xref: /vim-8.2.3635/src/eval.c (revision 81ea1dfb)
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 #ifdef FEAT_FLOAT
25 static char *e_float_as_string = N_("E806: using Float as a String");
26 #endif
27 
28 #define NAMESPACE_CHAR	(char_u *)"abglstvw"
29 
30 /*
31  * When recursively copying lists and dicts we need to remember which ones we
32  * have done to avoid endless recursiveness.  This unique ID is used for that.
33  * The last bit is used for previous_funccal, ignored when comparing.
34  */
35 static int current_copyID = 0;
36 
37 static int echo_attr = 0;   // attributes used for ":echo"
38 
39 /*
40  * Info used by a ":for" loop.
41  */
42 typedef struct
43 {
44     int		fi_semicolon;	// TRUE if ending in '; var]'
45     int		fi_varcount;	// nr of variables in the list
46     listwatch_T	fi_lw;		// keep an eye on the item used.
47     list_T	*fi_list;	// list being used
48     int		fi_bi;		// index of blob
49     blob_T	*fi_blob;	// blob being used
50 } forinfo_T;
51 
52 static int tv_op(typval_T *tv1, typval_T *tv2, char_u  *op);
53 static int eval2(char_u **arg, typval_T *rettv, int evaluate);
54 static int eval3(char_u **arg, typval_T *rettv, int evaluate);
55 static int eval4(char_u **arg, typval_T *rettv, int evaluate);
56 static int eval5(char_u **arg, typval_T *rettv, int evaluate);
57 static int eval6(char_u **arg, typval_T *rettv, int evaluate, int want_string);
58 static int eval7(char_u **arg, typval_T *rettv, int evaluate, int want_string);
59 static int eval7_leader(typval_T *rettv, char_u *start_leader, char_u **end_leaderp);
60 
61 static int free_unref_items(int copyID);
62 static char_u *make_expanded_name(char_u *in_start, char_u *expr_start, char_u *expr_end, char_u *in_end);
63 static int tv_check_lock(typval_T *tv, char_u *name, int use_gettext);
64 
65 /*
66  * Return "n1" divided by "n2", taking care of dividing by zero.
67  */
68 	varnumber_T
69 num_divide(varnumber_T n1, varnumber_T n2)
70 {
71     varnumber_T	result;
72 
73     if (n2 == 0)	// give an error message?
74     {
75 	if (n1 == 0)
76 	    result = VARNUM_MIN; // similar to NaN
77 	else if (n1 < 0)
78 	    result = -VARNUM_MAX;
79 	else
80 	    result = VARNUM_MAX;
81     }
82     else
83 	result = n1 / n2;
84 
85     return result;
86 }
87 
88 /*
89  * Return "n1" modulus "n2", taking care of dividing by zero.
90  */
91 	varnumber_T
92 num_modulus(varnumber_T n1, varnumber_T n2)
93 {
94     // Give an error when n2 is 0?
95     return (n2 == 0) ? 0 : (n1 % n2);
96 }
97 
98 #if defined(EBCDIC) || defined(PROTO)
99 /*
100  * Compare struct fst by function name.
101  */
102     static int
103 compare_func_name(const void *s1, const void *s2)
104 {
105     struct fst *p1 = (struct fst *)s1;
106     struct fst *p2 = (struct fst *)s2;
107 
108     return STRCMP(p1->f_name, p2->f_name);
109 }
110 
111 /*
112  * Sort the function table by function name.
113  * The sorting of the table above is ASCII dependent.
114  * On machines using EBCDIC we have to sort it.
115  */
116     static void
117 sortFunctions(void)
118 {
119     int		funcCnt = (int)(sizeof(functions) / sizeof(struct fst)) - 1;
120 
121     qsort(functions, (size_t)funcCnt, sizeof(struct fst), compare_func_name);
122 }
123 #endif
124 
125 /*
126  * Initialize the global and v: variables.
127  */
128     void
129 eval_init(void)
130 {
131     evalvars_init();
132     func_init();
133 
134 #ifdef EBCDIC
135     /*
136      * Sort the function table, to enable binary search.
137      */
138     sortFunctions();
139 #endif
140 }
141 
142 #if defined(EXITFREE) || defined(PROTO)
143     void
144 eval_clear(void)
145 {
146     evalvars_clear();
147     free_scriptnames();  // must come after evalvars_clear().
148     free_locales();
149 
150     // autoloaded script names
151     free_autoload_scriptnames();
152 
153     // unreferenced lists and dicts
154     (void)garbage_collect(FALSE);
155 
156     // functions not garbage collected
157     free_all_functions();
158 }
159 #endif
160 
161 /*
162  * Top level evaluation function, returning a boolean.
163  * Sets "error" to TRUE if there was an error.
164  * Return TRUE or FALSE.
