xref: /vim-8.2.3635/src/eval.c (revision a6e8bf2d)
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  * eval.c: Expression evaluation.
12  */
13 #define USING_FLOAT_STUFF
14 
15 #include "vim.h"
16 
17 #if defined(FEAT_EVAL) || defined(PROTO)
18 
19 #ifdef VMS
20 # include <float.h>
21 #endif
22 
23 static char *e_dictrange = N_("E719: Cannot use [:] with a Dictionary");
24 
25 #define NAMESPACE_CHAR	(char_u *)"abglstvw"
26 
27 /*
28  * When recursively copying lists and dicts we need to remember which ones we
29  * have done to avoid endless recursiveness.  This unique ID is used for that.
30  * The last bit is used for previous_funccal, ignored when comparing.
31  */
32 static int current_copyID = 0;
33 
34 /*
35  * Info used by a ":for" loop.
36  */
37 typedef struct
38 {
39     int		fi_semicolon;	// TRUE if ending in '; var]'
40     int		fi_varcount;	// nr of variables in the list
41     listwatch_T	fi_lw;		// keep an eye on the item used.
42     list_T	*fi_list;	// list being used
43     int		fi_bi;		// index of blob
44     blob_T	*fi_blob;	// blob being used
45 } forinfo_T;
46 
47 static int tv_op(typval_T *tv1, typval_T *tv2, char_u  *op);
48 static int eval2(char_u **arg, typval_T *rettv, int flags);
49 static int eval3(char_u **arg, typval_T *rettv, int flags);
50 static int eval4(char_u **arg, typval_T *rettv, int flags);
51 static int eval5(char_u **arg, typval_T *rettv, int flags);
52 static int eval6(char_u **arg, typval_T *rettv, int flags, int want_string);
53 static int eval7(char_u **arg, typval_T *rettv, int flags, int want_string);
54 static int eval7_leader(typval_T *rettv, char_u *start_leader, char_u **end_leaderp);
55 
56 static int free_unref_items(int copyID);
57 static char_u *make_expanded_name(char_u *in_start, char_u *expr_start, char_u *expr_end, char_u *in_end);
58 
59 /*
60  * Return "n1" divided by "n2", taking care of dividing by zero.
61  */
62 	varnumber_T
63 num_divide(varnumber_T n1, varnumber_T n2)
64 {
65     varnumber_T	result;
66 
67     if (n2 == 0)	// give an error message?
68     {
69 	if (n1 == 0)
70 	    result = VARNUM_MIN; // similar to NaN
71 	else if (n1 < 0)
72 	    result = -VARNUM_MAX;
73 	else
74 	    result = VARNUM_MAX;
75     }
76     else
77 	result = n1 / n2;
78 
79     return result;
80 }
81 
82 /*
83  * Return "n1" modulus "n2", taking care of dividing by zero.
84  */
85 	varnumber_T
86 num_modulus(varnumber_T n1, varnumber_T n2)
87 {
88     // Give an error when n2 is 0?
89     return (n2 == 0) ? 0 : (n1 % n2);
90 }
91 
92 #if defined(EBCDIC) || defined(PROTO)
93 /*
94  * Compare struct fst by function name.
95  */
96     static int
97 compare_func_name(const void *s1, const void *s2)
98 {
99     struct fst *p1 = (struct fst *)s1;
100     struct fst *p2 = (struct fst *)s2;
101 
102     return STRCMP(p1->f_name, p2->f_name);
103 }
104 
105 /*
106  * Sort the function table by function name.
107  * The sorting of the table above is ASCII dependent.
108  * On machines using EBCDIC we have to sort it.
109  */
110     static void
111 sortFunctions(void)
112 {
113     int		funcCnt = (int)(sizeof(functions) / sizeof(struct fst)) - 1;
114 
115     qsort(functions, (size_t)funcCnt, sizeof(struct fst), compare_func_name);
116 }
117 #endif
118 
119 /*
120  * Initialize the global and v: variables.
121  */
122     void
123 eval_init(void)
124 {
125     evalvars_init();
126     func_init();
127 
128 #ifdef EBCDIC
129     /*
130      * Sort the function table, to enable binary search.
131      */
132     sortFunctions();
133 #endif
134 }
135 
136 #if defined(EXITFREE) || defined(PROTO)
137     void
138 eval_clear(void)
139 {
140     evalvars_clear();
141     free_scriptnames();  // must come after evalvars_clear().
142     free_locales();
143 
144     // autoloaded script names
145     free_autoload_scriptnames();
146 
147     // unreferenced lists and dicts
148     (void)garbage_collect(FALSE);
149 
150     // functions not garbage collected
151     free_all_functions();
152 }
153 #endif
154 
155 /*
156  * Top level evaluation function, returning a boolean.
157  * Sets "error" to TRUE if there was an error.
158  * Return TRUE or FALSE.
159  */
160     int
161 eval_to_bool(
162     char_u	*arg,
163     int		*error,
164     char_u	**nextcmd,
165     int		skip)	    // only parse, don't execute
166 {
167     typval_T	tv;
168     varnumber_T	retval = FALSE;
169 
170     if (skip)
171 	++emsg_skip;
172     if (eval0(arg, &tv, nextcmd, skip ? 0 : EVAL_EVALUATE) == FAIL)
173 	*error = TRUE;
174     else
175     {
176 	*error = FALSE;
177 	if (!skip)
178 	{
179 	    retval = (tv_get_number_chk(&tv, error) != 0);
180 	    clear_tv(&tv);
181 	}
182     }
183     if (skip)
184 	--emsg_skip;
185 
186     return (int)retval;
187 }
188 
189 /*
190  * Call eval1() and give an error message if not done at a lower level.
191  */
192     static int
193 eval1_emsg(char_u **arg, typval_T *rettv, int evaluate)
194 {
195     char_u	*start = *arg;
196     int		ret;
197     int		did_emsg_before = did_emsg;
198     int		called_emsg_before = called_emsg;
199 
200     ret = eval1(arg, rettv, evaluate ? EVAL_EVALUATE : 0);
201     if (ret == FAIL)
202     {
203 	// Report the invalid expression unless the expression evaluation has
204 	// been cancelled due to an aborting error, an interrupt, or an
205 	// exception, or we already gave a more specific error.
206 	// Also check called_emsg for when using assert_fails().
207 	if (!aborting() && did_emsg == did_emsg_before
208 					  && called_emsg == called_emsg_before)
209 	    semsg(_(e_invexpr2), start);
210     }
211     return ret;
212 }
213 
214 /*
215  * Return whether a typval is a valid expression to pass to eval_expr_typval()
216  * or eval_expr_to_bool().  An empty string returns FALSE;
217  */
218     int
219 eval_expr_valid_arg(typval_T *tv)
220 {
221     return tv->v_type != VAR_UNKNOWN
222 	    && (tv->v_type != VAR_STRING
223 		  || (tv->vval.v_string != NULL && *tv->vval.v_string != NUL));
224 }
225 
226 /*
227  * Evaluate an expression, which can be a function, partial or string.
228  * Pass arguments "argv[argc]".
229  * Return the result in "rettv" and OK or FAIL.
230  */
231     int
232 eval_expr_typval(typval_T *expr, typval_T *argv, int argc, typval_T *rettv)
233 {
234     char_u	*s;
235     char_u	buf[NUMBUFLEN];
236     funcexe_T	funcexe;
237 
238     if (expr->v_type == VAR_FUNC)
239     {
240 	s = expr->vval.v_string;
241 	if (s == NULL || *s == NUL)
242 	    return FAIL;
243 	CLEAR_FIELD(funcexe);
244 	funcexe.evaluate = TRUE;
245 	if (call_func(s, -1, rettv, argc, argv, &funcexe) == FAIL)
246 	    return FAIL;
247     }
248     else if (expr->v_type == VAR_PARTIAL)
249     {
250 	partial_T   *partial = expr->vval.v_partial;
251 
252 	if (partial == NULL)
253 	    return FAIL;
254 
255 	if (partial->pt_func != NULL
256 			  && partial->pt_func->uf_dfunc_idx != UF_NOT_COMPILED)
257 	{
258 	    if (call_def_function(partial->pt_func, argc, argv,
259 						       partial, rettv) == FAIL)
260 		return FAIL;
261 	}
262 	else
263 	{
264 	    s = partial_name(partial);
265 	    if (s == NULL || *s == NUL)
266 		return FAIL;
267 	    CLEAR_FIELD(funcexe);
268 	    funcexe.evaluate = TRUE;
269 	    funcexe.partial = partial;
270 	    if (call_func(s, -1, rettv, argc, argv, &funcexe) == FAIL)
271 		return FAIL;
272 	}
273     }
274     else
275     {
276 	s = tv_get_string_buf_chk(expr, buf);
277 	if (s == NULL)
278 	    return FAIL;
279 	s = skipwhite(s);
280 	if (eval1_emsg(&s, rettv, TRUE) == FAIL)
281 	    return FAIL;
282 	if (*s != NUL)  // check for trailing chars after expr
283 	{
284 	    clear_tv(rettv);
285 	    semsg(_(e_invexpr2), s);
286 	    return FAIL;
287 	}
288     }
289     return OK;
290 }
291 
292 /*
293  * Like eval_to_bool() but using a typval_T instead of a string.
294  * Works for string, funcref and partial.
295  */
296     int
297 eval_expr_to_bool(typval_T *expr, int *error)
298 {
299     typval_T	rettv;
300     int		res;
301 
302     if (eval_expr_typval(expr, NULL, 0, &rettv) == FAIL)
303     {
304 	*error = TRUE;
305 	return FALSE;
306     }
307     res = (tv_get_number_chk(&rettv, error) != 0);
308     clear_tv(&rettv);
309     return res;
310 }
311 
312 /*
313  * Top level evaluation function, returning a string.  If "skip" is TRUE,
314  * only parsing to "nextcmd" is done, without reporting errors.  Return
315  * pointer to allocated memory, or NULL for failure or when "skip" is TRUE.
316  */
317     char_u *
318 eval_to_string_skip(
319     char_u	*arg,
320     char_u	**nextcmd,
321     int		skip)	    // only parse, don't execute
322 {
323     typval_T	tv;
324     char_u	*retval;
325 
326     if (skip)
327 	++emsg_skip;
328     if (eval0(arg, &tv, nextcmd, skip ? 0 : EVAL_EVALUATE) == FAIL || skip)
329 	retval = NULL;
330     else
331     {
332 	retval = vim_strsave(tv_get_string(&tv));
333 	clear_tv(&tv);
334     }
335     if (skip)
336 	--emsg_skip;
337 
338     return retval;
339 }
340 
341 /*
342  * Skip over an expression at "*pp".
343  * Return FAIL for an error, OK otherwise.
344  */
345     int
346 skip_expr(char_u **pp)
347 {
348     typval_T	rettv;
349 
350     *pp = skipwhite(*pp);
351     return eval1(pp, &rettv, 0);
352 }
353 
354 /*
355  * Top level evaluation function, returning a string.
356  * When "convert" is TRUE convert a List into a sequence of lines and convert
357  * a Float to a String.
358  * Return pointer to allocated memory, or NULL for failure.
359  */
360     char_u *
361 eval_to_string(
362     char_u	*arg,
363     char_u	**nextcmd,
364     int		convert)
365 {
366     typval_T	tv;
367     char_u	*retval;
368     garray_T	ga;
369 #ifdef FEAT_FLOAT
370     char_u	numbuf[NUMBUFLEN];
371 #endif
372 
373     if (eval0(arg, &tv, nextcmd, EVAL_EVALUATE) == FAIL)
374 	retval = NULL;
375     else
376     {
377 	if (convert && tv.v_type == VAR_LIST)
378 	{
379 	    ga_init2(&ga, (int)sizeof(char), 80);
380 	    if (tv.vval.v_list != NULL)
381 	    {
382 		list_join(&ga, tv.vval.v_list, (char_u *)"\n", TRUE, FALSE, 0);
383 		if (tv.vval.v_list->lv_len > 0)
384 		    ga_append(&ga, NL);
385 	    }
386 	    ga_append(&ga, NUL);
387 	    retval = (char_u *)ga.ga_data;
388 	}
389 #ifdef FEAT_FLOAT
390 	else if (convert && tv.v_type == VAR_FLOAT)
391 	{
392 	    vim_snprintf((char *)numbuf, NUMBUFLEN, "%g", tv.vval.v_float);
393 	    retval = vim_strsave(numbuf);
394 	}
395 #endif
396 	else
397 	    retval = vim_strsave(tv_get_string(&tv));
398 	clear_tv(&tv);
399     }
400 
401     return retval;
402 }
403 
404 /*
405  * Call eval_to_string() without using current local variables and using
406  * textwinlock.  When "use_sandbox" is TRUE use the sandbox.
407  */
408     char_u *
409 eval_to_string_safe(
410     char_u	*arg,
411     char_u	**nextcmd,
412     int		use_sandbox)
413 {
414     char_u	*retval;
415     funccal_entry_T funccal_entry;
416 
417     save_funccal(&funccal_entry);
418     if (use_sandbox)
419 	++sandbox;
420     ++textwinlock;
421     retval = eval_to_string(arg, nextcmd, FALSE);
422     if (use_sandbox)
423 	--sandbox;
424     --textwinlock;
425     restore_funccal();
426     return retval;
427 }
428 
429 /*
430  * Top level evaluation function, returning a number.
431  * Evaluates "expr" silently.
432  * Returns -1 for an error.
433  */
434     varnumber_T
435 eval_to_number(char_u *expr)
436 {
437     typval_T	rettv;
438     varnumber_T	retval;
439     char_u	*p = skipwhite(expr);
440 
441     ++emsg_off;
442 
443     if (eval1(&p, &rettv, EVAL_EVALUATE) == FAIL)
444 	retval = -1;
445     else
446     {
447 	retval = tv_get_number_chk(&rettv, NULL);
448 	clear_tv(&rettv);
449     }
450     --emsg_off;
451 
452     return retval;
453 }
454 
455 /*
456  * Top level evaluation function.
457  * Returns an allocated typval_T with the result.
458  * Returns NULL when there is an error.
459  */
460     typval_T *
461 eval_expr(char_u *arg, char_u **nextcmd)
462 {
463     typval_T	*tv;
464 
465     tv = ALLOC_ONE(typval_T);
466     if (tv != NULL && eval0(arg, tv, nextcmd, EVAL_EVALUATE) == FAIL)
467 	VIM_CLEAR(tv);
468 
469     return tv;
470 }
471 
472 /*
473  * Call some Vim script function and return the result in "*rettv".
474  * Uses argv[0] to argv[argc - 1] for the function arguments.  argv[argc]
475  * should have type VAR_UNKNOWN.
476  * Returns OK or FAIL.
477  */
478     int
479 call_vim_function(
480     char_u      *func,
481     int		argc,
482     typval_T	*argv,
483     typval_T	*rettv)
484 {
485     int		ret;
486     funcexe_T	funcexe;
487 
488     rettv->v_type = VAR_UNKNOWN;		// clear_tv() uses this
489     CLEAR_FIELD(funcexe);
490     funcexe.firstline = curwin->w_cursor.lnum;
491     funcexe.lastline = curwin->w_cursor.lnum;
492     funcexe.evaluate = TRUE;
493     ret = call_func(func, -1, rettv, argc, argv, &funcexe);
494     if (ret == FAIL)
495 	clear_tv(rettv);
496 
497     return ret;
498 }
499 
500 /*
501  * Call Vim script function "func" and return the result as a number.
502  * Returns -1 when calling the function fails.
503  * Uses argv[0] to argv[argc - 1] for the function arguments. argv[argc] should
504  * have type VAR_UNKNOWN.
505  */
506     varnumber_T
507 call_func_retnr(
508     char_u      *func,
509     int		argc,
510     typval_T	*argv)
511 {
512     typval_T	rettv;
513     varnumber_T	retval;
514 
515     if (call_vim_function(func, argc, argv, &rettv) == FAIL)
516 	return -1;
517 
518     retval = tv_get_number_chk(&rettv, NULL);
519     clear_tv(&rettv);
520     return retval;
521 }
522 
523 /*
524  * Call Vim script function "func" and return the result as a string.
525  * Returns NULL when calling the function fails.
526  * Uses argv[0] to argv[argc - 1] for the function arguments. argv[argc] should
527  * have type VAR_UNKNOWN.
528  */
529     void *
530 call_func_retstr(
531     char_u      *func,
532     int		argc,
533     typval_T	*argv)
534 {
535     typval_T	rettv;
536     char_u	*retval;
537 
538     if (call_vim_function(func, argc, argv, &rettv) == FAIL)
539 	return NULL;
540 
541     retval = vim_strsave(tv_get_string(&rettv));
542     clear_tv(&rettv);
543     return retval;
544 }
545 
546 /*
547  * Call Vim script function "func" and return the result as a List.
548  * Uses argv[0] to argv[argc - 1] for the function arguments. argv[argc] should
549  * have type VAR_UNKNOWN.
550  * Returns NULL when there is something wrong.
551  */
552     void *
553 call_func_retlist(
554     char_u      *func,
555     int		argc,
556     typval_T	*argv)
557 {
558     typval_T	rettv;
559 
560     if (call_vim_function(func, argc, argv, &rettv) == FAIL)
561 	return NULL;
562 
563     if (rettv.v_type != VAR_LIST)
564     {
565 	clear_tv(&rettv);
566 	return NULL;
567     }
568 
569     return rettv.vval.v_list;
570 }
571 
572 #ifdef FEAT_FOLDING
573 /*
574  * Evaluate 'foldexpr'.  Returns the foldlevel, and any character preceding
575  * it in "*cp".  Doesn't give error messages.
576  */
577     int
578 eval_foldexpr(char_u *arg, int *cp)
579 {
580     typval_T	tv;
581     varnumber_T	retval;
582     char_u	*s;
583     int		use_sandbox = was_set_insecurely((char_u *)"foldexpr",
584 								   OPT_LOCAL);
585 
586     ++emsg_off;
587     if (use_sandbox)
588 	++sandbox;
589     ++textwinlock;
590     *cp = NUL;
591     if (eval0(arg, &tv, NULL, EVAL_EVALUATE) == FAIL)
592 	retval = 0;
593     else
594     {
595 	// If the result is a number, just return the number.
596 	if (tv.v_type == VAR_NUMBER)
597 	    retval = tv.vval.v_number;
598 	else if (tv.v_type != VAR_STRING || tv.vval.v_string == NULL)
599 	    retval = 0;
600 	else
601 	{
602 	    // If the result is a string, check if there is a non-digit before
603 	    // the number.
604 	    s = tv.vval.v_string;
605 	    if (!VIM_ISDIGIT(*s) && *s != '-')
606 		*cp = *s++;
607 	    retval = atol((char *)s);
608 	}
609 	clear_tv(&tv);
610     }
611     --emsg_off;
612     if (use_sandbox)
613 	--sandbox;
614     --textwinlock;
615 
616     return (int)retval;
617 }
618 #endif
619 
620 /*
621  * Get an lval: variable, Dict item or List item that can be assigned a value
622  * to: "name", "na{me}", "name[expr]", "name[expr:expr]", "name[expr][expr]",
623  * "name.key", "name.key[expr]" etc.
624  * Indexing only works if "name" is an existing List or Dictionary.
625  * "name" points to the start of the name.
626  * If "rettv" is not NULL it points to the value to be assigned.
627  * "unlet" is TRUE for ":unlet": slightly different behavior when something is
628  * wrong; must end in space or cmd separator.
629  *
630  * flags:
631  *  GLV_QUIET:       do not give error messages
632  *  GLV_READ_ONLY:   will not change the variable
633  *  GLV_NO_AUTOLOAD: do not use script autoloading
634  *
635  * Returns a pointer to just after the name, including indexes.
636  * When an evaluation error occurs "lp->ll_name" is NULL;
637  * Returns NULL for a parsing error.  Still need to free items in "lp"!
638  */
639     char_u *
640 get_lval(
641     char_u	*name,
642     typval_T	*rettv,
643     lval_T	*lp,
644     int		unlet,
645     int		skip,
646     int		flags,	    // GLV_ values
647     int		fne_flags)  // flags for find_name_end()
648 {
649     char_u	*p;
650     char_u	*expr_start, *expr_end;
651     int		cc;
652     dictitem_T	*v;
653     typval_T	var1;
654     typval_T	var2;
655     int		empty1 = FALSE;
656     listitem_T	*ni;
657     char_u	*key = NULL;
658     int		len;
659     hashtab_T	*ht;
660     int		quiet = flags & GLV_QUIET;
661 
662     // Clear everything in "lp".
663     CLEAR_POINTER(lp);
664 
665     if (skip)
666     {
667 	// When skipping just find the end of the name.
668 	lp->ll_name = name;
669 	return find_name_end(name, NULL, NULL, FNE_INCL_BR | fne_flags);
670     }
671 
672     // Find the end of the name.
673     p = find_name_end(name, &expr_start, &expr_end, fne_flags);
674     lp->ll_name_end = p;
675     if (expr_start != NULL)
676     {
677 	// Don't expand the name when we already know there is an error.
678 	if (unlet && !VIM_ISWHITE(*p) && !ends_excmd(*p)
679 						    && *p != '[' && *p != '.')
680 	{
681 	    emsg(_(e_trailing));
682 	    return NULL;
683 	}
684 
685 	lp->ll_exp_name = make_expanded_name(name, expr_start, expr_end, p);
686 	if (lp->ll_exp_name == NULL)
687 	{
688 	    // Report an invalid expression in braces, unless the
689 	    // expression evaluation has been cancelled due to an
690 	    // aborting error, an interrupt, or an exception.
691 	    if (!aborting() && !quiet)
692 	    {
693 		emsg_severe = TRUE;
694 		semsg(_(e_invarg2), name);
695 		return NULL;
696 	    }
697 	}
698 	lp->ll_name = lp->ll_exp_name;
699     }
700     else
701     {
702 	lp->ll_name = name;
703 
704 	if (current_sctx.sc_version == SCRIPT_VERSION_VIM9 && *p == ':')
705 	{
706 	    scriptitem_T *si = SCRIPT_ITEM(current_sctx.sc_sid);
707 	    char_u	 *tp = skipwhite(p + 1);
708 
709 	    // parse the type after the name
710 	    lp->ll_type = parse_type(&tp, &si->sn_type_list);
711 	    lp->ll_name_end = tp;
712 	}
713     }
714 
715     // Without [idx] or .key we are done.
