xref: /netbsd-src/bin/ksh/syn.c (revision 76dfffe33547c37f8bdd446e3e4ab0f3c16cea4b)
1 /*
2  * shell parser (C version)
3  */
4 
5 #include "sh.h"
6 #include "c_test.h"
7 
8 struct multiline_state {
9 	int	on;		/* set in multiline commands (\n becomes ;) */
10 	int	start_token;	/* token multiline is for (eg, FOR, {, etc.) */
11 	int	start_line;	/* line multiline command started on */
12 };
13 
14 static void	yyparse		ARGS((void));
15 static struct op *pipeline	ARGS((int cf));
16 static struct op *andor		ARGS((void));
17 static struct op *c_list	ARGS((void));
18 static struct ioword *synio	ARGS((int cf));
19 static void	musthave	ARGS((int c, int cf));
20 static struct op *nested	ARGS((int type, int smark, int emark));
21 static struct op *get_command	ARGS((int cf));
22 static struct op *dogroup	ARGS((void));
23 static struct op *thenpart	ARGS((void));
24 static struct op *elsepart	ARGS((void));
25 static struct op *caselist	ARGS((void));
26 static struct op *casepart	ARGS((int endtok));
27 static struct op *function_body	ARGS((char *name, int ksh_func));
28 static char **	wordlist	ARGS((void));
29 static struct op *block		ARGS((int type, struct op *t1, struct op *t2,
30 				      char **wp));
31 static struct op *newtp		ARGS((int type));
32 static void	syntaxerr	ARGS((const char *what))
33 						GCC_FUNC_ATTR(noreturn);
34 static void	multiline_push ARGS((struct multiline_state *save, int tok));
35 static void	multiline_pop ARGS((struct multiline_state *saved));
36 static int	assign_command ARGS((char *s));
37 static int	inalias ARGS((struct source *s));
38 #ifdef KSH
39 static int	dbtestp_isa ARGS((Test_env *te, Test_meta meta));
40 static const char *dbtestp_getopnd ARGS((Test_env *te, Test_op op,
41 					int do_eval));
42 static int	dbtestp_eval ARGS((Test_env *te, Test_op op, const char *opnd1,
43 				const char *opnd2, int do_eval));
44 static void	dbtestp_error ARGS((Test_env *te, int offset, const char *msg));
45 #endif /* KSH */
46 
47 static	struct	op	*outtree; /* yyparse output */
48 
49 static struct multiline_state multiline;	/* \n changed to ; */
50 
51 static	int	reject;		/* token(cf) gets symbol again */
52 static	int	symbol;		/* yylex value */
53 
54 #define	REJECT	(reject = 1)
55 #define	ACCEPT	(reject = 0)
56 #define	token(cf) \
57 	((reject) ? (ACCEPT, symbol) : (symbol = yylex(cf)))
58 #define	tpeek(cf) \
59 	((reject) ? (symbol) : (REJECT, symbol = yylex(cf)))
60 
61 static void
62 yyparse()
63 {
64 	int c;
65 
66 	ACCEPT;
67 	yynerrs = 0;
68 
69 	outtree = c_list();
70 	c = tpeek(0);
71 	if (c == 0 && !outtree)
72 		outtree = newtp(TEOF);
73 	else if (c != '\n' && c != 0)
74 		syntaxerr((char *) 0);
75 }
76 
77 static struct op *
78 pipeline(cf)
79 	int cf;
80 {
81 	register struct op *t, *p, *tl = NULL;
82 
83 	t = get_command(cf);
84 	if (t != NULL) {
85 		while (token(0) == '|') {
