xref: /vim-8.2.3635/src/ex_eval.c (revision fcfe1a9b)
1 /* vi:set ts=8 sts=4 sw=4 noet:
2  *
3  * VIM - Vi IMproved	by Bram Moolenaar
4  *
5  * Do ":help uganda"  in Vim to read copying and usage conditions.
6  * Do ":help credits" in Vim to see a list of people who contributed.
7  * See README.txt for an overview of the Vim source code.
8  */
9 
10 /*
11  * ex_eval.c: functions for Ex command line for the +eval feature.
12  */
13 
14 #include "vim.h"
15 
16 #if defined(FEAT_EVAL) || defined(PROTO)
17 
18 static int	throw_exception(void *, except_type_T, char_u *);
19 static char	*get_end_emsg(struct condstack *cstack);
20 
21 /*
22  * Exception handling terms:
23  *
24  *	:try		":try" command		\
25  *	    ...		try block		|
26  *	:catch RE	":catch" command	|
27  *	    ...		catch clause		|- try conditional
28  *	:finally	":finally" command	|
29  *	    ...		finally clause		|
30  *	:endtry		":endtry" command	/
31  *
32  * The try conditional may have any number of catch clauses and at most one
33  * finally clause.  A ":throw" command can be inside the try block, a catch
34  * clause, the finally clause, or in a function called or script sourced from
35  * there or even outside the try conditional.  Try conditionals may be nested.
36  */
37 
38 /*
39  * Configuration whether an exception is thrown on error or interrupt.  When
40  * the preprocessor macros below evaluate to FALSE, an error (did_emsg) or
41  * interrupt (got_int) under an active try conditional terminates the script
42  * after the non-active finally clauses of all active try conditionals have been
43  * executed.  Otherwise, errors and/or interrupts are converted into catchable
44  * exceptions (did_throw additionally set), which terminate the script only if
45  * not caught.  For user exceptions, only did_throw is set.  (Note: got_int can
46  * be set asynchronously afterwards by a SIGINT, so did_throw && got_int is not
47  * a reliant test that the exception currently being thrown is an interrupt
48  * exception.  Similarly, did_emsg can be set afterwards on an error in an
49  * (unskipped) conditional command inside an inactive conditional, so did_throw
50  * && did_emsg is not a reliant test that the exception currently being thrown
51  * is an error exception.)  -  The macros can be defined as expressions checking
52  * for a variable that is allowed to be changed during execution of a script.
53  */
54 #if 0
55 /* Expressions used for testing during the development phase. */
56 # define THROW_ON_ERROR		(!eval_to_number("$VIMNOERRTHROW"))
57 # define THROW_ON_INTERRUPT	(!eval_to_number("$VIMNOINTTHROW"))
58 # define THROW_TEST
59 #else
60 /* Values used for the Vim release. */
61 # define THROW_ON_ERROR		TRUE
62 # define THROW_ON_ERROR_TRUE
63 # define THROW_ON_INTERRUPT	TRUE
64 # define THROW_ON_INTERRUPT_TRUE
65 #endif
66 
67 /*
68  * When several errors appear in a row, setting "force_abort" is delayed until
69  * the failing command returned.  "cause_abort" is set to TRUE meanwhile, in
70  * order to indicate that situation.  This is useful when "force_abort" was set
71  * during execution of a function call from an expression: the aborting of the
72  * expression evaluation is done without producing any error messages, but all
73  * error messages on parsing errors during the expression evaluation are given
74  * (even if a try conditional is active).
75  */
76 static int cause_abort = FALSE;
77 
78 /*
79  * Return TRUE when immediately aborting on error, or when an interrupt
80  * occurred or an exception was thrown but not caught.  Use for ":{range}call"
81  * to check whether an aborted function that does not handle a range itself
82  * should be called again for the next line in the range.  Also used for
83  * cancelling expression evaluation after a function call caused an immediate
84  * abort.  Note that the first emsg() call temporarily resets "force_abort"
85  * until the throw point for error messages has been reached.  That is, during
86  * cancellation of an expression evaluation after an aborting function call or
87  * due to a parsing error, aborting() always returns the same value.
88  */
89     int
90 aborting(void)
91 {
92     return (did_emsg && force_abort) || got_int || did_throw;
93 }
94 
95 /*
96  * The value of "force_abort" is temporarily reset by the first emsg() call
97  * during an expression evaluation, and "cause_abort" is used instead.  It might
98  * be necessary to restore "force_abort" even before the throw point for the
99  * error message has been reached.  update_force_abort() should be called then.
100  */
101     void
102 update_force_abort(void)
103 {
104     if (cause_abort)
105 	force_abort = TRUE;
106 }
107 
108 /*
109  * Return TRUE if a command with a subcommand resulting in "retcode" should
110  * abort the script processing.  Can be used to suppress an autocommand after
111  * execution of a failing subcommand as long as the error message has not been
112  * displayed and actually caused the abortion.
113  */
114     int
115 should_abort(int retcode)
116 {
117     return ((retcode == FAIL && trylevel != 0 && !emsg_silent) || aborting());
118 }
119 
120 /*
121  * Return TRUE if a function with the "abort" flag should not be considered
122  * ended on an error.  This means that parsing commands is continued in order
123  * to find finally clauses to be executed, and that some errors in skipped
124  * commands are still reported.
125  */
126     int
127 aborted_in_try(void)
128 {
129     /* This function is only called after an error.  In this case, "force_abort"
130      * determines whether searching for finally clauses is necessary. */
131     return force_abort;
132 }
133 
134 /*
135  * cause_errthrow(): Cause a throw of an error exception if appropriate.
136  * Return TRUE if the error message should not be displayed by emsg().
137  * Sets "ignore", if the emsg() call should be ignored completely.
138  *
139  * When several messages appear in the same command, the first is usually the
140  * most specific one and used as the exception value.  The "severe" flag can be
141  * set to TRUE, if a later but severer message should be used instead.
142  */
143     int
144 cause_errthrow(
145     char_u	*mesg,
146     int		severe,
147     int		*ignore)
148 {
149     struct msglist *elem;
150     struct msglist **plist;
151 
152     /*
153      * Do nothing when displaying the interrupt message or reporting an
154      * uncaught exception (which has already been discarded then) at the top
155      * level.  Also when no exception can be thrown.  The message will be
156      * displayed by emsg().
157      */
158     if (suppress_errthrow)
159 	return FALSE;
160 
161     /*
162      * If emsg() has not been called previously, temporarily reset
163      * "force_abort" until the throw point for error messages has been
164      * reached.  This ensures that aborting() returns the same value for all
165      * errors that appear in the same command.  This means particularly that
166      * for parsing errors during expression evaluation emsg() will be called
167      * multiply, even when the expression is evaluated from a finally clause
168      * that was activated due to an aborting error, interrupt, or exception.
169      */
170     if (!did_emsg)
171     {
172 	cause_abort = force_abort;
173 	force_abort = FALSE;
174     }
175 
176     /*
177      * If no try conditional is active and no exception is being thrown and
178      * there has not been an error in a try conditional or a throw so far, do
179      * nothing (for compatibility of non-EH scripts).  The message will then
180      * be displayed by emsg().  When ":silent!" was used and we are not
181      * currently throwing an exception, do nothing.  The message text will
182      * then be stored to v:errmsg by emsg() without displaying it.
183      */
184     if (((trylevel == 0 && !cause_abort) || emsg_silent) && !did_throw)
185 	return FALSE;
186 
187     /*
188      * Ignore an interrupt message when inside a try conditional or when an
189      * exception is being thrown or when an error in a try conditional or
190      * throw has been detected previously.  This is important in order that an
191      * interrupt exception is catchable by the innermost try conditional and
192      * not replaced by an interrupt message error exception.
193      */
194     if (mesg == (char_u *)_(e_interr))
195     {
196 	*ignore = TRUE;
197 	return TRUE;
198     }
199 
200     /*
201      * Ensure that all commands in nested function calls and sourced files
202      * are aborted immediately.
203      */
204     cause_abort = TRUE;
205 
206     /*
207      * When an exception is being thrown, some commands (like conditionals) are
208      * not skipped.  Errors in those commands may affect what of the subsequent
209      * commands are regarded part of catch and finally clauses.  Catching the
210      * exception would then cause execution of commands not intended by the
211      * user, who wouldn't even get aware of the problem.  Therefor, discard the
212      * exception currently being thrown to prevent it from being caught.  Just
213      * execute finally clauses and terminate.
214      */
215     if (did_throw)
216     {
217 	/* When discarding an interrupt exception, reset got_int to prevent the
218 	 * same interrupt being converted to an exception again and discarding
219 	 * the error exception we are about to throw here. */
220 	if (current_exception->type == ET_INTERRUPT)
221 	    got_int = FALSE;
222 	discard_current_exception();
223     }
224 
225 #ifdef THROW_TEST
226     if (!THROW_ON_ERROR)
227     {
228 	/*
229 	 * Print error message immediately without searching for a matching
230 	 * catch clause; just finally clauses are executed before the script
231 	 * is terminated.
232 	 */
233 	return FALSE;
234     }
235     else
236 #endif
237     {
238 	/*
239 	 * Prepare the throw of an error exception, so that everything will
240 	 * be aborted (except for executing finally clauses), until the error
241 	 * exception is caught; if still uncaught at the top level, the error
242 	 * message will be displayed and the script processing terminated
243 	 * then.  -  This function has no access to the conditional stack.
244 	 * Thus, the actual throw is made after the failing command has
245 	 * returned.  -  Throw only the first of several errors in a row, except
246 	 * a severe error is following.
247 	 */
248 	if (msg_list != NULL)
249 	{
250 	    plist = msg_list;
251 	    while (*plist != NULL)
252 		plist = &(*plist)->next;
253 
254 	    elem = ALLOC_ONE(struct msglist);
255 	    if (elem == NULL)
256 	    {
257 		suppress_errthrow = TRUE;
258 		emsg(_(e_outofmem));
259 	    }
260 	    else
261 	    {
262 		elem->msg = (char *)vim_strsave(mesg);
263 		if (elem->msg == NULL)
264 		{
265 		    vim_free(elem);
266 		    suppress_errthrow = TRUE;
267 		    emsg(_(e_outofmem));
268 		}
269 		else
270 		{
271 		    elem->next = NULL;
272 		    elem->throw_msg = NULL;
273 		    *plist = elem;
274 		    if (plist == msg_list || severe)
275 		    {
276 			char	    *tmsg;
277 
278 			/* Skip the extra "Vim " prefix for message "E458". */
279 			tmsg = elem->msg;
280 			if (STRNCMP(tmsg, "Vim E", 5) == 0
281 				&& VIM_ISDIGIT(tmsg[5])
282 				&& VIM_ISDIGIT(tmsg[6])
283 				&& VIM_ISDIGIT(tmsg[7])
284 				&& tmsg[8] == ':'
285 				&& tmsg[9] == ' ')
286 			    (*msg_list)->throw_msg = &tmsg[4];
287 			else
288 			    (*msg_list)->throw_msg = tmsg;
289 		    }
290 		}
291 	    }
292 	}
293 	return TRUE;
294     }
295 }
296 
297 /*
298  * Free a "msg_list" and the messages it contains.