716     if ((*p != '[' && *p != '.') || lp->ll_name == NULL)
717 	return p;
718 
719     cc = *p;
720     *p = NUL;
721     // Only pass &ht when we would write to the variable, it prevents autoload
722     // as well.
723     v = find_var(lp->ll_name, (flags & GLV_READ_ONLY) ? NULL : &ht,
724 						      flags & GLV_NO_AUTOLOAD);
725     if (v == NULL && !quiet)
726 	semsg(_(e_undefvar), lp->ll_name);
727     *p = cc;
728     if (v == NULL)
729 	return NULL;
730 
731     /*
732      * Loop until no more [idx] or .key is following.
733      */
734     lp->ll_tv = &v->di_tv;
735     var1.v_type = VAR_UNKNOWN;
736     var2.v_type = VAR_UNKNOWN;
737     while (*p == '[' || (*p == '.' && lp->ll_tv->v_type == VAR_DICT))
738     {
739 	if (!(lp->ll_tv->v_type == VAR_LIST && lp->ll_tv->vval.v_list != NULL)
740 		&& !(lp->ll_tv->v_type == VAR_DICT
741 					   && lp->ll_tv->vval.v_dict != NULL)
742 		&& !(lp->ll_tv->v_type == VAR_BLOB
743 					   && lp->ll_tv->vval.v_blob != NULL))
744 	{
745 	    if (!quiet)
746 		emsg(_("E689: Can only index a List, Dictionary or Blob"));
747 	    return NULL;
748 	}
749 	if (lp->ll_range)
750 	{
751 	    if (!quiet)
752 		emsg(_("E708: [:] must come last"));
753 	    return NULL;
754 	}
755 
756 	len = -1;
757 	if (*p == '.')
758 	{
759 	    key = p + 1;
760 	    for (len = 0; ASCII_ISALNUM(key[len]) || key[len] == '_'; ++len)
761 		;
762 	    if (len == 0)
763 	    {
764 		if (!quiet)
765 		    emsg(_(e_emptykey));
766 		return NULL;
767 	    }
768 	    p = key + len;
769 	}
770 	else
771 	{
772 	    // Get the index [expr] or the first index [expr: ].
773 	    p = skipwhite(p + 1);
774 	    if (*p == ':')
775 		empty1 = TRUE;
776 	    else
777 	    {
778 		empty1 = FALSE;
779 		if (eval1(&p, &var1, EVAL_EVALUATE) == FAIL)  // recursive!
780 		    return NULL;
781 		if (tv_get_string_chk(&var1) == NULL)
782 		{
783 		    // not a number or string
784 		    clear_tv(&var1);
785 		    return NULL;
786 		}
787 	    }
788 
789 	    // Optionally get the second index [ :expr].
790 	    if (*p == ':')
791 	    {
792 		if (lp->ll_tv->v_type == VAR_DICT)
793 		{
794 		    if (!quiet)
795 			emsg(_(e_dictrange));
796 		    clear_tv(&var1);
797 		    return NULL;
798 		}
799 		if (rettv != NULL
800 			&& !(rettv->v_type == VAR_LIST
801 						 && rettv->vval.v_list != NULL)
802 			&& !(rettv->v_type == VAR_BLOB
803 						&& rettv->vval.v_blob != NULL))
804 		{
805 		    if (!quiet)
806 			emsg(_("E709: [:] requires a List or Blob value"));
807 		    clear_tv(&var1);
808 		    return NULL;
809 		}
810 		p = skipwhite(p + 1);
811 		if (*p == ']')
812 		    lp->ll_empty2 = TRUE;
813 		else
814 		{
815 		    lp->ll_empty2 = FALSE;
816 		    // recursive!
817 		    if (eval1(&p, &var2, EVAL_EVALUATE) == FAIL)
818 		    {
819 			clear_tv(&var1);
820 			return NULL;
821 		    }
822 		    if (tv_get_string_chk(&var2) == NULL)
823 		    {
824 			// not a number or string
825 			clear_tv(&var1);
826 			clear_tv(&var2);
827 			return NULL;
828 		    }
829 		}
830 		lp->ll_range = TRUE;
831 	    }
832 	    else
833 		lp->ll_range = FALSE;
834 
835 	    if (*p != ']')
836 	    {
837 		if (!quiet)
838 		    emsg(_(e_missbrac));
839 		clear_tv(&var1);
840 		clear_tv(&var2);
841 		return NULL;
842 	    }
843 
844 	    // Skip to past ']'.
845 	    ++p;
846 	}
847 
848 	if (lp->ll_tv->v_type == VAR_DICT)
849 	{
850 	    if (len == -1)
851 	    {
852 		// "[key]": get key from "var1"
853 		key = tv_get_string_chk(&var1);	// is number or string
854 		if (key == NULL)
855 		{
856 		    clear_tv(&var1);
857 		    return NULL;
858 		}
859 	    }
860 	    lp->ll_list = NULL;
861 	    lp->ll_dict = lp->ll_tv->vval.v_dict;
862 	    lp->ll_di = dict_find(lp->ll_dict, key, len);
863 
864 	    // When assigning to a scope dictionary check that a function and
865 	    // variable name is valid (only variable name unless it is l: or
866 	    // g: dictionary). Disallow overwriting a builtin function.
867 	    if (rettv != NULL && lp->ll_dict->dv_scope != 0)
868 	    {
869 		int prevval;
870 		int wrong;
871 
872 		if (len != -1)
873 		{
874 		    prevval = key[len];
875 		    key[len] = NUL;
876 		}
877 		else
878 		    prevval = 0; // avoid compiler warning
879 		wrong = (lp->ll_dict->dv_scope == VAR_DEF_SCOPE
880 			       && rettv->v_type == VAR_FUNC
881 			       && var_check_func_name(key, lp->ll_di == NULL))
882 			|| !valid_varname(key);
883 		if (len != -1)
884 		    key[len] = prevval;
885 		if (wrong)
886 		{
887 		    clear_tv(&var1);
888 		    return NULL;
889 		}
890 	    }
891 
892 	    if (lp->ll_di == NULL)
893 	    {
894 		// Can't add "v:" or "a:" variable.
895 		if (lp->ll_dict == get_vimvar_dict()
896 			 || &lp->ll_dict->dv_hashtab == get_funccal_args_ht())
897 		{
898 		    semsg(_(e_illvar), name);
899 		    clear_tv(&var1);
900 		    return NULL;
901 		}
902 
903 		// Key does not exist in dict: may need to add it.
904 		if (*p == '[' || *p == '.' || unlet)
905 		{
906 		    if (!quiet)
907 			semsg(_(e_dictkey), key);
908 		    clear_tv(&var1);
909 		    return NULL;
910 		}
911 		if (len == -1)
912 		    lp->ll_newkey = vim_strsave(key);
913 		else
914 		    lp->ll_newkey = vim_strnsave(key, len);
915 		clear_tv(&var1);
916 		if (lp->ll_newkey == NULL)
917 		    p = NULL;
918 		break;
919 	    }
920 	    // existing variable, need to check if it can be changed
921 	    else if ((flags & GLV_READ_ONLY) == 0
922 			     && var_check_ro(lp->ll_di->di_flags, name, FALSE))
923 	    {
924 		clear_tv(&var1);
925 		return NULL;
926 	    }
927 
928 	    clear_tv(&var1);
929 	    lp->ll_tv = &lp->ll_di->di_tv;
930 	}
931 	else if (lp->ll_tv->v_type == VAR_BLOB)
932 	{
933 	    long bloblen = blob_len(lp->ll_tv->vval.v_blob);
934 
935 	    /*
936 	     * Get the number and item for the only or first index of the List.
937 	     */
938 	    if (empty1)
939 		lp->ll_n1 = 0;
940 	    else
941 		// is number or string
942 		lp->ll_n1 = (long)tv_get_number(&var1);
943 	    clear_tv(&var1);
944 
945 	    if (lp->ll_n1 < 0
946 		    || lp->ll_n1 > bloblen
947 		    || (lp->ll_range && lp->ll_n1 == bloblen))
948 	    {
949 		if (!quiet)
950 		    semsg(_(e_blobidx), lp->ll_n1);
951 		clear_tv(&var2);
952 		return NULL;
953 	    }
954 	    if (lp->ll_range && !lp->ll_empty2)
955 	    {
956 		lp->ll_n2 = (long)tv_get_number(&var2);
957 		clear_tv(&var2);
958 		if (lp->ll_n2 < 0
959 			|| lp->ll_n2 >= bloblen
960 			|| lp->ll_n2 < lp->ll_n1)
961 		{
962 		    if (!quiet)
963 			semsg(_(e_blobidx), lp->ll_n2);
964 		    return NULL;
965 		}
966 	    }
967 	    lp->ll_blob = lp->ll_tv->vval.v_blob;
968 	    lp->ll_tv = NULL;
969 	    break;
970 	}
971 	else
972 	{
973 	    /*
974 	     * Get the number and item for the only or first index of the List.
975 	     */
976 	    if (empty1)
977 		lp->ll_n1 = 0;
978 	    else
979 		// is number or string
980 		lp->ll_n1 = (long)tv_get_number(&var1);
981 	    clear_tv(&var1);
982 
983 	    lp->ll_dict = NULL;
984 	    lp->ll_list = lp->ll_tv->vval.v_list;
985 	    lp->ll_li = list_find(lp->ll_list, lp->ll_n1);
986 	    if (lp->ll_li == NULL)
987 	    {
988 		if (lp->ll_n1 < 0)
989 		{
990 		    lp->ll_n1 = 0;
991 		    lp->ll_li = list_find(lp->ll_list, lp->ll_n1);
992 		}
993 	    }
994 	    if (lp->ll_li == NULL)
995 	    {
996 		clear_tv(&var2);
997 		if (!quiet)
998 		    semsg(_(e_listidx), lp->ll_n1);
999 		return NULL;
1000 	    }
1001 
1002 	    /*
1003 	     * May need to find the item or absolute index for the second
1004 	     * index of a range.
1005 	     * When no index given: "lp->ll_empty2" is TRUE.
1006 	     * Otherwise "lp->ll_n2" is set to the second index.
1007 	     */
1008 	    if (lp->ll_range && !lp->ll_empty2)
1009 	    {
1010 		lp->ll_n2 = (long)tv_get_number(&var2);
1011 						    // is number or string
1012 		clear_tv(&var2);
1013 		if (lp->ll_n2 < 0)
1014 		{
1015 		    ni = list_find(lp->ll_list, lp->ll_n2);
1016 		    if (ni == NULL)
1017 		    {
1018 			if (!quiet)
1019 			    semsg(_(e_listidx), lp->ll_n2);
1020 			return NULL;
1021 		    }
1022 		    lp->ll_n2 = list_idx_of_item(lp->ll_list, ni);
1023 		}
1024 
1025 		// Check that lp->ll_n2 isn't before lp->ll_n1.
1026 		if (lp->ll_n1 < 0)
1027 		    lp->ll_n1 = list_idx_of_item(lp->ll_list, lp->ll_li);
1028 		if (lp->ll_n2 < lp->ll_n1)
1029 		{
1030 		    if (!quiet)
1031 			semsg(_(e_listidx), lp->ll_n2);
1032 		    return NULL;
1033 		}
1034 	    }
1035 
1036 	    lp->ll_tv = &lp->ll_li->li_tv;
1037 	}
1038     }
1039 
1040     clear_tv(&var1);
1041     lp->ll_name_end = p;
1042     return p;
1043 }
1044 
1045 /*
1046  * Clear lval "lp" that was filled by get_lval().
1047  */
1048     void
1049 clear_lval(lval_T *lp)
1050 {
1051     vim_free(lp->ll_exp_name);
1052     vim_free(lp->ll_newkey);
1053 }
1054 
1055 /*
1056  * Set a variable that was parsed by get_lval() to "rettv".
1057  * "endp" points to just after the parsed name.
1058  * "op" is NULL, "+" for "+=", "-" for "-=", "*" for "*=", "/" for "/=",
1059  * "%" for "%=", "." for ".=" or "=" for "=".
1060  */
1061     void
1062 set_var_lval(
1063     lval_T	*lp,
1064     char_u	*endp,
1065     typval_T	*rettv,
1066     int		copy,
1067     int		flags,    // LET_IS_CONST and/or LET_NO_COMMAND
1068     char_u	*op)
1069 {
1070     int		cc;
1071     listitem_T	*ri;
1072     dictitem_T	*di;
1073 
1074     if (lp->ll_tv == NULL)
1075     {
1076 	cc = *endp;
1077 	*endp = NUL;
1078 	if (lp->ll_blob != NULL)
1079 	{
1080 	    int	    error = FALSE, val;
1081 
1082 	    if (op != NULL && *op != '=')
1083 	    {
1084 		semsg(_(e_letwrong), op);
1085 		return;
1086 	    }
1087 
1088 	    if (lp->ll_range && rettv->v_type == VAR_BLOB)
1089 	    {
1090 		int	il, ir;
1091 
1092 		if (lp->ll_empty2)
1093 		    lp->ll_n2 = blob_len(lp->ll_blob) - 1;
1094 
1095 		if (lp->ll_n2 - lp->ll_n1 + 1 != blob_len(rettv->vval.v_blob))
1096 		{
1097 		    emsg(_("E972: Blob value does not have the right number of bytes"));
1098 		    return;
1099 		}
1100 		if (lp->ll_empty2)
1101 		    lp->ll_n2 = blob_len(lp->ll_blob);
1102 
1103 		ir = 0;
1104 		for (il = lp->ll_n1; il <= lp->ll_n2; il++)
1105 		    blob_set(lp->ll_blob, il,
1106 			    blob_get(rettv->vval.v_blob, ir++));
1107 	    }
1108 	    else
1109 	    {
1110 		val = (int)tv_get_number_chk(rettv, &error);
1111 		if (!error)
1112 		{
1113 		    garray_T *gap = &lp->ll_blob->bv_ga;
1114 
1115 		    // Allow for appending a byte.  Setting a byte beyond
1116 		    // the end is an error otherwise.
1117 		    if (lp->ll_n1 < gap->ga_len
1118 			    || (lp->ll_n1 == gap->ga_len
1119 				&& ga_grow(&lp->ll_blob->bv_ga, 1) == OK))
1120 		    {
1121 			blob_set(lp->ll_blob, lp->ll_n1, val);
1122 			if (lp->ll_n1 == gap->ga_len)
1123 			    ++gap->ga_len;
1124 		    }
1125 		    // error for invalid range was already given in get_lval()
1126 		}
1127 	    }
1128 	}
1129 	else if (op != NULL && *op != '=')
1130 	{
1131 	    typval_T tv;
1132 
1133 	    if (flags & LET_IS_CONST)
1134 	    {
1135 		emsg(_(e_cannot_mod));
1136 		*endp = cc;
1137 		return;
1138 	    }
1139 
1140 	    // handle +=, -=, *=, /=, %= and .=
1141 	    di = NULL;
1142 	    if (get_var_tv(lp->ll_name, (int)STRLEN(lp->ll_name),
1143 					     &tv, &di, TRUE, FALSE) == OK)
1144 	    {
1145 		if ((di == NULL
1146 			 || (!var_check_ro(di->di_flags, lp->ll_name, FALSE)
1147 			   && !tv_check_lock(&di->di_tv, lp->ll_name, FALSE)))
1148 			&& tv_op(&tv, rettv, op) == OK)
1149 		    set_var(lp->ll_name, &tv, FALSE);
1150 		clear_tv(&tv);
1151 	    }
1152 	}
1153 	else
1154 	    set_var_const(lp->ll_name, lp->ll_type, rettv, copy, flags);
1155 	*endp = cc;
1156     }
1157     else if (var_check_lock(lp->ll_newkey == NULL
1158 		? lp->ll_tv->v_lock
1159 		: lp->ll_tv->vval.v_dict->dv_lock, lp->ll_name, FALSE))
1160 	;
1161     else if (lp->ll_range)
1162     {
1163 	listitem_T *ll_li = lp->ll_li;
1164 	int	    ll_n1 = lp->ll_n1;
1165 
1166 	if (flags & LET_IS_CONST)
1167 	{
1168 	    emsg(_("E996: Cannot lock a range"));
1169 	    return;
1170 	}
1171 
1172 	/*
1173 	 * Check whether any of the list items is locked
1174 	 */
1175 	for (ri = rettv->vval.v_list->lv_first; ri != NULL && ll_li != NULL; )
1176 	{
1177 	    if (var_check_lock(ll_li->li_tv.v_lock, lp->ll_name, FALSE))
1178 		return;
1179 	    ri = ri->li_next;
1180 	    if (ri == NULL || (!lp->ll_empty2 && lp->ll_n2 == ll_n1))
1181 		break;
1182 	    ll_li = ll_li->li_next;
1183 	    ++ll_n1;
1184 	}
1185 
1186 	/*
1187 	 * Assign the List values to the list items.
1188 	 */
1189 	for (ri = rettv->vval.v_list->lv_first; ri != NULL; )
1190 	{
1191 	    if (op != NULL && *op != '=')
1192 		tv_op(&lp->ll_li->li_tv, &ri->li_tv, op);
1193 	    else
1194 	    {
1195 		clear_tv(&lp->ll_li->li_tv);
1196 		copy_tv(&ri->li_tv, &lp->ll_li->li_tv);
1197 	    }
1198 	    ri = ri->li_next;
1199 	    if (ri == NULL || (!lp->ll_empty2 && lp->ll_n2 == lp->ll_n1))
1200 		break;
1201 	    if (lp->ll_li->li_next == NULL)
1202 	    {
1203 		// Need to add an empty item.
1204 		if (list_append_number(lp->ll_list, 0) == FAIL)
1205 		{
1206 		    ri = NULL;
1207 		    break;
1208 		}
1209 	    }
1210 	    lp->ll_li = lp->ll_li->li_next;
1211 	    ++lp->ll_n1;
1212 	}
1213 	if (ri != NULL)
1214 	    emsg(_("E710: List value has more items than target"));
1215 	else if (lp->ll_empty2
1216 		? (lp->ll_li != NULL && lp->ll_li->li_next != NULL)
1217 		: lp->ll_n1 != lp->ll_n2)
1218 	    emsg(_("E711: List value has not enough items"));
1219     }
1220     else
1221     {
1222 	/*
1223 	 * Assign to a List or Dictionary item.
1224 	 */
1225 	if (flags & LET_IS_CONST)
1226 	{
1227 	    emsg(_("E996: Cannot lock a list or dict"));
1228 	    return;
1229 	}
1230 	if (lp->ll_newkey != NULL)
1231 	{
1232 	    if (op != NULL && *op != '=')
1233 	    {
1234 		semsg(_(e_letwrong), op);
1235 		return;
1236 	    }
1237 
1238 	    // Need to add an item to the Dictionary.
1239 	    di = dictitem_alloc(lp->ll_newkey);
1240 	    if (di == NULL)
1241 		return;
1242 	    if (dict_add(lp->ll_tv->vval.v_dict, di) == FAIL)
1243 	    {
1244 		vim_free(di);
1245 		return;
1246 	    }
1247 	    lp->ll_tv = &di->di_tv;
1248 	}
1249 	else if (op != NULL && *op != '=')
1250 	{
1251 	    tv_op(lp->ll_tv, rettv, op);
1252 	    return;
1253 	}
1254 	else
1255 	    clear_tv(lp->ll_tv);
1256 
1257 	/*
1258 	 * Assign the value to the variable or list item.
1259 	 */
1260 	if (copy)
1261 	    copy_tv(rettv, lp->ll_tv);
1262 	else
1263 	{
1264 	    *lp->ll_tv = *rettv;
1265 	    lp->ll_tv->v_lock = 0;
1266 	    init_tv(rettv);
1267 	}
1268     }
1269 }
1270 
1271 /*
1272  * Handle "tv1 += tv2", "tv1 -= tv2", "tv1 *= tv2", "tv1 /= tv2", "tv1 %= tv2"
1273  * and "tv1 .= tv2"
1274  * Returns OK or FAIL.
1275  */
1276     static int
1277 tv_op(typval_T *tv1, typval_T *tv2, char_u *op)
1278 {
1279     varnumber_T	n;
1280     char_u	numbuf[NUMBUFLEN];
1281     char_u	*s;
1282 
1283     // Can't do anything with a Funcref, Dict, v:true on the right.
1284     if (tv2->v_type != VAR_FUNC && tv2->v_type != VAR_DICT
1285 		      && tv2->v_type != VAR_BOOL && tv2->v_type != VAR_SPECIAL)
1286     {
1287 	switch (tv1->v_type)
1288 	{
1289 	    case VAR_UNKNOWN:
1290 	    case VAR_ANY:
1291 	    case VAR_VOID:
1292 	    case VAR_DICT:
1293 	    case VAR_FUNC:
1294 	    case VAR_PARTIAL:
1295 	    case VAR_BOOL:
1296 	    case VAR_SPECIAL:
1297 	    case VAR_JOB:
1298 	    case VAR_CHANNEL:
1299 		break;
1300 
1301 	    case VAR_BLOB:
1302 		if (*op != '+' || tv2->v_type != VAR_BLOB)
1303 		    break;
1304 		// BLOB += BLOB
1305 		if (tv1->vval.v_blob != NULL && tv2->vval.v_blob != NULL)
1306 		{
1307 		    blob_T  *b1 = tv1->vval.v_blob;
1308 		    blob_T  *b2 = tv2->vval.v_blob;
1309 		    int	i, len = blob_len(b2);
1310 		    for (i = 0; i < len; i++)
1311 			ga_append(&b1->bv_ga, blob_get(b2, i));
1312 		}
1313 		return OK;
1314 
1315 	    case VAR_LIST:
1316 		if (*op != '+' || tv2->v_type != VAR_LIST)
1317 		    break;
1318 		// List += List
1319 		if (tv1->vval.v_list != NULL && tv2->vval.v_list != NULL)
1320 		    list_extend(tv1->vval.v_list, tv2->vval.v_list, NULL);
1321 		return OK;
1322 
1323 	    case VAR_NUMBER:
1324 	    case VAR_STRING:
1325 		if (tv2->v_type == VAR_LIST)
1326 		    break;
1327 		if (vim_strchr((char_u *)"+-*/%", *op) != NULL)
1328 		{
1329 		    // nr += nr , nr -= nr , nr *=nr , nr /= nr , nr %= nr
1330 		    n = tv_get_number(tv1);
1331 #ifdef FEAT_FLOAT
1332 		    if (tv2->v_type == VAR_FLOAT)
1333 		    {
1334 			float_T f = n;
1335 
1336 			if (*op == '%')
1337 			    break;
1338 			switch (*op)
1339 			{
1340 			    case '+': f += tv2->vval.v_float; break;
1341 			    case '-': f -= tv2->vval.v_float; break;
1342 			    case '*': f *= tv2->vval.v_float; break;
1343 			    case '/': f /= tv2->vval.v_float; break;
1344 			}
1345 			clear_tv(tv1);
1346 			tv1->v_type = VAR_FLOAT;
1347 			tv1->vval.v_float = f;
1348 		    }
1349 		    else
1350 #endif
1351 		    {
1352 			switch (*op)
1353 			{
1354 			    case '+': n += tv_get_number(tv2); break;
1355 			    case '-': n -= tv_get_number(tv2); break;
1356 			    case '*': n *= tv_get_number(tv2); break;
1357 			    case '/': n = num_divide(n, tv_get_number(tv2)); break;
1358 			    case '%': n = num_modulus(n, tv_get_number(tv2)); break;
1359 			}
1360 			clear_tv(tv1);
1361 			tv1->v_type = VAR_NUMBER;
1362 			tv1->vval.v_number = n;
1363 		    }
1364 		}
1365 		else
1366 		{
1367 		    if (tv2->v_type == VAR_FLOAT)
1368 			break;
1369 
1370 		    // str .= str
1371 		    s = tv_get_string(tv1);
1372 		    s = concat_str(s, tv_get_string_buf(tv2, numbuf));
1373 		    clear_tv(tv1);
1374 		    tv1->v_type = VAR_STRING;
1375 		    tv1->vval.v_string = s;
1376 		}
1377 		return OK;
1378 
1379 	    case VAR_FLOAT:
1380 #ifdef FEAT_FLOAT
1381 		{
1382 		    float_T f;
1383 
1384 		    if (*op == '%' || *op == '.'