86 			if ((p = get_command(CONTIN)) == NULL)
87 				syntaxerr((char *) 0);
88 			if (tl == NULL)
89 				t = tl = block(TPIPE, t, p, NOWORDS);
90 			else
91 				tl = tl->right = block(TPIPE, tl->right, p, NOWORDS);
92 		}
93 		REJECT;
94 	}
95 	return (t);
96 }
97 
98 static struct op *
99 andor()
100 {
101 	register struct op *t, *p;
102 	register int c;
103 
104 	t = pipeline(0);
105 	if (t != NULL) {
106 		while ((c = token(0)) == LOGAND || c == LOGOR) {
107 			if ((p = pipeline(CONTIN)) == NULL)
108 				syntaxerr((char *) 0);
109 			t = block(c == LOGAND? TAND: TOR, t, p, NOWORDS);
110 		}
111 		REJECT;
112 	}
113 	return (t);
114 }
115 
116 static struct op *
117 c_list()
118 {
119 	register struct op *t, *p, *tl = NULL;
120 	register int c;
121 
122 	t = andor();
123 	if (t != NULL) {
124 		while ((c = token(0)) == ';' || c == '&' || c == COPROC ||
125 		       (c == '\n' && (multiline.on || inalias(source))))
126 		{
127 			if (c == '&' || c == COPROC) {
128 				int type = c == '&' ? TASYNC : TCOPROC;
129 				if (tl)
130 					tl->right = block(type, tl->right,
131 							  NOBLOCK, NOWORDS);
132 				else
133 					t = block(type, t, NOBLOCK, NOWORDS);
134 			}
135 			if ((p = andor()) == NULL)
136 				return (t);
137 			if (tl == NULL)
138 				t = tl = block(TLIST, t, p, NOWORDS);
139 			else
140 				tl = tl->right = block(TLIST, tl->right, p, NOWORDS);
141 		}
142 		REJECT;
143 	}
144 	return (t);
145 }
146 
147 static struct ioword *
148 synio(cf)
149 	int cf;
150 {
151 	register struct ioword *iop;
152 	int ishere;
153 
154 	if (tpeek(cf) != REDIR)
155 		return NULL;
156 	ACCEPT;
157 	iop = yylval.iop;
158 	ishere = (iop->flag&IOTYPE) == IOHERE;
159 	musthave(LWORD, ishere ? HEREDELIM : 0);
160 	if (ishere) {
161 		iop->delim = yylval.cp;
162 		if (*ident != 0) /* unquoted */
163 			iop->flag |= IOEVAL;
164 		if (herep >= &heres[HERES])
165 			yyerror("too many <<'s\n");
166 		*herep++ = iop;
167 	} else
168 		iop->name = yylval.cp;
169 	return iop;
170 }
171 
172 static void
173 musthave(c, cf)
174 	int c, cf;
175 {
176 	if ((token(cf)) != c)
177 		syntaxerr((char *) 0);
178 }
179 
180 static struct op *
181 nested(type, smark, emark)
182 	int type, smark, emark;
183 {
184 	register struct op *t;
185 	struct multiline_state old_multiline;
186 
187 	multiline_push(&old_multiline, smark);
188 	t = c_list();
189 	musthave(emark, KEYWORD|ALIAS);
190 	multiline_pop(&old_multiline);
191 	return (block(type, t, NOBLOCK, NOWORDS));
192 }
193 
194 static struct op *
195 get_command(cf)
196 	int cf;
197 {
198 	register struct op *t;
199 	register int c, iopn = 0, syniocf;
200 	struct ioword *iop, **iops;
201 	XPtrV args, vars;
202 	struct multiline_state old_multiline;
203 
204 	iops = (struct ioword **) alloc(sizeofN(struct ioword *, NUFILE+1),
205 					ATEMP);
206 	XPinit(args, 16);
207 	XPinit(vars, 16);
208 