299  */
300     static void
301 free_msglist(struct msglist *l)
302 {
303     struct msglist  *messages, *next;
304 
305     messages = l;
306     while (messages != NULL)
307     {
308 	next = messages->next;
309 	vim_free(messages->msg);
310 	vim_free(messages);
311 	messages = next;
312     }
313 }
314 
315 /*
316  * Free global "*msg_list" and the messages it contains, then set "*msg_list"
317  * to NULL.
318  */
319     void
320 free_global_msglist(void)
321 {
322     free_msglist(*msg_list);
323     *msg_list = NULL;
324 }
325 
326 /*
327  * Throw the message specified in the call to cause_errthrow() above as an
328  * error exception.  If cstack is NULL, postpone the throw until do_cmdline()
329  * has returned (see do_one_cmd()).
330  */
331     void
332 do_errthrow(struct condstack *cstack, char_u *cmdname)
333 {
334     /*
335      * Ensure that all commands in nested function calls and sourced files
336      * are aborted immediately.
337      */
338     if (cause_abort)
339     {
340 	cause_abort = FALSE;
341 	force_abort = TRUE;
342     }
343 
344     /* If no exception is to be thrown or the conversion should be done after
345      * returning to a previous invocation of do_one_cmd(), do nothing. */
346     if (msg_list == NULL || *msg_list == NULL)
347 	return;
348 
349     if (throw_exception(*msg_list, ET_ERROR, cmdname) == FAIL)
350 	free_msglist(*msg_list);
351     else
352     {
353 	if (cstack != NULL)
354 	    do_throw(cstack);
355 	else
356 	    need_rethrow = TRUE;
357     }
358     *msg_list = NULL;
359 }
360 
361 /*
362  * do_intthrow(): Replace the current exception by an interrupt or interrupt
363  * exception if appropriate.  Return TRUE if the current exception is discarded,
364  * FALSE otherwise.
365  */
366     int
367 do_intthrow(struct condstack *cstack)
368 {
369     /*
370      * If no interrupt occurred or no try conditional is active and no exception
371      * is being thrown, do nothing (for compatibility of non-EH scripts).
372      */
373     if (!got_int || (trylevel == 0 && !did_throw))
374 	return FALSE;
375 
376 #ifdef THROW_TEST	/* avoid warning for condition always true */
377     if (!THROW_ON_INTERRUPT)
378     {
379 	/*
380 	 * The interrupt aborts everything except for executing finally clauses.
381 	 * Discard any user or error or interrupt exception currently being
382 	 * thrown.
383 	 */
384 	if (did_throw)
385 	    discard_current_exception();
386     }
387     else
388 #endif
389     {
390 	/*
391 	 * Throw an interrupt exception, so that everything will be aborted
392 	 * (except for executing finally clauses), until the interrupt exception
393 	 * is caught; if still uncaught at the top level, the script processing
394 	 * will be terminated then.  -  If an interrupt exception is already
395 	 * being thrown, do nothing.
396 	 *
397 	 */
398 	if (did_throw)
399 	{
400 	    if (current_exception->type == ET_INTERRUPT)
401 		return FALSE;
402 
403 	    /* An interrupt exception replaces any user or error exception. */
404 	    discard_current_exception();
405 	}
406 	if (throw_exception("Vim:Interrupt", ET_INTERRUPT, NULL) != FAIL)
407 	    do_throw(cstack);
408     }
409 
410     return TRUE;
411 }
412 
413 /*
414  * Get an exception message that is to be stored in current_exception->value.
415  */
416     char *
417 get_exception_string(
418     void	*value,
419     except_type_T type,
420     char_u	*cmdname,
421     int		*should_free)
422 {
423     char	*ret;
424     char	*mesg;
425     int		cmdlen;
426     char	*p, *val;
427 
428     if (type == ET_ERROR)
429     {
430 	*should_free = TRUE;
431 	mesg = ((struct msglist *)value)->throw_msg;
432 	if (cmdname != NULL && *cmdname != NUL)
433 	{
434 	    cmdlen = (int)STRLEN(cmdname);
435 	    ret = (char *)vim_strnsave((char_u *)"Vim(",
436 					   4 + cmdlen + 2 + (int)STRLEN(mesg));
437 	    if (ret == NULL)
438 		return ret;
439 	    STRCPY(&ret[4], cmdname);
440 	    STRCPY(&ret[4 + cmdlen], "):");
441 	    val = ret + 4 + cmdlen + 2;
442 	}
443 	else
444 	{
445 	    ret = (char *)vim_strnsave((char_u *)"Vim:", 4 + (int)STRLEN(mesg));
446 	    if (ret == NULL)
447 		return ret;
448 	    val = ret + 4;
449 	}
450 
451 	/* msg_add_fname may have been used to prefix the message with a file
452 	 * name in quotes.  In the exception value, put the file name in
453 	 * parentheses and move it to the end. */
454 	for (p = mesg; ; p++)
455 	{
456 	    if (*p == NUL
457 		    || (*p == 'E'
458 			&& VIM_ISDIGIT(p[1])
459 			&& (p[2] == ':'
460 			    || (VIM_ISDIGIT(p[2])
461 				&& (p[3] == ':'
462 				    || (VIM_ISDIGIT(p[3])
463 					&& p[4] == ':'))))))
464 	    {
465 		if (*p == NUL || p == mesg)
466 		    STRCAT(val, mesg);  /* 'E123' missing or at beginning */
467 		else
468 		{
469 		    /* '"filename" E123: message text' */
470 		    if (mesg[0] != '"' || p-2 < &mesg[1] ||
471 			    p[-2] != '"' || p[-1] != ' ')
472 			/* "E123:" is part of the file name. */
473 			continue;
474 
475 		    STRCAT(val, p);
476 		    p[-2] = NUL;
477 		    sprintf((char *)(val + STRLEN(p)), " (%s)", &mesg[1]);
478 		    p[-2] = '"';
479 		}
480 		break;
481 	    }
482 	}
483     }
484     else
485     {
486 	*should_free = FALSE;
487 	ret = value;
488     }
489 
490     return ret;
491 }
492 
493 
494 /*
495  * Throw a new exception.  Return FAIL when out of memory or it was tried to
496  * throw an illegal user exception.  "value" is the exception string for a
497  * user or interrupt exception, or points to a message list in case of an
498  * error exception.
499  */
500     static int
501 throw_exception(void *value, except_type_T type, char_u *cmdname)
502 {
503     except_T	*excp;
504     int		should_free;
505 
506     /*
507      * Disallow faking Interrupt or error exceptions as user exceptions.  They
508      * would be treated differently from real interrupt or error exceptions
509      * when no active try block is found, see do_cmdline().
510      */
511     if (type == ET_USER)
512     {
513 	if (STRNCMP((char_u *)value, "Vim", 3) == 0
514 		&& (((char_u *)value)[3] == NUL || ((char_u *)value)[3] == ':'
515 		    || ((char_u *)value)[3] == '('))
516 	{
517 	    emsg(_("E608: Cannot :throw exceptions with 'Vim' prefix"));
518 	    goto fail;
519 	}
520     }
521 
522     excp = ALLOC_ONE(except_T);
523     if (excp == NULL)
524 	goto nomem;
525 
526     if (type == ET_ERROR)
527 	/* Store the original message and prefix the exception value with
528 	 * "Vim:" or, if a command name is given, "Vim(cmdname):". */
529 	excp->messages = (struct msglist *)value;
530 
531     excp->value = get_exception_string(value, type, cmdname, &should_free);
532     if (excp->value == NULL && should_free)
533 	goto nomem;
534 
535     excp->type = type;
536     excp->throw_name = vim_strsave(sourcing_name == NULL
537 					      ? (char_u *)"" : sourcing_name);
538     if (excp->throw_name == NULL)
539     {
540 	if (should_free)
541 	    vim_free(excp->value);
542 	goto nomem;
543     }
544     excp->throw_lnum = sourcing_lnum;
545 
546     if (p_verbose >= 13 || debug_break_level > 0)
547     {
548 	int	save_msg_silent = msg_silent;
549 
550 	if (debug_break_level > 0)
551 	    msg_silent = FALSE;		/* display messages */
552 	else
553 	    verbose_enter();
554 	++no_wait_return;
555 	if (debug_break_level > 0 || *p_vfile == NUL)
556 	    msg_scroll = TRUE;	    /* always scroll up, don't overwrite */
557 
558 	smsg(_("Exception thrown: %s"), excp->value);
559 	msg_puts("\n");   /* don't overwrite this either */
560 
561 	if (debug_break_level > 0 || *p_vfile == NUL)
562 	    cmdline_row = msg_row;
563 	--no_wait_return;
564 	if (debug_break_level > 0)
565 	    msg_silent = save_msg_silent;
566 	else
567 	    verbose_leave();
568     }
569 
570     current_exception = excp;
571     return OK;
572 
573 nomem:
574     vim_free(excp);
575     suppress_errthrow = TRUE;
576     emsg(_(e_outofmem));
577 fail:
578     current_exception = NULL;
579     return FAIL;
580 }
581 
582 /*
583  * Discard an exception.  "was_finished" is set when the exception has been
584  * caught and the catch clause has been ended normally.
585  */
586     static void
587 discard_exception(except_T *excp, int was_finished)
588 {
589     char_u		*saved_IObuff;
590 
591     if (excp == NULL)
592     {
593 	internal_error("discard_exception()");
594 	return;
595     }
596 
597     if (p_verbose >= 13 || debug_break_level > 0)
598     {
599 	int	save_msg_silent = msg_silent;
600 
601 	saved_IObuff = vim_strsave(IObuff);
602 	if (debug_break_level > 0)
603 	    msg_silent = FALSE;		/* display messages */
604 	else
605 	    verbose_enter();
606 	++no_wait_return;
607 	if (debug_break_level > 0 || *p_vfile == NUL)
608 	    msg_scroll = TRUE;	    /* always scroll up, don't overwrite */
609 	smsg(was_finished
610 		    ? _("Exception finished: %s")
611 		    : _("Exception discarded: %s"),
612 		excp->value);
613 	msg_puts("\n");   /* don't overwrite this either */
614 	if (debug_break_level > 0 || *p_vfile == NUL)
615 	    cmdline_row = msg_row;
616 	--no_wait_return;
617 	if (debug_break_level > 0)
618 	    msg_silent = save_msg_silent;
619 	else
620 	    verbose_leave();
621 	STRCPY(IObuff, saved_IObuff);
622 	vim_free(saved_IObuff);
623     }
624     if (excp->type != ET_INTERRUPT)
625 	vim_free(excp->value);
626     if (excp->type == ET_ERROR)
627 	free_msglist(excp->messages);
628     vim_free(excp->throw_name);
629     vim_free(excp);
630 }
631 
632 /*
633  * Discard the exception currently being thrown.
634  */
635     void
636 discard_current_exception(void)
637 {
638     if (current_exception != NULL)
639     {
640 	discard_exception(current_exception, FALSE);
641 	current_exception = NULL;
642     }
643     did_throw = FALSE;
644     need_rethrow = FALSE;
645 }
646 
647 /*
648  * Put an exception on the caught stack.