165  */
166     int
167 eval_to_bool(
168     char_u	*arg,
169     int		*error,
170     char_u	**nextcmd,
171     int		skip)	    // only parse, don't execute
172 {
173     typval_T	tv;
174     varnumber_T	retval = FALSE;
175 
176     if (skip)
177 	++emsg_skip;
178     if (eval0(arg, &tv, nextcmd, !skip) == FAIL)
179 	*error = TRUE;
180     else
181     {
182 	*error = FALSE;
183 	if (!skip)
184 	{
185 	    retval = (tv_get_number_chk(&tv, error) != 0);
186 	    clear_tv(&tv);
187 	}
188     }
189     if (skip)
190 	--emsg_skip;
191 
192     return (int)retval;
193 }
194 
195 /*
196  * Call eval1() and give an error message if not done at a lower level.
197  */
198     static int
199 eval1_emsg(char_u **arg, typval_T *rettv, int evaluate)
200 {
201     char_u	*start = *arg;
202     int		ret;
203     int		did_emsg_before = did_emsg;
204     int		called_emsg_before = called_emsg;
205 
206     ret = eval1(arg, rettv, evaluate);
207     if (ret == FAIL)
208     {
209 	// Report the invalid expression unless the expression evaluation has
210 	// been cancelled due to an aborting error, an interrupt, or an
211 	// exception, or we already gave a more specific error.
212 	// Also check called_emsg for when using assert_fails().
213 	if (!aborting() && did_emsg == did_emsg_before
214 					  && called_emsg == called_emsg_before)
215 	    semsg(_(e_invexpr2), start);
216     }
217     return ret;
218 }
219 
220 /*
221  * Evaluate an expression, which can be a function, partial or string.
222  * Pass arguments "argv[argc]".
223  * Return the result in "rettv" and OK or FAIL.
224  */
225     int
226 eval_expr_typval(typval_T *expr, typval_T *argv, int argc, typval_T *rettv)
227 {
228     char_u	*s;
229     char_u	buf[NUMBUFLEN];
230     funcexe_T	funcexe;
231 
232     if (expr->v_type == VAR_FUNC)
233     {
234 	s = expr->vval.v_string;
235 	if (s == NULL || *s == NUL)
236 	    return FAIL;
237 	vim_memset(&funcexe, 0, sizeof(funcexe));
238 	funcexe.evaluate = TRUE;
239 	if (call_func(s, -1, rettv, argc, argv, &funcexe) == FAIL)
240 	    return FAIL;
241     }
242     else if (expr->v_type == VAR_PARTIAL)
243     {
244 	partial_T   *partial = expr->vval.v_partial;
245 
246 	if (partial->pt_func != NULL && partial->pt_func->uf_dfunc_idx >= 0)
247 	{
248 	    if (call_def_function(partial->pt_func, argc, argv, rettv) == FAIL)
249 		return FAIL;
250 	}
251 	else
252 	{
253 	    s = partial_name(partial);
254 	    if (s == NULL || *s == NUL)
255 		return FAIL;
256 	    vim_memset(&funcexe, 0, sizeof(funcexe));
257 	    funcexe.evaluate = TRUE;
258 	    funcexe.partial = partial;
259 	    if (call_func(s, -1, rettv, argc, argv, &funcexe) == FAIL)
260 		return FAIL;
261 	}
262     }
263     else
264     {
265 	s = tv_get_string_buf_chk(expr, buf);
266 	if (s == NULL)
267 	    return FAIL;
268 	s = skipwhite(s);
269 	if (eval1_emsg(&s, rettv, TRUE) == FAIL)
270 	    return FAIL;
271 	if (*s != NUL)  // check for trailing chars after expr
272 	{
273 	    clear_tv(rettv);
274 	    semsg(_(e_invexpr2), s);
275 	    return FAIL;
276 	}
277     }
278     return OK;
279 }
280 
281 /*
282  * Like eval_to_bool() but using a typval_T instead of a string.
283  * Works for string, funcref and partial.
284  */
285     int
286 eval_expr_to_bool(typval_T *expr, int *error)
287 {
288     typval_T	rettv;
289     int		res;
290 
291     if (eval_expr_typval(expr, NULL, 0, &rettv) == FAIL)
292     {
293 	*error = TRUE;
294 	return FALSE;
295     }
296     res = (tv_get_number_chk(&rettv, error) != 0);
297     clear_tv(&rettv);
298     return res;
299 }
300 
301 /*
302  * Top level evaluation function, returning a string.  If "skip" is TRUE,
303  * only parsing to "nextcmd" is done, without reporting errors.  Return
304  * pointer to allocated memory, or NULL for failure or when "skip" is TRUE.
305  */
306     char_u *
307 eval_to_string_skip(
308     char_u	*arg,
309     char_u	**nextcmd,
310     int		skip)	    // only parse, don't execute
311 {
312     typval_T	tv;
313     char_u	*retval;
314 
315     if (skip)
316 	++emsg_skip;
317     if (eval0(arg, &tv, nextcmd, !skip) == FAIL || skip)
318 	retval = NULL;
319     else
320     {
321 	retval = vim_strsave(tv_get_string(&tv));
322 	clear_tv(&tv);
323     }
324     if (skip)
325 	--emsg_skip;
326 
327     return retval;
328 }
329 
330 /*
331  * Skip over an expression at "*pp".