209 	if (multiline.on)
210 		cf = CONTIN;
211 	syniocf = KEYWORD|ALIAS;
212 	switch (c = token(cf|KEYWORD|ALIAS|VARASN)) {
213 	  default:
214 		REJECT;
215 		afree((void*) iops, ATEMP);
216 		XPfree(args);
217 		XPfree(vars);
218 		return NULL; /* empty line */
219 
220 	  case LWORD:
221 	  case REDIR:
222 		REJECT;
223 		syniocf &= ~(KEYWORD|ALIAS);
224 		t = newtp(TCOM);
225 		while (1) {
226 			cf = (t->u.evalflags ? ARRAYVAR : 0)
227 			     | (XPsize(args) == 0 ? ALIAS|VARASN : CMDWORD);
228 			switch (tpeek(cf)) {
229 			  case REDIR:
230 				if (iopn >= NUFILE)
231 					yyerror("too many redirections\n");
232 				iops[iopn++] = synio(cf);
233 				break;
234 
235 			  case LWORD:
236 				ACCEPT;
237 				/* the iopn == 0 and XPsize(vars) == 0 are
238 				 * dubious but at&t ksh acts this way
239 				 */
240 				if (iopn == 0 && XPsize(vars) == 0
241 				    && XPsize(args) == 0
242 				    && assign_command(ident))
243 					t->u.evalflags = DOVACHECK;
244 				if ((XPsize(args) == 0 || Flag(FKEYWORD))
245 				    && is_wdvarassign(yylval.cp))
246 					XPput(vars, yylval.cp);
247 				else
248 					XPput(args, yylval.cp);
249 				break;
250 
251 			  case '(':
252 				/* Check for "> foo (echo hi)", which at&t ksh
253 				 * allows (not POSIX, but not disallowed)
254 				 */
255 				afree(t, ATEMP);
256 				if (XPsize(args) == 0 && XPsize(vars) == 0) {
257 					ACCEPT;
258 					goto Subshell;
259 				}
260 				/* Must be a function */
261 				if (iopn != 0 || XPsize(args) != 1
262 				    || XPsize(vars) != 0)
263 					syntaxerr((char *) 0);
264 				ACCEPT;
265 				/*(*/
266 				musthave(')', 0);
267 				t = function_body(XPptrv(args)[0], FALSE);
268 				goto Leave;
269 
270 			  default:
271 				goto Leave;
272 			}
273 		}
274 	  Leave:
275 		break;
276 
277 	  Subshell:
278 	  case '(':
279 		t = nested(TPAREN, '(', ')');
280 		break;
281 
282 	  case '{': /*}*/
283 		t = nested(TBRACE, '{', '}');
284 		break;
285 
286 #ifdef KSH
287 	  case MDPAREN:
288 	  {
289 		static const char let_cmd[] = { CHAR, 'l', CHAR, 'e',
290 						CHAR, 't', EOS };
291 		syniocf &= ~(KEYWORD|ALIAS);
292 		t = newtp(TCOM);
293 		ACCEPT;
294 		XPput(args, wdcopy(let_cmd, ATEMP));
295 		musthave(LWORD,LETEXPR);
296 		XPput(args, yylval.cp);
297 		break;
298 	  }
299 #endif /* KSH */
300 
301 #ifdef KSH
302 	  case DBRACKET: /* [[ .. ]] */
303 		syniocf &= ~(KEYWORD|ALIAS);
304 		t = newtp(TDBRACKET);
305 		ACCEPT;
306 		{
307 			Test_env te;
308 
309 			te.flags = TEF_DBRACKET;
310 			te.pos.av = &args;
311 			te.isa = dbtestp_isa;
312 			te.getopnd = dbtestp_getopnd;
313 			te.eval = dbtestp_eval;
314 			te.error = dbtestp_error;
315 
316 			test_parse(&te);
317 		}
318 		break;
319 #endif /* KSH */
320 
321 	  case FOR:
322 	  case SELECT:
323 		t = newtp((c == FOR) ? TFOR : TSELECT);
324 		musthave(LWORD, ARRAYVAR);
