xref: /openbsd-src/usr.bin/less/command.c (revision 91f110e064cd7c194e59e019b83bb7496c1c84d4)
1 /*
2  * Copyright (C) 1984-2011  Mark Nudelman
3  *
4  * You may distribute under the terms of either the GNU General Public
5  * License or the Less License, as specified in the README file.
6  *
7  * For more information about less, or for information on how to
8  * contact the author, see the README file.
9  */
10 
11 
12 /*
13  * User-level command processor.
14  */
15 
16 #include "less.h"
17 #if MSDOS_COMPILER==WIN32C
18 #include <windows.h>
19 #endif
20 #include "position.h"
21 #include "option.h"
22 #include "cmd.h"
23 
24 extern int erase_char, erase2_char, kill_char;
25 extern volatile sig_atomic_t sigs;
26 extern int quit_if_one_screen;
27 extern int squished;
28 extern int sc_width;
29 extern int sc_height;
30 extern int swindow;
31 extern int jump_sline;
32 extern int quitting;
33 extern int wscroll;
34 extern int top_scroll;
35 extern int ignore_eoi;
36 extern int secure;
37 extern int hshift;
38 extern int show_attn;
39 extern char *every_first_cmd;
40 extern char *curr_altfilename;
41 extern char version[];
42 extern struct scrpos initial_scrpos;
43 extern IFILE curr_ifile;
44 extern void constant *ml_search;
45 extern void constant *ml_examine;
46 #if SHELL_ESCAPE || PIPEC
47 extern void constant *ml_shell;
48 #endif
49 #if EDITOR
50 extern char *editor;
51 extern char *editproto;
52 #endif
53 extern int screen_trashed;	/* The screen has been overwritten */
54 extern int shift_count;
55 extern int oldbot;
56 extern int forw_prompt;
57 extern int be_helpful;
58 extern int less_is_more;
59 extern int quit_at_eof;
60 
61 #if SHELL_ESCAPE
62 static char *shellcmd = NULL;	/* For holding last shell command for "!!" */
63 #endif
64 static int mca;			/* The multicharacter command (action) */
65 static int search_type;		/* The previous type of search */
66 static LINENUM number;		/* The number typed by the user */
67 static long fraction;		/* The fractional part of the number */
68 static struct loption *curropt;
69 static int opt_lower;
70 static int optflag;
71 static int optgetname;
72 static POSITION bottompos;
73 static int save_hshift;
74 static char *help_prompt;
75 #if PIPEC
76 static char pipec;
77 #endif
78 
79 struct ungot {
80 	struct ungot *ug_next;
81 	char ug_char;
82 };
83 static struct ungot* ungot = NULL;
84 static int unget_end = 0;
85 
86 static void multi_search();
87 
88 /*
89  * Move the cursor to start of prompt line before executing a command.
90  * This looks nicer if the command takes a long time before
91  * updating the screen.
92  */
93 	static void
94 cmd_exec()
95 {
96 #if HILITE_SEARCH
97 	clear_attn();
98 #endif
99 	clear_bot();
100 	flush();
101 }
102 
103 /*
104  * Set up the display to start a new multi-character command.
105  */
106 	static void
107 start_mca(action, prompt, mlist, cmdflags)
108 	int action;
109 	char *prompt;
110 	void *mlist;
111 	int cmdflags;
112 {
113 	mca = action;
114 	clear_bot();
115 	clear_cmd();
116 	cmd_putstr(prompt);
117 	set_mlist(mlist, cmdflags);
118 }
119 
120 	public int
121 in_mca()
122 {
123 	return (mca != 0 && mca != A_PREFIX);
124 }
125 
126 /*
127  * Set up the display to start a new search command.
128  */
129 	static void
130 mca_search()
131 {
132 #if HILITE_SEARCH
133 	if (search_type & SRCH_FILTER)
134 		mca = A_FILTER;
135 	else
136 #endif
137 	if (search_type & SRCH_FORW)
138 		mca = A_F_SEARCH;
139 	else
140 		mca = A_B_SEARCH;
141 
142 	clear_bot();
143 	clear_cmd();
144 
145 	if (search_type & SRCH_NO_MATCH)
146 		cmd_putstr("Non-match ");
147 	if (search_type & SRCH_FIRST_FILE)
148 		cmd_putstr("First-file ");
149 	if (search_type & SRCH_PAST_EOF)
150 		cmd_putstr("EOF-ignore ");
151 	if (search_type & SRCH_NO_MOVE)
152 		cmd_putstr("Keep-pos ");
153 	if (search_type & SRCH_NO_REGEX)
154 		cmd_putstr("Regex-off ");
155 
156 #if HILITE_SEARCH
157 	if (search_type & SRCH_FILTER)
158 		cmd_putstr("&/");
159 	else
160 #endif
161 	if (search_type & SRCH_FORW)
162 		cmd_putstr("/");
163 	else
164 		cmd_putstr("?");
165 	set_mlist(ml_search, 0);
166 }
167 
168 /*
169  * Set up the display to start a new toggle-option command.
170  */
171 	static void
172 mca_opt_toggle()
173 {
174 	int no_prompt;
175 	int flag;
176 	char *dash;
177 
178 	no_prompt = (optflag & OPT_NO_PROMPT);
179 	flag = (optflag & ~OPT_NO_PROMPT);
180 	dash = (flag == OPT_NO_TOGGLE) ? "_" : "-";
181 
182 	mca = A_OPT_TOGGLE;
183 	clear_bot();
184 	clear_cmd();
185 	cmd_putstr(dash);
186 #if GNU_OPTIONS
187 	if (optgetname)
188 		cmd_putstr(dash);
189 #endif
190 	if (no_prompt)
191 		cmd_putstr("(P)");
192 	switch (flag)
193 	{
194 	case OPT_UNSET:
195 		cmd_putstr("+");
196 		break;
197 	case OPT_SET:
198 		cmd_putstr("!");
199 		break;
200 	}
201 	set_mlist(NULL, 0);
202 }
203 
204 /*
205  * Execute a multicharacter command.
206  */
207 	static void
208 exec_mca()
209 {
210 	register char *cbuf;
211 
212 	cmd_exec();
213 	cbuf = get_cmdbuf();
214 
215 	switch (mca)
216 	{
217 	case A_F_SEARCH:
218 	case A_B_SEARCH:
219 		multi_search(cbuf, (int) number);
220 		break;
221 #if HILITE_SEARCH
222 	case A_FILTER:
223 		search_type ^= SRCH_NO_MATCH;
224 		set_filter_pattern(cbuf, search_type);
225 		break;
226 #endif
227 	case A_FIRSTCMD:
228 		/*
229 		 * Skip leading spaces or + signs in the string.