649  */
650     static void
651 catch_exception(except_T *excp)
652 {
653     excp->caught = caught_stack;
654     caught_stack = excp;
655     set_vim_var_string(VV_EXCEPTION, (char_u *)excp->value, -1);
656     if (*excp->throw_name != NUL)
657     {
658 	if (excp->throw_lnum != 0)
659 	    vim_snprintf((char *)IObuff, IOSIZE, _("%s, line %ld"),
660 				    excp->throw_name, (long)excp->throw_lnum);
661 	else
662 	    vim_snprintf((char *)IObuff, IOSIZE, "%s", excp->throw_name);
663 	set_vim_var_string(VV_THROWPOINT, IObuff, -1);
664     }
665     else
666 	/* throw_name not set on an exception from a command that was typed. */
667 	set_vim_var_string(VV_THROWPOINT, NULL, -1);
668 
669     if (p_verbose >= 13 || debug_break_level > 0)
670     {
671 	int	save_msg_silent = msg_silent;
672 
673 	if (debug_break_level > 0)
674 	    msg_silent = FALSE;		/* display messages */
675 	else
676 	    verbose_enter();
677 	++no_wait_return;
678 	if (debug_break_level > 0 || *p_vfile == NUL)
679 	    msg_scroll = TRUE;	    /* always scroll up, don't overwrite */
680 
681 	smsg(_("Exception caught: %s"), excp->value);
682 	msg_puts("\n");   /* don't overwrite this either */
683 
684 	if (debug_break_level > 0 || *p_vfile == NUL)
685 	    cmdline_row = msg_row;
686 	--no_wait_return;
687 	if (debug_break_level > 0)
688 	    msg_silent = save_msg_silent;
689 	else
690 	    verbose_leave();
691     }
692 }
693 
694 /*
695  * Remove an exception from the caught stack.
696  */
697     static void
698 finish_exception(except_T *excp)
699 {
700     if (excp != caught_stack)
701 	internal_error("finish_exception()");
702     caught_stack = caught_stack->caught;
703     if (caught_stack != NULL)
704     {
705 	set_vim_var_string(VV_EXCEPTION, (char_u *)caught_stack->value, -1);
706 	if (*caught_stack->throw_name != NUL)
707 	{
708 	    if (caught_stack->throw_lnum != 0)
709 		vim_snprintf((char *)IObuff, IOSIZE,
710 			_("%s, line %ld"), caught_stack->throw_name,
711 			(long)caught_stack->throw_lnum);
712 	    else
713 		vim_snprintf((char *)IObuff, IOSIZE, "%s",
714 						    caught_stack->throw_name);
715 	    set_vim_var_string(VV_THROWPOINT, IObuff, -1);
716 	}
717 	else
718 	    /* throw_name not set on an exception from a command that was
719 	     * typed. */
720 	    set_vim_var_string(VV_THROWPOINT, NULL, -1);
721     }
722     else
723     {
724 	set_vim_var_string(VV_EXCEPTION, NULL, -1);
725 	set_vim_var_string(VV_THROWPOINT, NULL, -1);
726     }
727 
728     /* Discard the exception, but use the finish message for 'verbose'. */
729     discard_exception(excp, TRUE);
730 }
731 
732 /*
733  * Flags specifying the message displayed by report_pending.
734  */
735 #define RP_MAKE		0
736 #define RP_RESUME	1
737 #define RP_DISCARD	2
738 
739 /*
740  * Report information about something pending in a finally clause if required by
741  * the 'verbose' option or when debugging.  "action" tells whether something is
742  * made pending or something pending is resumed or discarded.  "pending" tells
743  * what is pending.  "value" specifies the return value for a pending ":return"
744  * or the exception value for a pending exception.
745  */
746     static void
747 report_pending(int action, int pending, void *value)
748 {
749     char	*mesg;
750     char	*s;
751     int		save_msg_silent;
752 
753 
754     switch (action)
755     {
756 	case RP_MAKE:
757 	    mesg = _("%s made pending");
758 	    break;
759 	case RP_RESUME:
760 	    mesg = _("%s resumed");
761 	    break;
762 	/* case RP_DISCARD: */
763 	default:
764 	    mesg = _("%s discarded");
765 	    break;
766     }
767 
768     switch (pending)
769     {
770 	case CSTP_NONE:
771 	    return;
772 
773 	case CSTP_CONTINUE:
774 	    s = ":continue";
775 	    break;
776 	case CSTP_BREAK:
777 	    s = ":break";
778 	    break;
779 	case CSTP_FINISH:
780 	    s = ":finish";
781 	    break;
782 	case CSTP_RETURN:
783 	    /* ":return" command producing value, allocated */
784 	    s = (char *)get_return_cmd(value);
785 	    break;
786 
787 	default:
788 	    if (pending & CSTP_THROW)
789 	    {
790 		vim_snprintf((char *)IObuff, IOSIZE, mesg, _("Exception"));
791 		mesg = (char *)vim_strnsave(IObuff, (int)STRLEN(IObuff) + 4);
792 		STRCAT(mesg, ": %s");
793 		s = (char *)((except_T *)value)->value;
794 	    }
795 	    else if ((pending & CSTP_ERROR) && (pending & CSTP_INTERRUPT))
796 		s = _("Error and interrupt");
797 	    else if (pending & CSTP_ERROR)
798 		s = _("Error");
799 	    else /* if (pending & CSTP_INTERRUPT) */
800 		s = _("Interrupt");
801     }
802 
803     save_msg_silent = msg_silent;
804     if (debug_break_level > 0)
805 	msg_silent = FALSE;	/* display messages */
806     ++no_wait_return;
807     msg_scroll = TRUE;		/* always scroll up, don't overwrite */
808     smsg(mesg, s);
809     msg_puts("\n");   /* don't overwrite this either */
810     cmdline_row = msg_row;
811     --no_wait_return;
812     if (debug_break_level > 0)
813 	msg_silent = save_msg_silent;
814 
815     if (pending == CSTP_RETURN)
816 	vim_free(s);
817     else if (pending & CSTP_THROW)
818 	vim_free(mesg);
819 }
820 
821 /*
822  * If something is made pending in a finally clause, report it if required by
823  * the 'verbose' option or when debugging.
824  */
825     void
826 report_make_pending(int pending, void *value)
827 {
828     if (p_verbose >= 14 || debug_break_level > 0)
829     {
830 	if (debug_break_level <= 0)
831 	    verbose_enter();
832 	report_pending(RP_MAKE, pending, value);
833 	if (debug_break_level <= 0)
834 	    verbose_leave();
835     }
836 }
837 
838 /*
839  * If something pending in a finally clause is resumed at the ":endtry", report
840  * it if required by the 'verbose' option or when debugging.
841  */
842     void
843 report_resume_pending(int pending, void *value)
844 {
845     if (p_verbose >= 14 || debug_break_level > 0)
846     {
847 	if (debug_break_level <= 0)
848 	    verbose_enter();
849 	report_pending(RP_RESUME, pending, value);
850 	if (debug_break_level <= 0)
851 	    verbose_leave();
852     }
853 }
854 
855 /*
856  * If something pending in a finally clause is discarded, report it if required
857  * by the 'verbose' option or when debugging.
858  */
859     void
860 report_discard_pending(int pending, void *value)
861 {
862     if (p_verbose >= 14 || debug_break_level > 0)
863     {
864 	if (debug_break_level <= 0)
865 	    verbose_enter();
866 	report_pending(RP_DISCARD, pending, value);
867 	if (debug_break_level <= 0)
868 	    verbose_leave();
869     }
870 }
871 
872 
873 /*
874  * ":eval".
875  */
876     void
877 ex_eval(exarg_T *eap)
878 {
879     typval_T	tv;
880 
881     if (eval0(eap->arg, &tv, &eap->nextcmd, !eap->skip) == OK)
882 	clear_tv(&tv);
883 }
884 
885 /*
886  * ":if".
887  */
888     void
889 ex_if(exarg_T *eap)
890 {
891     int		error;
892     int		skip;
893     int		result;
894     struct condstack	*cstack = eap->cstack;
895 
896     if (cstack->cs_idx == CSTACK_LEN - 1)
897 	eap->errmsg = N_("E579: :if nesting too deep");
898     else
899     {
900 	++cstack->cs_idx;
901 	cstack->cs_flags[cstack->cs_idx] = 0;
902 
903 	/*
904 	 * Don't do something after an error, interrupt, or throw, or when there
905 	 * is a surrounding conditional and it was not active.
906 	 */
907 	skip = did_emsg || got_int || did_throw || (cstack->cs_idx > 0
908 		&& !(cstack->cs_flags[cstack->cs_idx - 1] & CSF_ACTIVE));
909 
910 	result = eval_to_bool(eap->arg, &error, &eap->nextcmd, skip);
911 
912 	if (!skip && !error)
913 	{
914 	    if (result)
915 		cstack->cs_flags[cstack->cs_idx] = CSF_ACTIVE | CSF_TRUE;
916 	}
917 	else
918 	    /* set TRUE, so this conditional will never get active */
919 	    cstack->cs_flags[cstack->cs_idx] = CSF_TRUE;
920     }
921 }
922 
923 /*
924  * ":endif".
925  */
926     void
927 ex_endif(exarg_T *eap)
928 {
929     did_endif = TRUE;
930     if (eap->cstack->cs_idx < 0
931 	    || (eap->cstack->cs_flags[eap->cstack->cs_idx]
932 					   & (CSF_WHILE | CSF_FOR | CSF_TRY)))
933 	eap->errmsg = N_("E580: :endif without :if");
934     else
935     {
936 	/*
937 	 * When debugging or a breakpoint was encountered, display the debug
938 	 * prompt (if not already done).  This shows the user that an ":endif"
939 	 * is executed when the ":if" or a previous ":elseif" was not TRUE.
940 	 * Handle a ">quit" debug command as if an interrupt had occurred before
941 	 * the ":endif".  That is, throw an interrupt exception if appropriate.
942 	 * Doing this here prevents an exception for a parsing error being
943 	 * discarded by throwing the interrupt exception later on.
944 	 */
945 	if (!(eap->cstack->cs_flags[eap->cstack->cs_idx] & CSF_TRUE)
946 						    && dbg_check_skipped(eap))
947 	    (void)do_intthrow(eap->cstack);
948 
949 	--eap->cstack->cs_idx;
950     }
951 }
952 
953 /*
954  * ":else" and ":elseif".
955  */
956     void
957 ex_else(exarg_T *eap)
958 {
959     int		error;
960     int		skip;
961     int		result;
962     struct condstack	*cstack = eap->cstack;
963 
964     /*
965      * Don't do something after an error, interrupt, or throw, or when there is
966      * a surrounding conditional and it was not active.