325 		if (!is_wdvarname(yylval.cp, TRUE))
326 			yyerror("%s: bad identifier\n",
327 				c == FOR ? "for" : "select");
328 		t->str = str_save(ident, ATEMP);
329 		multiline_push(&old_multiline, c);
330 		t->vars = wordlist();
331 		t->left = dogroup();
332 		multiline_pop(&old_multiline);
333 		break;
334 
335 	  case WHILE:
336 	  case UNTIL:
337 		multiline_push(&old_multiline, c);
338 		t = newtp((c == WHILE) ? TWHILE : TUNTIL);
339 		t->left = c_list();
340 		t->right = dogroup();
341 		multiline_pop(&old_multiline);
342 		break;
343 
344 	  case CASE:
345 		t = newtp(TCASE);
346 		musthave(LWORD, 0);
347 		t->str = yylval.cp;
348 		multiline_push(&old_multiline, c);
349 		t->left = caselist();
350 		multiline_pop(&old_multiline);
351 		break;
352 
353 	  case IF:
354 		multiline_push(&old_multiline, c);
355 		t = newtp(TIF);
356 		t->left = c_list();
357 		t->right = thenpart();
358 		musthave(FI, KEYWORD|ALIAS);
359 		multiline_pop(&old_multiline);
360 		break;
361 
362 	  case BANG:
363 		syniocf &= ~(KEYWORD|ALIAS);
364 		t = pipeline(0);
365 		if (t == (struct op *) 0)
366 			syntaxerr((char *) 0);
367 		t = block(TBANG, NOBLOCK, t, NOWORDS);
368 		break;
369 
370 	  case TIME:
371 		syniocf &= ~(KEYWORD|ALIAS);
372 		t = pipeline(0);
373 		t = block(TTIME, t, NOBLOCK, NOWORDS);
374 		break;
375 
376 	  case FUNCTION:
377 		musthave(LWORD, 0);
378 		t = function_body(yylval.cp, TRUE);
379 		break;
380 	}
381 
382 	while ((iop = synio(syniocf)) != NULL) {
383 		if (iopn >= NUFILE)
384 			yyerror("too many redirections\n");
385 		iops[iopn++] = iop;
386 	}
387 
388 	if (iopn == 0) {
389 		afree((void*) iops, ATEMP);
390 		t->ioact = NULL;
391 	} else {
392 		iops[iopn++] = NULL;
393 		iops = (struct ioword **) aresize((void*) iops,
394 					sizeofN(struct ioword *, iopn), ATEMP);
395 		t->ioact = iops;
396 	}
397 
398 	if (t->type == TCOM || t->type == TDBRACKET) {
399 		XPput(args, NULL);
400 		t->args = (char **) XPclose(args);
401 		XPput(vars, NULL);
402 		t->vars = (char **) XPclose(vars);
403 	} else {
404 		XPfree(args);
405 		XPfree(vars);
406 	}
407 
408 	return t;
409 }
410 
411 static struct op *
412 dogroup()
413 {
414 	register int c;
415 	register struct op *list;
416 
417 	c = token(CONTIN|KEYWORD|ALIAS);
418 	/* A {...} can be used instead of do...done for for/select loops
419 	 * but not for while/until loops - we don't need to check if it
420 	 * is a while loop because it would have been parsed as part of
421 	 * the conditional command list...
422 	 */
423 	if (c == DO)
424 		c = DONE;
425 	else if (c == '{')
426 		c = '}';
427 	else
428 		syntaxerr((char *) 0);
429 	list = c_list();
430 	musthave(c, KEYWORD|ALIAS);
431 	return list;
432 }
433 
434 static struct op *
435 thenpart()
436 {
437 	register struct op *t;
438 
439 	musthave(THEN, KEYWORD|ALIAS);
440 	t = newtp(0);
441 	t->left = c_list();