1385 				   || (tv2->v_type != VAR_FLOAT
1386 				    && tv2->v_type != VAR_NUMBER
1387 				    && tv2->v_type != VAR_STRING))
1388 			break;
1389 		    if (tv2->v_type == VAR_FLOAT)
1390 			f = tv2->vval.v_float;
1391 		    else
1392 			f = tv_get_number(tv2);
1393 		    switch (*op)
1394 		    {
1395 			case '+': tv1->vval.v_float += f; break;
1396 			case '-': tv1->vval.v_float -= f; break;
1397 			case '*': tv1->vval.v_float *= f; break;
1398 			case '/': tv1->vval.v_float /= f; break;
1399 		    }
1400 		}
1401 #endif
1402 		return OK;
1403 	}
1404     }
1405 
1406     semsg(_(e_letwrong), op);
1407     return FAIL;
1408 }
1409 
1410 /*
1411  * Evaluate the expression used in a ":for var in expr" command.
1412  * "arg" points to "var".
1413  * Set "*errp" to TRUE for an error, FALSE otherwise;
1414  * Return a pointer that holds the info.  Null when there is an error.
1415  */
1416     void *
1417 eval_for_line(
1418     char_u	*arg,
1419     int		*errp,
1420     char_u	**nextcmdp,
1421     int		skip)
1422 {
1423     forinfo_T	*fi;
1424     char_u	*expr;
1425     typval_T	tv;
1426     list_T	*l;
1427 
1428     *errp = TRUE;	// default: there is an error
1429 
1430     fi = ALLOC_CLEAR_ONE(forinfo_T);
1431     if (fi == NULL)
1432 	return NULL;
1433 
1434     expr = skip_var_list(arg, TRUE, &fi->fi_varcount, &fi->fi_semicolon, FALSE);
1435     if (expr == NULL)
1436 	return fi;
1437 
1438     expr = skipwhite(expr);
1439     if (expr[0] != 'i' || expr[1] != 'n' || !VIM_ISWHITE(expr[2]))
1440     {
1441 	emsg(_(e_missing_in));
1442 	return fi;
1443     }
1444 
1445     if (skip)
1446 	++emsg_skip;
1447     if (eval0(skipwhite(expr + 2), &tv, nextcmdp, skip ? 0 : EVAL_EVALUATE)
1448 									 == OK)
1449     {
1450 	*errp = FALSE;
1451 	if (!skip)
1452 	{
1453 	    if (tv.v_type == VAR_LIST)
1454 	    {
1455 		l = tv.vval.v_list;
1456 		if (l == NULL)
1457 		{
1458 		    // a null list is like an empty list: do nothing
1459 		    clear_tv(&tv);
1460 		}
1461 		else
1462 		{
1463 		    // Need a real list here.
1464 		    CHECK_LIST_MATERIALIZE(l);
1465 
1466 		    // No need to increment the refcount, it's already set for
1467 		    // the list being used in "tv".
1468 		    fi->fi_list = l;
1469 		    list_add_watch(l, &fi->fi_lw);
1470 		    fi->fi_lw.lw_item = l->lv_first;
1471 		}
1472 	    }
1473 	    else if (tv.v_type == VAR_BLOB)
1474 	    {
1475 		fi->fi_bi = 0;
1476 		if (tv.vval.v_blob != NULL)
1477 		{
1478 		    typval_T btv;
1479 
1480 		    // Make a copy, so that the iteration still works when the
1481 		    // blob is changed.
1482 		    blob_copy(tv.vval.v_blob, &btv);
1483 		    fi->fi_blob = btv.vval.v_blob;
1484 		}
1485 		clear_tv(&tv);
1486 	    }
1487 	    else
1488 	    {
1489 		emsg(_(e_listreq));
1490 		clear_tv(&tv);
1491 	    }
1492 	}
1493     }
1494     if (skip)
1495 	--emsg_skip;
1496 
1497     return fi;
1498 }
1499 
1500 /*
1501  * Use the first item in a ":for" list.  Advance to the next.
1502  * Assign the values to the variable (list).  "arg" points to the first one.
1503  * Return TRUE when a valid item was found, FALSE when at end of list or
1504  * something wrong.
1505  */
1506     int
1507 next_for_item(void *fi_void, char_u *arg)
1508 {
1509     forinfo_T	*fi = (forinfo_T *)fi_void;
1510     int		result;
1511     int		flag = current_sctx.sc_version == SCRIPT_VERSION_VIM9 ?
1512 							LET_NO_COMMAND : 0;
1513     listitem_T	*item;
1514 
1515     if (fi->fi_blob != NULL)
1516     {
1517 	typval_T	tv;
1518 
1519 	if (fi->fi_bi >= blob_len(fi->fi_blob))
1520 	    return FALSE;
1521 	tv.v_type = VAR_NUMBER;
1522 	tv.v_lock = VAR_FIXED;
1523 	tv.vval.v_number = blob_get(fi->fi_blob, fi->fi_bi);
1524 	++fi->fi_bi;
1525 	return ex_let_vars(arg, &tv, TRUE, fi->fi_semicolon,
1526 				       fi->fi_varcount, flag, NULL) == OK;
1527     }
1528 
1529     item = fi->fi_lw.lw_item;
1530     if (item == NULL)
1531 	result = FALSE;
1532     else
1533     {
1534 	fi->fi_lw.lw_item = item->li_next;
1535 	result = (ex_let_vars(arg, &item->li_tv, TRUE, fi->fi_semicolon,
1536 				      fi->fi_varcount, flag, NULL) == OK);
1537     }
1538     return result;
1539 }
1540 
1541 /*
1542  * Free the structure used to store info used by ":for".
1543  */
1544     void
1545 free_for_info(void *fi_void)
1546 {
1547     forinfo_T    *fi = (forinfo_T *)fi_void;
1548 
1549     if (fi != NULL && fi->fi_list != NULL)
1550     {
1551 	list_rem_watch(fi->fi_list, &fi->fi_lw);
1552 	list_unref(fi->fi_list);
1553     }
1554     if (fi != NULL && fi->fi_blob != NULL)
1555 	blob_unref(fi->fi_blob);
1556     vim_free(fi);
1557 }
1558 
1559     void
1560 set_context_for_expression(
1561     expand_T	*xp,
1562     char_u	*arg,
1563     cmdidx_T	cmdidx)
1564 {
1565     int		got_eq = FALSE;
1566     int		c;
1567     char_u	*p;
1568 
1569     if (cmdidx == CMD_let || cmdidx == CMD_const)
1570     {
1571 	xp->xp_context = EXPAND_USER_VARS;
1572 	if (vim_strpbrk(arg, (char_u *)"\"'+-*/%.=!?~|&$([<>,#") == NULL)
1573 	{
1574 	    // ":let var1 var2 ...": find last space.
1575 	    for (p = arg + STRLEN(arg); p >= arg; )
1576 	    {
1577 		xp->xp_pattern = p;
1578 		MB_PTR_BACK(arg, p);
1579 		if (VIM_ISWHITE(*p))
1580 		    break;
1581 	    }
1582 	    return;
1583 	}
1584     }
1585     else
1586 	xp->xp_context = cmdidx == CMD_call ? EXPAND_FUNCTIONS
1587 							  : EXPAND_EXPRESSION;
1588     while ((xp->xp_pattern = vim_strpbrk(arg,
1589 				  (char_u *)"\"'+-*/%.=!?~|&$([<>,#")) != NULL)
1590     {
1591 	c = *xp->xp_pattern;
1592 	if (c == '&')
1593 	{
1594 	    c = xp->xp_pattern[1];
1595 	    if (c == '&')
1596 	    {
1597 		++xp->xp_pattern;
1598 		xp->xp_context = cmdidx != CMD_let || got_eq
1599 					 ? EXPAND_EXPRESSION : EXPAND_NOTHING;
1600 	    }
1601 	    else if (c != ' ')
1602 	    {
1603 		xp->xp_context = EXPAND_SETTINGS;
1604 		if ((c == 'l' || c == 'g') && xp->xp_pattern[2] == ':')
1605 		    xp->xp_pattern += 2;
1606 
1607 	    }
1608 	}
1609 	else if (c == '$')
1610 	{
1611 	    // environment variable
1612 	    xp->xp_context = EXPAND_ENV_VARS;
1613 	}
1614 	else if (c == '=')
1615 	{
1616 	    got_eq = TRUE;
1617 	    xp->xp_context = EXPAND_EXPRESSION;
1618 	}
1619 	else if (c == '#'
1620 		&& xp->xp_context == EXPAND_EXPRESSION)
1621 	{
1622 	    // Autoload function/variable contains '#'.
1623 	    break;
1624 	}
1625 	else if ((c == '<' || c == '#')
1626 		&& xp->xp_context == EXPAND_FUNCTIONS
1627 		&& vim_strchr(xp->xp_pattern, '(') == NULL)
1628 	{
1629 	    // Function name can start with "<SNR>" and contain '#'.
1630 	    break;
1631 	}
1632 	else if (cmdidx != CMD_let || got_eq)
1633 	{
1634 	    if (c == '"')	    // string
1635 	    {
1636 		while ((c = *++xp->xp_pattern) != NUL && c != '"')
1637 		    if (c == '\\' && xp->xp_pattern[1] != NUL)
1638 			++xp->xp_pattern;
1639 		xp->xp_context = EXPAND_NOTHING;
1640 	    }
1641 	    else if (c == '\'')	    // literal string
1642 	    {
1643 		// Trick: '' is like stopping and starting a literal string.
1644 		while ((c = *++xp->xp_pattern) != NUL && c != '\'')
1645 		    /* skip */ ;
1646 		xp->xp_context = EXPAND_NOTHING;
1647 	    }
1648 	    else if (c == '|')
1649 	    {
1650 		if (xp->xp_pattern[1] == '|')
1651 		{
1652 		    ++xp->xp_pattern;
1653 		    xp->xp_context = EXPAND_EXPRESSION;
1654 		}
1655 		else
1656 		    xp->xp_context = EXPAND_COMMANDS;
1657 	    }
1658 	    else
1659 		xp->xp_context = EXPAND_EXPRESSION;
1660 	}
1661 	else
1662 	    // Doesn't look like something valid, expand as an expression
1663 	    // anyway.
1664 	    xp->xp_context = EXPAND_EXPRESSION;
1665 	arg = xp->xp_pattern;
1666 	if (*arg != NUL)
1667 	    while ((c = *++arg) != NUL && (c == ' ' || c == '\t'))
1668 		/* skip */ ;
1669     }
1670     xp->xp_pattern = arg;
1671 }
1672 
1673 /*
1674  * Return TRUE if "pat" matches "text".
1675  * Does not use 'cpo' and always uses 'magic'.
1676  */
1677     int
1678 pattern_match(char_u *pat, char_u *text, int ic)
1679 {
1680     int		matches = FALSE;
1681     char_u	*save_cpo;
1682     regmatch_T	regmatch;
1683 
1684     // avoid 'l' flag in 'cpoptions'
1685     save_cpo = p_cpo;
1686     p_cpo = (char_u *)"";
1687     regmatch.regprog = vim_regcomp(pat, RE_MAGIC + RE_STRING);
1688     if (regmatch.regprog != NULL)
1689     {
1690 	regmatch.rm_ic = ic;
1691 	matches = vim_regexec_nl(&regmatch, text, (colnr_T)0);
1692 	vim_regfree(regmatch.regprog);
1693     }
1694     p_cpo = save_cpo;
1695     return matches;
1696 }
1697 
1698 /*
1699  * Handle a name followed by "(".  Both for just "name(arg)" and for
1700  * "expr->name(arg)".
1701  * Returns OK or FAIL.
1702  */
1703     static int
1704 eval_func(
1705 	char_u	    **arg,	// points to "(", will be advanced
1706 	char_u	    *name,
1707 	int	    name_len,
1708 	typval_T    *rettv,
1709 	int	    flags,
1710 	typval_T    *basetv)	// "expr" for "expr->name(arg)"
1711 {
1712     int		evaluate = flags & EVAL_EVALUATE;
1713     char_u	*s = name;
1714     int		len = name_len;
1715     partial_T	*partial;
1716     int		ret = OK;
1717 
1718     if (!evaluate)
1719 	check_vars(s, len);
1720 
1721     // If "s" is the name of a variable of type VAR_FUNC
1722     // use its contents.
1723     s = deref_func_name(s, &len, &partial, !evaluate);
1724 
1725     // Need to make a copy, in case evaluating the arguments makes
1726     // the name invalid.
1727     s = vim_strsave(s);
1728     if (s == NULL || (flags & EVAL_CONSTANT))
1729 	ret = FAIL;
1730     else
1731     {
1732 	funcexe_T funcexe;
1733 
1734 	// Invoke the function.
1735 	CLEAR_FIELD(funcexe);
1736 	funcexe.firstline = curwin->w_cursor.lnum;
1737 	funcexe.lastline = curwin->w_cursor.lnum;
1738 	funcexe.evaluate = evaluate;
1739 	funcexe.partial = partial;
1740 	funcexe.basetv = basetv;
1741 	ret = get_func_tv(s, len, rettv, arg, &funcexe);
1742     }
1743     vim_free(s);
1744 
1745     // If evaluate is FALSE rettv->v_type was not set in
1746     // get_func_tv, but it's needed in handle_subscript() to parse
1747     // what follows. So set it here.
1748     if (rettv->v_type == VAR_UNKNOWN && !evaluate && **arg == '(')
1749     {
1750 	rettv->vval.v_string = NULL;
1751 	rettv->v_type = VAR_FUNC;
1752     }
1753 
1754     // Stop the expression evaluation when immediately
1755     // aborting on error, or when an interrupt occurred or
1756     // an exception was thrown but not caught.
1757     if (evaluate && aborting())
1758     {
1759 	if (ret == OK)
1760 	    clear_tv(rettv);
1761 	ret = FAIL;
1762     }
1763     return ret;
1764 }
1765 
1766 /*
1767  * The "evaluate" argument: When FALSE, the argument is only parsed but not
1768  * executed.  The function may return OK, but the rettv will be of type
1769  * VAR_UNKNOWN.  The function still returns FAIL for a syntax error.
1770  */
1771 
1772 /*
1773  * Handle zero level expression.
1774  * This calls eval1() and handles error message and nextcmd.
1775  * Put the result in "rettv" when returning OK and "evaluate" is TRUE.
1776  * Note: "rettv.v_lock" is not set.
1777  * "flags" has EVAL_EVALUATE and similar flags.
1778  * Return OK or FAIL.
1779  */
1780     int
1781 eval0(
1782     char_u	*arg,
1783     typval_T	*rettv,
1784     char_u	**nextcmd,
1785     int		flags)
1786 {
1787     int		ret;
1788     char_u	*p;
1789     int		did_emsg_before = did_emsg;
1790     int		called_emsg_before = called_emsg;
1791 
1792     p = skipwhite(arg);
1793     ret = eval1(&p, rettv, flags);
1794     if (ret == FAIL || !ends_excmd2(arg, p))
1795     {
1796 	if (ret != FAIL)
1797 	    clear_tv(rettv);
1798 	/*
1799 	 * Report the invalid expression unless the expression evaluation has
1800 	 * been cancelled due to an aborting error, an interrupt, or an
1801 	 * exception, or we already gave a more specific error.
1802 	 * Also check called_emsg for when using assert_fails().
1803 	 */
1804 	if (!aborting()
1805 		&& did_emsg == did_emsg_before
1806 		&& called_emsg == called_emsg_before
1807 		&& (flags & EVAL_CONSTANT) == 0)
1808 	    semsg(_(e_invexpr2), arg);
1809 	ret = FAIL;
1810     }
1811     if (nextcmd != NULL)
1812 	*nextcmd = check_nextcmd(p);
1813 
1814     return ret;
1815 }
1816 
1817 /*
1818  * Handle top level expression:
1819  *	expr2 ? expr1 : expr1
1820  *
1821  * "arg" must point to the first non-white of the expression.
1822  * "arg" is advanced to the next non-white after the recognized expression.
1823  *
1824  * Note: "rettv.v_lock" is not set.
1825  *
1826  * Return OK or FAIL.
1827  */
1828     int
1829 eval1(char_u **arg, typval_T *rettv, int flags)
1830 {
1831     int		result;
1832     typval_T	var2;
1833 
1834     /*
1835      * Get the first variable.
1836      */
1837     if (eval2(arg, rettv, flags) == FAIL)
1838 	return FAIL;
1839 
1840     if ((*arg)[0] == '?')
1841     {
1842 	int evaluate = flags & EVAL_EVALUATE;
1843 
1844 	result = FALSE;
1845 	if (flags & EVAL_EVALUATE)
1846 	{
1847 	    int		error = FALSE;
1848 
1849 	    if (tv_get_number_chk(rettv, &error) != 0)
1850 		result = TRUE;
1851 	    clear_tv(rettv);
1852 	    if (error)
1853 		return FAIL;
1854 	}
1855 
1856 	/*
1857 	 * Get the second variable.  Recursive!
1858 	 */
1859 	*arg = skipwhite(*arg + 1);
1860 	if (eval1(arg, rettv, result ? flags : flags & ~EVAL_EVALUATE) == FAIL)
1861 	    return FAIL;
1862 
1863 	/*
1864 	 * Check for the ":".
1865 	 */
1866 	if ((*arg)[0] != ':')
1867 	{
1868 	    emsg(_(e_missing_colon));
1869 	    if (evaluate && result)
1870 		clear_tv(rettv);
1871 	    return FAIL;
1872 	}
1873 
1874 	/*
1875 	 * Get the third variable.  Recursive!
1876 	 */
1877 	*arg = skipwhite(*arg + 1);
1878 	if (eval1(arg, &var2, !result ? flags : flags & ~EVAL_EVALUATE) == FAIL)
1879 	{
1880 	    if (evaluate && result)
1881 		clear_tv(rettv);
1882 	    return FAIL;
1883 	}
1884 	if (evaluate && !result)
1885 	    *rettv = var2;
1886     }
1887 
1888     return OK;
1889 }
1890 
1891 /*
1892  * Handle first level expression:
1893  *	expr2 || expr2 || expr2	    logical OR
1894  *
1895  * "arg" must point to the first non-white of the expression.
1896  * "arg" is advanced to the next non-white after the recognized expression.
1897  *
1898  * Return OK or FAIL.
1899  */
1900     static int
1901 eval2(char_u **arg, typval_T *rettv, int flags)
1902 {
1903     typval_T	var2;
1904     long	result;
1905     int		first;
1906     int		error = FALSE;
1907 
1908     /*
1909      * Get the first variable.
1910      */
1911     if (eval3(arg, rettv, flags) == FAIL)
1912 	return FAIL;
1913 
1914     /*
1915      * Repeat until there is no following "||".
1916      */
1917     first = TRUE;
1918     result = FALSE;
1919     while ((*arg)[0] == '|' && (*arg)[1] == '|')
1920     {
1921 	int evaluate = flags & EVAL_EVALUATE;
1922 
1923 	if (evaluate && first)
1924 	{
1925 	    if (tv_get_number_chk(rettv, &error) != 0)
1926 		result = TRUE;
1927 	    clear_tv(rettv);
1928 	    if (error)
1929 		return FAIL;
1930 	    first = FALSE;
1931 	}
1932 
1933 	/*
1934 	 * Get the second variable.
1935 	 */
1936 	*arg = skipwhite(*arg + 2);
1937 	if (eval3(arg, &var2, !result ? flags : flags & ~EVAL_EVALUATE)
1938 								       == FAIL)
1939 	    return FAIL;
1940 
1941 	/*
1942 	 * Compute the result.
1943 	 */
1944 	if (evaluate && !result)
1945 	{
1946 	    if (tv_get_number_chk(&var2, &error) != 0)
1947 		result = TRUE;
1948 	    clear_tv(&var2);
1949 	    if (error)
1950 		return FAIL;
1951 	}
1952 	if (evaluate)
1953 	{
1954 	    rettv->v_type = VAR_NUMBER;
1955 	    rettv->vval.v_number = result;
1956 	}
1957     }
1958 
1959     return OK;
1960 }
1961 
1962 /*
1963  * Handle second level expression:
1964  *	expr3 && expr3 && expr3	    logical AND
1965  *
1966  * "arg" must point to the first non-white of the expression.
1967  * "arg" is advanced to the next non-white after the recognized expression.
1968  *
1969  * Return OK or FAIL.
1970  */
1971     static int
1972 eval3(char_u **arg, typval_T *rettv, int flags)
1973 {
1974     typval_T	var2;
1975     long	result;
1976     int		first;
1977     int		error = FALSE;
1978 
1979     /*
1980      * Get the first variable.