230 		 */
231 		while (*cbuf == '+' || *cbuf == ' ')
232 			cbuf++;
233 		if (every_first_cmd != NULL)
234 			free(every_first_cmd);
235 		if (*cbuf == '\0')
236 			every_first_cmd = NULL;
237 		else
238 			every_first_cmd = save(cbuf);
239 		break;
240 	case A_OPT_TOGGLE:
241 		toggle_option(curropt, opt_lower, cbuf, optflag);
242 		curropt = NULL;
243 		break;
244 	case A_F_BRACKET:
245 		match_brac(cbuf[0], cbuf[1], 1, (int) number);
246 		break;
247 	case A_B_BRACKET:
248 		match_brac(cbuf[1], cbuf[0], 0, (int) number);
249 		break;
250 #if EXAMINE
251 	case A_EXAMINE:
252 		if (secure)
253 			break;
254 		edit_list(cbuf);
255 #if TAGS
256 		/* If tag structure is loaded then clean it up. */
257 		cleantags();
258 #endif
259 		break;
260 #endif
261 #if SHELL_ESCAPE
262 	case A_SHELL:
263 		/*
264 		 * !! just uses whatever is in shellcmd.
265 		 * Otherwise, copy cmdbuf to shellcmd,
266 		 * expanding any special characters ("%" or "#").
267 		 */
268 		if (*cbuf != '!')
269 		{
270 			if (shellcmd != NULL)
271 				free(shellcmd);
272 			shellcmd = fexpand(cbuf);
273 		}
274 
275 		if (secure)
276 			break;
277 		if (shellcmd == NULL)
278 			lsystem("", "!done");
279 		else
280 			lsystem(shellcmd, "!done");
281 		break;
282 #endif
283 #if PIPEC
284 	case A_PIPE:
285 		if (secure)
286 			break;
287 		(void) pipe_mark(pipec, cbuf);
288 		error("|done", NULL_PARG);
289 		break;
290 #endif
291 	}
292 }
293 
294 /*
295  * Is a character an erase or kill char?
296  */
297 	static int
298 is_erase_char(c)
299 	int c;
300 {
301 	return (c == erase_char || c == erase2_char || c == kill_char);
302 }
303 
304 /*
305  * Handle the first char of an option (after the initial dash).
306  */
307 	static int
308 mca_opt_first_char(c)
309     int c;
310 {
311 	int flag = (optflag & ~OPT_NO_PROMPT);
312 #if GNU_OPTIONS
313 	if (flag == OPT_NO_TOGGLE)
314 	{
315 		switch (c)
316 		{
317 		case '_':
318 			/* "__" = long option name. */
319 			optgetname = TRUE;
320 			mca_opt_toggle();
321 			return (MCA_MORE);
322 		}
323 	} else
324 #endif
325 	{
326 		switch (c)
327 		{
328 		case '+':
329 			/* "-+" = UNSET. */
330 			optflag = (flag == OPT_UNSET) ?
331 				OPT_TOGGLE : OPT_UNSET;
332 			mca_opt_toggle();
333 			return (MCA_MORE);
334 		case '!':
335 			/* "-!" = SET */
336 			optflag = (flag == OPT_SET) ?
337 				OPT_TOGGLE : OPT_SET;
338 			mca_opt_toggle();
339 			return (MCA_MORE);
340 		case CONTROL('P'):
341 			optflag ^= OPT_NO_PROMPT;
342 			mca_opt_toggle();
343 			return (MCA_MORE);
344 #if GNU_OPTIONS
345 		case '-':
346 			/* "--" = long option name. */
347 			optgetname = TRUE;
348 			mca_opt_toggle();
349 			return (MCA_MORE);
350 #endif
351 		}
352 	}
353 	/* Char was not handled here. */
354 	return (NO_MCA);
355 }
356 
357 #if GNU_OPTIONS
358 /*
359  * Add a char to a long option name.
360  * See if we've got a match for an option name yet.
361  * If so, display the complete name and stop
362  * accepting chars until user hits RETURN.
363  */
364 	static int
365 mca_opt_nonfirst_char(c)
366 	int c;
367 {
368 	char *p;
369 	char *oname;
370 
371 	if (curropt != NULL)
372 	{
373 		/*
374 		 * Already have a match for the name.
375 		 * Don't accept anything but erase/kill.
376 		 */
377 		if (is_erase_char(c))
378 			return (MCA_DONE);
379 		return (MCA_MORE);
380 	}
381 	/*
382 	 * Add char to cmd buffer and try to match
383 	 * the option name.
384 	 */
385 	if (cmd_char(c) == CC_QUIT)
386 		return (MCA_DONE);
387 	p = get_cmdbuf();
388 	opt_lower = ASCII_IS_LOWER(p[0]);
389 	curropt = findopt_name(&p, &oname, NULL);
390 	if (curropt != NULL)
391 	{
392 		/*
393 		 * Got a match.
394 		 * Remember the option and
395 		 * display the full option name.
396 		 */
397 		cmd_reset();
398 		mca_opt_toggle();
399 		for (p = oname;  *p != '\0';  p++)
400 		{
401 			c = *p;
402 			if (!opt_lower && ASCII_IS_LOWER(c))
403 				c = ASCII_TO_UPPER(c);
404 			if (cmd_char(c) != CC_OK)
405 				return (MCA_DONE);
406 		}
407 	}
408 	return (MCA_MORE);
409 }
410 #endif
411 
412 /*
413  * Handle a char of an option toggle command.
414  */
415 	static int
416 mca_opt_char(c)
417 	int c;
418 {
419 	PARG parg;
420 
421 	/*
422 	 * This may be a short option (single char),
423 	 * or one char of a long option name,
424 	 * or one char of the option parameter.
425 	 */
426 	if (curropt == NULL && len_cmdbuf() == 0)
427 	{
428 		int ret = mca_opt_first_char(c);
429 		if (ret != NO_MCA)
430 			return (ret);
431 	}
432 #if GNU_OPTIONS
433 	if (optgetname)
434 	{
435 		/* We're getting a long option name.  */
436 		if (c != '\n' && c != '\r')
437 			return (mca_opt_nonfirst_char(c));
438 		if (curropt == NULL)
439 		{
440 			parg.p_string = get_cmdbuf();
441 			error("There is no --%s option", &parg);
442 			return (MCA_DONE);
443 		}
444 		optgetname = FALSE;
445 		cmd_reset();
446 	} else
447 #endif
448 	{
449 		if (is_erase_char(c))
450 			return (NO_MCA);
451 		if (curropt != NULL)
452 			/* We're getting the option parameter. */
453 			return (NO_MCA);
454 		curropt = findopt(c);
455 		if (curropt == NULL)
456 		{
457 			parg.p_string = propt(c);
458 			error("There is no %s option", &parg);
459 			return (MCA_DONE);
460 		}
461 	}
462 	/*
463 	 * If the option which was entered does not take a
464 	 * parameter, toggle the option immediately,
465 	 * so user doesn't have to hit RETURN.