442 	if (t->left == NULL)
443 		syntaxerr((char *) 0);
444 	t->right = elsepart();
445 	return (t);
446 }
447 
448 static struct op *
449 elsepart()
450 {
451 	register struct op *t;
452 
453 	switch (token(KEYWORD|ALIAS|VARASN)) {
454 	  case ELSE:
455 		if ((t = c_list()) == NULL)
456 			syntaxerr((char *) 0);
457 		return (t);
458 
459 	  case ELIF:
460 		t = newtp(TELIF);
461 		t->left = c_list();
462 		t->right = thenpart();
463 		return (t);
464 
465 	  default:
466 		REJECT;
467 	}
468 	return NULL;
469 }
470 
471 static struct op *
472 caselist()
473 {
474 	register struct op *t, *tl;
475 	int c;
476 
477 	c = token(CONTIN|KEYWORD|ALIAS);
478 	/* A {...} can be used instead of in...esac for case statements */
479 	if (c == IN)
480 		c = ESAC;
481 	else if (c == '{')
482 		c = '}';
483 	else
484 		syntaxerr((char *) 0);
485 	t = tl = NULL;
486 	while ((tpeek(CONTIN|KEYWORD|ESACONLY)) != c) { /* no ALIAS here */
487 		struct op *tc = casepart(c);
488 		if (tl == NULL)
489 			t = tl = tc, tl->right = NULL;
490 		else
491 			tl->right = tc, tl = tc;
492 	}
493 	musthave(c, KEYWORD|ALIAS);
494 	return (t);
495 }
496 
497 static struct op *
498 casepart(endtok)
499 	int endtok;
500 {
501 	register struct op *t;
502 	register int c;
503 	XPtrV ptns;
504 
505 	XPinit(ptns, 16);
506 	t = newtp(TPAT);
507 	c = token(CONTIN|KEYWORD); /* no ALIAS here */
508 	if (c != '(')
509 		REJECT;
510 	do {
511 		musthave(LWORD, 0);
512 		XPput(ptns, yylval.cp);
513 	} while ((c = token(0)) == '|');
514 	REJECT;
515 	XPput(ptns, NULL);
516 	t->vars = (char **) XPclose(ptns);
517 	musthave(')', 0);
518 
519 	t->left = c_list();
520 	if ((tpeek(CONTIN|KEYWORD|ALIAS)) != endtok)
521 		musthave(BREAK, CONTIN|KEYWORD|ALIAS);
522 	return (t);
523 }
524 
525 static struct op *
526 function_body(name, ksh_func)
527 	char *name;
528 	int ksh_func;	/* function foo { ... } vs foo() { .. } */
529 {
530 	XString xs;
531 	char *xp, *p;
532 	struct op *t;
533 	int old_func_parse;
534 
535 	Xinit(xs, xp, 16, ATEMP);
536 	for (p = name; ; ) {
537 		if ((*p == EOS && Xlength(xs, xp) == 0)
538 		    || (*p != EOS && *p != CHAR && *p != QCHAR
539 			&& *p != OQUOTE && *p != CQUOTE))
540 		{
541 			p = snptreef((char *) 0, 32, "%S", name);
542 			yyerror("%s: invalid function name\n", p);
543 		}
544 		Xcheck(xs, xp);
545 		if (*p == EOS) {
546 			Xput(xs, xp, '\0');
547 			break;
548 		} else if (*p == CHAR || *p == QCHAR) {
549 			Xput(xs, xp, p[1]);
550 			p += 2;
551 		} else
552 			p++;	/* OQUOTE/CQUOTE */
553 	}
554 	t = newtp(TFUNCT);
555 	t->str = Xclose(xs, xp);
556 	t->u.ksh_func = ksh_func;
557 
558 	/* Note that POSIX allows only compound statements after foo(), sh and
559 	 * at&t ksh allow any command, go with the later since it shouldn't
560 	 * break anything.  However, for function foo, at&t ksh only accepts
561 	 * an open-brace.