1981      */
1982     if (eval4(arg, rettv, flags) == FAIL)
1983 	return FAIL;
1984 
1985     /*
1986      * Repeat until there is no following "&&".
1987      */
1988     first = TRUE;
1989     result = TRUE;
1990     while ((*arg)[0] == '&' && (*arg)[1] == '&')
1991     {
1992 	int evaluate = flags & EVAL_EVALUATE;
1993 
1994 	if (evaluate && first)
1995 	{
1996 	    if (tv_get_number_chk(rettv, &error) == 0)
1997 		result = FALSE;
1998 	    clear_tv(rettv);
1999 	    if (error)
2000 		return FAIL;
2001 	    first = FALSE;
2002 	}
2003 
2004 	/*
2005 	 * Get the second variable.
2006 	 */
2007 	*arg = skipwhite(*arg + 2);
2008 	if (eval4(arg, &var2, result ? flags : flags & ~EVAL_EVALUATE) == FAIL)
2009 	    return FAIL;
2010 
2011 	/*
2012 	 * Compute the result.
2013 	 */
2014 	if (evaluate && result)
2015 	{
2016 	    if (tv_get_number_chk(&var2, &error) == 0)
2017 		result = FALSE;
2018 	    clear_tv(&var2);
2019 	    if (error)
2020 		return FAIL;
2021 	}
2022 	if (evaluate)
2023 	{
2024 	    rettv->v_type = VAR_NUMBER;
2025 	    rettv->vval.v_number = result;
2026 	}
2027     }
2028 
2029     return OK;
2030 }
2031 
2032 /*
2033  * Handle third level expression:
2034  *	var1 == var2
2035  *	var1 =~ var2
2036  *	var1 != var2
2037  *	var1 !~ var2
2038  *	var1 > var2
2039  *	var1 >= var2
2040  *	var1 < var2
2041  *	var1 <= var2
2042  *	var1 is var2
2043  *	var1 isnot var2
2044  *
2045  * "arg" must point to the first non-white of the expression.
2046  * "arg" is advanced to the next non-white after the recognized expression.
2047  *
2048  * Return OK or FAIL.
2049  */
2050     static int
2051 eval4(char_u **arg, typval_T *rettv, int flags)
2052 {
2053     typval_T	var2;
2054     char_u	*p;
2055     int		i;
2056     exptype_T	type = EXPR_UNKNOWN;
2057     int		len = 2;
2058     int		ic;
2059 
2060     /*
2061      * Get the first variable.
2062      */
2063     if (eval5(arg, rettv, flags) == FAIL)
2064 	return FAIL;
2065 
2066     p = *arg;
2067     switch (p[0])
2068     {
2069 	case '=':   if (p[1] == '=')
2070 			type = EXPR_EQUAL;
2071 		    else if (p[1] == '~')
2072 			type = EXPR_MATCH;
2073 		    break;
2074 	case '!':   if (p[1] == '=')
2075 			type = EXPR_NEQUAL;
2076 		    else if (p[1] == '~')
2077 			type = EXPR_NOMATCH;
2078 		    break;
2079 	case '>':   if (p[1] != '=')
2080 		    {
2081 			type = EXPR_GREATER;
2082 			len = 1;
2083 		    }
2084 		    else
2085 			type = EXPR_GEQUAL;
2086 		    break;
2087 	case '<':   if (p[1] != '=')
2088 		    {
2089 			type = EXPR_SMALLER;
2090 			len = 1;
2091 		    }
2092 		    else
2093 			type = EXPR_SEQUAL;
2094 		    break;
2095 	case 'i':   if (p[1] == 's')
2096 		    {
2097 			if (p[2] == 'n' && p[3] == 'o' && p[4] == 't')
2098 			    len = 5;
2099 			i = p[len];
2100 			if (!isalnum(i) && i != '_')
2101 			    type = len == 2 ? EXPR_IS : EXPR_ISNOT;
2102 		    }
2103 		    break;
2104     }
2105 
2106     /*
2107      * If there is a comparative operator, use it.
2108      */
2109     if (type != EXPR_UNKNOWN)
2110     {
2111 	// extra question mark appended: ignore case
2112 	if (p[len] == '?')
2113 	{
2114 	    ic = TRUE;
2115 	    ++len;
2116 	}
2117 	// extra '#' appended: match case
2118 	else if (p[len] == '#')
2119 	{
2120 	    ic = FALSE;
2121 	    ++len;
2122 	}
2123 	// nothing appended: use 'ignorecase'
2124 	else
2125 	    ic = p_ic;
2126 
2127 	/*
2128 	 * Get the second variable.
2129 	 */
2130 	*arg = skipwhite(p + len);
2131 	if (eval5(arg, &var2, flags) == FAIL)
2132 	{
2133 	    clear_tv(rettv);
2134 	    return FAIL;
2135 	}
2136 	if (flags & EVAL_EVALUATE)
2137 	{
2138 	    int ret = typval_compare(rettv, &var2, type, ic);
2139 
2140 	    clear_tv(&var2);
2141 	    return ret;
2142 	}
2143     }
2144 
2145     return OK;
2146 }
2147 
2148     void
2149 eval_addblob(typval_T *tv1, typval_T *tv2)
2150 {
2151     blob_T  *b1 = tv1->vval.v_blob;
2152     blob_T  *b2 = tv2->vval.v_blob;
2153     blob_T  *b = blob_alloc();
2154     int	    i;
2155 
2156     if (b != NULL)
2157     {
2158 	for (i = 0; i < blob_len(b1); i++)
2159 	    ga_append(&b->bv_ga, blob_get(b1, i));
2160 	for (i = 0; i < blob_len(b2); i++)
2161 	    ga_append(&b->bv_ga, blob_get(b2, i));
2162 
2163 	clear_tv(tv1);
2164 	rettv_blob_set(tv1, b);
2165     }
2166 }
2167 
2168     int
2169 eval_addlist(typval_T *tv1, typval_T *tv2)
2170 {
2171     typval_T var3;
2172 
2173     // concatenate Lists
2174     if (list_concat(tv1->vval.v_list, tv2->vval.v_list, &var3) == FAIL)
2175     {
2176 	clear_tv(tv1);
2177 	clear_tv(tv2);
2178 	return FAIL;
2179     }
2180     clear_tv(tv1);
2181     *tv1 = var3;
2182     return OK;
2183 }
2184 
2185 /*
2186  * Handle fourth level expression:
2187  *	+	number addition
2188  *	-	number subtraction
2189  *	.	string concatenation (if script version is 1)
2190  *	..	string concatenation
2191  *
2192  * "arg" must point to the first non-white of the expression.
2193  * "arg" is advanced to the next non-white after the recognized expression.
2194  *
2195  * Return OK or FAIL.
2196  */
2197     static int
2198 eval5(char_u **arg, typval_T *rettv, int flags)
2199 {
2200     typval_T	var2;
2201     int		op;
2202     varnumber_T	n1, n2;
2203 #ifdef FEAT_FLOAT
2204     float_T	f1 = 0, f2 = 0;
2205 #endif
2206     char_u	*s1, *s2;
2207     char_u	buf1[NUMBUFLEN], buf2[NUMBUFLEN];
2208     char_u	*p;
2209     int		concat;
2210 
2211     /*
2212      * Get the first variable.
2213      */
2214     if (eval6(arg, rettv, flags, FALSE) == FAIL)
2215 	return FAIL;
2216 
2217     /*
2218      * Repeat computing, until no '+', '-' or '.' is following.
2219      */
2220     for (;;)
2221     {
2222 	// "." is only string concatenation when scriptversion is 1
2223 	op = **arg;
2224 	concat = op == '.'
2225 			&& (*(*arg + 1) == '.' || current_sctx.sc_version < 2);
2226 	if (op != '+' && op != '-' && !concat)
2227 	    break;
2228 
2229 	if ((op != '+' || (rettv->v_type != VAR_LIST
2230 						 && rettv->v_type != VAR_BLOB))
2231 #ifdef FEAT_FLOAT
2232 		&& (op == '.' || rettv->v_type != VAR_FLOAT)
2233 #endif
2234 		)
2235 	{
2236 	    // For "list + ...", an illegal use of the first operand as
2237 	    // a number cannot be determined before evaluating the 2nd
2238 	    // operand: if this is also a list, all is ok.
2239 	    // For "something . ...", "something - ..." or "non-list + ...",
2240 	    // we know that the first operand needs to be a string or number
2241 	    // without evaluating the 2nd operand.  So check before to avoid
2242 	    // side effects after an error.
2243 	    if ((flags & EVAL_EVALUATE) && tv_get_string_chk(rettv) == NULL)
2244 	    {
2245 		clear_tv(rettv);
2246 		return FAIL;
2247 	    }
2248 	}
2249 
2250 	/*
2251 	 * Get the second variable.
2252 	 */
2253 	if (op == '.' && *(*arg + 1) == '.')  // .. string concatenation
2254 	    ++*arg;
2255 	*arg = skipwhite(*arg + 1);
2256 	if (eval6(arg, &var2, flags, op == '.') == FAIL)
2257 	{
2258 	    clear_tv(rettv);
2259 	    return FAIL;
2260 	}
2261 
2262 	if (flags & EVAL_EVALUATE)
2263 	{
2264 	    /*
2265 	     * Compute the result.
2266 	     */
2267 	    if (op == '.')
2268 	    {
2269 		s1 = tv_get_string_buf(rettv, buf1);	// already checked
2270 		s2 = tv_get_string_buf_chk(&var2, buf2);
2271 		if (s2 == NULL)		// type error ?
2272 		{
2273 		    clear_tv(rettv);
2274 		    clear_tv(&var2);
2275 		    return FAIL;
2276 		}
2277 		p = concat_str(s1, s2);
2278 		clear_tv(rettv);
2279 		rettv->v_type = VAR_STRING;
2280 		rettv->vval.v_string = p;
2281 	    }
2282 	    else if (op == '+' && rettv->v_type == VAR_BLOB
2283 						   && var2.v_type == VAR_BLOB)
2284 		eval_addblob(rettv, &var2);
2285 	    else if (op == '+' && rettv->v_type == VAR_LIST
2286 						   && var2.v_type == VAR_LIST)
2287 	    {
2288 		if (eval_addlist(rettv, &var2) == FAIL)
2289 		    return FAIL;
2290 	    }
2291 	    else
2292 	    {
2293 		int	    error = FALSE;
2294 
2295 #ifdef FEAT_FLOAT
2296 		if (rettv->v_type == VAR_FLOAT)
2297 		{
2298 		    f1 = rettv->vval.v_float;
2299 		    n1 = 0;
2300 		}
2301 		else
2302 #endif
2303 		{
2304 		    n1 = tv_get_number_chk(rettv, &error);
2305 		    if (error)
2306 		    {
2307 			// This can only happen for "list + non-list".  For
2308 			// "non-list + ..." or "something - ...", we returned
2309 			// before evaluating the 2nd operand.
2310 			clear_tv(rettv);
2311 			return FAIL;
2312 		    }
2313 #ifdef FEAT_FLOAT
2314 		    if (var2.v_type == VAR_FLOAT)
2315 			f1 = n1;
2316 #endif
2317 		}
2318 #ifdef FEAT_FLOAT
2319 		if (var2.v_type == VAR_FLOAT)
2320 		{
2321 		    f2 = var2.vval.v_float;
2322 		    n2 = 0;
2323 		}
2324 		else
2325 #endif
2326 		{
2327 		    n2 = tv_get_number_chk(&var2, &error);
2328 		    if (error)
2329 		    {
2330 			clear_tv(rettv);
2331 			clear_tv(&var2);
2332 			return FAIL;
2333 		    }
2334 #ifdef FEAT_FLOAT
2335 		    if (rettv->v_type == VAR_FLOAT)
2336 			f2 = n2;
2337 #endif
2338 		}
2339 		clear_tv(rettv);
2340 
2341 #ifdef FEAT_FLOAT
2342 		// If there is a float on either side the result is a float.
2343 		if (rettv->v_type == VAR_FLOAT || var2.v_type == VAR_FLOAT)
2344 		{
2345 		    if (op == '+')
2346 			f1 = f1 + f2;
2347 		    else
2348 			f1 = f1 - f2;
2349 		    rettv->v_type = VAR_FLOAT;
2350 		    rettv->vval.v_float = f1;
2351 		}
2352 		else
2353 #endif
2354 		{
2355 		    if (op == '+')
2356 			n1 = n1 + n2;
2357 		    else
2358 			n1 = n1 - n2;
2359 		    rettv->v_type = VAR_NUMBER;
2360 		    rettv->vval.v_number = n1;
2361 		}
2362 	    }
2363 	    clear_tv(&var2);
2364 	}
2365     }
2366     return OK;
2367 }
2368 
2369 /*
2370  * Handle fifth level expression:
2371  *	*	number multiplication
2372  *	/	number division
2373  *	%	number modulo
2374  *
2375  * "arg" must point to the first non-white of the expression.
2376  * "arg" is advanced to the next non-white after the recognized expression.
2377  *
2378  * Return OK or FAIL.
2379  */
2380     static int
2381 eval6(
2382     char_u	**arg,
2383     typval_T	*rettv,
2384     int		flags,
2385     int		want_string)  // after "." operator
2386 {
2387     typval_T	var2;
2388     int		op;
2389     varnumber_T	n1, n2;
2390 #ifdef FEAT_FLOAT
2391     int		use_float = FALSE;
2392     float_T	f1 = 0, f2 = 0;
2393 #endif
2394     int		error = FALSE;
2395 
2396     /*
2397      * Get the first variable.
2398      */
2399     if (eval7(arg, rettv, flags, want_string) == FAIL)
2400 	return FAIL;
2401 
2402     /*
2403      * Repeat computing, until no '*', '/' or '%' is following.
2404      */
2405     for (;;)
2406     {
2407 	op = **arg;
2408 	if (op != '*' && op != '/' && op != '%')
2409 	    break;
2410 
2411 	if (flags & EVAL_EVALUATE)
2412 	{
2413 #ifdef FEAT_FLOAT
2414 	    if (rettv->v_type == VAR_FLOAT)
2415 	    {
2416 		f1 = rettv->vval.v_float;
2417 		use_float = TRUE;
2418 		n1 = 0;
2419 	    }
2420 	    else
2421 #endif
2422 		n1 = tv_get_number_chk(rettv, &error);
2423 	    clear_tv(rettv);
2424 	    if (error)
2425 		return FAIL;
2426 	}
2427 	else
2428 	    n1 = 0;
2429 
2430 	/*
2431 	 * Get the second variable.
2432 	 */
2433 	*arg = skipwhite(*arg + 1);
2434 	if (eval7(arg, &var2, flags, FALSE) == FAIL)
2435 	    return FAIL;
2436 
2437 	if (flags & EVAL_EVALUATE)
2438 	{
2439 #ifdef FEAT_FLOAT
2440 	    if (var2.v_type == VAR_FLOAT)
2441 	    {
2442 		if (!use_float)
2443 		{
2444 		    f1 = n1;
2445 		    use_float = TRUE;
2446 		}
2447 		f2 = var2.vval.v_float;
2448 		n2 = 0;
2449 	    }
2450 	    else
2451 #endif
2452 	    {
2453 		n2 = tv_get_number_chk(&var2, &error);
2454 		clear_tv(&var2);
2455 		if (error)
2456 		    return FAIL;
2457 #ifdef FEAT_FLOAT
2458 		if (use_float)
2459 		    f2 = n2;
2460 #endif
2461 	    }
2462 
2463 	    /*
2464 	     * Compute the result.
2465 	     * When either side is a float the result is a float.
2466 	     */
2467 #ifdef FEAT_FLOAT
2468 	    if (use_float)
2469 	    {
2470 		if (op == '*')
2471 		    f1 = f1 * f2;
2472 		else if (op == '/')
2473 		{
2474 # ifdef VMS
2475 		    // VMS crashes on divide by zero, work around it
2476 		    if (f2 == 0.0)
2477 		    {
2478 			if (f1 == 0)
2479 			    f1 = -1 * __F_FLT_MAX - 1L;   // similar to NaN
2480 			else if (f1 < 0)
2481 			    f1 = -1 * __F_FLT_MAX;
2482 			else
2483 			    f1 = __F_FLT_MAX;
2484 		    }
2485 		    else
2486 			f1 = f1 / f2;
2487 # else
2488 		    // We rely on the floating point library to handle divide
2489 		    // by zero to result in "inf" and not a crash.
2490 		    f1 = f1 / f2;
2491 # endif
2492 		}
2493 		else
2494 		{
2495 		    emsg(_(e_modulus));
2496 		    return FAIL;
2497 		}
2498 		rettv->v_type = VAR_FLOAT;
2499 		rettv->vval.v_float = f1;
2500 	    }
2501 	    else
2502 #endif
2503 	    {
2504 		if (op == '*')
2505 		    n1 = n1 * n2;
2506 		else if (op == '/')
2507 		    n1 = num_divide(n1, n2);
2508 		else
2509 		    n1 = num_modulus(n1, n2);
2510 
2511 		rettv->v_type = VAR_NUMBER;
2512 		rettv->vval.v_number = n1;
2513 	    }
2514 	}
2515     }
2516 
2517     return OK;
2518 }
2519 
2520 /*
2521  * Handle sixth level expression:
2522  *  number		number constant
2523  *  0zFFFFFFFF		Blob constant
2524  *  "string"		string constant
2525  *  'string'		literal string constant
2526  *  &option-name	option value
2527  *  @r			register contents
2528  *  identifier		variable value
2529  *  function()		function call
2530  *  $VAR		environment variable
2531  *  (expression)	nested expression
2532  *  [expr, expr]	List
2533  *  {arg, arg -> expr}	Lambda
2534  *  {key: val, key: val}   Dictionary
2535  *  #{key: val, key: val}  Dictionary with literal keys
2536  *
2537  *  Also handle:
2538  *  ! in front		logical NOT
2539  *  - in front		unary minus
2540  *  + in front		unary plus (ignored)
2541  *  trailing []		subscript in String or List
2542  *  trailing .name	entry in Dictionary
2543  *  trailing ->name()	method call
2544  *
2545  * "arg" must point to the first non-white of the expression.
2546  * "arg" is advanced to the next non-white after the recognized expression.
2547  *
2548  * Return OK or FAIL.
2549  */
2550     static int
2551 eval7(
2552     char_u	**arg,
2553     typval_T	*rettv,
2554     int		flags,
2555     int		want_string)	// after "." operator
2556 {
2557     int		evaluate = flags & EVAL_EVALUATE;
2558     int		len;
2559     char_u	*s;
2560     char_u	*start_leader, *end_leader;
2561     int		ret = OK;
2562     char_u	*alias;
2563 
2564     /*
2565      * Initialise variable so that clear_tv() can't mistake this for a
2566      * string and free a string that isn't there.
2567      */
2568     rettv->v_type = VAR_UNKNOWN;
2569 
2570     /*
2571      * Skip '!', '-' and '+' characters.  They are handled later.
2572      */
2573     start_leader = *arg;
2574     while (**arg == '!' || **arg == '-' || **arg == '+')
2575 	*arg = skipwhite(*arg + 1);
2576     end_leader = *arg;
2577 
2578     if (**arg == '.' && (!isdigit(*(*arg + 1))
2579 #ifdef FEAT_FLOAT
2580 	    || current_sctx.sc_version < 2
2581 #endif
2582 	    ))
2583     {
2584 	semsg(_(e_invexpr2), *arg);
2585 	++*arg;
2586 	return FAIL;
2587     }
2588 
2589     switch (**arg)
2590     {
2591     /*
2592      * Number constant.
2593      */
2594     case '0':
2595     case '1':
2596     case '2':
2597     case '3':
2598     case '4':
2599     case '5':
2600     case '6':
2601     case '7':
2602     case '8':
2603     case '9':
2604     case '.':	ret = get_number_tv(arg, rettv, evaluate, want_string);
2605 		break;
2606 
2607     /*
2608      * String constant: "string".
2609      */
2610     case '"':	ret = get_string_tv(arg, rettv, evaluate);
2611 		break;
2612 
2613     /*
2614      * Literal string constant: 'str''ing'.
2615      */
2616     case '\'':	ret = get_lit_string_tv(arg, rettv, evaluate);
2617 		break;
2618 
2619     /*
2620      * List: [expr, expr]
2621      */
2622     case '[':	ret = get_list_tv(arg, rettv, flags, TRUE);
2623 		break;
2624 
2625     /*
2626      * Dictionary: #{key: val, key: val}
2627      */
2628     case '#':	if ((*arg)[1] == '{')
2629 		{
2630 		    ++*arg;
2631 		    ret = eval_dict(arg, rettv, flags, TRUE);
2632 		}
2633 		else
2634 		    ret = NOTDONE;
2635 		break;
2636 
2637     /*
2638      * Lambda: {arg, arg -> expr}
2639      * Dictionary: {'key': val, 'key': val}
2640      */
2641     case '{':	ret = get_lambda_tv(arg, rettv, evaluate);
2642 		if (ret == NOTDONE)
2643 		    ret = eval_dict(arg, rettv, flags, FALSE);
2644 		break;
2645 
2646     /*
2647      * Option value: &name
2648      */
2649     case '&':	ret = get_option_tv(arg, rettv, evaluate);
2650 		break;
2651 
2652     /*
2653      * Environment variable: $VAR.
2654      */
2655     case '$':	ret = get_env_tv(arg, rettv, evaluate);
2656 		break;
2657 
2658     /*
2659      * Register contents: @r.
2660      */
2661     case '@':	++*arg;
2662 		if (evaluate)
2663 		{
2664 		    rettv->v_type = VAR_STRING;
2665 		    rettv->vval.v_string = get_reg_contents(**arg,
2666 							    GREG_EXPR_SRC);
2667 		}
2668 		if (**arg != NUL)
2669 		    ++*arg;
2670 		break;
2671 
2672     /*
2673      * nested expression: (expression).
2674      */
2675     case '(':	*arg = skipwhite(*arg + 1);
2676 		ret = eval1(arg, rettv, flags);	// recursive!
2677 		if (**arg == ')')
2678 		    ++*arg;
2679 		else if (ret == OK)
2680 		{
2681 		    emsg(_(e_missing_close));
2682 		    clear_tv(rettv);
2683 		    ret = FAIL;
2684 		}
2685 		break;
2686 
2687     default:	ret = NOTDONE;
2688 		break;
2689     }
2690 
2691     if (ret == NOTDONE)
2692     {
2693 	/*
2694 	 * Must be a variable or function name.