466 	 */
467 	if ((optflag & ~OPT_NO_PROMPT) != OPT_TOGGLE ||
468 	    !opt_has_param(curropt))
469 	{
470 		toggle_option(curropt, ASCII_IS_LOWER(c), "", optflag);
471 		return (MCA_DONE);
472 	}
473 	/*
474 	 * Display a prompt appropriate for the option parameter.
475 	 */
476 	start_mca(A_OPT_TOGGLE, opt_prompt(curropt), (void*)NULL, 0);
477 	return (MCA_MORE);
478 }
479 
480 /*
481  * Handle a char of a search command.
482  */
483 	static int
484 mca_search_char(c)
485 	int c;
486 {
487 	int flag = 0;
488 
489 	/*
490 	 * Certain characters as the first char of
491 	 * the pattern have special meaning:
492 	 *	!  Toggle the NO_MATCH flag
493 	 *	*  Toggle the PAST_EOF flag
494 	 *	@  Toggle the FIRST_FILE flag
495 	 */
496 	if (len_cmdbuf() > 0)
497 		return (NO_MCA);
498 
499 	switch (c)
500 	{
501 	case CONTROL('E'): /* ignore END of file */
502 	case '*':
503 		if (mca != A_FILTER)
504 			flag = SRCH_PAST_EOF;
505 		break;
506 	case CONTROL('F'): /* FIRST file */
507 	case '@':
508 		if (mca != A_FILTER)
509 			flag = SRCH_FIRST_FILE;
510 		break;
511 	case CONTROL('K'): /* KEEP position */
512 		if (mca != A_FILTER)
513 			flag = SRCH_NO_MOVE;
514 		break;
515 	case CONTROL('R'): /* Don't use REGULAR EXPRESSIONS */
516 		flag = SRCH_NO_REGEX;
517 		break;
518 	case CONTROL('N'): /* NOT match */
519 	case '!':
520 		flag = SRCH_NO_MATCH;
521 		break;
522 	}
523 
524 	if (flag != 0)
525 	{
526 		search_type ^= flag;
527 		mca_search();
528 		return (MCA_MORE);
529 	}
530 	return (NO_MCA);
531 }
532 
533 /*
534  * Handle a character of a multi-character command.
535  */
536 	static int
537 mca_char(c)
538 	int c;
539 {
540 	int ret;
541 
542 	switch (mca)
543 	{
544 	case 0:
545 		/*
546 		 * We're not in a multicharacter command.
547 		 */
548 		return (NO_MCA);
549 
550 	case A_PREFIX:
551 		/*
552 		 * In the prefix of a command.
553 		 * This not considered a multichar command
554 		 * (even tho it uses cmdbuf, etc.).
555 		 * It is handled in the commands() switch.
556 		 */
557 		return (NO_MCA);
558 
559 	case A_DIGIT:
560 		/*
561 		 * Entering digits of a number.
562 		 * Terminated by a non-digit.
563 		 */
564 		if (!((c >= '0' && c <= '9') || c == '.') &&
565 		  editchar(c, EC_PEEK|EC_NOHISTORY|EC_NOCOMPLETE|EC_NORIGHTLEFT) == A_INVALID)
566 		{
567 			/*
568 			 * Not part of the number.
569 			 * End the number and treat this char
570 			 * as a normal command character.
571 			 */
572 			number = cmd_int(&fraction);
573 			mca = 0;
574 			cmd_accept();
575 			return (NO_MCA);
576 		}
577 		break;
578 
579 	case A_OPT_TOGGLE:
580 		ret = mca_opt_char(c);
581 		if (ret != NO_MCA)
582 			return (ret);
583 		break;
584 
585 	case A_F_SEARCH:
586 	case A_B_SEARCH:
587 	case A_FILTER:
588 		ret = mca_search_char(c);
589 		if (ret != NO_MCA)
590 			return (ret);
591 		break;
592 
593 	default:
594 		/* Other multicharacter command. */
595 		break;
596 	}
597 
598 	/*
599 	 * The multichar command is terminated by a newline.
600 	 */
601 	if (c == '\n' || c == '\r')
602 	{
603 		/*
604 		 * Execute the command.
605 		 */
606 		exec_mca();
607 		return (MCA_DONE);
608 	}
609 
610 	/*
611 	 * Append the char to the command buffer.
612 	 */
613 	if (cmd_char(c) == CC_QUIT)
614 		/*
615 		 * Abort the multi-char command.
616 		 */
617 		return (MCA_DONE);
618 
619 	if ((mca == A_F_BRACKET || mca == A_B_BRACKET) && len_cmdbuf() >= 2)
620 	{
621 		/*
622 		 * Special case for the bracket-matching commands.
623 		 * Execute the command after getting exactly two
624 		 * characters from the user.
625 		 */
626 		exec_mca();
627 		return (MCA_DONE);
628 	}
629 
630 	/*
631 	 * Need another character.
632 	 */
633 	return (MCA_MORE);
634 }
635 
636 /*
637  * Discard any buffered file data.
638  */
639 	static void
640 clear_buffers()
641 {
642 	if (!(ch_getflags() & CH_CANSEEK))
643 		return;
644 	ch_flush();
645 	clr_linenum();
646 #if HILITE_SEARCH
647 	clr_hilite();
648 #endif
649 }
650 
651 /*
652  * Make sure the screen is displayed.
653  */
654 	static void
655 make_display()
656 {
657 	/*
658 	 * If nothing is displayed yet, display starting from initial_scrpos.
659 	 */
660 	if (empty_screen())
661 	{
662 		if (initial_scrpos.pos == NULL_POSITION)
663 			/*
664 			 * {{ Maybe this should be:
665 			 *    jump_loc(ch_zero(), jump_sline);
666 			 *    but this behavior seems rather unexpected
667 			 *    on the first screen. }}
668 			 */
669 			jump_loc(ch_zero(), 1);
670 		else
671 			jump_loc(initial_scrpos.pos, initial_scrpos.ln);
672 	} else if (screen_trashed)
673 	{
674 		int save_top_scroll = top_scroll;
675 		int save_ignore_eoi = ignore_eoi;
676 		top_scroll = 1;
677 		ignore_eoi = 0;
678 		if (screen_trashed == 2)
679 		{
680 			/* Special case used by ignore_eoi: re-open the input file
681 			 * and jump to the end of the file. */
682 			reopen_curr_ifile();
683 			jump_forw();
684 		}
685 		repaint();
686 		top_scroll = save_top_scroll;
687 		ignore_eoi = save_ignore_eoi;
688 	}
689 }
690 
691 /*
692  * Display the appropriate prompt.