967      */
968     skip = did_emsg || got_int || did_throw || (cstack->cs_idx > 0
969 	    && !(cstack->cs_flags[cstack->cs_idx - 1] & CSF_ACTIVE));
970 
971     if (cstack->cs_idx < 0
972 	    || (cstack->cs_flags[cstack->cs_idx]
973 					   & (CSF_WHILE | CSF_FOR | CSF_TRY)))
974     {
975 	if (eap->cmdidx == CMD_else)
976 	{
977 	    eap->errmsg = N_("E581: :else without :if");
978 	    return;
979 	}
980 	eap->errmsg = N_("E582: :elseif without :if");
981 	skip = TRUE;
982     }
983     else if (cstack->cs_flags[cstack->cs_idx] & CSF_ELSE)
984     {
985 	if (eap->cmdidx == CMD_else)
986 	{
987 	    eap->errmsg = N_("E583: multiple :else");
988 	    return;
989 	}
990 	eap->errmsg = N_("E584: :elseif after :else");
991 	skip = TRUE;
992     }
993 
994     /* if skipping or the ":if" was TRUE, reset ACTIVE, otherwise set it */
995     if (skip || cstack->cs_flags[cstack->cs_idx] & CSF_TRUE)
996     {
997 	if (eap->errmsg == NULL)
998 	    cstack->cs_flags[cstack->cs_idx] = CSF_TRUE;
999 	skip = TRUE;	/* don't evaluate an ":elseif" */
1000     }
1001     else
1002 	cstack->cs_flags[cstack->cs_idx] = CSF_ACTIVE;
1003 
1004     /*
1005      * When debugging or a breakpoint was encountered, display the debug prompt
1006      * (if not already done).  This shows the user that an ":else" or ":elseif"
1007      * is executed when the ":if" or previous ":elseif" was not TRUE.  Handle
1008      * a ">quit" debug command as if an interrupt had occurred before the
1009      * ":else" or ":elseif".  That is, set "skip" and throw an interrupt
1010      * exception if appropriate.  Doing this here prevents that an exception
1011      * for a parsing errors is discarded when throwing the interrupt exception
1012      * later on.
1013      */
1014     if (!skip && dbg_check_skipped(eap) && got_int)
1015     {
1016 	(void)do_intthrow(cstack);
1017 	skip = TRUE;
1018     }
1019 
1020     if (eap->cmdidx == CMD_elseif)
1021     {
1022 	result = eval_to_bool(eap->arg, &error, &eap->nextcmd, skip);
1023 	/* When throwing error exceptions, we want to throw always the first
1024 	 * of several errors in a row.  This is what actually happens when
1025 	 * a conditional error was detected above and there is another failure
1026 	 * when parsing the expression.  Since the skip flag is set in this
1027 	 * case, the parsing error will be ignored by emsg(). */
1028 
1029 	if (!skip && !error)
1030 	{
1031 	    if (result)
1032 		cstack->cs_flags[cstack->cs_idx] = CSF_ACTIVE | CSF_TRUE;
1033 	    else
1034 		cstack->cs_flags[cstack->cs_idx] = 0;
1035 	}
1036 	else if (eap->errmsg == NULL)
1037 	    /* set TRUE, so this conditional will never get active */
1038 	    cstack->cs_flags[cstack->cs_idx] = CSF_TRUE;
1039     }
1040     else
1041 	cstack->cs_flags[cstack->cs_idx] |= CSF_ELSE;
1042 }
1043 
1044 /*
1045  * Handle ":while" and ":for".
1046  */
1047     void
1048 ex_while(exarg_T *eap)
1049 {
1050     int		error;
1051     int		skip;
1052     int		result;
1053     struct condstack	*cstack = eap->cstack;
1054 
1055     if (cstack->cs_idx == CSTACK_LEN - 1)
1056 	eap->errmsg = N_("E585: :while/:for nesting too deep");
1057     else
1058     {
1059 	/*
1060 	 * The loop flag is set when we have jumped back from the matching
1061 	 * ":endwhile" or ":endfor".  When not set, need to initialise this
1062 	 * cstack entry.
1063 	 */
1064 	if ((cstack->cs_lflags & CSL_HAD_LOOP) == 0)
1065 	{
1066 	    ++cstack->cs_idx;
1067 	    ++cstack->cs_looplevel;
1068 	    cstack->cs_line[cstack->cs_idx] = -1;
1069 	}
1070 	cstack->cs_flags[cstack->cs_idx] =
1071 			       eap->cmdidx == CMD_while ? CSF_WHILE : CSF_FOR;
1072 
1073 	/*
1074 	 * Don't do something after an error, interrupt, or throw, or when
1075 	 * there is a surrounding conditional and it was not active.
1076 	 */
1077 	skip = did_emsg || got_int || did_throw || (cstack->cs_idx > 0
1078 		&& !(cstack->cs_flags[cstack->cs_idx - 1] & CSF_ACTIVE));
1079 	if (eap->cmdidx == CMD_while)
1080 	{
1081 	    /*
1082 	     * ":while bool-expr"
1083 	     */
1084 	    result = eval_to_bool(eap->arg, &error, &eap->nextcmd, skip);
1085 	}
1086 	else
1087 	{
1088 	    void *fi;
1089 
1090 	    /*
1091 	     * ":for var in list-expr"
1092 	     */
1093 	    if ((cstack->cs_lflags & CSL_HAD_LOOP) != 0)
1094 	    {
1095 		/* Jumping here from a ":continue" or ":endfor": use the
1096 		 * previously evaluated list. */
1097 		fi = cstack->cs_forinfo[cstack->cs_idx];
1098 		error = FALSE;
1099 	    }
1100 	    else
1101 	    {
1102 		/* Evaluate the argument and get the info in a structure. */
1103 		fi = eval_for_line(eap->arg, &error, &eap->nextcmd, skip);
1104 		cstack->cs_forinfo[cstack->cs_idx] = fi;
1105 	    }
1106 
1107 	    /* use the element at the start of the list and advance */
1108 	    if (!error && fi != NULL && !skip)
1109 		result = next_for_item(fi, eap->arg);
1110 	    else
1111 		result = FALSE;
1112 
1113 	    if (!result)
1114 	    {
1115 		free_for_info(fi);
1116 		cstack->cs_forinfo[cstack->cs_idx] = NULL;
1117 	    }
1118 	}
1119 
1120 	/*
1121 	 * If this cstack entry was just initialised and is active, set the
1122 	 * loop flag, so do_cmdline() will set the line number in cs_line[].
1123 	 * If executing the command a second time, clear the loop flag.
1124 	 */
1125 	if (!skip && !error && result)
1126 	{
1127 	    cstack->cs_flags[cstack->cs_idx] |= (CSF_ACTIVE | CSF_TRUE);
1128 	    cstack->cs_lflags ^= CSL_HAD_LOOP;
1129 	}
1130 	else
1131 	{
1132 	    cstack->cs_lflags &= ~CSL_HAD_LOOP;
1133 	    /* If the ":while" evaluates to FALSE or ":for" is past the end of
1134 	     * the list, show the debug prompt at the ":endwhile"/":endfor" as
1135 	     * if there was a ":break" in a ":while"/":for" evaluating to
1136 	     * TRUE. */
1137 	    if (!skip && !error)
1138 		cstack->cs_flags[cstack->cs_idx] |= CSF_TRUE;
1139 	}
1140     }
1141 }
1142 
1143 /*
1144  * ":continue"
1145  */
1146     void
1147 ex_continue(exarg_T *eap)
1148 {
1149     int		idx;
1150     struct condstack	*cstack = eap->cstack;
1151 
1152     if (cstack->cs_looplevel <= 0 || cstack->cs_idx < 0)
1153 	eap->errmsg = N_("E586: :continue without :while or :for");
1154     else
1155     {
1156 	/* Try to find the matching ":while".  This might stop at a try
1157 	 * conditional not in its finally clause (which is then to be executed
1158 	 * next).  Therefor, inactivate all conditionals except the ":while"
1159 	 * itself (if reached). */
1160 	idx = cleanup_conditionals(cstack, CSF_WHILE | CSF_FOR, FALSE);
1161 	if (idx >= 0 && (cstack->cs_flags[idx] & (CSF_WHILE | CSF_FOR)))
1162 	{
1163 	    rewind_conditionals(cstack, idx, CSF_TRY, &cstack->cs_trylevel);
1164 
1165 	    /*
1166 	     * Set CSL_HAD_CONT, so do_cmdline() will jump back to the
1167 	     * matching ":while".
1168 	     */
1169 	    cstack->cs_lflags |= CSL_HAD_CONT;	/* let do_cmdline() handle it */
1170 	}
1171 	else
1172 	{
1173 	    /* If a try conditional not in its finally clause is reached first,
1174 	     * make the ":continue" pending for execution at the ":endtry". */
1175 	    cstack->cs_pending[idx] = CSTP_CONTINUE;
1176 	    report_make_pending(CSTP_CONTINUE, NULL);
1177 	}
1178     }
1179 }
1180 
1181 /*
1182  * ":break"
1183  */
1184     void
1185 ex_break(exarg_T *eap)
1186 {
1187     int		idx;
1188     struct condstack	*cstack = eap->cstack;
1189 
1190     if (cstack->cs_looplevel <= 0 || cstack->cs_idx < 0)
1191 	eap->errmsg = N_("E587: :break without :while or :for");
1192     else
1193     {
1194 	/* Inactivate conditionals until the matching ":while" or a try
1195 	 * conditional not in its finally clause (which is then to be
1196 	 * executed next) is found.  In the latter case, make the ":break"
1197 	 * pending for execution at the ":endtry". */
1198 	idx = cleanup_conditionals(cstack, CSF_WHILE | CSF_FOR, TRUE);
1199 	if (idx >= 0 && !(cstack->cs_flags[idx] & (CSF_WHILE | CSF_FOR)))
1200 	{
1201 	    cstack->cs_pending[idx] = CSTP_BREAK;
1202 	    report_make_pending(CSTP_BREAK, NULL);
1203 	}
1204     }
1205 }
1206 
1207 /*
1208  * ":endwhile" and ":endfor"
1209  */
1210     void
1211 ex_endwhile(exarg_T *eap)
1212 {
1213     struct condstack	*cstack = eap->cstack;
1214     int			idx;
1215     char		*err;
1216     int			csf;
1217     int			fl;
1218 
1219     if (eap->cmdidx == CMD_endwhile)
1220     {
1221 	err = e_while;
1222 	csf = CSF_WHILE;
1223     }
1224     else
1225     {
1226 	err = e_for;
1227 	csf = CSF_FOR;
1228     }
1229 
1230     if (cstack->cs_looplevel <= 0 || cstack->cs_idx < 0)
1231 	eap->errmsg = err;
1232     else
1233     {
1234 	fl =  cstack->cs_flags[cstack->cs_idx];
1235 	if (!(fl & csf))
1236 	{
1237 	    /* If we are in a ":while" or ":for" but used the wrong endloop
1238 	     * command, do not rewind to the next enclosing ":for"/":while". */
1239 	    if (fl & CSF_WHILE)
1240 		eap->errmsg = _("E732: Using :endfor with :while");
1241 	    else if (fl & CSF_FOR)
1242 		eap->errmsg = _("E733: Using :endwhile with :for");
1243 	}
1244 	if (!(fl & (CSF_WHILE | CSF_FOR)))
1245 	{
1246 	    if (!(fl & CSF_TRY))
1247 		eap->errmsg = e_endif;
1248 	    else if (fl & CSF_FINALLY)
1249 		eap->errmsg = e_endtry;
1250 	    /* Try to find the matching ":while" and report what's missing. */
1251 	    for (idx = cstack->cs_idx; idx > 0; --idx)
1252 	    {
1253 		fl =  cstack->cs_flags[idx];
1254 		if ((fl & CSF_TRY) && !(fl & CSF_FINALLY))
1255 		{
1256 		    /* Give up at a try conditional not in its finally clause.