2695 	 * Can also be a curly-braces kind of name: {expr}.
2696 	 */
2697 	s = *arg;
2698 	len = get_name_len(arg, &alias, evaluate, TRUE);
2699 	if (alias != NULL)
2700 	    s = alias;
2701 
2702 	if (len <= 0)
2703 	    ret = FAIL;
2704 	else
2705 	{
2706 	    if (**arg == '(')		// recursive!
2707 		ret = eval_func(arg, s, len, rettv, flags, NULL);
2708 	    else if (flags & EVAL_CONSTANT)
2709 		ret = FAIL;
2710 	    else if (evaluate)
2711 		ret = get_var_tv(s, len, rettv, NULL, TRUE, FALSE);
2712 	    else
2713 	    {
2714 		check_vars(s, len);
2715 		ret = OK;
2716 	    }
2717 	}
2718 	vim_free(alias);
2719     }
2720 
2721     *arg = skipwhite(*arg);
2722 
2723     // Handle following '[', '(' and '.' for expr[expr], expr.name,
2724     // expr(expr), expr->name(expr)
2725     if (ret == OK)
2726 	ret = handle_subscript(arg, rettv, flags, TRUE,
2727 						    start_leader, &end_leader);
2728 
2729     /*
2730      * Apply logical NOT and unary '-', from right to left, ignore '+'.
2731      */
2732     if (ret == OK && evaluate && end_leader > start_leader)
2733 	ret = eval7_leader(rettv, start_leader, &end_leader);
2734     return ret;
2735 }
2736 
2737 /*
2738  * Apply the leading "!" and "-" before an eval7 expression to "rettv".
2739  * Adjusts "end_leaderp" until it is at "start_leader".
2740  */
2741     static int
2742 eval7_leader(typval_T *rettv, char_u *start_leader, char_u **end_leaderp)
2743 {
2744     char_u	*end_leader = *end_leaderp;
2745     int		ret = OK;
2746     int		error = FALSE;
2747     varnumber_T val = 0;
2748 #ifdef FEAT_FLOAT
2749     float_T	    f = 0.0;
2750 
2751     if (rettv->v_type == VAR_FLOAT)
2752 	f = rettv->vval.v_float;
2753     else
2754 #endif
2755 	val = tv_get_number_chk(rettv, &error);
2756     if (error)
2757     {
2758 	clear_tv(rettv);
2759 	ret = FAIL;
2760     }
2761     else
2762     {
2763 	while (end_leader > start_leader)
2764 	{
2765 	    --end_leader;
2766 	    if (*end_leader == '!')
2767 	    {
2768 #ifdef FEAT_FLOAT
2769 		if (rettv->v_type == VAR_FLOAT)
2770 		    f = !f;
2771 		else
2772 #endif
2773 		    val = !val;
2774 	    }
2775 	    else if (*end_leader == '-')
2776 	    {
2777 #ifdef FEAT_FLOAT
2778 		if (rettv->v_type == VAR_FLOAT)
2779 		    f = -f;
2780 		else
2781 #endif
2782 		    val = -val;
2783 	    }
2784 	}
2785 #ifdef FEAT_FLOAT
2786 	if (rettv->v_type == VAR_FLOAT)
2787 	{
2788 	    clear_tv(rettv);
2789 	    rettv->vval.v_float = f;
2790 	}
2791 	else
2792 #endif
2793 	{
2794 	    clear_tv(rettv);
2795 	    rettv->v_type = VAR_NUMBER;
2796 	    rettv->vval.v_number = val;
2797 	}
2798     }
2799     *end_leaderp = end_leader;
2800     return ret;
2801 }
2802 
2803 /*
2804  * Call the function referred to in "rettv".
2805  */
2806     static int
2807 call_func_rettv(
2808 	char_u	    **arg,
2809 	typval_T    *rettv,
2810 	int	    evaluate,
2811 	dict_T	    *selfdict,
2812 	typval_T    *basetv)
2813 {
2814     partial_T	*pt = NULL;
2815     funcexe_T	funcexe;
2816     typval_T	functv;
2817     char_u	*s;
2818     int		ret;
2819 
2820     // need to copy the funcref so that we can clear rettv
2821     if (evaluate)
2822     {
2823 	functv = *rettv;
2824 	rettv->v_type = VAR_UNKNOWN;
2825 
2826 	// Invoke the function.  Recursive!
2827 	if (functv.v_type == VAR_PARTIAL)
2828 	{
2829 	    pt = functv.vval.v_partial;
2830 	    s = partial_name(pt);
2831 	}
2832 	else
2833 	    s = functv.vval.v_string;
2834     }
2835     else
2836 	s = (char_u *)"";
2837 
2838     CLEAR_FIELD(funcexe);
2839     funcexe.firstline = curwin->w_cursor.lnum;
2840     funcexe.lastline = curwin->w_cursor.lnum;
2841     funcexe.evaluate = evaluate;
2842     funcexe.partial = pt;
2843     funcexe.selfdict = selfdict;
2844     funcexe.basetv = basetv;
2845     ret = get_func_tv(s, -1, rettv, arg, &funcexe);
2846 
2847     // Clear the funcref afterwards, so that deleting it while
2848     // evaluating the arguments is possible (see test55).
2849     if (evaluate)
2850 	clear_tv(&functv);
2851 
2852     return ret;
2853 }
2854 
2855 /*
2856  * Evaluate "->method()".
2857  * "*arg" points to the '-'.
2858  * Returns FAIL or OK. "*arg" is advanced to after the ')'.
2859  */
2860     static int
2861 eval_lambda(
2862     char_u	**arg,
2863     typval_T	*rettv,
2864     int		evaluate,
2865     int		verbose)	// give error messages
2866 {
2867     typval_T	base = *rettv;
2868     int		ret;
2869 
2870     // Skip over the ->.
2871     *arg += 2;
2872     rettv->v_type = VAR_UNKNOWN;
2873 
2874     ret = get_lambda_tv(arg, rettv, evaluate);
2875     if (ret != OK)
2876 	return FAIL;
2877     else if (**arg != '(')
2878     {
2879 	if (verbose)
2880 	{
2881 	    if (*skipwhite(*arg) == '(')
2882 		emsg(_(e_nowhitespace));
2883 	    else
2884 		semsg(_(e_missing_paren), "lambda");
2885 	}
2886 	clear_tv(rettv);
2887 	ret = FAIL;
2888     }
2889     else
2890 	ret = call_func_rettv(arg, rettv, evaluate, NULL, &base);
2891 
2892     // Clear the funcref afterwards, so that deleting it while
2893     // evaluating the arguments is possible (see test55).
2894     if (evaluate)
2895 	clear_tv(&base);
2896 
2897     return ret;
2898 }
2899 
2900 /*
2901  * Evaluate "->method()".
2902  * "*arg" points to the '-'.
2903  * Returns FAIL or OK. "*arg" is advanced to after the ')'.
2904  */
2905     static int
2906 eval_method(
2907     char_u	**arg,
2908     typval_T	*rettv,
2909     int		evaluate,
2910     int		verbose)	// give error messages
2911 {
2912     char_u	*name;
2913     long	len;
2914     char_u	*alias;
2915     typval_T	base = *rettv;
2916     int		ret;
2917 
2918     // Skip over the ->.
2919     *arg += 2;
2920     rettv->v_type = VAR_UNKNOWN;
2921 
2922     name = *arg;
2923     len = get_name_len(arg, &alias, evaluate, TRUE);
2924     if (alias != NULL)
2925 	name = alias;
2926 
2927     if (len <= 0)
2928     {
2929 	if (verbose)
2930 	    emsg(_("E260: Missing name after ->"));
2931 	ret = FAIL;
2932     }
2933     else
2934     {
2935 	if (**arg != '(')
2936 	{
2937 	    if (verbose)
2938 		semsg(_(e_missing_paren), name);
2939 	    ret = FAIL;
2940 	}
2941 	else if (VIM_ISWHITE((*arg)[-1]))
2942 	{
2943 	    if (verbose)
2944 		emsg(_(e_nowhitespace));
2945 	    ret = FAIL;
2946 	}
2947 	else
2948 	    ret = eval_func(arg, name, len, rettv,
2949 					  evaluate ? EVAL_EVALUATE : 0, &base);
2950     }
2951 
2952     // Clear the funcref afterwards, so that deleting it while
2953     // evaluating the arguments is possible (see test55).
2954     if (evaluate)
2955 	clear_tv(&base);
2956 
2957     return ret;
2958 }
2959 
2960 /*
2961  * Evaluate an "[expr]" or "[expr:expr]" index.  Also "dict.key".
2962  * "*arg" points to the '[' or '.'.
2963  * Returns FAIL or OK. "*arg" is advanced to after the ']'.
2964  */
2965     static int
2966 eval_index(
2967     char_u	**arg,
2968     typval_T	*rettv,
2969     int		flags,
2970     int		verbose)	// give error messages
2971 {
2972     int		evaluate = flags & EVAL_EVALUATE;
2973     int		empty1 = FALSE, empty2 = FALSE;
2974     typval_T	var1, var2;
2975     long	i;
2976     long	n1, n2 = 0;
2977     long	len = -1;
2978     int		range = FALSE;
2979     char_u	*s;
2980     char_u	*key = NULL;
2981 
2982     switch (rettv->v_type)
2983     {
2984 	case VAR_FUNC:
2985 	case VAR_PARTIAL:
2986 	    if (verbose)
2987 		emsg(_("E695: Cannot index a Funcref"));
2988 	    return FAIL;
2989 	case VAR_FLOAT:
2990 #ifdef FEAT_FLOAT
2991 	    if (verbose)
2992 		emsg(_(e_float_as_string));
2993 	    return FAIL;
2994 #endif
2995 	case VAR_BOOL:
2996 	case VAR_SPECIAL:
2997 	case VAR_JOB:
2998 	case VAR_CHANNEL:
2999 	    if (verbose)
3000 		emsg(_("E909: Cannot index a special variable"));
3001 	    return FAIL;
3002 	case VAR_UNKNOWN:
3003 	case VAR_ANY:
3004 	case VAR_VOID:
3005 	    if (evaluate)
3006 		return FAIL;
3007 	    // FALLTHROUGH
3008 
3009 	case VAR_STRING:
3010 	case VAR_NUMBER:
3011 	case VAR_LIST:
3012 	case VAR_DICT:
3013 	case VAR_BLOB:
3014 	    break;
3015     }
3016 
3017     init_tv(&var1);
3018     init_tv(&var2);
3019     if (**arg == '.')
3020     {
3021 	/*
3022 	 * dict.name
3023 	 */
3024 	key = *arg + 1;
3025 	for (len = 0; ASCII_ISALNUM(key[len]) || key[len] == '_'; ++len)
3026 	    ;
3027 	if (len == 0)
3028 	    return FAIL;
3029 	*arg = skipwhite(key + len);
3030     }
3031     else
3032     {
3033 	/*
3034 	 * something[idx]
3035 	 *
3036 	 * Get the (first) variable from inside the [].
3037 	 */
3038 	*arg = skipwhite(*arg + 1);
3039 	if (**arg == ':')
3040 	    empty1 = TRUE;
3041 	else if (eval1(arg, &var1, flags) == FAIL)	// recursive!
3042 	    return FAIL;
3043 	else if (evaluate && tv_get_string_chk(&var1) == NULL)
3044 	{
3045 	    // not a number or string
3046 	    clear_tv(&var1);
3047 	    return FAIL;
3048 	}
3049 
3050 	/*
3051 	 * Get the second variable from inside the [:].
3052 	 */
3053 	if (**arg == ':')
3054 	{
3055 	    range = TRUE;
3056 	    *arg = skipwhite(*arg + 1);
3057 	    if (**arg == ']')
3058 		empty2 = TRUE;
3059 	    else if (eval1(arg, &var2, flags) == FAIL)	// recursive!
3060 	    {
3061 		if (!empty1)
3062 		    clear_tv(&var1);
3063 		return FAIL;
3064 	    }
3065 	    else if (evaluate && tv_get_string_chk(&var2) == NULL)
3066 	    {
3067 		// not a number or string
3068 		if (!empty1)
3069 		    clear_tv(&var1);
3070 		clear_tv(&var2);
3071 		return FAIL;
3072 	    }
3073 	}
3074 
3075 	// Check for the ']'.
3076 	if (**arg != ']')
3077 	{
3078 	    if (verbose)
3079 		emsg(_(e_missbrac));
3080 	    clear_tv(&var1);
3081 	    if (range)
3082 		clear_tv(&var2);
3083 	    return FAIL;
3084 	}
3085 	*arg = skipwhite(*arg + 1);	// skip the ']'
3086     }
3087 
3088     if (evaluate)
3089     {
3090 	n1 = 0;
3091 	if (!empty1 && rettv->v_type != VAR_DICT)
3092 	{
3093 	    n1 = tv_get_number(&var1);
3094 	    clear_tv(&var1);
3095 	}
3096 	if (range)
3097 	{
3098 	    if (empty2)
3099 		n2 = -1;
3100 	    else
3101 	    {
3102 		n2 = tv_get_number(&var2);
3103 		clear_tv(&var2);
3104 	    }
3105 	}
3106 
3107 	switch (rettv->v_type)
3108 	{
3109 	    case VAR_UNKNOWN:
3110 	    case VAR_ANY:
3111 	    case VAR_VOID:
3112 	    case VAR_FUNC:
3113 	    case VAR_PARTIAL:
3114 	    case VAR_FLOAT:
3115 	    case VAR_BOOL:
3116 	    case VAR_SPECIAL:
3117 	    case VAR_JOB:
3118 	    case VAR_CHANNEL:
3119 		break; // not evaluating, skipping over subscript
3120 
3121 	    case VAR_NUMBER:
3122 	    case VAR_STRING:
3123 		s = tv_get_string(rettv);
3124 		len = (long)STRLEN(s);
3125 		if (range)
3126 		{
3127 		    // The resulting variable is a substring.  If the indexes
3128 		    // are out of range the result is empty.
3129 		    if (n1 < 0)
3130 		    {
3131 			n1 = len + n1;
3132 			if (n1 < 0)
3133 			    n1 = 0;
3134 		    }
3135 		    if (n2 < 0)
3136 			n2 = len + n2;
3137 		    else if (n2 >= len)
3138 			n2 = len;
3139 		    if (n1 >= len || n2 < 0 || n1 > n2)
3140 			s = NULL;
3141 		    else
3142 			s = vim_strnsave(s + n1, n2 - n1 + 1);
3143 		}
3144 		else
3145 		{
3146 		    // The resulting variable is a string of a single
3147 		    // character.  If the index is too big or negative the
3148 		    // result is empty.
3149 		    if (n1 >= len || n1 < 0)
3150 			s = NULL;
3151 		    else
3152 			s = vim_strnsave(s + n1, 1);
3153 		}
3154 		clear_tv(rettv);
3155 		rettv->v_type = VAR_STRING;
3156 		rettv->vval.v_string = s;
3157 		break;
3158 
3159 	    case VAR_BLOB:
3160 		len = blob_len(rettv->vval.v_blob);
3161 		if (range)
3162 		{
3163 		    // The resulting variable is a sub-blob.  If the indexes
3164 		    // are out of range the result is empty.
3165 		    if (n1 < 0)
3166 		    {
3167 			n1 = len + n1;
3168 			if (n1 < 0)
3169 			    n1 = 0;
3170 		    }
3171 		    if (n2 < 0)
3172 			n2 = len + n2;
3173 		    else if (n2 >= len)
3174 			n2 = len - 1;
3175 		    if (n1 >= len || n2 < 0 || n1 > n2)
3176 		    {
3177 			clear_tv(rettv);
3178 			rettv->v_type = VAR_BLOB;
3179 			rettv->vval.v_blob = NULL;
3180 		    }
3181 		    else
3182 		    {
3183 			blob_T  *blob = blob_alloc();
3184 
3185 			if (blob != NULL)
3186 			{
3187 			    if (ga_grow(&blob->bv_ga, n2 - n1 + 1) == FAIL)
3188 			    {
3189 				blob_free(blob);
3190 				return FAIL;
3191 			    }
3192 			    blob->bv_ga.ga_len = n2 - n1 + 1;
3193 			    for (i = n1; i <= n2; i++)
3194 				blob_set(blob, i - n1,
3195 					      blob_get(rettv->vval.v_blob, i));
3196 
3197 			    clear_tv(rettv);
3198 			    rettv_blob_set(rettv, blob);
3199 			}
3200 		    }
3201 		}
3202 		else
3203 		{
3204 		    // The resulting variable is a byte value.
3205 		    // If the index is too big or negative that is an error.
3206 		    if (n1 < 0)
3207 			n1 = len + n1;
3208 		    if (n1 < len && n1 >= 0)
3209 		    {
3210 			int v = blob_get(rettv->vval.v_blob, n1);
3211 
3212 			clear_tv(rettv);
3213 			rettv->v_type = VAR_NUMBER;
3214 			rettv->vval.v_number = v;
3215 		    }
3216 		    else
3217 			semsg(_(e_blobidx), n1);
3218 		}
3219 		break;
3220 
3221 	    case VAR_LIST:
3222 		len = list_len(rettv->vval.v_list);
3223 		if (n1 < 0)
3224 		    n1 = len + n1;
3225 		if (!empty1 && (n1 < 0 || n1 >= len))
3226 		{
3227 		    // For a range we allow invalid values and return an empty
3228 		    // list.  A list index out of range is an error.
3229 		    if (!range)
3230 		    {
3231 			if (verbose)
3232 			    semsg(_(e_listidx), n1);
3233 			return FAIL;
3234 		    }
3235 		    n1 = len;
3236 		}
3237 		if (range)
3238 		{
3239 		    list_T	*l;
3240 
3241 		    if (n2 < 0)
3242 			n2 = len + n2;
3243 		    else if (n2 >= len)
3244 			n2 = len - 1;
3245 		    if (!empty2 && (n2 < 0 || n2 + 1 < n1))
3246 			n2 = -1;
3247 		    l = list_slice(rettv->vval.v_list, n1, n2);
3248 		    if (l == NULL)
3249 			return FAIL;
3250 		    clear_tv(rettv);
3251 		    rettv_list_set(rettv, l);
3252 		}
3253 		else
3254 		{
3255 		    copy_tv(&list_find(rettv->vval.v_list, n1)->li_tv, &var1);
3256 		    clear_tv(rettv);
3257 		    *rettv = var1;
3258 		}
3259 		break;
3260 
3261 	    case VAR_DICT:
3262 		if (range)
3263 		{
3264 		    if (verbose)
3265 			emsg(_(e_dictrange));
3266 		    if (len == -1)
3267 			clear_tv(&var1);
3268 		    return FAIL;
3269 		}
3270 		{
3271 		    dictitem_T	*item;
3272 
3273 		    if (len == -1)
3274 		    {
3275 			key = tv_get_string_chk(&var1);
3276 			if (key == NULL)
3277 			{
3278 			    clear_tv(&var1);
3279 			    return FAIL;
3280 			}
3281 		    }
3282 
3283 		    item = dict_find(rettv->vval.v_dict, key, (int)len);
3284 
3285 		    if (item == NULL && verbose)
3286 			semsg(_(e_dictkey), key);
3287 		    if (len == -1)
3288 			clear_tv(&var1);
3289 		    if (item == NULL)
3290 			return FAIL;
3291 
3292 		    copy_tv(&item->di_tv, &var1);
3293 		    clear_tv(rettv);
3294 		    *rettv = var1;
3295 		}
3296 		break;
3297 	}
3298     }
3299 
3300     return OK;
3301 }
3302 
3303 /*
3304  * Return the function name of partial "pt".
3305  */
3306     char_u *
3307 partial_name(partial_T *pt)
3308 {
3309     if (pt->pt_name != NULL)
3310 	return pt->pt_name;
3311     if (pt->pt_func != NULL)
3312 	return pt->pt_func->uf_name;
3313     return (char_u *)"";
3314 }
3315 
3316     static void
3317 partial_free(partial_T *pt)
3318 {
3319     int i;
3320 
3321     for (i = 0; i < pt->pt_argc; ++i)
3322 	clear_tv(&pt->pt_argv[i]);
3323     vim_free(pt->pt_argv);
3324     dict_unref(pt->pt_dict);
3325     if (pt->pt_name != NULL)
3326     {
3327 	func_unref(pt->pt_name);
3328 	vim_free(pt->pt_name);
3329     }
3330     else
3331 	func_ptr_unref(pt->pt_func);
3332 
3333     if (pt->pt_funcstack != NULL)
3334     {
3335 	// Decrease the reference count for the context of a closure.  If down
3336 	// to zero free it and clear the variables on the stack.
3337 	if (--pt->pt_funcstack->fs_refcount == 0)
3338 	{
3339 	    garray_T	*gap = &pt->pt_funcstack->fs_ga;
3340 	    typval_T	*stack = gap->ga_data;
3341 
3342 	    for (i = 0; i < gap->ga_len; ++i)
3343 		clear_tv(stack + i);
3344 	    ga_clear(gap);
3345 	    vim_free(pt->pt_funcstack);
3346 	}
3347 	pt->pt_funcstack = NULL;
3348     }
3349 
3350     vim_free(pt);
3351 }
3352 
3353 /*
3354  * Unreference a closure: decrement the reference count and free it when it
3355  * becomes zero.
3356  */
3357     void
3358 partial_unref(partial_T *pt)
3359 {
3360     if (pt != NULL && --pt->pt_refcount <= 0)
3361 	partial_free(pt);
3362 }
3363 
3364 /*
3365  * Return the next (unique) copy ID.
3366  * Used for serializing nested structures.
3367  */
3368     int
3369 get_copyID(void)
3370 {
3371     current_copyID += COPYID_INC;
3372     return current_copyID;
3373 }
3374 
3375 /*
3376  * Garbage collection for lists and dictionaries.
3377  *
3378  * We use reference counts to be able to free most items right away when they
3379  * are no longer used.  But for composite items it's possible that it becomes
3380  * unused while the reference count is > 0: When there is a recursive
3381  * reference.  Example:
3382  *	:let l = [1, 2, 3]
3383  *	:let d = {9: l}
3384  *	:let l[1] = d
3385  *
3386  * Since this is quite unusual we handle this with garbage collection: every
3387  * once in a while find out which lists and dicts are not referenced from any
3388  * variable.