693  */
694 	static void
695 prompt()
696 {
697 	register char *p;
698 
699 	if (ungot != NULL)
700 	{
701 		/*
702 		 * No prompt necessary if commands are from
703 		 * ungotten chars rather than from the user.
704 		 */
705 		return;
706 	}
707 
708 	/*
709 	 * Make sure the screen is displayed.
710 	 */
711 	make_display();
712 	bottompos = position(BOTTOM_PLUS_ONE);
713 
714 	/*
715 	 * If we've hit EOF on the last file and the -E flag is set, quit.
716 	 */
717 	if (get_quit_at_eof() == OPT_ONPLUS &&
718 	    eof_displayed() && !(ch_getflags() & CH_HELPFILE) &&
719 	    next_ifile(curr_ifile) == NULL_IFILE)
720 		quit(QUIT_OK);
721 
722 	/*
723 	 * If the entire file is displayed and the -F flag is set, quit.
724 	 */
725 	if (quit_if_one_screen &&
726 	    entire_file_displayed() && !(ch_getflags() & CH_HELPFILE) &&
727 	    next_ifile(curr_ifile) == NULL_IFILE)
728 		quit(QUIT_OK);
729 
730 #if MSDOS_COMPILER==WIN32C
731 	/*
732 	 * In Win32, display the file name in the window title.
733 	 */
734 	if (!(ch_getflags() & CH_HELPFILE))
735 		SetConsoleTitle(pr_expand("Less?f - %f.", 0));
736 #endif
737 	/*
738 	 * Select the proper prompt and display it.
739 	 */
740 	/*
741 	 * If the previous action was a forward movement,
742 	 * don't clear the bottom line of the display;
743 	 * just print the prompt since the forward movement guarantees
744 	 * that we're in the right position to display the prompt.
745 	 * Clearing the line could cause a problem: for example, if the last
746 	 * line displayed ended at the right screen edge without a newline,
747 	 * then clearing would clear the last displayed line rather than
748 	 * the prompt line.
749 	 */
750 	if (!forw_prompt)
751 		clear_bot();
752 	clear_cmd();
753 	forw_prompt = 0;
754 	p = help_prompt ? help_prompt : pr_string();
755 	if (is_filtering())
756 		putstr("& ");
757 	if (p == NULL || *p == '\0')
758 		putchr(':');
759 	else
760 	{
761 		at_enter(AT_STANDOUT);
762 		putstr(p);
763 		if (be_helpful && !help_prompt && strlen(p) + 40 < sc_width)
764 			putstr(" [Press space to continue, 'q' to quit.]");
765 		at_exit();
766 	}
767 	help_prompt = NULL;
768 	clear_eol();
769 }
770 
771 /*
772  * Display the less version message.
773  */
774 	public void
775 dispversion()
776 {
777 	PARG parg;
778 
779 	parg.p_string = version;
780 	error("less %s", &parg);
781 }
782 
783 /*
784  * Get command character.
785  * The character normally comes from the keyboard,
786  * but may come from ungotten characters
787  * (characters previously given to ungetcc or ungetsc).
788  */
789 	public int
790 getcc()
791 {
792 	if (unget_end)
793 	{
794 		/*
795 		 * We have just run out of ungotten chars.
796 		 */
797 		unget_end = 0;
798 		if (len_cmdbuf() == 0 || !empty_screen())
799 			return (getchr());
800 		/*
801 		 * Command is incomplete, so try to complete it.
802 		 */
803 		switch (mca)
804 		{
805 		case A_DIGIT:
806 			/*
807 			 * We have a number but no command.  Treat as #g.
808 			 */
809 			return ('g');
810 
811 		case A_F_SEARCH:
812 		case A_B_SEARCH:
813 			/*
814 			 * We have "/string" but no newline.  Add the \n.
815 			 */
816 			return ('\n');
817 
818 		default:
819 			/*
820 			 * Some other incomplete command.  Let user complete it.
821 			 */
822 			return (getchr());
823 		}
824 	}
825 
826 	if (ungot == NULL)
827 	{
828 		/*
829 		 * Normal case: no ungotten chars, so get one from the user.
830 		 */
831 		return (getchr());
832 	}
833 
834 	/*
835 	 * Return the next ungotten char.
836 	 */
837 	{
838 		struct ungot *ug = ungot;
839 		char c = ug->ug_char;
840 		ungot = ug->ug_next;
841 		free(ug);
842 		unget_end = (ungot == NULL);
843 		return (c);
844 	}
845 }
846 
847 /*
848  * "Unget" a command character.
849  * The next getcc() will return this character.
850  */
851 	public void
852 ungetcc(c)
853 	int c;
854 {
855 	struct ungot *ug = (struct ungot *) ecalloc(1, sizeof(struct ungot));
856 
857 	ug->ug_char = c;
858 	ug->ug_next = ungot;
859 	ungot = ug;
860 	unget_end = 0;
861 }
862 
863 /*
864  * Unget a whole string of command characters.
865  * The next sequence of getcc()'s will return this string.
866  */
867 	public void
868 ungetsc(s)
869 	char *s;
870 {
871 	register char *p;
872 
873 	for (p = s + strlen(s) - 1;  p >= s;  p--)
874 		ungetcc(*p);
875 }
876 
877 /*
878  * Search for a pattern, possibly in multiple files.
879  * If SRCH_FIRST_FILE is set, begin searching at the first file.
880  * If SRCH_PAST_EOF is set, continue the search thru multiple files.
881  */
882 	static void
883 multi_search(pattern, n)
884 	char *pattern;
885 	int n;
886 {
887 	register int nomore;
888 	IFILE save_ifile;
889 	int changed_file;
890 
891 	changed_file = 0;
892 	save_ifile = save_curr_ifile();
893 
894 	if (search_type & SRCH_FIRST_FILE)
895 	{
896 		/*
897 		 * Start at the first (or last) file
898 		 * in the command line list.