1257 		     * Ignore the ":endwhile"/":endfor". */
1258 		    eap->errmsg = err;
1259 		    return;
1260 		}
1261 		if (fl & csf)
1262 		    break;
1263 	    }
1264 	    /* Cleanup and rewind all contained (and unclosed) conditionals. */
1265 	    (void)cleanup_conditionals(cstack, CSF_WHILE | CSF_FOR, FALSE);
1266 	    rewind_conditionals(cstack, idx, CSF_TRY, &cstack->cs_trylevel);
1267 	}
1268 
1269 	/*
1270 	 * When debugging or a breakpoint was encountered, display the debug
1271 	 * prompt (if not already done).  This shows the user that an
1272 	 * ":endwhile"/":endfor" is executed when the ":while" was not TRUE or
1273 	 * after a ":break".  Handle a ">quit" debug command as if an
1274 	 * interrupt had occurred before the ":endwhile"/":endfor".  That is,
1275 	 * throw an interrupt exception if appropriate.  Doing this here
1276 	 * prevents that an exception for a parsing error is discarded when
1277 	 * throwing the interrupt exception later on.
1278 	 */
1279 	else if (cstack->cs_flags[cstack->cs_idx] & CSF_TRUE
1280 		&& !(cstack->cs_flags[cstack->cs_idx] & CSF_ACTIVE)
1281 		&& dbg_check_skipped(eap))
1282 	    (void)do_intthrow(cstack);
1283 
1284 	/*
1285 	 * Set loop flag, so do_cmdline() will jump back to the matching
1286 	 * ":while" or ":for".
1287 	 */
1288 	cstack->cs_lflags |= CSL_HAD_ENDLOOP;
1289     }
1290 }
1291 
1292 
1293 /*
1294  * ":throw expr"
1295  */
1296     void
1297 ex_throw(exarg_T *eap)
1298 {
1299     char_u	*arg = eap->arg;
1300     char_u	*value;
1301 
1302     if (*arg != NUL && *arg != '|' && *arg != '\n')
1303 	value = eval_to_string_skip(arg, &eap->nextcmd, eap->skip);
1304     else
1305     {
1306 	emsg(_(e_argreq));
1307 	value = NULL;
1308     }
1309 
1310     /* On error or when an exception is thrown during argument evaluation, do
1311      * not throw. */
1312     if (!eap->skip && value != NULL)
1313     {
1314 	if (throw_exception(value, ET_USER, NULL) == FAIL)
1315 	    vim_free(value);
1316 	else
1317 	    do_throw(eap->cstack);
1318     }
1319 }
1320 
1321 /*
1322  * Throw the current exception through the specified cstack.  Common routine
1323  * for ":throw" (user exception) and error and interrupt exceptions.  Also
1324  * used for rethrowing an uncaught exception.
1325  */
1326     void
1327 do_throw(struct condstack *cstack)
1328 {
1329     int		idx;
1330     int		inactivate_try = FALSE;
1331 
1332     /*
1333      * Cleanup and inactivate up to the next surrounding try conditional that
1334      * is not in its finally clause.  Normally, do not inactivate the try
1335      * conditional itself, so that its ACTIVE flag can be tested below.  But
1336      * if a previous error or interrupt has not been converted to an exception,
1337      * inactivate the try conditional, too, as if the conversion had been done,
1338      * and reset the did_emsg or got_int flag, so this won't happen again at
1339      * the next surrounding try conditional.
1340      */
1341 #ifndef THROW_ON_ERROR_TRUE
1342     if (did_emsg && !THROW_ON_ERROR)
1343     {
1344 	inactivate_try = TRUE;
1345 	did_emsg = FALSE;
1346     }
1347 #endif
1348 #ifndef THROW_ON_INTERRUPT_TRUE
1349     if (got_int && !THROW_ON_INTERRUPT)
1350     {
1351 	inactivate_try = TRUE;
1352 	got_int = FALSE;
1353     }
1354 #endif
1355     idx = cleanup_conditionals(cstack, 0, inactivate_try);
1356     if (idx >= 0)
1357     {
1358 	/*
1359 	 * If this try conditional is active and we are before its first
1360 	 * ":catch", set THROWN so that the ":catch" commands will check
1361 	 * whether the exception matches.  When the exception came from any of
1362 	 * the catch clauses, it will be made pending at the ":finally" (if
1363 	 * present) and rethrown at the ":endtry".  This will also happen if
1364 	 * the try conditional is inactive.  This is the case when we are
1365 	 * throwing an exception due to an error or interrupt on the way from
1366 	 * a preceding ":continue", ":break", ":return", ":finish", error or
1367 	 * interrupt (not converted to an exception) to the finally clause or
1368 	 * from a preceding throw of a user or error or interrupt exception to
1369 	 * the matching catch clause or the finally clause.
1370 	 */
1371 	if (!(cstack->cs_flags[idx] & CSF_CAUGHT))
1372 	{
1373 	    if (cstack->cs_flags[idx] & CSF_ACTIVE)
1374 		cstack->cs_flags[idx] |= CSF_THROWN;
1375 	    else
1376 		/* THROWN may have already been set for a catchable exception
1377 		 * that has been discarded.  Ensure it is reset for the new
1378 		 * exception. */
1379 		cstack->cs_flags[idx] &= ~CSF_THROWN;
1380 	}
1381 	cstack->cs_flags[idx] &= ~CSF_ACTIVE;
1382 	cstack->cs_exception[idx] = current_exception;
1383     }
1384 #if 0
1385     /* TODO: Add optimization below.  Not yet done because of interface
1386      * problems to eval.c and ex_cmds2.c. (Servatius) */
1387     else
1388     {
1389 	/*
1390 	 * There are no catch clauses to check or finally clauses to execute.
1391 	 * End the current script or function.  The exception will be rethrown
1392 	 * in the caller.
1393 	 */
1394 	if (getline_equal(eap->getline, eap->cookie, get_func_line))
1395 	    current_funccal->returned = TRUE;
1396 	elseif (eap->get_func_line == getsourceline)
1397 	    ((struct source_cookie *)eap->cookie)->finished = TRUE;
1398     }
1399 #endif
1400 
1401     did_throw = TRUE;
1402 }
1403 
1404 /*
1405  * ":try"
1406  */
1407     void
1408 ex_try(exarg_T *eap)
1409 {
1410     int		skip;
1411     struct condstack	*cstack = eap->cstack;
1412 
1413     if (cstack->cs_idx == CSTACK_LEN - 1)
1414 	eap->errmsg = N_("E601: :try nesting too deep");
1415     else
1416     {
1417 	++cstack->cs_idx;
1418 	++cstack->cs_trylevel;
1419 	cstack->cs_flags[cstack->cs_idx] = CSF_TRY;
1420 	cstack->cs_pending[cstack->cs_idx] = CSTP_NONE;
1421 
1422 	/*
1423 	 * Don't do something after an error, interrupt, or throw, or when there
1424 	 * is a surrounding conditional and it was not active.
1425 	 */
1426 	skip = did_emsg || got_int || did_throw || (cstack->cs_idx > 0
1427 		&& !(cstack->cs_flags[cstack->cs_idx - 1] & CSF_ACTIVE));
1428 
1429 	if (!skip)
1430 	{
1431 	    /* Set ACTIVE and TRUE.  TRUE means that the corresponding ":catch"
1432 	     * commands should check for a match if an exception is thrown and
1433 	     * that the finally clause needs to be executed. */
1434 	    cstack->cs_flags[cstack->cs_idx] |= CSF_ACTIVE | CSF_TRUE;
1435 
1436 	    /*
1437 	     * ":silent!", even when used in a try conditional, disables
1438 	     * displaying of error messages and conversion of errors to
1439 	     * exceptions.  When the silent commands again open a try
1440 	     * conditional, save "emsg_silent" and reset it so that errors are
1441 	     * again converted to exceptions.  The value is restored when that
1442 	     * try conditional is left.  If it is left normally, the commands
1443 	     * following the ":endtry" are again silent.  If it is left by
1444 	     * a ":continue", ":break", ":return", or ":finish", the commands
1445 	     * executed next are again silent.  If it is left due to an
1446 	     * aborting error, an interrupt, or an exception, restoring
1447 	     * "emsg_silent" does not matter since we are already in the
1448 	     * aborting state and/or the exception has already been thrown.
1449 	     * The effect is then just freeing the memory that was allocated
1450 	     * to save the value.
1451 	     */
1452 	    if (emsg_silent)
1453 	    {
1454 		eslist_T	*elem;
1455 
1456 		elem = ALLOC_ONE(struct eslist_elem);
1457 		if (elem == NULL)
1458 		    emsg(_(e_outofmem));
1459 		else
1460 		{
1461 		    elem->saved_emsg_silent = emsg_silent;
1462 		    elem->next = cstack->cs_emsg_silent_list;
1463 		    cstack->cs_emsg_silent_list = elem;
1464 		    cstack->cs_flags[cstack->cs_idx] |= CSF_SILENT;
1465 		    emsg_silent = 0;
1466 		}
1467 	    }
1468 	}
1469 
1470     }
1471 }
1472 
1473 /*
1474  * ":catch /{pattern}/" and ":catch"
1475  */
1476     void
1477 ex_catch(exarg_T *eap)
1478 {
1479     int		idx = 0;
1480     int		give_up = FALSE;
1481     int		skip = FALSE;
1482     int		caught = FALSE;
1483     char_u	*end;
1484     int		save_char = 0;
1485     char_u	*save_cpo;
1486     regmatch_T	regmatch;
1487     int		prev_got_int;
1488     struct condstack	*cstack = eap->cstack;
1489     char_u	*pat;
1490 
1491     if (cstack->cs_trylevel <= 0 || cstack->cs_idx < 0)
1492     {
1493 	eap->errmsg = N_("E603: :catch without :try");
1494 	give_up = TRUE;
1495     }
1496     else
1497     {
1498 	if (!(cstack->cs_flags[cstack->cs_idx] & CSF_TRY))
1499 	{
1500 	    /* Report what's missing if the matching ":try" is not in its
1501 	     * finally clause. */
1502 	    eap->errmsg = get_end_emsg(cstack);
1503 	    skip = TRUE;
1504 	}
1505 	for (idx = cstack->cs_idx; idx > 0; --idx)
1506 	    if (cstack->cs_flags[idx] & CSF_TRY)
1507 		break;
1508 	if (cstack->cs_flags[idx] & CSF_FINALLY)
1509 	{
1510 	    /* Give up for a ":catch" after ":finally" and ignore it.