3389  *
3390  * Here is a good reference text about garbage collection (refers to Python
3391  * but it applies to all reference-counting mechanisms):
3392  *	http://python.ca/nas/python/gc/
3393  */
3394 
3395 /*
3396  * Do garbage collection for lists and dicts.
3397  * When "testing" is TRUE this is called from test_garbagecollect_now().
3398  * Return TRUE if some memory was freed.
3399  */
3400     int
3401 garbage_collect(int testing)
3402 {
3403     int		copyID;
3404     int		abort = FALSE;
3405     buf_T	*buf;
3406     win_T	*wp;
3407     int		did_free = FALSE;
3408     tabpage_T	*tp;
3409 
3410     if (!testing)
3411     {
3412 	// Only do this once.
3413 	want_garbage_collect = FALSE;
3414 	may_garbage_collect = FALSE;
3415 	garbage_collect_at_exit = FALSE;
3416     }
3417 
3418     // The execution stack can grow big, limit the size.
3419     if (exestack.ga_maxlen - exestack.ga_len > 500)
3420     {
3421 	size_t	new_len;
3422 	char_u	*pp;
3423 	int	n;
3424 
3425 	// Keep 150% of the current size, with a minimum of the growth size.
3426 	n = exestack.ga_len / 2;
3427 	if (n < exestack.ga_growsize)
3428 	    n = exestack.ga_growsize;
3429 
3430 	// Don't make it bigger though.
3431 	if (exestack.ga_len + n < exestack.ga_maxlen)
3432 	{
3433 	    new_len = exestack.ga_itemsize * (exestack.ga_len + n);
3434 	    pp = vim_realloc(exestack.ga_data, new_len);
3435 	    if (pp == NULL)
3436 		return FAIL;
3437 	    exestack.ga_maxlen = exestack.ga_len + n;
3438 	    exestack.ga_data = pp;
3439 	}
3440     }
3441 
3442     // We advance by two because we add one for items referenced through
3443     // previous_funccal.
3444     copyID = get_copyID();
3445 
3446     /*
3447      * 1. Go through all accessible variables and mark all lists and dicts
3448      *    with copyID.
3449      */
3450 
3451     // Don't free variables in the previous_funccal list unless they are only
3452     // referenced through previous_funccal.  This must be first, because if
3453     // the item is referenced elsewhere the funccal must not be freed.
3454     abort = abort || set_ref_in_previous_funccal(copyID);
3455 
3456     // script-local variables
3457     abort = abort || garbage_collect_scriptvars(copyID);
3458 
3459     // buffer-local variables
3460     FOR_ALL_BUFFERS(buf)
3461 	abort = abort || set_ref_in_item(&buf->b_bufvar.di_tv, copyID,
3462 								  NULL, NULL);
3463 
3464     // window-local variables
3465     FOR_ALL_TAB_WINDOWS(tp, wp)
3466 	abort = abort || set_ref_in_item(&wp->w_winvar.di_tv, copyID,
3467 								  NULL, NULL);
3468     if (aucmd_win != NULL)
3469 	abort = abort || set_ref_in_item(&aucmd_win->w_winvar.di_tv, copyID,
3470 								  NULL, NULL);
3471 #ifdef FEAT_PROP_POPUP
3472     FOR_ALL_POPUPWINS(wp)
3473 	abort = abort || set_ref_in_item(&wp->w_winvar.di_tv, copyID,
3474 								  NULL, NULL);
3475     FOR_ALL_TABPAGES(tp)
3476 	FOR_ALL_POPUPWINS_IN_TAB(tp, wp)
3477 		abort = abort || set_ref_in_item(&wp->w_winvar.di_tv, copyID,
3478 								  NULL, NULL);
3479 #endif
3480 
3481     // tabpage-local variables
3482     FOR_ALL_TABPAGES(tp)
3483 	abort = abort || set_ref_in_item(&tp->tp_winvar.di_tv, copyID,
3484 								  NULL, NULL);
3485     // global variables
3486     abort = abort || garbage_collect_globvars(copyID);
3487 
3488     // function-local variables
3489     abort = abort || set_ref_in_call_stack(copyID);
3490 
3491     // named functions (matters for closures)
3492     abort = abort || set_ref_in_functions(copyID);
3493 
3494     // function call arguments, if v:testing is set.
3495     abort = abort || set_ref_in_func_args(copyID);
3496 
3497     // v: vars
3498     abort = abort || garbage_collect_vimvars(copyID);
3499 
3500     // callbacks in buffers
3501     abort = abort || set_ref_in_buffers(copyID);
3502 
3503 #ifdef FEAT_LUA
3504     abort = abort || set_ref_in_lua(copyID);
3505 #endif
3506 
3507 #ifdef FEAT_PYTHON
3508     abort = abort || set_ref_in_python(copyID);
3509 #endif
3510 
3511 #ifdef FEAT_PYTHON3
3512     abort = abort || set_ref_in_python3(copyID);
3513 #endif
3514 
3515 #ifdef FEAT_JOB_CHANNEL
3516     abort = abort || set_ref_in_channel(copyID);
3517     abort = abort || set_ref_in_job(copyID);
3518 #endif
3519 #ifdef FEAT_NETBEANS_INTG
3520     abort = abort || set_ref_in_nb_channel(copyID);
3521 #endif
3522 
3523 #ifdef FEAT_TIMERS
3524     abort = abort || set_ref_in_timer(copyID);
3525 #endif
3526 
3527 #ifdef FEAT_QUICKFIX
3528     abort = abort || set_ref_in_quickfix(copyID);
3529 #endif
3530 
3531 #ifdef FEAT_TERMINAL
3532     abort = abort || set_ref_in_term(copyID);
3533 #endif
3534 
3535 #ifdef FEAT_PROP_POPUP
3536     abort = abort || set_ref_in_popups(copyID);
3537 #endif
3538 
3539     if (!abort)
3540     {
3541 	/*
3542 	 * 2. Free lists and dictionaries that are not referenced.
3543 	 */
3544 	did_free = free_unref_items(copyID);
3545 
3546 	/*
3547 	 * 3. Check if any funccal can be freed now.
3548 	 *    This may call us back recursively.
3549 	 */
3550 	free_unref_funccal(copyID, testing);
3551     }
3552     else if (p_verbose > 0)
3553     {
3554 	verb_msg(_("Not enough memory to set references, garbage collection aborted!"));
3555     }
3556 
3557     return did_free;
3558 }
3559 
3560 /*
3561  * Free lists, dictionaries, channels and jobs that are no longer referenced.
3562  */
3563     static int
3564 free_unref_items(int copyID)
3565 {
3566     int		did_free = FALSE;
3567 
3568     // Let all "free" functions know that we are here.  This means no
3569     // dictionaries, lists, channels or jobs are to be freed, because we will
3570     // do that here.
3571     in_free_unref_items = TRUE;
3572 
3573     /*
3574      * PASS 1: free the contents of the items.  We don't free the items
3575      * themselves yet, so that it is possible to decrement refcount counters
3576      */
3577 
3578     // Go through the list of dicts and free items without the copyID.
3579     did_free |= dict_free_nonref(copyID);
3580 
3581     // Go through the list of lists and free items without the copyID.
3582     did_free |= list_free_nonref(copyID);
3583 
3584 #ifdef FEAT_JOB_CHANNEL
3585     // Go through the list of jobs and free items without the copyID. This
3586     // must happen before doing channels, because jobs refer to channels, but
3587     // the reference from the channel to the job isn't tracked.
3588     did_free |= free_unused_jobs_contents(copyID, COPYID_MASK);
3589 
3590     // Go through the list of channels and free items without the copyID.
3591     did_free |= free_unused_channels_contents(copyID, COPYID_MASK);
3592 #endif
3593 
3594     /*
3595      * PASS 2: free the items themselves.
3596      */
3597     dict_free_items(copyID);
3598     list_free_items(copyID);
3599 
3600 #ifdef FEAT_JOB_CHANNEL
3601     // Go through the list of jobs and free items without the copyID. This
3602     // must happen before doing channels, because jobs refer to channels, but
3603     // the reference from the channel to the job isn't tracked.
3604     free_unused_jobs(copyID, COPYID_MASK);
3605 
3606     // Go through the list of channels and free items without the copyID.
3607     free_unused_channels(copyID, COPYID_MASK);
3608 #endif
3609 
3610     in_free_unref_items = FALSE;
3611 
3612     return did_free;
3613 }
3614 
3615 /*
3616  * Mark all lists and dicts referenced through hashtab "ht" with "copyID".
3617  * "list_stack" is used to add lists to be marked.  Can be NULL.
3618  *
3619  * Returns TRUE if setting references failed somehow.
3620  */
3621     int
3622 set_ref_in_ht(hashtab_T *ht, int copyID, list_stack_T **list_stack)
3623 {
3624     int		todo;
3625     int		abort = FALSE;
3626     hashitem_T	*hi;
3627     hashtab_T	*cur_ht;
3628     ht_stack_T	*ht_stack = NULL;
3629     ht_stack_T	*tempitem;
3630 
3631     cur_ht = ht;
3632     for (;;)
3633     {
3634 	if (!abort)
3635 	{
3636 	    // Mark each item in the hashtab.  If the item contains a hashtab
3637 	    // it is added to ht_stack, if it contains a list it is added to
3638 	    // list_stack.
3639 	    todo = (int)cur_ht->ht_used;
3640 	    for (hi = cur_ht->ht_array; todo > 0; ++hi)
3641 		if (!HASHITEM_EMPTY(hi))
3642 		{
3643 		    --todo;
3644 		    abort = abort || set_ref_in_item(&HI2DI(hi)->di_tv, copyID,
3645 						       &ht_stack, list_stack);
3646 		}
3647 	}
3648 
3649 	if (ht_stack == NULL)
3650 	    break;
3651 
3652 	// take an item from the stack
3653 	cur_ht = ht_stack->ht;
3654 	tempitem = ht_stack;
3655 	ht_stack = ht_stack->prev;
3656 	free(tempitem);
3657     }
3658 
3659     return abort;
3660 }
3661 
3662 /*
3663  * Mark a dict and its items with "copyID".
3664  * Returns TRUE if setting references failed somehow.
3665  */
3666     int
3667 set_ref_in_dict(dict_T *d, int copyID)
3668 {
3669     if (d != NULL && d->dv_copyID != copyID)
3670     {
3671 	d->dv_copyID = copyID;
3672 	return set_ref_in_ht(&d->dv_hashtab, copyID, NULL);
3673     }
3674     return FALSE;
3675 }
3676 
3677 /*
3678  * Mark a list and its items with "copyID".
3679  * Returns TRUE if setting references failed somehow.
3680  */
3681     int
3682 set_ref_in_list(list_T *ll, int copyID)
3683 {
3684     if (ll != NULL && ll->lv_copyID != copyID)
3685     {
3686 	ll->lv_copyID = copyID;
3687 	return set_ref_in_list_items(ll, copyID, NULL);
3688     }
3689     return FALSE;
3690 }
3691 
3692 /*
3693  * Mark all lists and dicts referenced through list "l" with "copyID".
3694  * "ht_stack" is used to add hashtabs to be marked.  Can be NULL.
3695  *
3696  * Returns TRUE if setting references failed somehow.
3697  */
3698     int
3699 set_ref_in_list_items(list_T *l, int copyID, ht_stack_T **ht_stack)
3700 {
3701     listitem_T	 *li;
3702     int		 abort = FALSE;
3703     list_T	 *cur_l;
3704     list_stack_T *list_stack = NULL;
3705     list_stack_T *tempitem;
3706 
3707     cur_l = l;
3708     for (;;)
3709     {
3710 	if (!abort && cur_l->lv_first != &range_list_item)
3711 	    // Mark each item in the list.  If the item contains a hashtab
3712 	    // it is added to ht_stack, if it contains a list it is added to
3713 	    // list_stack.
3714 	    for (li = cur_l->lv_first; !abort && li != NULL; li = li->li_next)
3715 		abort = abort || set_ref_in_item(&li->li_tv, copyID,
3716 						       ht_stack, &list_stack);
3717 	if (list_stack == NULL)
3718 	    break;
3719 
3720 	// take an item from the stack
3721 	cur_l = list_stack->list;
3722 	tempitem = list_stack;
3723 	list_stack = list_stack->prev;
3724 	free(tempitem);
3725     }
3726 
3727     return abort;
3728 }
3729 
3730 /*
3731  * Mark all lists and dicts referenced through typval "tv" with "copyID".
3732  * "list_stack" is used to add lists to be marked.  Can be NULL.
3733  * "ht_stack" is used to add hashtabs to be marked.  Can be NULL.
3734  *
3735  * Returns TRUE if setting references failed somehow.
3736  */
3737     int
3738 set_ref_in_item(
3739     typval_T	    *tv,
3740     int		    copyID,
3741     ht_stack_T	    **ht_stack,
3742     list_stack_T    **list_stack)
3743 {
3744     int		abort = FALSE;
3745 
3746     if (tv->v_type == VAR_DICT)
3747     {
3748 	dict_T	*dd = tv->vval.v_dict;
3749 
3750 	if (dd != NULL && dd->dv_copyID != copyID)
3751 	{
3752 	    // Didn't see this dict yet.
3753 	    dd->dv_copyID = copyID;
3754 	    if (ht_stack == NULL)
3755 	    {
3756 		abort = set_ref_in_ht(&dd->dv_hashtab, copyID, list_stack);
3757 	    }
3758 	    else
3759 	    {
3760 		ht_stack_T *newitem = (ht_stack_T*)malloc(sizeof(ht_stack_T));
3761 		if (newitem == NULL)
3762 		    abort = TRUE;
3763 		else
3764 		{
3765 		    newitem->ht = &dd->dv_hashtab;
3766 		    newitem->prev = *ht_stack;
3767 		    *ht_stack = newitem;
3768 		}
3769 	    }
3770 	}
3771     }
3772     else if (tv->v_type == VAR_LIST)
3773     {
3774 	list_T	*ll = tv->vval.v_list;
3775 
3776 	if (ll != NULL && ll->lv_copyID != copyID)
3777 	{
3778 	    // Didn't see this list yet.
3779 	    ll->lv_copyID = copyID;
3780 	    if (list_stack == NULL)
3781 	    {
3782 		abort = set_ref_in_list_items(ll, copyID, ht_stack);
3783 	    }
3784 	    else
3785 	    {
3786 		list_stack_T *newitem = (list_stack_T*)malloc(
3787 							sizeof(list_stack_T));
3788 		if (newitem == NULL)
3789 		    abort = TRUE;
3790 		else
3791 		{
3792 		    newitem->list = ll;
3793 		    newitem->prev = *list_stack;
3794 		    *list_stack = newitem;
3795 		}
3796 	    }
3797 	}
3798     }
3799     else if (tv->v_type == VAR_FUNC)
3800     {
3801 	abort = set_ref_in_func(tv->vval.v_string, NULL, copyID);
3802     }
3803     else if (tv->v_type == VAR_PARTIAL)
3804     {
3805 	partial_T	*pt = tv->vval.v_partial;
3806 	int		i;
3807 
3808 	if (pt != NULL && pt->pt_copyID != copyID)
3809 	{
3810 	    // Didn't see this partial yet.
3811 	    pt->pt_copyID = copyID;
3812 
3813 	    abort = set_ref_in_func(pt->pt_name, pt->pt_func, copyID);
3814 
3815 	    if (pt->pt_dict != NULL)
3816 	    {
3817 		typval_T dtv;
3818 
3819 		dtv.v_type = VAR_DICT;
3820 		dtv.vval.v_dict = pt->pt_dict;
3821 		set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
3822 	    }
3823 
3824 	    for (i = 0; i < pt->pt_argc; ++i)
3825 		abort = abort || set_ref_in_item(&pt->pt_argv[i], copyID,
3826 							ht_stack, list_stack);
3827 	    if (pt->pt_funcstack != NULL)
3828 	    {
3829 		typval_T    *stack = pt->pt_funcstack->fs_ga.ga_data;
3830 
3831 		for (i = 0; i < pt->pt_funcstack->fs_ga.ga_len; ++i)
3832 		    abort = abort || set_ref_in_item(stack + i, copyID,
3833 							 ht_stack, list_stack);
3834 	    }
3835 
3836 	}
3837     }
3838 #ifdef FEAT_JOB_CHANNEL
3839     else if (tv->v_type == VAR_JOB)
3840     {
3841 	job_T	    *job = tv->vval.v_job;
3842 	typval_T    dtv;
3843 
3844 	if (job != NULL && job->jv_copyID != copyID)
3845 	{
3846 	    job->jv_copyID = copyID;
3847 	    if (job->jv_channel != NULL)
3848 	    {
3849 		dtv.v_type = VAR_CHANNEL;
3850 		dtv.vval.v_channel = job->jv_channel;
3851 		set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
3852 	    }
3853 	    if (job->jv_exit_cb.cb_partial != NULL)
3854 	    {
3855 		dtv.v_type = VAR_PARTIAL;
3856 		dtv.vval.v_partial = job->jv_exit_cb.cb_partial;
3857 		set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
3858 	    }
3859 	}
3860     }
3861     else if (tv->v_type == VAR_CHANNEL)
3862     {
3863 	channel_T   *ch =tv->vval.v_channel;
3864 	ch_part_T   part;
3865 	typval_T    dtv;
3866 	jsonq_T	    *jq;
3867 	cbq_T	    *cq;
3868 
3869 	if (ch != NULL && ch->ch_copyID != copyID)
3870 	{
3871 	    ch->ch_copyID = copyID;
3872 	    for (part = PART_SOCK; part < PART_COUNT; ++part)
3873 	    {
3874 		for (jq = ch->ch_part[part].ch_json_head.jq_next; jq != NULL;
3875 							     jq = jq->jq_next)
3876 		    set_ref_in_item(jq->jq_value, copyID, ht_stack, list_stack);
3877 		for (cq = ch->ch_part[part].ch_cb_head.cq_next; cq != NULL;
3878 							     cq = cq->cq_next)
3879 		    if (cq->cq_callback.cb_partial != NULL)
3880 		    {
3881 			dtv.v_type = VAR_PARTIAL;
3882 			dtv.vval.v_partial = cq->cq_callback.cb_partial;
3883 			set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
3884 		    }
3885 		if (ch->ch_part[part].ch_callback.cb_partial != NULL)
3886 		{
3887 		    dtv.v_type = VAR_PARTIAL;
3888 		    dtv.vval.v_partial =
3889 				      ch->ch_part[part].ch_callback.cb_partial;
3890 		    set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
3891 		}
3892 	    }
3893 	    if (ch->ch_callback.cb_partial != NULL)
3894 	    {
3895 		dtv.v_type = VAR_PARTIAL;
3896 		dtv.vval.v_partial = ch->ch_callback.cb_partial;
3897 		set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
3898 	    }
3899 	    if (ch->ch_close_cb.cb_partial != NULL)
3900 	    {
3901 		dtv.v_type = VAR_PARTIAL;
3902 		dtv.vval.v_partial = ch->ch_close_cb.cb_partial;
3903 		set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
3904 	    }
3905 	}
3906     }
3907 #endif
3908     return abort;
3909 }
3910 
3911 /*
3912  * Return a string with the string representation of a variable.
3913  * If the memory is allocated "tofree" is set to it, otherwise NULL.
3914  * "numbuf" is used for a number.
3915  * When "copyID" is not NULL replace recursive lists and dicts with "...".
3916  * When both "echo_style" and "composite_val" are FALSE, put quotes around
3917  * stings as "string()", otherwise does not put quotes around strings, as
3918  * ":echo" displays values.
3919  * When "restore_copyID" is FALSE, repeated items in dictionaries and lists
3920  * are replaced with "...".
3921  * May return NULL.
3922  */
3923     char_u *
3924 echo_string_core(
3925     typval_T	*tv,
3926     char_u	**tofree,
3927     char_u	*numbuf,
3928     int		copyID,
3929     int		echo_style,
3930     int		restore_copyID,
3931     int		composite_val)
3932 {
3933     static int	recurse = 0;
3934     char_u	*r = NULL;
3935 
3936     if (recurse >= DICT_MAXNEST)
3937     {
3938 	if (!did_echo_string_emsg)
3939 	{
3940 	    // Only give this message once for a recursive call to avoid
3941 	    // flooding the user with errors.  And stop iterating over lists
3942 	    // and dicts.
3943 	    did_echo_string_emsg = TRUE;
3944 	    emsg(_("E724: variable nested too deep for displaying"));
3945 	}
3946 	*tofree = NULL;
3947 	return (char_u *)"{E724}";
3948     }
3949     ++recurse;
3950 
3951     switch (tv->v_type)
3952     {
3953 	case VAR_STRING:
3954 	    if (echo_style && !composite_val)
3955 	    {
3956 		*tofree = NULL;
3957 		r = tv->vval.v_string;
3958 		if (r == NULL)
3959 		    r = (char_u *)"";
3960 	    }
3961 	    else
3962 	    {
3963 		*tofree = string_quote(tv->vval.v_string, FALSE);
3964 		r = *tofree;
3965 	    }
3966 	    break;
3967 
3968 	case VAR_FUNC:
3969 	    if (echo_style)
3970 	    {
3971 		*tofree = NULL;
3972 		r = tv->vval.v_string;
3973 	    }
3974 	    else
3975 	    {
3976 		*tofree = string_quote(tv->vval.v_string, TRUE);
3977 		r = *tofree;
3978 	    }
3979 	    break;
3980 
3981 	case VAR_PARTIAL:
3982 	    {
3983 		partial_T   *pt = tv->vval.v_partial;
3984 		char_u	    *fname = string_quote(pt == NULL ? NULL
3985 						    : partial_name(pt), FALSE);
3986 		garray_T    ga;
3987 		int	    i;
3988 		char_u	    *tf;
3989 
3990 		ga_init2(&ga, 1, 100);
3991 		ga_concat(&ga, (char_u *)"function(");
3992 		if (fname != NULL)
3993 		{
3994 		    ga_concat(&ga, fname);
3995 		    vim_free(fname);
3996 		}
3997 		if (pt != NULL && pt->pt_argc > 0)
3998 		{
3999 		    ga_concat(&ga, (char_u *)", [");
4000 		    for (i = 0; i < pt->pt_argc; ++i)
4001 		    {
4002 			if (i > 0)
4003 			    ga_concat(&ga, (char_u *)", ");
4004 			ga_concat(&ga,
4005 			     tv2string(&pt->pt_argv[i], &tf, numbuf, copyID));
4006 			vim_free(tf);
4007 		    }
4008 		    ga_concat(&ga, (char_u *)"]");
4009 		}
4010 		if (pt != NULL && pt->pt_dict != NULL)
4011 		{
4012 		    typval_T dtv;
4013 
4014 		    ga_concat(&ga, (char_u *)", ");
4015 		    dtv.v_type = VAR_DICT;
4016 		    dtv.vval.v_dict = pt->pt_dict;
4017 		    ga_concat(&ga, tv2string(&dtv, &tf, numbuf, copyID));
4018 		    vim_free(tf);
4019 		}
4020 		ga_concat(&ga, (char_u *)")");
4021 
4022 		*tofree = ga.ga_data;
4023 		r = *tofree;
4024 		break;
4025 	    }
4026 
4027 	case VAR_BLOB:
4028 	    r = blob2string(tv->vval.v_blob, tofree, numbuf);
4029 	    break;
4030 
4031 	case VAR_LIST:
4032 	    if (tv->vval.v_list == NULL)
4033 	    {
4034 		// NULL list is equivalent to empty list.