899 		 */
900 		if (search_type & SRCH_FORW)
901 			nomore = edit_first();
902 		else
903 			nomore = edit_last();
904 		if (nomore)
905 		{
906 			unsave_ifile(save_ifile);
907 			return;
908 		}
909 		changed_file = 1;
910 		search_type &= ~SRCH_FIRST_FILE;
911 	}
912 
913 	for (;;)
914 	{
915 		n = search(search_type, pattern, n);
916 		/*
917 		 * The SRCH_NO_MOVE flag doesn't "stick": it gets cleared
918 		 * after being used once.  This allows "n" to work after
919 		 * using a /@@ search.
920 		 */
921 		search_type &= ~SRCH_NO_MOVE;
922 		if (n == 0)
923 		{
924 			/*
925 			 * Found it.
926 			 */
927 			unsave_ifile(save_ifile);
928 			return;
929 		}
930 
931 		if (n < 0)
932 			/*
933 			 * Some kind of error in the search.
934 			 * Error message has been printed by search().
935 			 */
936 			break;
937 
938 		if ((search_type & SRCH_PAST_EOF) == 0)
939 			/*
940 			 * We didn't find a match, but we're
941 			 * supposed to search only one file.
942 			 */
943 			break;
944 		/*
945 		 * Move on to the next file.
946 		 */
947 		if (search_type & SRCH_FORW)
948 			nomore = edit_next(1);
949 		else
950 			nomore = edit_prev(1);
951 		if (nomore)
952 			break;
953 		changed_file = 1;
954 	}
955 
956 	/*
957 	 * Didn't find it.
958 	 * Print an error message if we haven't already.
959 	 */
960 	if (n > 0)
961 		error("Pattern not found", NULL_PARG);
962 
963 	if (changed_file)
964 	{
965 		/*
966 		 * Restore the file we were originally viewing.
967 		 */
968 		reedit_ifile(save_ifile);
969 	} else
970 	{
971 		unsave_ifile(save_ifile);
972 	}
973 }
974 
975 /*
976  * Main command processor.
977  * Accept and execute commands until a quit command.
978  */
979 	public void
980 commands()
981 {
982 	register int c;
983 	register int action;
984 	register char *cbuf;
985 	int newaction;
986 	int save_search_type;
987 	char *extra;
988 	char tbuf[2];
989 	PARG parg;
990 	IFILE old_ifile;
991 	IFILE new_ifile;
992 	char *tagfile;
993 
994 	search_type = SRCH_FORW;
995 	wscroll = (sc_height + 1) / 2;
996 	newaction = A_NOACTION;
997 
998 	for (;;)
999 	{
1000 		mca = 0;
1001 		cmd_accept();
1002 		number = 0;
1003 		curropt = NULL;
1004 
1005 		/*
1006 		 * See if any signals need processing.
1007 		 */
1008 		if (sigs)
1009 		{
1010 			psignals();
1011 			if (quitting)
1012 				quit(QUIT_SAVED_STATUS);
1013 		}
1014 
1015 		/*
1016 		 * See if window size changed, for systems that don't
1017 		 * generate SIGWINCH.
1018 		 */
1019 		check_winch();
1020 
1021 		/*
1022 		 * Display prompt and accept a character.
1023 		 */
1024 		cmd_reset();
1025 		prompt();
1026 		if (sigs)
1027 			continue;
1028 		if (newaction == A_NOACTION)
1029 			c = getcc();
1030 
1031 	again:
1032 		if (sigs)
1033 			continue;
1034 
1035 		if (newaction != A_NOACTION)
1036 		{
1037 			action = newaction;
1038 			newaction = A_NOACTION;
1039 		} else
1040 		{
1041 			/*
1042 			 * If we are in a multicharacter command, call mca_char.
1043 			 * Otherwise we call fcmd_decode to determine the
1044 			 * action to be performed.
1045 			 */
1046 			if (mca)
1047 				switch (mca_char(c))
1048 				{
1049 				case MCA_MORE:
1050 					/*
1051 					 * Need another character.
1052 					 */
1053 					c = getcc();
1054 					goto again;
1055 				case MCA_DONE:
1056 					/*
1057 					 * Command has been handled by mca_char.
1058 					 * Start clean with a prompt.
1059 					 */
1060 					continue;
1061 				case NO_MCA:
1062 					/*
1063 					 * Not a multi-char command
1064 					 * (at least, not anymore).
1065 					 */
1066 					break;
1067 				}
1068 
1069 			/*
1070 			 * Decode the command character and decide what to do.
1071 			 */
1072 			if (mca)
1073 			{
1074 				/*
1075 				 * We're in a multichar command.
1076 				 * Add the character to the command buffer
1077 				 * and display it on the screen.
1078 				 * If the user backspaces past the start
1079 				 * of the line, abort the command.
1080 				 */
1081 				if (cmd_char(c) == CC_QUIT || len_cmdbuf() == 0)
1082 					continue;
1083 				cbuf = get_cmdbuf();
1084 			} else
1085 			{
1086 				/*
1087 				 * Don't use cmd_char if we're starting fresh
1088 				 * at the beginning of a command, because we
1089 				 * don't want to echo the command until we know
1090 				 * it is a multichar command.  We also don't
1091 				 * want erase_char/kill_char to be treated
1092 				 * as line editing characters.
1093 				 */
1094 				tbuf[0] = c;
1095 				tbuf[1] = '\0';
1096 				cbuf = tbuf;
1097 			}
1098 			extra = NULL;
1099 			action = fcmd_decode(cbuf, &extra);
1100 			/*
1101 			 * If an "extra" string was returned,
1102 			 * process it as a string of command characters.
1103 			 */
1104 			if (extra != NULL)
1105 				ungetsc(extra);
1106 		}
1107 		/*
1108 		 * Clear the cmdbuf string.
1109 		 * (But not if we're in the prefix of a command,
1110 		 * because the partial command string is kept there.)
1111 		 */
1112 		if (action != A_PREFIX)
1113 			cmd_reset();
1114 
1115 		switch (action)
1116 		{
1117 		case A_DIGIT:
1118 			/*
1119 			 * First digit of a number.
1120 			 */
1121 			start_mca(A_DIGIT, ":", (void*)NULL, CF_QUIT_ON_ERASE);
1122 			goto again;
1123 
1124 		case A_F_WINDOW:
1125 			/*
1126 			 * Forward one window (and set the window size).
1127 			 */
1128 			if (number > 0)
1129 				swindow = (int) number;
1130 			/* FALLTHRU */
1131 		case A_F_SCREEN:
1132 			/*
1133 			 * Forward one screen.