1511 	     * Just parse. */
1512 	    eap->errmsg = N_("E604: :catch after :finally");
1513 	    give_up = TRUE;
1514 	}
1515 	else
1516 	    rewind_conditionals(cstack, idx, CSF_WHILE | CSF_FOR,
1517 						       &cstack->cs_looplevel);
1518     }
1519 
1520     if (ends_excmd(*eap->arg))	/* no argument, catch all errors */
1521     {
1522 	pat = (char_u *)".*";
1523 	end = NULL;
1524 	eap->nextcmd = find_nextcmd(eap->arg);
1525     }
1526     else
1527     {
1528 	pat = eap->arg + 1;
1529 	end = skip_regexp(pat, *eap->arg, TRUE, NULL);
1530     }
1531 
1532     if (!give_up)
1533     {
1534 	/*
1535 	 * Don't do something when no exception has been thrown or when the
1536 	 * corresponding try block never got active (because of an inactive
1537 	 * surrounding conditional or after an error or interrupt or throw).
1538 	 */
1539 	if (!did_throw || !(cstack->cs_flags[idx] & CSF_TRUE))
1540 	    skip = TRUE;
1541 
1542 	/*
1543 	 * Check for a match only if an exception is thrown but not caught by
1544 	 * a previous ":catch".  An exception that has replaced a discarded
1545 	 * exception is not checked (THROWN is not set then).
1546 	 */
1547 	if (!skip && (cstack->cs_flags[idx] & CSF_THROWN)
1548 		&& !(cstack->cs_flags[idx] & CSF_CAUGHT))
1549 	{
1550 	    if (end != NULL && *end != NUL && !ends_excmd(*skipwhite(end + 1)))
1551 	    {
1552 		emsg(_(e_trailing));
1553 		return;
1554 	    }
1555 
1556 	    /* When debugging or a breakpoint was encountered, display the
1557 	     * debug prompt (if not already done) before checking for a match.
1558 	     * This is a helpful hint for the user when the regular expression
1559 	     * matching fails.  Handle a ">quit" debug command as if an
1560 	     * interrupt had occurred before the ":catch".  That is, discard
1561 	     * the original exception, replace it by an interrupt exception,
1562 	     * and don't catch it in this try block. */
1563 	    if (!dbg_check_skipped(eap) || !do_intthrow(cstack))
1564 	    {
1565 		/* Terminate the pattern and avoid the 'l' flag in 'cpoptions'
1566 		 * while compiling it. */
1567 		if (end != NULL)
1568 		{
1569 		    save_char = *end;
1570 		    *end = NUL;
1571 		}
1572 		save_cpo  = p_cpo;
1573 		p_cpo = (char_u *)"";
1574 		/* Disable error messages, it will make current_exception
1575 		 * invalid. */
1576 		++emsg_off;
1577 		regmatch.regprog = vim_regcomp(pat, RE_MAGIC + RE_STRING);
1578 		--emsg_off;
1579 		regmatch.rm_ic = FALSE;
1580 		if (end != NULL)
1581 		    *end = save_char;
1582 		p_cpo = save_cpo;
1583 		if (regmatch.regprog == NULL)
1584 		    semsg(_(e_invarg2), pat);
1585 		else
1586 		{
1587 		    /*
1588 		     * Save the value of got_int and reset it.  We don't want
1589 		     * a previous interruption cancel matching, only hitting
1590 		     * CTRL-C while matching should abort it.
1591 		     */
1592 		    prev_got_int = got_int;
1593 		    got_int = FALSE;
1594 		    caught = vim_regexec_nl(&regmatch,
1595 			       (char_u *)current_exception->value, (colnr_T)0);
1596 		    got_int |= prev_got_int;
1597 		    vim_regfree(regmatch.regprog);
1598 		}
1599 	    }
1600 	}
1601 
1602 	if (caught)
1603 	{
1604 	    /* Make this ":catch" clause active and reset did_emsg, got_int,
1605 	     * and did_throw.  Put the exception on the caught stack. */
1606 	    cstack->cs_flags[idx] |= CSF_ACTIVE | CSF_CAUGHT;
1607 	    did_emsg = got_int = did_throw = FALSE;
1608 	    catch_exception((except_T *)cstack->cs_exception[idx]);
1609 	    /* It's mandatory that the current exception is stored in the cstack
1610 	     * so that it can be discarded at the next ":catch", ":finally", or
1611 	     * ":endtry" or when the catch clause is left by a ":continue",
1612 	     * ":break", ":return", ":finish", error, interrupt, or another
1613 	     * exception. */
1614 	    if (cstack->cs_exception[cstack->cs_idx] != current_exception)
1615 		internal_error("ex_catch()");
1616 	}
1617 	else
1618 	{
1619 	    /*
1620 	     * If there is a preceding catch clause and it caught the exception,
1621 	     * finish the exception now.  This happens also after errors except
1622 	     * when this ":catch" was after the ":finally" or not within
1623 	     * a ":try".  Make the try conditional inactive so that the
1624 	     * following catch clauses are skipped.  On an error or interrupt
1625 	     * after the preceding try block or catch clause was left by
1626 	     * a ":continue", ":break", ":return", or ":finish", discard the
1627 	     * pending action.
1628 	     */
1629 	    cleanup_conditionals(cstack, CSF_TRY, TRUE);
1630 	}
1631     }
1632 
1633     if (end != NULL)
1634 	eap->nextcmd = find_nextcmd(end);
1635 }
1636 
1637 /*
1638  * ":finally"
1639  */
1640     void
1641 ex_finally(exarg_T *eap)
1642 {
1643     int		idx;
1644     int		skip = FALSE;
1645     int		pending = CSTP_NONE;
1646     struct condstack	*cstack = eap->cstack;
1647 
1648     if (cstack->cs_trylevel <= 0 || cstack->cs_idx < 0)
1649 	eap->errmsg = N_("E606: :finally without :try");
1650     else
1651     {
1652 	if (!(cstack->cs_flags[cstack->cs_idx] & CSF_TRY))
1653 	{
1654 	    eap->errmsg = get_end_emsg(cstack);
1655 	    for (idx = cstack->cs_idx - 1; idx > 0; --idx)
1656 		if (cstack->cs_flags[idx] & CSF_TRY)
1657 		    break;
1658 	    /* Make this error pending, so that the commands in the following
1659 	     * finally clause can be executed.  This overrules also a pending
1660 	     * ":continue", ":break", ":return", or ":finish". */
1661 	    pending = CSTP_ERROR;
1662 	}
1663 	else
1664 	    idx = cstack->cs_idx;
1665 
1666 	if (cstack->cs_flags[idx] & CSF_FINALLY)
1667 	{
1668 	    /* Give up for a multiple ":finally" and ignore it. */
1669 	    eap->errmsg = N_("E607: multiple :finally");
1670 	    return;
1671 	}
1672 	rewind_conditionals(cstack, idx, CSF_WHILE | CSF_FOR,
1673 						       &cstack->cs_looplevel);
1674 
1675 	/*
1676 	 * Don't do something when the corresponding try block never got active
1677 	 * (because of an inactive surrounding conditional or after an error or
1678 	 * interrupt or throw) or for a ":finally" without ":try" or a multiple
1679 	 * ":finally".  After every other error (did_emsg or the conditional
1680 	 * errors detected above) or after an interrupt (got_int) or an
1681 	 * exception (did_throw), the finally clause must be executed.
1682 	 */
1683 	skip = !(cstack->cs_flags[cstack->cs_idx] & CSF_TRUE);
1684 
1685 	if (!skip)
1686 	{
1687 	    /* When debugging or a breakpoint was encountered, display the
1688 	     * debug prompt (if not already done).  The user then knows that the
1689 	     * finally clause is executed. */
1690 	    if (dbg_check_skipped(eap))
1691 	    {
1692 		/* Handle a ">quit" debug command as if an interrupt had
1693 		 * occurred before the ":finally".  That is, discard the
1694 		 * original exception and replace it by an interrupt
1695 		 * exception. */
1696 		(void)do_intthrow(cstack);
1697 	    }
1698 
1699 	    /*
1700 	     * If there is a preceding catch clause and it caught the exception,
1701 	     * finish the exception now.  This happens also after errors except
1702 	     * when this is a multiple ":finally" or one not within a ":try".
1703 	     * After an error or interrupt, this also discards a pending
1704 	     * ":continue", ":break", ":finish", or ":return" from the preceding
1705 	     * try block or catch clause.
1706 	     */
1707 	    cleanup_conditionals(cstack, CSF_TRY, FALSE);
1708 
1709 	    /*
1710 	     * Make did_emsg, got_int, did_throw pending.  If set, they overrule
1711 	     * a pending ":continue", ":break", ":return", or ":finish".  Then
1712 	     * we have particularly to discard a pending return value (as done
1713 	     * by the call to cleanup_conditionals() above when did_emsg or
1714 	     * got_int is set).  The pending values are restored by the
1715 	     * ":endtry", except if there is a new error, interrupt, exception,
1716 	     * ":continue", ":break", ":return", or ":finish" in the following
1717 	     * finally clause.  A missing ":endwhile", ":endfor" or ":endif"
1718 	     * detected here is treated as if did_emsg and did_throw had
1719 	     * already been set, respectively in case that the error is not
1720 	     * converted to an exception, did_throw had already been unset.
1721 	     * We must not set did_emsg here since that would suppress the
1722 	     * error message.
1723 	     */
1724 	    if (pending == CSTP_ERROR || did_emsg || got_int || did_throw)
1725 	    {
1726 		if (cstack->cs_pending[cstack->cs_idx] == CSTP_RETURN)
1727 		{
1728 		    report_discard_pending(CSTP_RETURN,
1729 					   cstack->cs_rettv[cstack->cs_idx]);
1730 		    discard_pending_return(cstack->cs_rettv[cstack->cs_idx]);
1731 		}
1732 		if (pending == CSTP_ERROR && !did_emsg)
1733 		    pending |= (THROW_ON_ERROR) ? CSTP_THROW : 0;
1734 		else
1735 		    pending |= did_throw ? CSTP_THROW : 0;
1736 		pending |= did_emsg  ? CSTP_ERROR     : 0;
1737 		pending |= got_int   ? CSTP_INTERRUPT : 0;
1738 		cstack->cs_pending[cstack->cs_idx] = pending;
1739 
1740 		/* It's mandatory that the current exception is stored in the
1741 		 * cstack so that it can be rethrown at the ":endtry" or be
1742 		 * discarded if the finally clause is left by a ":continue",
1743 		 * ":break", ":return", ":finish", error, interrupt, or another
1744 		 * exception.  When emsg() is called for a missing ":endif" or
1745 		 * a missing ":endwhile"/":endfor" detected here, the
1746 		 * exception will be discarded. */
1747 		if (did_throw && cstack->cs_exception[cstack->cs_idx]
1748 							 != current_exception)
1749 		    internal_error("ex_finally()");
1750 	    }
1751 
1752 	    /*
1753 	     * Set CSL_HAD_FINA, so do_cmdline() will reset did_emsg,
1754 	     * got_int, and did_throw and make the finally clause active.
1755 	     * This will happen after emsg() has been called for a missing
1756 	     * ":endif" or a missing ":endwhile"/":endfor" detected here, so
1757 	     * that the following finally clause will be executed even then.