4035 		*tofree = NULL;
4036 		r = (char_u *)"[]";
4037 	    }
4038 	    else if (copyID != 0 && tv->vval.v_list->lv_copyID == copyID
4039 		    && tv->vval.v_list->lv_len > 0)
4040 	    {
4041 		*tofree = NULL;
4042 		r = (char_u *)"[...]";
4043 	    }
4044 	    else
4045 	    {
4046 		int old_copyID = tv->vval.v_list->lv_copyID;
4047 
4048 		tv->vval.v_list->lv_copyID = copyID;
4049 		*tofree = list2string(tv, copyID, restore_copyID);
4050 		if (restore_copyID)
4051 		    tv->vval.v_list->lv_copyID = old_copyID;
4052 		r = *tofree;
4053 	    }
4054 	    break;
4055 
4056 	case VAR_DICT:
4057 	    if (tv->vval.v_dict == NULL)
4058 	    {
4059 		// NULL dict is equivalent to empty dict.
4060 		*tofree = NULL;
4061 		r = (char_u *)"{}";
4062 	    }
4063 	    else if (copyID != 0 && tv->vval.v_dict->dv_copyID == copyID
4064 		    && tv->vval.v_dict->dv_hashtab.ht_used != 0)
4065 	    {
4066 		*tofree = NULL;
4067 		r = (char_u *)"{...}";
4068 	    }
4069 	    else
4070 	    {
4071 		int old_copyID = tv->vval.v_dict->dv_copyID;
4072 
4073 		tv->vval.v_dict->dv_copyID = copyID;
4074 		*tofree = dict2string(tv, copyID, restore_copyID);
4075 		if (restore_copyID)
4076 		    tv->vval.v_dict->dv_copyID = old_copyID;
4077 		r = *tofree;
4078 	    }
4079 	    break;
4080 
4081 	case VAR_NUMBER:
4082 	case VAR_UNKNOWN:
4083 	case VAR_ANY:
4084 	case VAR_VOID:
4085 	    *tofree = NULL;
4086 	    r = tv_get_string_buf(tv, numbuf);
4087 	    break;
4088 
4089 	case VAR_JOB:
4090 	case VAR_CHANNEL:
4091 	    *tofree = NULL;
4092 	    r = tv_get_string_buf(tv, numbuf);
4093 	    if (composite_val)
4094 	    {
4095 		*tofree = string_quote(r, FALSE);
4096 		r = *tofree;
4097 	    }
4098 	    break;
4099 
4100 	case VAR_FLOAT:
4101 #ifdef FEAT_FLOAT
4102 	    *tofree = NULL;
4103 	    vim_snprintf((char *)numbuf, NUMBUFLEN, "%g", tv->vval.v_float);
4104 	    r = numbuf;
4105 	    break;
4106 #endif
4107 
4108 	case VAR_BOOL:
4109 	case VAR_SPECIAL:
4110 	    *tofree = NULL;
4111 	    r = (char_u *)get_var_special_name(tv->vval.v_number);
4112 	    break;
4113     }
4114 
4115     if (--recurse == 0)
4116 	did_echo_string_emsg = FALSE;
4117     return r;
4118 }
4119 
4120 /*
4121  * Return a string with the string representation of a variable.
4122  * If the memory is allocated "tofree" is set to it, otherwise NULL.
4123  * "numbuf" is used for a number.
4124  * Does not put quotes around strings, as ":echo" displays values.
4125  * When "copyID" is not NULL replace recursive lists and dicts with "...".
4126  * May return NULL.
4127  */
4128     char_u *
4129 echo_string(
4130     typval_T	*tv,
4131     char_u	**tofree,
4132     char_u	*numbuf,
4133     int		copyID)
4134 {
4135     return echo_string_core(tv, tofree, numbuf, copyID, TRUE, FALSE, FALSE);
4136 }
4137 
4138 /*
4139  * Return string "str" in ' quotes, doubling ' characters.
4140  * If "str" is NULL an empty string is assumed.
4141  * If "function" is TRUE make it function('string').
4142  */
4143     char_u *
4144 string_quote(char_u *str, int function)
4145 {
4146     unsigned	len;
4147     char_u	*p, *r, *s;
4148 
4149     len = (function ? 13 : 3);
4150     if (str != NULL)
4151     {
4152 	len += (unsigned)STRLEN(str);
4153 	for (p = str; *p != NUL; MB_PTR_ADV(p))
4154 	    if (*p == '\'')
4155 		++len;
4156     }
4157     s = r = alloc(len);
4158     if (r != NULL)
4159     {
4160 	if (function)
4161 	{
4162 	    STRCPY(r, "function('");
4163 	    r += 10;
4164 	}
4165 	else
4166 	    *r++ = '\'';
4167 	if (str != NULL)
4168 	    for (p = str; *p != NUL; )
4169 	    {
4170 		if (*p == '\'')
4171 		    *r++ = '\'';
4172 		MB_COPY_CHAR(p, r);
4173 	    }
4174 	*r++ = '\'';
4175 	if (function)
4176 	    *r++ = ')';
4177 	*r++ = NUL;
4178     }
4179     return s;
4180 }
4181 
4182 #if defined(FEAT_FLOAT) || defined(PROTO)
4183 /*
4184  * Convert the string "text" to a floating point number.
4185  * This uses strtod().  setlocale(LC_NUMERIC, "C") has been used to make sure
4186  * this always uses a decimal point.
4187  * Returns the length of the text that was consumed.
4188  */
4189     int
4190 string2float(
4191     char_u	*text,
4192     float_T	*value)	    // result stored here
4193 {
4194     char	*s = (char *)text;
4195     float_T	f;
4196 
4197     // MS-Windows does not deal with "inf" and "nan" properly.
4198     if (STRNICMP(text, "inf", 3) == 0)
4199     {
4200 	*value = INFINITY;
4201 	return 3;
4202     }
4203     if (STRNICMP(text, "-inf", 3) == 0)
4204     {
4205 	*value = -INFINITY;
4206 	return 4;
4207     }
4208     if (STRNICMP(text, "nan", 3) == 0)
4209     {
4210 	*value = NAN;
4211 	return 3;
4212     }
4213     f = strtod(s, &s);
4214     *value = f;
4215     return (int)((char_u *)s - text);
4216 }
4217 #endif
4218 
4219 /*
4220  * Translate a String variable into a position.
4221  * Returns NULL when there is an error.
4222  */
4223     pos_T *
4224 var2fpos(
4225     typval_T	*varp,
4226     int		dollar_lnum,	// TRUE when $ is last line
4227     int		*fnum)		// set to fnum for '0, 'A, etc.
4228 {
4229     char_u		*name;
4230     static pos_T	pos;
4231     pos_T		*pp;
4232 
4233     // Argument can be [lnum, col, coladd].
4234     if (varp->v_type == VAR_LIST)
4235     {
4236 	list_T		*l;
4237 	int		len;
4238 	int		error = FALSE;
4239 	listitem_T	*li;
4240 
4241 	l = varp->vval.v_list;
4242 	if (l == NULL)
4243 	    return NULL;
4244 
4245 	// Get the line number
4246 	pos.lnum = list_find_nr(l, 0L, &error);
4247 	if (error || pos.lnum <= 0 || pos.lnum > curbuf->b_ml.ml_line_count)
4248 	    return NULL;	// invalid line number
4249 
4250 	// Get the column number
4251 	pos.col = list_find_nr(l, 1L, &error);
4252 	if (error)
4253 	    return NULL;
4254 	len = (long)STRLEN(ml_get(pos.lnum));
4255 
4256 	// We accept "$" for the column number: last column.
4257 	li = list_find(l, 1L);
4258 	if (li != NULL && li->li_tv.v_type == VAR_STRING
4259 		&& li->li_tv.vval.v_string != NULL
4260 		&& STRCMP(li->li_tv.vval.v_string, "$") == 0)
4261 	    pos.col = len + 1;
4262 
4263 	// Accept a position up to the NUL after the line.
4264 	if (pos.col == 0 || (int)pos.col > len + 1)
4265 	    return NULL;	// invalid column number
4266 	--pos.col;
4267 
4268 	// Get the virtual offset.  Defaults to zero.
4269 	pos.coladd = list_find_nr(l, 2L, &error);
4270 	if (error)
4271 	    pos.coladd = 0;
4272 
4273 	return &pos;
4274     }
4275 
4276     name = tv_get_string_chk(varp);
4277     if (name == NULL)
4278 	return NULL;
4279     if (name[0] == '.')				// cursor
4280 	return &curwin->w_cursor;
4281     if (name[0] == 'v' && name[1] == NUL)	// Visual start
4282     {
4283 	if (VIsual_active)
4284 	    return &VIsual;
4285 	return &curwin->w_cursor;
4286     }
4287     if (name[0] == '\'')			// mark
4288     {
4289 	pp = getmark_buf_fnum(curbuf, name[1], FALSE, fnum);
4290 	if (pp == NULL || pp == (pos_T *)-1 || pp->lnum <= 0)
4291 	    return NULL;
4292 	return pp;
4293     }
4294 
4295     pos.coladd = 0;
4296 
4297     if (name[0] == 'w' && dollar_lnum)
4298     {
4299 	pos.col = 0;
4300 	if (name[1] == '0')		// "w0": first visible line
4301 	{
4302 	    update_topline();
4303 	    // In silent Ex mode topline is zero, but that's not a valid line
4304 	    // number; use one instead.
4305 	    pos.lnum = curwin->w_topline > 0 ? curwin->w_topline : 1;
4306 	    return &pos;
4307 	}
4308 	else if (name[1] == '$')	// "w$": last visible line
4309 	{
4310 	    validate_botline();
4311 	    // In silent Ex mode botline is zero, return zero then.
4312 	    pos.lnum = curwin->w_botline > 0 ? curwin->w_botline - 1 : 0;
4313 	    return &pos;
4314 	}
4315     }
4316     else if (name[0] == '$')		// last column or line
4317     {
4318 	if (dollar_lnum)
4319 	{
4320 	    pos.lnum = curbuf->b_ml.ml_line_count;
4321 	    pos.col = 0;
4322 	}
4323 	else
4324 	{
4325 	    pos.lnum = curwin->w_cursor.lnum;
4326 	    pos.col = (colnr_T)STRLEN(ml_get_curline());
4327 	}
4328 	return &pos;
4329     }
4330     return NULL;
4331 }
4332 
4333 /*
4334  * Convert list in "arg" into a position and optional file number.
4335  * When "fnump" is NULL there is no file number, only 3 items.
4336  * Note that the column is passed on as-is, the caller may want to decrement
4337  * it to use 1 for the first column.
4338  * Return FAIL when conversion is not possible, doesn't check the position for
4339  * validity.
4340  */
4341     int
4342 list2fpos(
4343     typval_T	*arg,
4344     pos_T	*posp,
4345     int		*fnump,
4346     colnr_T	*curswantp)
4347 {
4348     list_T	*l = arg->vval.v_list;
4349     long	i = 0;
4350     long	n;
4351 
4352     // List must be: [fnum, lnum, col, coladd, curswant], where "fnum" is only
4353     // there when "fnump" isn't NULL; "coladd" and "curswant" are optional.
4354     if (arg->v_type != VAR_LIST
4355 	    || l == NULL
4356 	    || l->lv_len < (fnump == NULL ? 2 : 3)
4357 	    || l->lv_len > (fnump == NULL ? 4 : 5))
4358 	return FAIL;
4359 
4360     if (fnump != NULL)
4361     {
4362 	n = list_find_nr(l, i++, NULL);	// fnum
4363 	if (n < 0)
4364 	    return FAIL;
4365 	if (n == 0)
4366 	    n = curbuf->b_fnum;		// current buffer
4367 	*fnump = n;
4368     }
4369 
4370     n = list_find_nr(l, i++, NULL);	// lnum
4371     if (n < 0)
4372 	return FAIL;
4373     posp->lnum = n;
4374 
4375     n = list_find_nr(l, i++, NULL);	// col
4376     if (n < 0)
4377 	return FAIL;
4378     posp->col = n;
4379 
4380     n = list_find_nr(l, i, NULL);	// off
4381     if (n < 0)
4382 	posp->coladd = 0;
4383     else
4384 	posp->coladd = n;
4385 
4386     if (curswantp != NULL)
4387 	*curswantp = list_find_nr(l, i + 1, NULL);  // curswant
4388 
4389     return OK;
4390 }
4391 
4392 /*
4393  * Get the length of an environment variable name.
4394  * Advance "arg" to the first character after the name.
4395  * Return 0 for error.
4396  */
4397     int
4398 get_env_len(char_u **arg)
4399 {
4400     char_u	*p;
4401     int		len;
4402 
4403     for (p = *arg; vim_isIDc(*p); ++p)
4404 	;
4405     if (p == *arg)	    // no name found
4406 	return 0;
4407 
4408     len = (int)(p - *arg);
4409     *arg = p;
4410     return len;
4411 }
4412 
4413 /*
4414  * Get the length of the name of a function or internal variable.
4415  * "arg" is advanced to the first non-white character after the name.
4416  * Return 0 if something is wrong.
4417  */
4418     int
4419 get_id_len(char_u **arg)
4420 {
4421     char_u	*p;
4422     int		len;
4423 
4424     // Find the end of the name.
4425     for (p = *arg; eval_isnamec(*p); ++p)
4426     {
4427 	if (*p == ':')
4428 	{
4429 	    // "s:" is start of "s:var", but "n:" is not and can be used in
4430 	    // slice "[n:]".  Also "xx:" is not a namespace.
4431 	    len = (int)(p - *arg);
4432 	    if ((len == 1 && vim_strchr(NAMESPACE_CHAR, **arg) == NULL)
4433 		    || len > 1)
4434 		break;
4435 	}
4436     }
4437     if (p == *arg)	    // no name found
4438 	return 0;
4439 
4440     len = (int)(p - *arg);
4441     *arg = skipwhite(p);
4442 
4443     return len;
4444 }
4445 
4446 /*
4447  * Get the length of the name of a variable or function.
4448  * Only the name is recognized, does not handle ".key" or "[idx]".
4449  * "arg" is advanced to the first non-white character after the name.
4450  * Return -1 if curly braces expansion failed.
4451  * Return 0 if something else is wrong.
4452  * If the name contains 'magic' {}'s, expand them and return the
4453  * expanded name in an allocated string via 'alias' - caller must free.
4454  */
4455     int
4456 get_name_len(
4457     char_u	**arg,
4458     char_u	**alias,
4459     int		evaluate,
4460     int		verbose)
4461 {
4462     int		len;
4463     char_u	*p;
4464     char_u	*expr_start;
4465     char_u	*expr_end;
4466 
4467     *alias = NULL;  // default to no alias
4468 
4469     if ((*arg)[0] == K_SPECIAL && (*arg)[1] == KS_EXTRA
4470 						  && (*arg)[2] == (int)KE_SNR)
4471     {
4472 	// hard coded <SNR>, already translated
4473 	*arg += 3;
4474 	return get_id_len(arg) + 3;
4475     }
4476     len = eval_fname_script(*arg);
4477     if (len > 0)
4478     {
4479 	// literal "<SID>", "s:" or "<SNR>"
4480 	*arg += len;
4481     }
4482 
4483     /*
4484      * Find the end of the name; check for {} construction.
4485      */
4486     p = find_name_end(*arg, &expr_start, &expr_end,
4487 					       len > 0 ? 0 : FNE_CHECK_START);
4488     if (expr_start != NULL)
4489     {
4490 	char_u	*temp_string;
4491 
4492 	if (!evaluate)
4493 	{
4494 	    len += (int)(p - *arg);
4495 	    *arg = skipwhite(p);
4496 	    return len;
4497 	}
4498 
4499 	/*
4500 	 * Include any <SID> etc in the expanded string:
4501 	 * Thus the -len here.
4502 	 */
4503 	temp_string = make_expanded_name(*arg - len, expr_start, expr_end, p);
4504 	if (temp_string == NULL)
4505 	    return -1;
4506 	*alias = temp_string;
4507 	*arg = skipwhite(p);
4508 	return (int)STRLEN(temp_string);
4509     }
4510 
4511     len += get_id_len(arg);
4512     // Only give an error when there is something, otherwise it will be
4513     // reported at a higher level.
4514     if (len == 0 && verbose && **arg != NUL)
4515 	semsg(_(e_invexpr2), *arg);
4516 
4517     return len;
4518 }
4519 
4520 /*
4521  * Find the end of a variable or function name, taking care of magic braces.
4522  * If "expr_start" is not NULL then "expr_start" and "expr_end" are set to the
4523  * start and end of the first magic braces item.
4524  * "flags" can have FNE_INCL_BR and FNE_CHECK_START.
4525  * Return a pointer to just after the name.  Equal to "arg" if there is no
4526  * valid name.
4527  */
4528     char_u *
4529 find_name_end(
4530     char_u	*arg,
4531     char_u	**expr_start,
4532     char_u	**expr_end,
4533     int		flags)
4534 {
4535     int		mb_nest = 0;
4536     int		br_nest = 0;
4537     char_u	*p;
4538     int		len;
4539     int		vim9script = current_sctx.sc_version == SCRIPT_VERSION_VIM9;
4540 
4541     if (expr_start != NULL)
4542     {
4543 	*expr_start = NULL;
4544 	*expr_end = NULL;
4545     }
4546 
4547     // Quick check for valid starting character.
4548     if ((flags & FNE_CHECK_START) && !eval_isnamec1(*arg)
4549 						&& (*arg != '{' || vim9script))
4550 	return arg;
4551 
4552     for (p = arg; *p != NUL
4553 		    && (eval_isnamec(*p)
4554 			|| (*p == '{' && !vim9script)
4555 			|| ((flags & FNE_INCL_BR) && (*p == '[' || *p == '.'))
4556 			|| mb_nest != 0
4557 			|| br_nest != 0); MB_PTR_ADV(p))
4558     {
4559 	if (*p == '\'')
4560 	{
4561 	    // skip over 'string' to avoid counting [ and ] inside it.
4562 	    for (p = p + 1; *p != NUL && *p != '\''; MB_PTR_ADV(p))
4563 		;
4564 	    if (*p == NUL)
4565 		break;
4566 	}
4567 	else if (*p == '"')
4568 	{
4569 	    // skip over "str\"ing" to avoid counting [ and ] inside it.
4570 	    for (p = p + 1; *p != NUL && *p != '"'; MB_PTR_ADV(p))
4571 		if (*p == '\\' && p[1] != NUL)
4572 		    ++p;
4573 	    if (*p == NUL)
4574 		break;
4575 	}
4576 	else if (br_nest == 0 && mb_nest == 0 && *p == ':')
4577 	{
4578 	    // "s:" is start of "s:var", but "n:" is not and can be used in
4579 	    // slice "[n:]".  Also "xx:" is not a namespace. But {ns}: is.
4580 	    len = (int)(p - arg);
4581 	    if ((len == 1 && vim_strchr(NAMESPACE_CHAR, *arg) == NULL)
4582 		    || (len > 1 && p[-1] != '}'))
4583 		break;
4584 	}
4585 
4586 	if (mb_nest == 0)
4587 	{
4588 	    if (*p == '[')
4589 		++br_nest;
4590 	    else if (*p == ']')
4591 		--br_nest;
4592 	}
4593 
4594 	if (br_nest == 0 && !vim9script)
4595 	{
4596 	    if (*p == '{')
4597 	    {
4598 		mb_nest++;
4599 		if (expr_start != NULL && *expr_start == NULL)
4600 		    *expr_start = p;
4601 	    }
4602 	    else if (*p == '}')
4603 	    {
4604 		mb_nest--;
4605 		if (expr_start != NULL && mb_nest == 0 && *expr_end == NULL)
4606 		    *expr_end = p;
4607 	    }
4608 	}
4609     }
4610 
4611     return p;
4612 }
4613 
4614 /*
4615  * Expands out the 'magic' {}'s in a variable/function name.
4616  * Note that this can call itself recursively, to deal with
4617  * constructs like foo{bar}{baz}{bam}
4618  * The four pointer arguments point to "foo{expre}ss{ion}bar"
4619  *			"in_start"      ^
4620  *			"expr_start"	   ^
4621  *			"expr_end"		 ^
4622  *			"in_end"			    ^
4623  *
4624  * Returns a new allocated string, which the caller must free.
4625  * Returns NULL for failure.
4626  */
4627     static char_u *
4628 make_expanded_name(
4629     char_u	*in_start,
4630     char_u	*expr_start,
4631     char_u	*expr_end,
4632     char_u	*in_end)
4633 {
4634     char_u	c1;
4635     char_u	*retval = NULL;
4636     char_u	*temp_result;
4637     char_u	*nextcmd = NULL;
4638 
4639     if (expr_end == NULL || in_end == NULL)
4640 	return NULL;
4641     *expr_start	= NUL;
4642     *expr_end = NUL;
4643     c1 = *in_end;
4644     *in_end = NUL;
4645 
4646     temp_result = eval_to_string(expr_start + 1, &nextcmd, FALSE);
4647     if (temp_result != NULL && nextcmd == NULL)
4648     {
4649 	retval = alloc(STRLEN(temp_result) + (expr_start - in_start)
4650 						   + (in_end - expr_end) + 1);
4651 	if (retval != NULL)
4652 	{
4653 	    STRCPY(retval, in_start);
4654 	    STRCAT(retval, temp_result);
4655 	    STRCAT(retval, expr_end + 1);
4656 	}
4657     }
4658     vim_free(temp_result);
4659 
4660     *in_end = c1;		// put char back for error messages
4661     *expr_start = '{';
4662     *expr_end = '}';
4663 
4664     if (retval != NULL)
4665     {
4666 	temp_result = find_name_end(retval, &expr_start, &expr_end, 0);
4667 	if (expr_start != NULL)
4668 	{
4669 	    // Further expansion!
