default:
1317 				p = strchr(types, c);
1318 				if (p == NULL)
1319 					goto badsub;
1320 				subtype = p - types + VSNORMAL;
1321 				break;
1322 			case '%':
1323 			case '#':
1324 				{
1325 					int cc = c;
1326 					subtype = c == '#' ? VSTRIMLEFT :
1327 							     VSTRIMRIGHT;
1328 					c = pgetc();
1329 					if (c == cc)
1330 						subtype++;
1331 					else
1332 						pungetc();
1333 					break;
1334 				}
1335 			}
1336 		} else {
1337 			pungetc();
1338 		}
1339 		if (ISDBLQUOTE() || arinest)
1340 			flags |= VSQUOTE;
1341 		*(stackblock() + typeloc) = subtype | flags;
1342 		if (subtype != VSNORMAL) {
1343 			varnest++;
1344 			if (varnest >= maxnest) {
1345 				dblquotep = ckrealloc(dblquotep, maxnest / 8);
1346 				dblquotep[(maxnest / 32) - 1] = 0;
1347 				maxnest += 32;
1348 			}
1349 		}
1350 	}
1351 	goto parsesub_return;
1352 }
1353 
1354 
1355 /*
1356  * Called to parse command substitutions.  Newstyle is set if the command
1357  * is enclosed inside $(...); nlpp is a pointer to the head of the linked
1358  * list of commands (passed by reference), and savelen is the number of
1359  * characters on the top of the stack which must be preserved.
1360  */
1361 
1362 parsebackq: {
1363 	struct nodelist **nlpp;
1364 	int savepbq;
1365 	union node *n;
1366 	char *volatile str;
1367 	struct jmploc jmploc;
1368 	struct jmploc *volatile savehandler;
1369 	int savelen;
1370 	int saveprompt;
1371 
1372 	savepbq = parsebackquote;
1373 	if (setjmp(jmploc.loc)) {
1374 		if (str)
1375 			ckfree(str);
1376 		parsebackquote = 0;
1377 		handler = savehandler;
1378 		longjmp(handler->loc, 1);
1379 	}
1380 	INTOFF;
1381 	str = NULL;
1382 	savelen = out - stackblock();
1383 	if (savelen > 0) {
1384 		str = ckmalloc(savelen);
1385 		memcpy(str, stackblock(), savelen);
1386 	}
1387 	savehandler = handler;
1388 	handler = &jmploc;
1389 	INTON;
1390         if (oldstyle) {
1391                 /* We must read until the closing backquote, giving special
1392                    treatment to some slashes, and then push the string and
1393                    reread it as input, interpreting it normally.  */
1394                 char *pout;
1395                 int pc;
1396                 int psavelen;
1397                 char *pstr;
1398 
1399 
1400                 STARTSTACKSTR(pout);
1401 		for (;;) {
1402 			if (needprompt) {
1403 				setprompt(2);
1404 				needprompt = 0;
1405 			}
1406 			switch (pc = pgetc()) {
1407 			case '`':
1408 				goto done;
1409 
1410 			case '\\':
1411                                 if ((pc = pgetc()) == '\n') {
1412 					plinno++;
1413 					if (doprompt)
1414 						setprompt(2);
1415 					else
1416 						setprompt(0);
1417 					/*
1418 					 * If eating a newline, avoid putting
1419 					 * the newline into the new character
1420 					 * stream (via the STPUTC after the
1421 					 * switch).
1422 					 */
1423 					continue;
1424 				}
1425                                 if (pc != '\\' && pc != '`' && pc != '$'
1426                                     && (!ISDBLQUOTE() || pc != '"'))
1427                                         STPUTC('\\', pout);
1428 				break;
1429 
1430 			case '\n':
1431 				plinno++;
1432 				needprompt = doprompt;
1433 				break;
1434 
1435 			case PEOF:
1436 			        startlinno = plinno;
1437 				synerror("EOF in backquote substitution");
1438  				break;
1439 
1440 			default:
1441 				break;
1442 			}
1443 			STPUTC(pc, pout);
1444                 }
1445 done:
1446                 STPUTC('\0', pout);
1447                 psavelen = pout - stackblock();
1448                 if (psavelen > 0) {
1449 			pstr = grabstackstr(pout);
1450 			setinputstring(pstr, 1);
1451                 }
1452         }
1453 	nlpp = &bqlist;
1454 	while (*nlpp)
1455 		nlpp = &(*nlpp)->next;
1456 	*nlpp = (struct nodelist *)stalloc(sizeof (struct nodelist));
1457 	(*nlpp)->next = NULL;
1458 	parsebackquote = oldstyle;
1459 
1460 	if (oldstyle) {
1461 		saveprompt = doprompt;