1134 			 */
1135 			if (number <= 0)
1136 				number = get_swindow();
1137 			cmd_exec();
1138 			if (show_attn)
1139 				set_attnpos(bottompos);
1140 			forward((int) number, 0, 1);
1141 			break;
1142 
1143 		case A_B_WINDOW:
1144 			/*
1145 			 * Backward one window (and set the window size).
1146 			 */
1147 			if (number > 0)
1148 				swindow = (int) number;
1149 			/* FALLTHRU */
1150 		case A_B_SCREEN:
1151 			/*
1152 			 * Backward one screen.
1153 			 */
1154 			if (number <= 0)
1155 				number = get_swindow();
1156 			cmd_exec();
1157 			backward((int) number, 0, 1);
1158 			break;
1159 
1160 		case A_F_LINE:
1161 			/*
1162 			 * Forward N (default 1) line.
1163 			 */
1164 			if (number <= 0)
1165 				number = 1;
1166 			cmd_exec();
1167 			if (show_attn == OPT_ONPLUS && number > 1)
1168 				set_attnpos(bottompos);
1169 			forward((int) number, 0, 0);
1170 			break;
1171 
1172 		case A_B_LINE:
1173 			/*
1174 			 * Backward N (default 1) line.
1175 			 */
1176 			if (number <= 0)
1177 				number = 1;
1178 			cmd_exec();
1179 			backward((int) number, 0, 0);
1180 			break;
1181 
1182 		case A_FF_LINE:
1183 			/*
1184 			 * Force forward N (default 1) line.
1185 			 */
1186 			if (number <= 0)
1187 				number = 1;
1188 			cmd_exec();
1189 			if (show_attn == OPT_ONPLUS && number > 1)
1190 				set_attnpos(bottompos);
1191 			forward((int) number, 1, 0);
1192 			break;
1193 
1194 		case A_BF_LINE:
1195 			/*
1196 			 * Force backward N (default 1) line.
1197 			 */
1198 			if (number <= 0)
1199 				number = 1;
1200 			cmd_exec();
1201 			backward((int) number, 1, 0);
1202 			break;
1203 
1204 		case A_FF_SCREEN:
1205 			/*
1206 			 * Force forward one screen.
1207 			 */
1208 			if (number <= 0)
1209 				number = get_swindow();
1210 			cmd_exec();
1211 			if (show_attn == OPT_ONPLUS)
1212 				set_attnpos(bottompos);
1213 			forward((int) number, 1, 0);
1214 			break;
1215 
1216 		case A_F_FOREVER:
1217 			/*
1218 			 * Forward forever, ignoring EOF.
1219 			 */
1220 			if (ch_getflags() & CH_HELPFILE)
1221 				break;
1222 			cmd_exec();
1223 			jump_forw();
1224 			ignore_eoi = 1;
1225 			while (!sigs)
1226 			{
1227 				make_display();
1228 				forward(1, 0, 0);
1229 			}
1230 			ignore_eoi = 0;
1231 			/*
1232 			 * This gets us back in "F mode" after processing
1233 			 * a non-abort signal (e.g. window-change).
1234 			 */
1235 			if (sigs && !ABORT_SIGS())
1236 				newaction = A_F_FOREVER;
1237 			if (less_is_more)
1238 				quit_at_eof = OPT_ON;
1239 			break;
1240 
1241 		case A_F_SCROLL:
1242 			/*
1243 			 * Forward N lines
1244 			 * (default same as last 'd' or 'u' command).
1245 			 */
1246 			if (number > 0)
1247 				wscroll = (int) number;
1248 			cmd_exec();
1249 			if (show_attn == OPT_ONPLUS)
1250 				set_attnpos(bottompos);
1251 			forward(wscroll, 0, 0);
1252 			break;
1253 
1254 		case A_B_SCROLL:
1255 			/*
1256 			 * Forward N lines
1257 			 * (default same as last 'd' or 'u' command).
1258 			 */
1259 			if (number > 0)
1260 				wscroll = (int) number;
1261 			cmd_exec();
1262 			backward(wscroll, 0, 0);
1263 			break;
1264 
1265 		case A_FREPAINT:
1266 			/*
1267 			 * Flush buffers, then repaint screen.
1268 			 * Don't flush the buffers on a pipe!
1269 			 */
1270 			clear_buffers();
1271 			/* FALLTHRU */
1272 		case A_REPAINT:
1273 			/*
1274 			 * Repaint screen.
1275 			 */
1276 			cmd_exec();
1277 			repaint();
1278 			break;
1279 
1280 		case A_GOLINE:
1281 			/*
1282 			 * Go to line N, default beginning of file.
1283 			 */
1284 			if (number <= 0)
1285 				number = 1;
1286 			cmd_exec();
1287 			jump_back(number);
1288 			break;
1289 
1290 		case A_PERCENT:
1291 			/*
1292 			 * Go to a specified percentage into the file.
1293 			 */
1294 			if (number < 0)
1295 			{
1296 				number = 0;
1297 				fraction = 0;
1298 			}
1299 			if (number > 100)
1300 			{
1301 				number = 100;
1302 				fraction = 0;
1303 			}
1304 			cmd_exec();
1305 			jump_percent((int) number, fraction);
1306 			break;
1307 
1308 		case A_GOEND:
1309 			/*
1310 			 * Go to line N, default end of file.
1311 			 */
1312 			cmd_exec();
1313 			if (number <= 0)
1314 				jump_forw();
1315 			else
1316 				jump_back(number);
1317 			break;
1318 
1319 		case A_GOPOS:
1320 			/*
1321 			 * Go to a specified byte position in the file.
1322 			 */
1323 			cmd_exec();
1324 			if (number < 0)
1325 				number = 0;
1326 			jump_line_loc((POSITION) number, jump_sline);
1327 			break;
1328 
1329 		case A_STAT:
1330 			/*
1331 			 * Print file name, etc.
1332 			 */
1333 			if (ch_getflags() & CH_HELPFILE)
1334 				break;
1335 			cmd_exec();
1336 			parg.p_string = eq_message();
1337 			error("%s", &parg);
1338 			break;
1339 
1340 		case A_VERSION:
1341 			/*
1342 			 * Print version number, without the "@(#)".
1343 			 */
1344 			cmd_exec();
1345 			dispversion();
1346 			break;
1347 
1348 		case A_QUIT:
1349 			/*
1350 			 * Exit.
1351 			 */
1352 #if !SMALL
1353 			if (curr_ifile != NULL_IFILE &&
1354 			    ch_getflags() & CH_HELPFILE)
1355 			{
1356 				/*
1357 				 * Quit while viewing the help file
1358 				 * just means return to viewing the
1359 				 * previous file.