1758 	     */
1759 	    cstack->cs_lflags |= CSL_HAD_FINA;
1760 	}
1761     }
1762 }
1763 
1764 /*
1765  * ":endtry"
1766  */
1767     void
1768 ex_endtry(exarg_T *eap)
1769 {
1770     int		idx;
1771     int		skip;
1772     int		rethrow = FALSE;
1773     int		pending = CSTP_NONE;
1774     void	*rettv = NULL;
1775     struct condstack	*cstack = eap->cstack;
1776 
1777     if (cstack->cs_trylevel <= 0 || cstack->cs_idx < 0)
1778 	eap->errmsg = N_("E602: :endtry without :try");
1779     else
1780     {
1781 	/*
1782 	 * Don't do something after an error, interrupt or throw in the try
1783 	 * block, catch clause, or finally clause preceding this ":endtry" or
1784 	 * when an error or interrupt occurred after a ":continue", ":break",
1785 	 * ":return", or ":finish" in a try block or catch clause preceding this
1786 	 * ":endtry" or when the try block never got active (because of an
1787 	 * inactive surrounding conditional or after an error or interrupt or
1788 	 * throw) or when there is a surrounding conditional and it has been
1789 	 * made inactive by a ":continue", ":break", ":return", or ":finish" in
1790 	 * the finally clause.  The latter case need not be tested since then
1791 	 * anything pending has already been discarded. */
1792 	skip = did_emsg || got_int || did_throw ||
1793 	    !(cstack->cs_flags[cstack->cs_idx] & CSF_TRUE);
1794 
1795 	if (!(cstack->cs_flags[cstack->cs_idx] & CSF_TRY))
1796 	{
1797 	    eap->errmsg = get_end_emsg(cstack);
1798 	    /* Find the matching ":try" and report what's missing. */
1799 	    idx = cstack->cs_idx;
1800 	    do
1801 		--idx;
1802 	    while (idx > 0 && !(cstack->cs_flags[idx] & CSF_TRY));
1803 	    rewind_conditionals(cstack, idx, CSF_WHILE | CSF_FOR,
1804 						       &cstack->cs_looplevel);
1805 	    skip = TRUE;
1806 
1807 	    /*
1808 	     * If an exception is being thrown, discard it to prevent it from
1809 	     * being rethrown at the end of this function.  It would be
1810 	     * discarded by the error message, anyway.  Resets did_throw.
1811 	     * This does not affect the script termination due to the error
1812 	     * since "trylevel" is decremented after emsg() has been called.
1813 	     */
1814 	    if (did_throw)
1815 		discard_current_exception();
1816 	}
1817 	else
1818 	{
1819 	    idx = cstack->cs_idx;
1820 
1821 	    /*
1822 	     * If we stopped with the exception currently being thrown at this
1823 	     * try conditional since we didn't know that it doesn't have
1824 	     * a finally clause, we need to rethrow it after closing the try
1825 	     * conditional.
1826 	     */
1827 	    if (did_throw && (cstack->cs_flags[idx] & CSF_TRUE)
1828 		    && !(cstack->cs_flags[idx] & CSF_FINALLY))
1829 		rethrow = TRUE;
1830 	}
1831 
1832 	/* If there was no finally clause, show the user when debugging or
1833 	 * a breakpoint was encountered that the end of the try conditional has
1834 	 * been reached: display the debug prompt (if not already done).  Do
1835 	 * this on normal control flow or when an exception was thrown, but not
1836 	 * on an interrupt or error not converted to an exception or when
1837 	 * a ":break", ":continue", ":return", or ":finish" is pending.  These
1838 	 * actions are carried out immediately.
1839 	 */
1840 	if ((rethrow || (!skip
1841 			&& !(cstack->cs_flags[idx] & CSF_FINALLY)
1842 			&& !cstack->cs_pending[idx]))
1843 		&& dbg_check_skipped(eap))
1844 	{
1845 	    /* Handle a ">quit" debug command as if an interrupt had occurred
1846 	     * before the ":endtry".  That is, throw an interrupt exception and
1847 	     * set "skip" and "rethrow". */
1848 	    if (got_int)
1849 	    {
1850 		skip = TRUE;
1851 		(void)do_intthrow(cstack);
1852 		/* The do_intthrow() call may have reset did_throw or
1853 		 * cstack->cs_pending[idx].*/
1854 		rethrow = FALSE;
1855 		if (did_throw && !(cstack->cs_flags[idx] & CSF_FINALLY))
1856 		    rethrow = TRUE;
1857 	    }
1858 	}
1859 
1860 	/*
1861 	 * If a ":return" is pending, we need to resume it after closing the
1862 	 * try conditional; remember the return value.  If there was a finally
1863 	 * clause making an exception pending, we need to rethrow it.  Make it
1864 	 * the exception currently being thrown.
1865 	 */
1866 	if (!skip)
1867 	{
1868 	    pending = cstack->cs_pending[idx];
1869 	    cstack->cs_pending[idx] = CSTP_NONE;
1870 	    if (pending == CSTP_RETURN)
1871 		rettv = cstack->cs_rettv[idx];
1872 	    else if (pending & CSTP_THROW)
1873 		current_exception = cstack->cs_exception[idx];
1874 	}
1875 
1876 	/*
1877 	 * Discard anything pending on an error, interrupt, or throw in the
1878 	 * finally clause.  If there was no ":finally", discard a pending
1879 	 * ":continue", ":break", ":return", or ":finish" if an error or
1880 	 * interrupt occurred afterwards, but before the ":endtry" was reached.
1881 	 * If an exception was caught by the last of the catch clauses and there
1882 	 * was no finally clause, finish the exception now.  This happens also
1883 	 * after errors except when this ":endtry" is not within a ":try".
1884 	 * Restore "emsg_silent" if it has been reset by this try conditional.
1885 	 */
1886 	(void)cleanup_conditionals(cstack, CSF_TRY | CSF_SILENT, TRUE);
1887 
1888 	--cstack->cs_idx;
1889 	--cstack->cs_trylevel;
1890 
1891 	if (!skip)
1892 	{
1893 	    report_resume_pending(pending,
1894 		    (pending == CSTP_RETURN) ? rettv :
1895 		    (pending & CSTP_THROW) ? (void *)current_exception : NULL);
1896 	    switch (pending)
1897 	    {
1898 		case CSTP_NONE:
1899 		    break;
1900 
1901 		/* Reactivate a pending ":continue", ":break", ":return",
1902 		 * ":finish" from the try block or a catch clause of this try
1903 		 * conditional.  This is skipped, if there was an error in an
1904 		 * (unskipped) conditional command or an interrupt afterwards
1905 		 * or if the finally clause is present and executed a new error,
1906 		 * interrupt, throw, ":continue", ":break", ":return", or
1907 		 * ":finish". */
1908 		case CSTP_CONTINUE:
1909 		    ex_continue(eap);
1910 		    break;
1911 		case CSTP_BREAK:
1912 		    ex_break(eap);
1913 		    break;
1914 		case CSTP_RETURN:
1915 		    do_return(eap, FALSE, FALSE, rettv);
1916 		    break;
1917 		case CSTP_FINISH:
1918 		    do_finish(eap, FALSE);
1919 		    break;
1920 
1921 		/* When the finally clause was entered due to an error,
1922 		 * interrupt or throw (as opposed to a ":continue", ":break",
1923 		 * ":return", or ":finish"), restore the pending values of
1924 		 * did_emsg, got_int, and did_throw.  This is skipped, if there
1925 		 * was a new error, interrupt, throw, ":continue", ":break",
1926 		 * ":return", or ":finish".  in the finally clause. */
1927 		default:
1928 		    if (pending & CSTP_ERROR)
1929 			did_emsg = TRUE;
1930 		    if (pending & CSTP_INTERRUPT)
1931 			got_int = TRUE;
1932 		    if (pending & CSTP_THROW)
1933 			rethrow = TRUE;
1934 		    break;
1935 	    }
1936 	}
1937 
1938 	if (rethrow)
1939 	    /* Rethrow the current exception (within this cstack). */
1940 	    do_throw(cstack);
1941     }
1942 }
1943 
1944 /*
1945  * enter_cleanup() and leave_cleanup()
1946  *
1947  * Functions to be called before/after invoking a sequence of autocommands for
1948  * cleanup for a failed command.  (Failure means here that a call to emsg()
1949  * has been made, an interrupt occurred, or there is an uncaught exception
1950  * from a previous autocommand execution of the same command.)
1951  *
1952  * Call enter_cleanup() with a pointer to a cleanup_T and pass the same
1953  * pointer to leave_cleanup().  The cleanup_T structure stores the pending
1954  * error/interrupt/exception state.
1955  */
1956 
1957 /*
1958  * This function works a bit like ex_finally() except that there was not
1959  * actually an extra try block around the part that failed and an error or
1960  * interrupt has not (yet) been converted to an exception.  This function
1961  * saves the error/interrupt/ exception state and prepares for the call to
1962  * do_cmdline() that is going to be made for the cleanup autocommand
1963  * execution.
1964  */
1965     void
1966 enter_cleanup(cleanup_T *csp)
1967 {
1968     int		pending = CSTP_NONE;
1969 
1970     /*
1971      * Postpone did_emsg, got_int, did_throw.  The pending values will be
1972      * restored by leave_cleanup() except if there was an aborting error,
1973      * interrupt, or uncaught exception after this function ends.
1974      */
1975     if (did_emsg || got_int || did_throw || need_rethrow)
1976     {
1977 	csp->pending = (did_emsg     ? CSTP_ERROR     : 0)
1978 		     | (got_int      ? CSTP_INTERRUPT : 0)
1979 		     | (did_throw    ? CSTP_THROW     : 0)
1980 		     | (need_rethrow ? CSTP_THROW     : 0);
1981 
1982 	/* If we are currently throwing an exception (did_throw), save it as
1983 	 * well.  On an error not yet converted to an exception, update
1984 	 * "force_abort" and reset "cause_abort" (as do_errthrow() would do).
1985 	 * This is needed for the do_cmdline() call that is going to be made
1986 	 * for autocommand execution.  We need not save *msg_list because
1987 	 * there is an extra instance for every call of do_cmdline(), anyway.
1988 	 */
1989 	if (did_throw || need_rethrow)
1990 	{
1991 	    csp->exception = current_exception;
1992 	    current_exception = NULL;
1993 	}
1994 	else
1995 	{
1996 	    csp->exception = NULL;
1997 	    if (did_emsg)
1998 	    {
1999 		force_abort |= cause_abort;
2000 		cause_abort = FALSE;
2001 	    }
2002 	}
2003 	did_emsg = got_int = did_throw = need_rethrow = FALSE;
2004 
2005 	/* Report if required by the 'verbose' option or when debugging.  */
2006 	report_make_pending(pending, csp->exception);
2007     }
2008     else
2009     {
2010 	csp->pending = CSTP_NONE;
2011 	csp->exception = NULL;
2012     }
2013 }
2014 
2015 /*
2016  * See comment above enter_cleanup() for how this function is used.
2017  *
2018  * This function is a bit like ex_endtry() except that there was not actually
2019  * an extra try block around the part that failed and an error or interrupt
2020  * had not (yet) been converted to an exception when the cleanup autocommand
2021  * sequence was invoked.