4670 	    temp_result = make_expanded_name(retval, expr_start,
4671 						       expr_end, temp_result);
4672 	    vim_free(retval);
4673 	    retval = temp_result;
4674 	}
4675     }
4676 
4677     return retval;
4678 }
4679 
4680 /*
4681  * Return TRUE if character "c" can be used in a variable or function name.
4682  * Does not include '{' or '}' for magic braces.
4683  */
4684     int
4685 eval_isnamec(int c)
4686 {
4687     return (ASCII_ISALNUM(c) || c == '_' || c == ':' || c == AUTOLOAD_CHAR);
4688 }
4689 
4690 /*
4691  * Return TRUE if character "c" can be used as the first character in a
4692  * variable or function name (excluding '{' and '}').
4693  */
4694     int
4695 eval_isnamec1(int c)
4696 {
4697     return (ASCII_ISALPHA(c) || c == '_');
4698 }
4699 
4700 /*
4701  * Handle:
4702  * - expr[expr], expr[expr:expr] subscript
4703  * - ".name" lookup
4704  * - function call with Funcref variable: func(expr)
4705  * - method call: var->method()
4706  *
4707  * Can all be combined in any order: dict.func(expr)[idx]['func'](expr)->len()
4708  */
4709     int
4710 handle_subscript(
4711     char_u	**arg,
4712     typval_T	*rettv,
4713     int		flags,		// do more than finding the end
4714     int		verbose,	// give error messages
4715     char_u	*start_leader,	// start of '!' and '-' prefixes
4716     char_u	**end_leaderp)  // end of '!' and '-' prefixes
4717 {
4718     int		evaluate = flags & EVAL_EVALUATE;
4719     int		ret = OK;
4720     dict_T	*selfdict = NULL;
4721 
4722     // "." is ".name" lookup when we found a dict or when evaluating and
4723     // scriptversion is at least 2, where string concatenation is "..".
4724     while (ret == OK
4725 	    && (((**arg == '['
4726 		    || (**arg == '.' && (rettv->v_type == VAR_DICT
4727 			|| (!evaluate
4728 			    && (*arg)[1] != '.'
4729 			    && current_sctx.sc_version >= 2)))
4730 		    || (**arg == '(' && (!evaluate || rettv->v_type == VAR_FUNC
4731 					    || rettv->v_type == VAR_PARTIAL)))
4732 		&& !VIM_ISWHITE(*(*arg - 1)))
4733 	    || (**arg == '-' && (*arg)[1] == '>')))
4734     {
4735 	if (**arg == '(')
4736 	{
4737 	    ret = call_func_rettv(arg, rettv, evaluate, selfdict, NULL);
4738 
4739 	    // Stop the expression evaluation when immediately aborting on
4740 	    // error, or when an interrupt occurred or an exception was thrown
4741 	    // but not caught.
4742 	    if (aborting())
4743 	    {
4744 		if (ret == OK)
4745 		    clear_tv(rettv);
4746 		ret = FAIL;
4747 	    }
4748 	    dict_unref(selfdict);
4749 	    selfdict = NULL;
4750 	}
4751 	else if (**arg == '-')
4752 	{
4753 	    // Expression "-1.0->method()" applies the leader "-" before
4754 	    // applying ->.
4755 	    if (evaluate && *end_leaderp > start_leader)
4756 		ret = eval7_leader(rettv, start_leader, end_leaderp);
4757 	    if (ret == OK)
4758 	    {
4759 		if ((*arg)[2] == '{')
4760 		    // expr->{lambda}()
4761 		    ret = eval_lambda(arg, rettv, evaluate, verbose);
4762 		else
4763 		    // expr->name()
4764 		    ret = eval_method(arg, rettv, evaluate, verbose);
4765 	    }
4766 	}
4767 	else // **arg == '[' || **arg == '.'
4768 	{
4769 	    dict_unref(selfdict);
4770 	    if (rettv->v_type == VAR_DICT)
4771 	    {
4772 		selfdict = rettv->vval.v_dict;
4773 		if (selfdict != NULL)
4774 		    ++selfdict->dv_refcount;
4775 	    }
4776 	    else
4777 		selfdict = NULL;
4778 	    if (eval_index(arg, rettv, flags, verbose) == FAIL)
4779 	    {
4780 		clear_tv(rettv);
4781 		ret = FAIL;
4782 	    }
4783 	}
4784     }
4785 
4786     // Turn "dict.Func" into a partial for "Func" bound to "dict".
4787     // Don't do this when "Func" is already a partial that was bound
4788     // explicitly (pt_auto is FALSE).
4789     if (selfdict != NULL
4790 	    && (rettv->v_type == VAR_FUNC
4791 		|| (rettv->v_type == VAR_PARTIAL
4792 		    && (rettv->vval.v_partial->pt_auto
4793 			|| rettv->vval.v_partial->pt_dict == NULL))))
4794 	selfdict = make_partial(selfdict, rettv);
4795 
4796     dict_unref(selfdict);
4797     return ret;
4798 }
4799 
4800 /*
4801  * Make a copy of an item.
4802  * Lists and Dictionaries are also copied.  A deep copy if "deep" is set.
4803  * For deepcopy() "copyID" is zero for a full copy or the ID for when a
4804  * reference to an already copied list/dict can be used.
4805  * Returns FAIL or OK.
4806  */
4807     int
4808 item_copy(
4809     typval_T	*from,
4810     typval_T	*to,
4811     int		deep,
4812     int		copyID)
4813 {
4814     static int	recurse = 0;
4815     int		ret = OK;
4816 
4817     if (recurse >= DICT_MAXNEST)
4818     {
4819 	emsg(_("E698: variable nested too deep for making a copy"));
4820 	return FAIL;
4821     }
4822     ++recurse;
4823 
4824     switch (from->v_type)
4825     {
4826 	case VAR_NUMBER:
4827 	case VAR_FLOAT:
4828 	case VAR_STRING:
4829 	case VAR_FUNC:
4830 	case VAR_PARTIAL:
4831 	case VAR_BOOL:
4832 	case VAR_SPECIAL:
4833 	case VAR_JOB:
4834 	case VAR_CHANNEL:
4835 	    copy_tv(from, to);
4836 	    break;
4837 	case VAR_LIST:
4838 	    to->v_type = VAR_LIST;
4839 	    to->v_lock = 0;
4840 	    if (from->vval.v_list == NULL)
4841 		to->vval.v_list = NULL;
4842 	    else if (copyID != 0 && from->vval.v_list->lv_copyID == copyID)
4843 	    {
4844 		// use the copy made earlier
4845 		to->vval.v_list = from->vval.v_list->lv_copylist;
4846 		++to->vval.v_list->lv_refcount;
4847 	    }
4848 	    else
4849 		to->vval.v_list = list_copy(from->vval.v_list, deep, copyID);
4850 	    if (to->vval.v_list == NULL)
4851 		ret = FAIL;
4852 	    break;
4853 	case VAR_BLOB:
4854 	    ret = blob_copy(from->vval.v_blob, to);
4855 	    break;
4856 	case VAR_DICT:
4857 	    to->v_type = VAR_DICT;
4858 	    to->v_lock = 0;
4859 	    if (from->vval.v_dict == NULL)
4860 		to->vval.v_dict = NULL;
4861 	    else if (copyID != 0 && from->vval.v_dict->dv_copyID == copyID)
4862 	    {
4863 		// use the copy made earlier
4864 		to->vval.v_dict = from->vval.v_dict->dv_copydict;
4865 		++to->vval.v_dict->dv_refcount;
4866 	    }
4867 	    else
4868 		to->vval.v_dict = dict_copy(from->vval.v_dict, deep, copyID);
4869 	    if (to->vval.v_dict == NULL)
4870 		ret = FAIL;
4871 	    break;
4872 	case VAR_UNKNOWN:
4873 	case VAR_ANY:
4874 	case VAR_VOID:
4875 	    internal_error_no_abort("item_copy(UNKNOWN)");
4876 	    ret = FAIL;
4877     }
4878     --recurse;
4879     return ret;
4880 }
4881 
4882     void
4883 echo_one(typval_T *rettv, int with_space, int *atstart, int *needclr)
4884 {
4885     char_u	*tofree;
4886     char_u	numbuf[NUMBUFLEN];
4887     char_u	*p = echo_string(rettv, &tofree, numbuf, get_copyID());
4888 
4889     if (*atstart)
4890     {
4891 	*atstart = FALSE;
4892 	// Call msg_start() after eval1(), evaluating the expression
4893 	// may cause a message to appear.
4894 	if (with_space)
4895 	{
4896 	    // Mark the saved text as finishing the line, so that what
4897 	    // follows is displayed on a new line when scrolling back
4898 	    // at the more prompt.
4899 	    msg_sb_eol();
4900 	    msg_start();
4901 	}
4902     }
4903     else if (with_space)
4904 	msg_puts_attr(" ", echo_attr);
4905 
4906     if (p != NULL)
4907 	for ( ; *p != NUL && !got_int; ++p)
4908 	{
4909 	    if (*p == '\n' || *p == '\r' || *p == TAB)
4910 	    {
4911 		if (*p != TAB && *needclr)
4912 		{
4913 		    // remove any text still there from the command
4914 		    msg_clr_eos();
4915 		    *needclr = FALSE;
4916 		}
4917 		msg_putchar_attr(*p, echo_attr);
4918 	    }
4919 	    else
4920 	    {
4921 		if (has_mbyte)
4922 		{
4923 		    int i = (*mb_ptr2len)(p);
4924 
4925 		    (void)msg_outtrans_len_attr(p, i, echo_attr);
4926 		    p += i - 1;
4927 		}
4928 		else
4929 		    (void)msg_outtrans_len_attr(p, 1, echo_attr);
4930 	    }
4931 	}
4932     vim_free(tofree);
4933 }
4934 
4935 /*
4936  * ":echo expr1 ..."	print each argument separated with a space, add a
4937  *			newline at the end.
4938  * ":echon expr1 ..."	print each argument plain.
4939  */
4940     void
4941 ex_echo(exarg_T *eap)
4942 {
4943     char_u	*arg = eap->arg;
4944     typval_T	rettv;
4945     char_u	*p;
4946     int		needclr = TRUE;
4947     int		atstart = TRUE;
4948     int		did_emsg_before = did_emsg;
4949     int		called_emsg_before = called_emsg;
4950 
4951     if (eap->skip)
4952 	++emsg_skip;
4953     while ((!ends_excmd2(eap->cmd, arg) || *arg == '"') && !got_int)
4954     {
4955 	// If eval1() causes an error message the text from the command may
4956 	// still need to be cleared. E.g., "echo 22,44".
4957 	need_clr_eos = needclr;
4958 
4959 	p = arg;
4960 	if (eval1(&arg, &rettv, eap->skip ? 0 : EVAL_EVALUATE) == FAIL)
4961 	{
4962 	    /*
4963 	     * Report the invalid expression unless the expression evaluation
4964 	     * has been cancelled due to an aborting error, an interrupt, or an
4965 	     * exception.
4966 	     */
4967 	    if (!aborting() && did_emsg == did_emsg_before
4968 					  && called_emsg == called_emsg_before)
4969 		semsg(_(e_invexpr2), p);
4970 	    need_clr_eos = FALSE;
4971 	    break;
4972 	}
4973 	need_clr_eos = FALSE;
4974 
4975 	if (!eap->skip)
4976 	    echo_one(&rettv, eap->cmdidx == CMD_echo, &atstart, &needclr);
4977 
4978 	clear_tv(&rettv);
4979 	arg = skipwhite(arg);
4980     }
4981     eap->nextcmd = check_nextcmd(arg);
4982 
4983     if (eap->skip)
4984 	--emsg_skip;
4985     else
4986     {
4987 	// remove text that may still be there from the command
4988 	if (needclr)
4989 	    msg_clr_eos();
4990 	if (eap->cmdidx == CMD_echo)
4991 	    msg_end();
4992     }
4993 }
4994 
4995 /*
4996  * ":echohl {name}".
4997  */
4998     void
4999 ex_echohl(exarg_T *eap)
5000 {
5001     echo_attr = syn_name2attr(eap->arg);
5002 }
5003 
5004 /*
5005  * Returns the :echo attribute
5006  */
5007     int
5008 get_echo_attr(void)
5009 {
5010     return echo_attr;
5011 }
5012 
5013 /*
5014  * ":execute expr1 ..."	execute the result of an expression.
5015  * ":echomsg expr1 ..."	Print a message
5016  * ":echoerr expr1 ..."	Print an error
5017  * Each gets spaces around each argument and a newline at the end for
5018  * echo commands
5019  */
5020     void
5021 ex_execute(exarg_T *eap)
5022 {
5023     char_u	*arg = eap->arg;
5024     typval_T	rettv;
5025     int		ret = OK;
5026     char_u	*p;
5027     garray_T	ga;
5028     int		len;
5029 
5030     ga_init2(&ga, 1, 80);
5031 
5032     if (eap->skip)
5033 	++emsg_skip;
5034     while (!ends_excmd2(eap->cmd, arg) || *arg == '"')
5035     {
5036 	ret = eval1_emsg(&arg, &rettv, !eap->skip);
5037 	if (ret == FAIL)
5038 	    break;
5039 
5040 	if (!eap->skip)
5041 	{
5042 	    char_u   buf[NUMBUFLEN];
5043 
5044 	    if (eap->cmdidx == CMD_execute)
5045 	    {
5046 		if (rettv.v_type == VAR_CHANNEL || rettv.v_type == VAR_JOB)
5047 		{
5048 		    emsg(_(e_inval_string));
5049 		    p = NULL;
5050 		}
5051 		else
5052 		    p = tv_get_string_buf(&rettv, buf);
5053 	    }
5054 	    else
5055 		p = tv_stringify(&rettv, buf);
5056 	    if (p == NULL)
5057 	    {
5058 		clear_tv(&rettv);
5059 		ret = FAIL;
5060 		break;
5061 	    }
5062 	    len = (int)STRLEN(p);
5063 	    if (ga_grow(&ga, len + 2) == FAIL)
5064 	    {
5065 		clear_tv(&rettv);
5066 		ret = FAIL;
5067 		break;
5068 	    }
5069 	    if (ga.ga_len)
5070 		((char_u *)(ga.ga_data))[ga.ga_len++] = ' ';
5071 	    STRCPY((char_u *)(ga.ga_data) + ga.ga_len, p);
5072 	    ga.ga_len += len;
5073 	}
5074 
5075 	clear_tv(&rettv);
5076 	arg = skipwhite(arg);
5077     }
5078 
5079     if (ret != FAIL && ga.ga_data != NULL)
5080     {
5081 	if (eap->cmdidx == CMD_echomsg || eap->cmdidx == CMD_echoerr)
5082 	{
5083 	    // Mark the already saved text as finishing the line, so that what
5084 	    // follows is displayed on a new line when scrolling back at the
5085 	    // more prompt.
5086 	    msg_sb_eol();
5087 	}
5088 
5089 	if (eap->cmdidx == CMD_echomsg)
5090 	{
5091 	    msg_attr(ga.ga_data, echo_attr);
5092 	    out_flush();
5093 	}
5094 	else if (eap->cmdidx == CMD_echoerr)
5095 	{
5096 	    int		save_did_emsg = did_emsg;
5097 
5098 	    // We don't want to abort following commands, restore did_emsg.
5099 	    emsg(ga.ga_data);
5100 	    if (!force_abort)
5101 		did_emsg = save_did_emsg;
5102 	}
5103 	else if (eap->cmdidx == CMD_execute)
5104 	    do_cmdline((char_u *)ga.ga_data,
5105 		       eap->getline, eap->cookie, DOCMD_NOWAIT|DOCMD_VERBOSE);
5106     }
5107 
5108     ga_clear(&ga);
5109 
5110     if (eap->skip)
5111 	--emsg_skip;
5112 
5113     eap->nextcmd = check_nextcmd(arg);
5114 }
5115 
5116 /*
5117  * Skip over the name of an option: "&option", "&g:option" or "&l:option".
5118  * "arg" points to the "&" or '+' when called, to "option" when returning.
5119  * Returns NULL when no option name found.  Otherwise pointer to the char
5120  * after the option name.
5121  */
5122     char_u *
5123 find_option_end(char_u **arg, int *opt_flags)
5124 {
5125     char_u	*p = *arg;
5126 
5127     ++p;
5128     if (*p == 'g' && p[1] == ':')
5129     {
5130 	*opt_flags = OPT_GLOBAL;
5131 	p += 2;
5132     }
5133     else if (*p == 'l' && p[1] == ':')
5134     {
5135 	*opt_flags = OPT_LOCAL;
5136 	p += 2;
5137     }
5138     else
5139 	*opt_flags = 0;
5140 
5141     if (!ASCII_ISALPHA(*p))
5142 	return NULL;
5143     *arg = p;
5144 
5145     if (p[0] == 't' && p[1] == '_' && p[2] != NUL && p[3] != NUL)
5146 	p += 4;	    // termcap option
5147     else
5148 	while (ASCII_ISALPHA(*p))
5149 	    ++p;
5150     return p;
5151 }
5152 
5153 /*
5154  * Display script name where an item was last set.
5155  * Should only be invoked when 'verbose' is non-zero.
5156  */
5157     void
5158 last_set_msg(sctx_T script_ctx)
5159 {
5160     char_u *p;
5161 
5162     if (script_ctx.sc_sid != 0)
5163     {
5164 	p = home_replace_save(NULL, get_scriptname(script_ctx.sc_sid));
5165 	if (p != NULL)
5166 	{
5167 	    verbose_enter();
5168 	    msg_puts(_("\n\tLast set from "));
5169 	    msg_puts((char *)p);
5170 	    if (script_ctx.sc_lnum > 0)
5171 	    {
5172 		msg_puts(_(line_msg));
5173 		msg_outnum((long)script_ctx.sc_lnum);
5174 	    }
5175 	    verbose_leave();
5176 	    vim_free(p);
5177 	}
5178     }
5179 }
5180 
5181 #endif // FEAT_EVAL
5182 
5183 /*
5184  * Perform a substitution on "str" with pattern "pat" and substitute "sub".
5185  * When "sub" is NULL "expr" is used, must be a VAR_FUNC or VAR_PARTIAL.
5186  * "flags" can be "g" to do a global substitute.
5187  * Returns an allocated string, NULL for error.
5188  */
5189     char_u *
5190 do_string_sub(
5191     char_u	*str,
5192     char_u	*pat,
5193     char_u	*sub,
5194     typval_T	*expr,
5195     char_u	*flags)
5196 {
5197     int		sublen;
5198     regmatch_T	regmatch;
5199     int		i;
5200     int		do_all;
5201     char_u	*tail;
5202     char_u	*end;
5203     garray_T	ga;
5204     char_u	*ret;
5205     char_u	*save_cpo;
5206     char_u	*zero_width = NULL;
5207 
5208     // Make 'cpoptions' empty, so that the 'l' flag doesn't work here
5209     save_cpo = p_cpo;
5210     p_cpo = empty_option;
5211 
5212     ga_init2(&ga, 1, 200);
5213 
5214     do_all = (flags[0] == 'g');
5215 
5216     regmatch.rm_ic = p_ic;
5217     regmatch.regprog = vim_regcomp(pat, RE_MAGIC + RE_STRING);
5218     if (regmatch.regprog != NULL)
5219     {
5220 	tail = str;
5221 	end = str + STRLEN(str);
5222 	while (vim_regexec_nl(&regmatch, str, (colnr_T)(tail - str)))
5223 	{
5224 	    // Skip empty match except for first match.
5225 	    if (regmatch.startp[0] == regmatch.endp[0])
5226 	    {
5227 		if (zero_width == regmatch.startp[0])
5228 		{
5229 		    // avoid getting stuck on a match with an empty string
5230 		    i = mb_ptr2len(tail);
5231 		    mch_memmove((char_u *)ga.ga_data + ga.ga_len, tail,
5232 								   (size_t)i);
5233 		    ga.ga_len += i;
5234 		    tail += i;
5235 		    continue;
5236 		}
5237 		zero_width = regmatch.startp[0];
5238 	    }
5239 
5240 	    /*
5241 	     * Get some space for a temporary buffer to do the substitution
5242 	     * into.  It will contain:
5243 	     * - The text up to where the match is.
5244 	     * - The substituted text.
5245 	     * - The text after the match.
5246 	     */
5247 	    sublen = vim_regsub(&regmatch, sub, expr, tail, FALSE, TRUE, FALSE);
5248 	    if (ga_grow(&ga, (int)((end - tail) + sublen -
5249 			    (regmatch.endp[0] - regmatch.startp[0]))) == FAIL)
5250 	    {
5251 		ga_clear(&ga);
5252 		break;
5253 	    }
5254 
5255 	    // copy the text up to where the match is
5256 	    i = (int)(regmatch.startp[0] - tail);
5257 	    mch_memmove((char_u *)ga.ga_data + ga.ga_len, tail, (size_t)i);
5258 	    // add the substituted text
5259 	    (void)vim_regsub(&regmatch, sub, expr, (char_u *)ga.ga_data
5260 					  + ga.ga_len + i, TRUE, TRUE, FALSE);
5261 	    ga.ga_len += i + sublen - 1;
5262 	    tail = regmatch.endp[0];
5263 	    if (*tail == NUL)
5264 		break;
5265 	    if (!do_all)
5266 		break;
5267 	}
5268 
5269 	if (ga.ga_data != NULL)
5270 	    STRCPY((char *)ga.ga_data + ga.ga_len, tail);
5271 
5272 	vim_regfree(regmatch.regprog);
5273     }
5274 
5275     ret = vim_strsave(ga.ga_data == NULL ? str : (char_u *)ga.ga_data);
5276     ga_clear(&ga);
5277     if (p_cpo == empty_option)
5278 	p_cpo = save_cpo;
5279     else
5280 	// Darn, evaluating {sub} expression or {expr} changed the value.
5281 	free_string_option(save_cpo);
5282 
5283     return ret;
5284 }
5285