1360 				 */
1361 				hshift = save_hshift;
1362 				if (edit_prev(1) == 0)
1363 					break;
1364 			}
1365 #endif /* !SMALL */
1366 			if (extra != NULL)
1367 				quit(*extra);
1368 			quit(QUIT_OK);
1369 			break;
1370 
1371 /*
1372  * Define abbreviation for a commonly used sequence below.
1373  */
1374 #define	DO_SEARCH() \
1375 			if (number <= 0) number = 1;	\
1376 			mca_search();			\
1377 			cmd_exec();			\
1378 			multi_search((char *)NULL, (int) number);
1379 
1380 
1381 		case A_F_SEARCH:
1382 			/*
1383 			 * Search forward for a pattern.
1384 			 * Get the first char of the pattern.
1385 			 */
1386 			search_type = SRCH_FORW;
1387 			if (number <= 0)
1388 				number = 1;
1389 			mca_search();
1390 			c = getcc();
1391 			goto again;
1392 
1393 		case A_B_SEARCH:
1394 			/*
1395 			 * Search backward for a pattern.
1396 			 * Get the first char of the pattern.
1397 			 */
1398 			search_type = SRCH_BACK;
1399 			if (number <= 0)
1400 				number = 1;
1401 			mca_search();
1402 			c = getcc();
1403 			goto again;
1404 
1405 		case A_FILTER:
1406 #if HILITE_SEARCH
1407 			search_type = SRCH_FORW | SRCH_FILTER;
1408 			mca_search();
1409 			c = getcc();
1410 			goto again;
1411 #else
1412 			error("Command not available", NULL_PARG);
1413 			break;
1414 #endif
1415 
1416 		case A_AGAIN_SEARCH:
1417 			/*
1418 			 * Repeat previous search.
1419 			 */
1420 			DO_SEARCH();
1421 			break;
1422 
1423 		case A_T_AGAIN_SEARCH:
1424 			/*
1425 			 * Repeat previous search, multiple files.
1426 			 */
1427 			search_type |= SRCH_PAST_EOF;
1428 			DO_SEARCH();
1429 			break;
1430 
1431 		case A_REVERSE_SEARCH:
1432 			/*
1433 			 * Repeat previous search, in reverse direction.
1434 			 */
1435 			save_search_type = search_type;
1436 			search_type = SRCH_REVERSE(search_type);
1437 			DO_SEARCH();
1438 			search_type = save_search_type;
1439 			break;
1440 
1441 		case A_T_REVERSE_SEARCH:
1442 			/*
1443 			 * Repeat previous search,
1444 			 * multiple files in reverse direction.
1445 			 */
1446 			save_search_type = search_type;
1447 			search_type = SRCH_REVERSE(search_type);
1448 			search_type |= SRCH_PAST_EOF;
1449 			DO_SEARCH();
1450 			search_type = save_search_type;
1451 			break;
1452 
1453 		case A_UNDO_SEARCH:
1454 			undo_search();
1455 			break;
1456 
1457 		case A_HELP:
1458 #if !SMALL
1459 			/*
1460 			 * Help.
1461 			 */
1462 			if (ch_getflags() & CH_HELPFILE)
1463 				break;
1464 			cmd_exec();
1465 			save_hshift = hshift;
1466 			hshift = 0;
1467 			(void) edit(HELPFILE);
1468 #endif /* !SMALL */
1469 			break;
1470 
1471 		case A_EXAMINE:
1472 #if EXAMINE
1473 			/*
1474 			 * Edit a new file.  Get the filename.
1475 			 */
1476 			if (secure)
1477 			{
1478 				error("Command not available", NULL_PARG);
1479 				break;
1480 			}
1481 			start_mca(A_EXAMINE, "Examine: ", ml_examine, 0);
1482 			c = getcc();
1483 			goto again;
1484 #else
1485 			error("Command not available", NULL_PARG);
1486 			break;
1487 #endif
1488 
1489 		case A_VISUAL:
1490 			/*
1491 			 * Invoke an editor on the input file.
1492 			 */
1493 #if EDITOR
1494 			if (secure)
1495 			{
1496 				error("Command not available", NULL_PARG);
1497 				break;
1498 			}
1499 			if (ch_getflags() & CH_HELPFILE)
1500 				break;
1501 			if (strcmp(get_filename(curr_ifile), "-") == 0)
1502 			{
1503 				error("Cannot edit standard input", NULL_PARG);
1504 				break;
1505 			}
1506 			if (curr_altfilename != NULL)
1507 			{
1508 				error("WARNING: This file was viewed via LESSOPEN",
1509 					NULL_PARG);
1510 			}
1511 			start_mca(A_SHELL, "!", ml_shell, 0);
1512 			/*
1513 			 * Expand the editor prototype string
1514 			 * and pass it to the system to execute.
1515 			 * (Make sure the screen is displayed so the
1516 			 * expansion of "+%lm" works.)
1517 			 */
1518 			make_display();
1519 			cmd_exec();
1520 			lsystem(pr_expand(editproto, 0), (char*)NULL);
1521 			break;
1522 #else
1523 			error("Command not available", NULL_PARG);
1524 			break;
1525 #endif
1526 
1527 		case A_NEXT_FILE:
1528 			/*
1529 			 * Examine next file.
1530 			 */
1531 #if TAGS
1532 			if (ntags())
1533 			{
1534 				error("No next file", NULL_PARG);
1535 				break;
1536 			}
1537 #endif
1538 			if (number <= 0)
1539 				number = 1;
1540 			if (edit_next((int) number))
1541 			{
1542 				if (get_quit_at_eof() && eof_displayed() &&
1543 				    !(ch_getflags() & CH_HELPFILE))
1544 					quit(QUIT_OK);
1545 				parg.p_string = (number > 1) ? "(N-th) " : "";
1546 				error("No %snext file", &parg);
1547 			}
1548 			break;
1549 
1550 		case A_PREV_FILE:
1551 			/*
1552 			 * Examine previous file.