1462 		doprompt = 0;
1463 	} else
1464 		saveprompt = 0;
1465 
1466 	n = list(0, oldstyle);
1467 
1468 	if (oldstyle)
1469 		doprompt = saveprompt;
1470 	else {
1471 		if (readtoken() != TRP)
1472 			synexpect(TRP);
1473 	}
1474 
1475 	(*nlpp)->n = n;
1476         if (oldstyle) {
1477 		/*
1478 		 * Start reading from old file again, ignoring any pushed back
1479 		 * tokens left from the backquote parsing
1480 		 */
1481                 popfile();
1482 		tokpushback = 0;
1483 	}
1484 	while (stackblocksize() <= savelen)
1485 		growstackblock();
1486 	STARTSTACKSTR(out);
1487 	if (str) {
1488 		memcpy(out, str, savelen);
1489 		STADJUST(savelen, out);
1490 		INTOFF;
1491 		ckfree(str);
1492 		str = NULL;
1493 		INTON;
1494 	}
1495 	parsebackquote = savepbq;
1496 	handler = savehandler;
1497 	if (arinest || ISDBLQUOTE())
1498 		USTPUTC(CTLBACKQ | CTLQUOTE, out);
1499 	else
1500 		USTPUTC(CTLBACKQ, out);
1501 	if (oldstyle)
1502 		goto parsebackq_oldreturn;
1503 	else
1504 		goto parsebackq_newreturn;
1505 }
1506 
1507 /*
1508  * Parse an arithmetic expansion (indicate start of one and set state)
1509  */
1510 parsearith: {
1511 
1512 	if (++arinest == 1) {
1513 		prevsyntax = syntax;
1514 		syntax = ARISYNTAX;
1515 		USTPUTC(CTLARI, out);
1516 		if (ISDBLQUOTE())
1517 			USTPUTC('"',out);
1518 		else
1519 			USTPUTC(' ',out);
1520 	} else {
1521 		/*
1522 		 * we collapse embedded arithmetic expansion to
1523 		 * parenthesis, which should be equivalent
1524 		 */
1525 		USTPUTC('(', out);
1526 	}
1527 	goto parsearith_return;
1528 }
1529 
1530 } /* end of readtoken */
1531 
1532 
1533 
1534 #ifdef mkinit
1535 RESET {
1536 	tokpushback = 0;
1537 	checkkwd = 0;
1538 }
1539 #endif
1540 
1541 /*
1542  * Returns true if the text contains nothing to expand (no dollar signs
1543  * or backquotes).
1544  */
1545 
1546 STATIC int
1547 noexpand(char *text)
1548 {
1549 	char *p;
1550 	char c;
1551 
1552 	p = text;
1553 	while ((c = *p++) != '\0') {
1554 		if (c == CTLQUOTEMARK)
1555 			continue;
1556 		if (c == CTLESC)
1557 			p++;
1558 		else if (BASESYNTAX[(int)c] == CCTL)
1559 			return 0;
1560 	}
1561 	return 1;
1562 }
1563 
1564 
1565 /*
1566  * Return true if the argument is a legal variable name (a letter or
1567  * underscore followed by zero or more letters, underscores, and digits).
1568  */
1569 
1570 int
1571 goodname(char *name)
1572 	{
1573 	char *p;
1574 
1575 	p = name;
1576 	if (! is_name(*p))
1577 		return 0;
1578 	while (*++p) {
1579 		if (! is_in_name(*p))
1580 			return 0;
1581 	}
1582 	return 1;
1583 }
1584 
1585 
1586 /*
1587  * Called when an unexpected token is read during the parse.  The argument
1588  * is the token that is expected, or -1 if more than one type of token can
1589  * occur at this point.
1590  */
1591 
1592 STATIC void
1593 synexpect(int token)
1594 {
1595 	char msg[64];
1596 
1597 	if (token >= 0) {
1598 		fmtstr(msg, 64, "%s unexpected (expecting %s)",
1599 			tokname[lasttoken], tokname[token]);
1600 	} else {
1601 		fmtstr(msg, 64, "%s unexpected", tokname[lasttoken]);
1602 	}
1603 	synerror(msg);
1604 	/* NOTREACHED */
1605 }
1606 
1607 
1608 STATIC void
1609 synerror(const char *msg)
1610 {
1611 	if (commandname)
1612 		outfmt(&errout, "%s: %d: ", commandname, startlinno);
1613 	else
1614 		outfmt(&errout, "%s: ", getprogname());
1615 	outfmt(&errout, "Syntax error: %s\n", msg);
1616 	error((char *)NULL);
1617 	/* NOTREACHED */
1618 }
1619 
1620 STATIC void
1621 setprompt(int which)
1622 {
1623 	whichprompt = which;
1624 
1625 #ifndef SMALL
1626 	if (!el)
1627 #endif
1628 		out2str(getprompt(NULL));
1629 }
1630 
1631 /*
1632  * called by editline -- any expansions to the prompt
1633  *    should be added here.
1634  */
1635 const char *
1636 getprompt(void *unused)
1637 	{
1638 	switch (whichprompt) {
1639 	case 0:
1640 		return "";
1641 	case 1:
1642 		return ps1val();
1643 	case 2:
1644 		return ps2val();
1645 	default:
1646 		return "<internal prompt error>";
1647 	}
1648 }
1649