562 	 */
563 	if (ksh_func) {
564 		musthave('{', CONTIN|KEYWORD|ALIAS); /* } */
565 		REJECT;
566 	}
567 
568 	old_func_parse = e->flags & EF_FUNC_PARSE;
569 	e->flags |= EF_FUNC_PARSE;
570 	if ((t->left = get_command(CONTIN)) == (struct op *) 0) {
571 		/* create empty command so foo(): will work */
572 		t->left = newtp(TCOM);
573 		t->args = (char **) alloc(sizeof(char *), ATEMP);
574 		t->args[0] = (char *) 0;
575 		t->vars = (char **) alloc(sizeof(char *), ATEMP);
576 		t->vars[0] = (char *) 0;
577 	}
578 	if (!old_func_parse)
579 		e->flags &= ~EF_FUNC_PARSE;
580 
581 	return t;
582 }
583 
584 static char **
585 wordlist()
586 {
587 	register int c;
588 	XPtrV args;
589 
590 	XPinit(args, 16);
591 	if ((c = token(CONTIN|KEYWORD|ALIAS)) != IN) {
592 		if (c != ';') /* non-POSIX, but at&t ksh accepts a ; here */
593 			REJECT;
594 		return NULL;
595 	}
596 	while ((c = token(0)) == LWORD)
597 		XPput(args, yylval.cp);
598 	if (c != '\n' && c != ';')
599 		syntaxerr((char *) 0);
600 	if (XPsize(args) == 0) {
601 		XPfree(args);
602 		return NULL;
603 	} else {
604 		XPput(args, NULL);
605 		return (char **) XPclose(args);
606 	}
607 }
608 
609 /*
610  * supporting functions
611  */
612 
613 static struct op *
614 block(type, t1, t2, wp)
615 	int type;
616 	struct op *t1, *t2;
617 	char **wp;
618 {
619 	register struct op *t;
620 
621 	t = newtp(type);
622 	t->left = t1;
623 	t->right = t2;
624 	t->vars = wp;
625 	return (t);
626 }
627 
628 const	struct tokeninfo {
629 	const char *name;
630 	short	val;
631 	short	reserved;
632 } tokentab[] = {
633 	/* Reserved words */
634 	{ "if",		IF,	TRUE },
635 	{ "then",	THEN,	TRUE },
636 	{ "else",	ELSE,	TRUE },
637 	{ "elif",	ELIF,	TRUE },
638 	{ "fi",		FI,	TRUE },
639 	{ "case",	CASE,	TRUE },
640 	{ "esac",	ESAC,	TRUE },
641 	{ "for",	FOR,	TRUE },
642 #ifdef KSH
643 	{ "select",	SELECT,	TRUE },
644 #endif /* KSH */
645 	{ "while",	WHILE,	TRUE },
646 	{ "until",	UNTIL,	TRUE },
647 	{ "do",		DO,	TRUE },
648 	{ "done",	DONE,	TRUE },
649 	{ "in",		IN,	TRUE },
650 	{ "function",	FUNCTION, TRUE },
651 	{ "time",	TIME,	TRUE },
652 	{ "{",		'{',	TRUE },
653 	{ "}",		'}',	TRUE },
654 	{ "!",		BANG,	TRUE },
655 #ifdef KSH
656 	{ "[[",		DBRACKET, TRUE },
657 #endif /* KSH */
658 	/* Lexical tokens (0[EOF], LWORD and REDIR handled specially) */
659 	{ "&&",		LOGAND,	FALSE },
660 	{ "||",		LOGOR,	FALSE },
661 	{ ";;",		BREAK,	FALSE },
662 #ifdef KSH
663 	{ "((",		MDPAREN, FALSE },
664 	{ "|&",		COPROC,	FALSE },
665 #endif /* KSH */
666 	/* and some special cases... */
667 	{ "newline",	'\n',	FALSE },
668 	{ 0 }
669 };
670 
671 void
672 initkeywords()
673 {
674 	register struct tokeninfo const *tt;
675 	register struct tbl *p;
676 
677 	tinit(&keywords, APERM, 32); /* must be 2^n (currently 20 keywords) */
678 	for (tt = tokentab; tt->name; tt++) {
679 		if (tt->reserved) {
680 			p = tenter(&keywords, tt->name, hash(tt->name));
681 			p->flag |= DEFINED|ISSET;
682 			p->type = CKEYWD;
683 			p->val.i = tt->val;
684 		}
685 	}
686 }
687 
688 static void
689 syntaxerr(what)
690 	const char *what;
691 {
692 	char redir[6];	/* 2<<- is the longest redirection, I think */
693 	const char *s;
694 	struct tokeninfo const *tt;
695 	int c;