1553 			 */
1554 #if TAGS
1555 			if (ntags())
1556 			{
1557 				error("No previous file", NULL_PARG);
1558 				break;
1559 			}
1560 #endif
1561 			if (number <= 0)
1562 				number = 1;
1563 			if (edit_prev((int) number))
1564 			{
1565 				parg.p_string = (number > 1) ? "(N-th) " : "";
1566 				error("No %sprevious file", &parg);
1567 			}
1568 			break;
1569 
1570 		case A_NEXT_TAG:
1571 #if TAGS
1572 			if (number <= 0)
1573 				number = 1;
1574 			tagfile = nexttag((int) number);
1575 			if (tagfile == NULL)
1576 			{
1577 				error("No next tag", NULL_PARG);
1578 				break;
1579 			}
1580 			if (edit(tagfile) == 0)
1581 			{
1582 				POSITION pos = tagsearch();
1583 				if (pos != NULL_POSITION)
1584 					jump_loc(pos, jump_sline);
1585 			}
1586 #else
1587 			error("Command not available", NULL_PARG);
1588 #endif
1589 			break;
1590 
1591 		case A_PREV_TAG:
1592 #if TAGS
1593 			if (number <= 0)
1594 				number = 1;
1595 			tagfile = prevtag((int) number);
1596 			if (tagfile == NULL)
1597 			{
1598 				error("No previous tag", NULL_PARG);
1599 				break;
1600 			}
1601 			if (edit(tagfile) == 0)
1602 			{
1603 				POSITION pos = tagsearch();
1604 				if (pos != NULL_POSITION)
1605 					jump_loc(pos, jump_sline);
1606 			}
1607 #else
1608 			error("Command not available", NULL_PARG);
1609 #endif
1610 			break;
1611 
1612 		case A_INDEX_FILE:
1613 			/*
1614 			 * Examine a particular file.
1615 			 */
1616 			if (number <= 0)
1617 				number = 1;
1618 			if (edit_index((int) number))
1619 				error("No such file", NULL_PARG);
1620 			break;
1621 
1622 		case A_REMOVE_FILE:
1623 			if (ch_getflags() & CH_HELPFILE)
1624 				break;
1625 			old_ifile = curr_ifile;
1626 			new_ifile = getoff_ifile(curr_ifile);
1627 			if (new_ifile == NULL_IFILE)
1628 			{
1629 				bell();
1630 				break;
1631 			}
1632 			if (edit_ifile(new_ifile) != 0)
1633 			{
1634 				reedit_ifile(old_ifile);
1635 				break;
1636 			}
1637 			del_ifile(old_ifile);
1638 			break;
1639 
1640 		case A_OPT_TOGGLE:
1641 			optflag = OPT_TOGGLE;
1642 			optgetname = FALSE;
1643 			mca_opt_toggle();
1644 			c = getcc();
1645 			goto again;
1646 
1647 		case A_DISP_OPTION:
1648 			/*
1649 			 * Report a flag setting.
1650 			 */
1651 			optflag = OPT_NO_TOGGLE;
1652 			optgetname = FALSE;
1653 			mca_opt_toggle();
1654 			c = getcc();
1655 			goto again;
1656 
1657 		case A_FIRSTCMD:
1658 			/*
1659 			 * Set an initial command for new files.
1660 			 */
1661 			start_mca(A_FIRSTCMD, "+", (void*)NULL, 0);
1662 			c = getcc();
1663 			goto again;
1664 
1665 		case A_SHELL:
1666 			/*
1667 			 * Shell escape.
1668 			 */
1669 #if SHELL_ESCAPE
1670 			if (secure)
1671 			{
1672 				error("Command not available", NULL_PARG);
1673 				break;
1674 			}
1675 			start_mca(A_SHELL, "!", ml_shell, 0);
1676 			c = getcc();
1677 			goto again;
1678 #else
1679 			error("Command not available", NULL_PARG);
1680 			break;
1681 #endif
1682 
1683 		case A_SETMARK:
1684 			/*
1685 			 * Set a mark.
1686 			 */
1687 			if (ch_getflags() & CH_HELPFILE)
1688 				break;
1689 			start_mca(A_SETMARK, "mark: ", (void*)NULL, 0);
1690 			c = getcc();
1691 			if (c == erase_char || c == erase2_char ||
1692 			    c == kill_char || c == '\n' || c == '\r')
1693 				break;
1694 			setmark(c);
1695 			break;
1696 
1697 		case A_GOMARK:
1698 			/*
1699 			 * Go to a mark.
1700 			 */
1701 			start_mca(A_GOMARK, "goto mark: ", (void*)NULL, 0);
1702 			c = getcc();
1703 			if (c == erase_char || c == erase2_char ||
1704 			    c == kill_char || c == '\n' || c == '\r')
1705 				break;
1706 			cmd_exec();
1707 			gomark(c);
1708 			break;
1709 
1710 		case A_PIPE:
1711 #if PIPEC
1712 			if (secure)
1713 			{
1714 				error("Command not available", NULL_PARG);
1715 				break;
1716 			}
1717 			start_mca(A_PIPE, "|mark: ", (void*)NULL, 0);
1718 			c = getcc();
1719 			if (c == erase_char || c == erase2_char || c == kill_char)
1720 				break;
1721 			if (c == '\n' || c == '\r')
1722 				c = '.';
1723 			if (badmark(c))
1724 				break;
1725 			pipec = c;
1726 			start_mca(A_PIPE, "!", ml_shell, 0);
1727 			c = getcc();
1728 			goto again;
1729 #else
1730 			error("Command not available", NULL_PARG);
1731 			break;
1732 #endif
1733 
1734 		case A_B_BRACKET:
1735 		case A_F_BRACKET:
1736 			start_mca(action, "Brackets: ", (void*)NULL, 0);
1737 			c = getcc();
1738 			goto again;
1739 
1740 		case A_LSHIFT:
1741 			if (number > 0)
1742 				shift_count = number;
1743 			else
1744 				number = (shift_count > 0) ?
1745 					shift_count : sc_width / 2;
1746 			if (number > hshift)
1747 				number = hshift;
1748 			hshift -= number;
1749 			screen_trashed = 1;
1750 			break;
1751 
1752 		case A_RSHIFT:
1753 			if (number > 0)
1754 				shift_count = number;
1755 			else
1756 				number = (shift_count > 0) ?
1757 					shift_count : sc_width / 2;
1758 			hshift += number;
1759 			screen_trashed = 1;
1760 			break;
1761 
1762 		case A_PREFIX:
1763 			/*
1764 			 * The command is incomplete (more chars are needed).
1765 			 * Display the current char, so the user knows
1766 			 * what's going on, and get another character.
1767 			 */
1768 			if (mca != A_PREFIX)
1769 			{
1770 				cmd_reset();
1771 				start_mca(A_PREFIX, " ", (void*)NULL,
1772 					CF_QUIT_ON_ERASE);
1773 				(void) cmd_char(c);
1774 			}
1775 			c = getcc();
1776 			goto again;
1777 
1778 		case A_NOACTION:
1779 			break;
1780 
1781 		default:
1782 			if (be_helpful)
1783 				help_prompt = "[Press 'h' for instructions.]";
1784 			else
1785 				bell();
1786 			break;
1787 		}
1788 	}
1789 }
1790