2022  *
2023  * This function has to be called with the address of the cleanup_T structure
2024  * filled by enter_cleanup() as an argument; it restores the error/interrupt/
2025  * exception state saved by that function - except there was an aborting
2026  * error, an interrupt or an uncaught exception during execution of the
2027  * cleanup autocommands.  In the latter case, the saved error/interrupt/
2028  * exception state is discarded.
2029  */
2030     void
2031 leave_cleanup(cleanup_T *csp)
2032 {
2033     int		pending = csp->pending;
2034 
2035     if (pending == CSTP_NONE)	/* nothing to do */
2036 	return;
2037 
2038     /* If there was an aborting error, an interrupt, or an uncaught exception
2039      * after the corresponding call to enter_cleanup(), discard what has been
2040      * made pending by it.  Report this to the user if required by the
2041      * 'verbose' option or when debugging. */
2042     if (aborting() || need_rethrow)
2043     {
2044 	if (pending & CSTP_THROW)
2045 	    /* Cancel the pending exception (includes report). */
2046 	    discard_exception((except_T *)csp->exception, FALSE);
2047 	else
2048 	    report_discard_pending(pending, NULL);
2049 
2050 	/* If an error was about to be converted to an exception when
2051 	 * enter_cleanup() was called, free the message list. */
2052 	if (msg_list != NULL)
2053 	    free_global_msglist();
2054     }
2055 
2056     /*
2057      * If there was no new error, interrupt, or throw between the calls
2058      * to enter_cleanup() and leave_cleanup(), restore the pending
2059      * error/interrupt/exception state.
2060      */
2061     else
2062     {
2063 	/*
2064 	 * If there was an exception being thrown when enter_cleanup() was
2065 	 * called, we need to rethrow it.  Make it the exception currently
2066 	 * being thrown.
2067 	 */
2068 	if (pending & CSTP_THROW)
2069 	    current_exception = csp->exception;
2070 
2071 	/*
2072 	 * If an error was about to be converted to an exception when
2073 	 * enter_cleanup() was called, let "cause_abort" take the part of
2074 	 * "force_abort" (as done by cause_errthrow()).
2075 	 */
2076 	else if (pending & CSTP_ERROR)
2077 	{
2078 	    cause_abort = force_abort;
2079 	    force_abort = FALSE;
2080 	}
2081 
2082 	/*
2083 	 * Restore the pending values of did_emsg, got_int, and did_throw.
2084 	 */
2085 	if (pending & CSTP_ERROR)
2086 	    did_emsg = TRUE;
2087 	if (pending & CSTP_INTERRUPT)
2088 	    got_int = TRUE;
2089 	if (pending & CSTP_THROW)
2090 	    need_rethrow = TRUE;    /* did_throw will be set by do_one_cmd() */
2091 
2092 	/* Report if required by the 'verbose' option or when debugging. */
2093 	report_resume_pending(pending,
2094 		   (pending & CSTP_THROW) ? (void *)current_exception : NULL);
2095     }
2096 }
2097 
2098 
2099 /*
2100  * Make conditionals inactive and discard what's pending in finally clauses
2101  * until the conditional type searched for or a try conditional not in its
2102  * finally clause is reached.  If this is in an active catch clause, finish
2103  * the caught exception.
2104  * Return the cstack index where the search stopped.
2105  * Values used for "searched_cond" are (CSF_WHILE | CSF_FOR) or CSF_TRY or 0,
2106  * the latter meaning the innermost try conditional not in its finally clause.
2107  * "inclusive" tells whether the conditional searched for should be made
2108  * inactive itself (a try conditional not in its finally clause possibly find
2109  * before is always made inactive).  If "inclusive" is TRUE and
2110  * "searched_cond" is CSF_TRY|CSF_SILENT, the saved former value of
2111  * "emsg_silent", if reset when the try conditional finally reached was
2112  * entered, is restored (used by ex_endtry()).  This is normally done only
2113  * when such a try conditional is left.
2114  */
2115     int
2116 cleanup_conditionals(
2117     struct condstack   *cstack,
2118     int		searched_cond,
2119     int		inclusive)
2120 {
2121     int		idx;
2122     int		stop = FALSE;
2123 
2124     for (idx = cstack->cs_idx; idx >= 0; --idx)
2125     {
2126 	if (cstack->cs_flags[idx] & CSF_TRY)
2127 	{
2128 	    /*
2129 	     * Discard anything pending in a finally clause and continue the
2130 	     * search.  There may also be a pending ":continue", ":break",
2131 	     * ":return", or ":finish" before the finally clause.  We must not
2132 	     * discard it, unless an error or interrupt occurred afterwards.
2133 	     */
2134 	    if (did_emsg || got_int || (cstack->cs_flags[idx] & CSF_FINALLY))
2135 	    {
2136 		switch (cstack->cs_pending[idx])
2137 		{
2138 		    case CSTP_NONE:
2139 			break;
2140 
2141 		    case CSTP_CONTINUE:
2142 		    case CSTP_BREAK:
2143 		    case CSTP_FINISH:
2144 			report_discard_pending(cstack->cs_pending[idx], NULL);
2145 			cstack->cs_pending[idx] = CSTP_NONE;
2146 			break;
2147 
2148 		    case CSTP_RETURN:
2149 			report_discard_pending(CSTP_RETURN,
2150 						      cstack->cs_rettv[idx]);
2151 			discard_pending_return(cstack->cs_rettv[idx]);
2152 			cstack->cs_pending[idx] = CSTP_NONE;
2153 			break;
2154 
2155 		    default:
2156 			if (cstack->cs_flags[idx] & CSF_FINALLY)
2157 			{
2158 			    if (cstack->cs_pending[idx] & CSTP_THROW)
2159 			    {
2160 				/* Cancel the pending exception.  This is in the
2161 				 * finally clause, so that the stack of the
2162 				 * caught exceptions is not involved. */
2163 				discard_exception((except_T *)
2164 					cstack->cs_exception[idx],
2165 					FALSE);
2166 			    }
2167 			    else
2168 				report_discard_pending(cstack->cs_pending[idx],
2169 					NULL);
2170 			    cstack->cs_pending[idx] = CSTP_NONE;
2171 			}
2172 			break;
2173 		}
2174 	    }
2175 
2176 	    /*
2177 	     * Stop at a try conditional not in its finally clause.  If this try
2178 	     * conditional is in an active catch clause, finish the caught
2179 	     * exception.
2180 	     */
2181 	    if (!(cstack->cs_flags[idx] & CSF_FINALLY))
2182 	    {
2183 		if ((cstack->cs_flags[idx] & CSF_ACTIVE)
2184 			&& (cstack->cs_flags[idx] & CSF_CAUGHT))
2185 		    finish_exception((except_T *)cstack->cs_exception[idx]);
2186 		/* Stop at this try conditional - except the try block never
2187 		 * got active (because of an inactive surrounding conditional
2188 		 * or when the ":try" appeared after an error or interrupt or
2189 		 * throw). */
2190 		if (cstack->cs_flags[idx] & CSF_TRUE)
2191 		{
2192 		    if (searched_cond == 0 && !inclusive)
2193 			break;
2194 		    stop = TRUE;
2195 		}
2196 	    }
2197 	}
2198 
2199 	/* Stop on the searched conditional type (even when the surrounding
2200 	 * conditional is not active or something has been made pending).
2201 	 * If "inclusive" is TRUE and "searched_cond" is CSF_TRY|CSF_SILENT,
2202 	 * check first whether "emsg_silent" needs to be restored. */
2203 	if (cstack->cs_flags[idx] & searched_cond)
2204 	{
2205 	    if (!inclusive)
2206 		break;
2207 	    stop = TRUE;
2208 	}
2209 	cstack->cs_flags[idx] &= ~CSF_ACTIVE;
2210 	if (stop && searched_cond != (CSF_TRY | CSF_SILENT))
2211 	    break;
2212 
2213 	/*
2214 	 * When leaving a try conditional that reset "emsg_silent" on its
2215 	 * entry after saving the original value, restore that value here and
2216 	 * free the memory used to store it.
2217 	 */
2218 	if ((cstack->cs_flags[idx] & CSF_TRY)
2219 		&& (cstack->cs_flags[idx] & CSF_SILENT))
2220 	{
2221 	    eslist_T	*elem;
2222 
2223 	    elem = cstack->cs_emsg_silent_list;
2224 	    cstack->cs_emsg_silent_list = elem->next;
2225 	    emsg_silent = elem->saved_emsg_silent;
2226 	    vim_free(elem);
2227 	    cstack->cs_flags[idx] &= ~CSF_SILENT;
2228 	}
2229 	if (stop)
2230 	    break;
2231     }
2232     return idx;
2233 }
2234 
2235 /*
2236  * Return an appropriate error message for a missing endwhile/endfor/endif.
2237  */
2238    static char *
2239 get_end_emsg(struct condstack *cstack)
2240 {
2241     if (cstack->cs_flags[cstack->cs_idx] & CSF_WHILE)
2242 	return e_endwhile;
2243     if (cstack->cs_flags[cstack->cs_idx] & CSF_FOR)
2244 	return e_endfor;
2245     return e_endif;
2246 }
2247 
2248 
2249 /*
2250  * Rewind conditionals until index "idx" is reached.  "cond_type" and
2251  * "cond_level" specify a conditional type and the address of a level variable
2252  * which is to be decremented with each skipped conditional of the specified
2253  * type.
2254  * Also free "for info" structures where needed.
2255  */
2256     void
2257 rewind_conditionals(
2258     struct condstack   *cstack,
2259     int		idx,
2260     int		cond_type,
2261     int		*cond_level)
2262 {
2263     while (cstack->cs_idx > idx)
2264     {
2265 	if (cstack->cs_flags[cstack->cs_idx] & cond_type)
2266 	    --*cond_level;
2267 	if (cstack->cs_flags[cstack->cs_idx] & CSF_FOR)
2268 	    free_for_info(cstack->cs_forinfo[cstack->cs_idx]);
2269 	--cstack->cs_idx;
2270     }
2271 }
2272 
2273 /*
2274  * ":endfunction" when not after a ":function"
2275  */
2276     void
2277 ex_endfunction(exarg_T *eap UNUSED)
2278 {
2279     emsg(_("E193: :endfunction not inside a function"));
2280 }
2281 
2282 /*
2283  * Return TRUE if the string "p" looks like a ":while" or ":for" command.
2284  */
2285     int
2286 has_loop_cmd(char_u *p)
2287 {
2288     int		len;
2289 
2290     /* skip modifiers, white space and ':' */
2291     for (;;)
2292     {
2293 	while (*p == ' ' || *p == '\t' || *p == ':')
2294 	    ++p;
2295 	len = modifier_len(p);
2296 	if (len == 0)
2297 	    break;
2298 	p += len;
2299     }
2300     if ((p[0] == 'w' && p[1] == 'h')
2301 	    || (p[0] == 'f' && p[1] == 'o' && p[2] == 'r'))
2302 	return TRUE;
2303     return FALSE;
2304 }
2305 
2306 #endif /* FEAT_EVAL */
2307