696 
697 	if (!what)
698 		what = "unexpected";
699 	REJECT;
700 	c = token(0);
701     Again:
702 	switch (c) {
703 	case 0:
704 		if (multiline.on && multiline.start_token) {
705 			multiline.on = FALSE; /* avoid infinate loops */
706 			c = multiline.start_token;
707 			source->errline = multiline.start_line;
708 			what = "unmatched";
709 			goto Again;
710 		}
711 		/* don't quote the EOF */
712 		yyerror("syntax error: unexpected EOF\n");
713 		/*NOTREACHED*/
714 
715 	case LWORD:
716 		s = snptreef((char *) 0, 32, "%S", yylval.cp);
717 		break;
718 
719 	case REDIR:
720 		s = snptreef(redir, sizeof(redir), "%R", yylval.iop);
721 		break;
722 
723 	default:
724 		for (tt = tokentab; tt->name; tt++)
725 			if (tt->val == c)
726 			    break;
727 		if (tt->name)
728 			s = tt->name;
729 		else {
730 			if (c > 0 && c < 256) {
731 				redir[0] = c;
732 				redir[1] = '\0';
733 			} else
734 				shf_snprintf(redir, sizeof(redir),
735 					"?%d", c);
736 			s = redir;
737 		}
738 	}
739 	yyerror("syntax error: `%s' %s\n", s, what);
740 }
741 
742 static void
743 multiline_push(save, tok)
744 	struct multiline_state *save;
745 	int tok;
746 {
747 	*save = multiline;
748 	multiline.on = TRUE;
749 	multiline.start_token = tok;
750 	multiline.start_line = source->line;
751 }
752 
753 static void
754 multiline_pop(saved)
755 	struct multiline_state *saved;
756 {
757 	multiline = *saved;
758 }
759 
760 static struct op *
761 newtp(type)
762 	int type;
763 {
764 	register struct op *t;
765 
766 	t = (struct op *) alloc(sizeof(*t), ATEMP);
767 	t->type = type;
768 	t->u.evalflags = 0;
769 	t->args = t->vars = NULL;
770 	t->ioact = NULL;
771 	t->left = t->right = NULL;
772 	t->str = NULL;
773 	return (t);
774 }
775 
776 struct op *
777 compile(s)
778 	Source *s;
779 {
780 	yynerrs = 0;
781 	multiline.on = s->type == SSTRING;
782 	multiline.start_token = 0;
783 	multiline.start_line = 0;
784 	herep = heres;
785 	source = s;
786 	yyparse();
787 	return outtree;
788 }
789 
790 /* This kludge exists to take care of sh/at&t ksh oddity in which
791  * the arguments of alias/export/readonly/typeset have no field
792  * splitting, file globbing, or (normal) tilde expansion done.
793  * at&t ksh seems to do something similar to this since
794  *	$ touch a=a; typeset a=[ab]; echo "$a"
795  *	a=[ab]
796  *	$ x=typeset; $x a=[ab]; echo "$a"
797  *	a=a
798  *	$
799  */
800 static int
801 assign_command(s)
802 	char *s;
803 {
804 	char c = *s;
805 
806 	if (Flag(FPOSIX) || !*s)
807 		return 0;
808 	return     (c == 'a' && strcmp(s, "alias") == 0)
809 		|| (c == 'e' && strcmp(s, "export") == 0)
810 		|| (c == 'r' && strcmp(s, "readonly") == 0)
811 		|| (c == 't' && strcmp(s, "typeset") == 0);
812 }
813 
814 /* Check if we are in the middle of reading an alias */
815 static int
816 inalias(s)
817 	struct source *s;
818 {
819 	for (; s && s->type == SALIAS; s = s->next)
820 		if (!(s->flags & SF_ALIASEND))
821 			return 1;
822 	return 0;
823 }
824 
825 
826 #ifdef KSH
827 /* Order important - indexed by Test_meta values
828  * Note that ||, &&, ( and ) can't appear in as unquoted strings
829  * in normal shell input, so these can be interpreted unambiguously
830  * in the evaluation pass.
831  */
832 static const char dbtest_or[] = { CHAR, '|', CHAR, '|', EOS };
833 static const char dbtest_and[] = { CHAR, '&', CHAR, '&', EOS };
834 static const char dbtest_not[] = { CHAR, '!', EOS };
835 static const char dbtest_oparen[] = { CHAR, '(', EOS };
836 static const char dbtest_cparen[] = { CHAR, ')', EOS };
837 const char *const dbtest_tokens[] = {
838 			dbtest_or, dbtest_and, dbtest_not,
839 			dbtest_oparen, dbtest_cparen
840 		};
841 const char db_close[] = { CHAR, ']', CHAR, ']', EOS };
842 const char db_lthan[] = { CHAR, '<', EOS };
843 const char db_gthan[] = { CHAR, '>', EOS };
844 
845 /* Test if the current token is a whatever.  Accepts the current token if
846  * it is.  Returns 0 if it is not, non-zero if it is (in the case of
847  * TM_UNOP and TM_BINOP, the returned value is a Test_op).
848  */
849 static int
850 dbtestp_isa(te, meta)
851 	Test_env *te;
852 	Test_meta meta;
853 {
854 	int c = tpeek(ARRAYVAR | (meta == TM_BINOP ? 0 : CONTIN));
855 	int uqword = 0;
856 	char *save = (char *) 0;
857 	int ret = 0;
858 
859 	/* unquoted word? */
860 	uqword = c == LWORD && *ident;
861 
862 	if (meta == TM_OR)
863 		ret = c == LOGOR;
864 	else if (meta == TM_AND)
865 		ret = c == LOGAND;
866 	else if (meta == TM_NOT)
867 		ret = uqword && strcmp(yylval.cp, dbtest_tokens[(int) TM_NOT]) == 0;
868 	else if (meta == TM_OPAREN)
869 		ret = c == '(' /*)*/;
870 	else if (meta == TM_CPAREN)
871 		ret = c == /*(*/ ')';
872 	else if (meta == TM_UNOP || meta == TM_BINOP) {
873 		if (meta == TM_BINOP && c == REDIR
874 		    && (yylval.iop->flag == IOREAD
875 			|| yylval.iop->flag == IOWRITE))
876 		{
877 			ret = 1;
878 			save = wdcopy(yylval.iop->flag == IOREAD ?
879 				db_lthan : db_gthan, ATEMP);
880 		} else if (uqword && (ret = (int) test_isop(te, meta, ident)))
881 			save = yylval.cp;
882 	} else /* meta == TM_END */
883 		ret = uqword && strcmp(yylval.cp, db_close) == 0;
884 	if (ret) {
885 		ACCEPT;
886 		if (meta != TM_END) {
887 			if (!save)
888 				save = wdcopy(dbtest_tokens[(int) meta], ATEMP);
889 			XPput(*te->pos.av, save);
890 		}
891 	}
892 	return ret;
893 }
894 
895 static const char *
896 dbtestp_getopnd(te, op, do_eval)
897 	Test_env *te;
898 	Test_op op;
899 	int do_eval;
900 {
901 	int c = tpeek(ARRAYVAR);
902 
903 	if (c != LWORD)
904 		return (const char *) 0;
905 
906 	ACCEPT;
907 	XPput(*te->pos.av, yylval.cp);
908 
909 	return null;
910 }
911 
912 static int
913 dbtestp_eval(te, op, opnd1, opnd2, do_eval)
914 	Test_env *te;
915 	Test_op op;
916 	const char *opnd1;
917 	const char *opnd2;
918 	int do_eval;
919 {
920 	return 1;
921 }
922 
923 static void
924 dbtestp_error(te, offset, msg)
925 	Test_env *te;
926 	int offset;
927 	const char *msg;
928 {
929 	te->flags |= TEF_ERROR;
930 
931 	if (offset < 0) {
932 		REJECT;
933 		/* Kludgy to say the least... */
934 		symbol = LWORD;
935 		yylval.cp = *(XPptrv(*te->pos.av) + XPsize(*te->pos.av)
936 				+ offset);
937 	}
938 	syntaxerr(msg);
939 }
940 #endif /* KSH */
941