332  * Return FAIL for an error, OK otherwise.
333  */
334     int
335 skip_expr(char_u **pp)
336 {
337     typval_T	rettv;
338 
339     *pp = skipwhite(*pp);
340     return eval1(pp, &rettv, FALSE);
341 }
342 
343 /*
344  * Top level evaluation function, returning a string.
345  * When "convert" is TRUE convert a List into a sequence of lines and convert
346  * a Float to a String.
347  * Return pointer to allocated memory, or NULL for failure.
348  */
349     char_u *
350 eval_to_string(
351     char_u	*arg,
352     char_u	**nextcmd,
353     int		convert)
354 {
355     typval_T	tv;
356     char_u	*retval;
357     garray_T	ga;
358 #ifdef FEAT_FLOAT
359     char_u	numbuf[NUMBUFLEN];
360 #endif
361 
362     if (eval0(arg, &tv, nextcmd, TRUE) == FAIL)
363 	retval = NULL;
364     else
365     {
366 	if (convert && tv.v_type == VAR_LIST)
367 	{
368 	    ga_init2(&ga, (int)sizeof(char), 80);
369 	    if (tv.vval.v_list != NULL)
370 	    {
371 		list_join(&ga, tv.vval.v_list, (char_u *)"\n", TRUE, FALSE, 0);
372 		if (tv.vval.v_list->lv_len > 0)
373 		    ga_append(&ga, NL);
374 	    }
375 	    ga_append(&ga, NUL);
376 	    retval = (char_u *)ga.ga_data;
377 	}
378 #ifdef FEAT_FLOAT
379 	else if (convert && tv.v_type == VAR_FLOAT)
380 	{
381 	    vim_snprintf((char *)numbuf, NUMBUFLEN, "%g", tv.vval.v_float);
382 	    retval = vim_strsave(numbuf);
383 	}
384 #endif
385 	else
386 	    retval = vim_strsave(tv_get_string(&tv));
387 	clear_tv(&tv);
388     }
389 
390     return retval;
391 }
392 
393 /*
394  * Call eval_to_string() without using current local variables and using
395  * textlock.  When "use_sandbox" is TRUE use the sandbox.
396  */
397     char_u *
398 eval_to_string_safe(
399     char_u	*arg,
400     char_u	**nextcmd,
401     int		use_sandbox)
402 {
403     char_u	*retval;
404     funccal_entry_T funccal_entry;
405 
406     save_funccal(&funccal_entry);
407     if (use_sandbox)
408 	++sandbox;
409     ++textlock;
410     retval = eval_to_string(arg, nextcmd, FALSE);
411     if (use_sandbox)
412 	--sandbox;
413     --textlock;
414     restore_funccal();
415     return retval;
416 }
417 
418 /*
419  * Top level evaluation function, returning a number.
420  * Evaluates "expr" silently.
421  * Returns -1 for an error.
422  */
423     varnumber_T
424 eval_to_number(char_u *expr)
425 {
426     typval_T	rettv;
427     varnumber_T	retval;
428     char_u	*p = skipwhite(expr);
429 
430     ++emsg_off;
431 
432     if (eval1(&p, &rettv, TRUE) == FAIL)
433 	retval = -1;
434     else
435     {
436 	retval = tv_get_number_chk(&rettv, NULL);
437 	clear_tv(&rettv);
438     }
439     --emsg_off;
440 
441     return retval;
442 }
443 
444 /*
445  * Top level evaluation function.
446  * Returns an allocated typval_T with the result.
447  * Returns NULL when there is an error.
448  */
449     typval_T *
450 eval_expr(char_u *arg, char_u **nextcmd)
451 {
452     typval_T	*tv;
453 
454     tv = ALLOC_ONE(typval_T);
455     if (tv != NULL && eval0(arg, tv, nextcmd, TRUE) == FAIL)
456 	VIM_CLEAR(tv);
457 
458     return tv;
459 }
460 
461 /*
462  * Call some Vim script function and return the result in "*rettv".
463  * Uses argv[0] to argv[argc - 1] for the function arguments.  argv[argc]
464  * should have type VAR_UNKNOWN.
465  * Returns OK or FAIL.
466  */
467     int
468 call_vim_function(
469     char_u      *func,
470     int		argc,
471     typval_T	*argv,
472     typval_T	*rettv)
473 {
474     int		ret;
475     funcexe_T	funcexe;
476 
477     rettv->v_type = VAR_UNKNOWN;		// clear_tv() uses this
478     vim_memset(&funcexe, 0, sizeof(funcexe));
479     funcexe.firstline = curwin->w_cursor.lnum;
480     funcexe.lastline = curwin->w_cursor.lnum;
481     funcexe.evaluate = TRUE;
482     ret = call_func(func, -1, rettv, argc, argv, &funcexe);
483     if (ret == FAIL)
484 	clear_tv(rettv);
485 
486     return ret;
487 }
488 
489 /*
490  * Call Vim script function "func" and return the result as a number.
491  * Returns -1 when calling the function fails.
492  * Uses argv[0] to argv[argc - 1] for the function arguments. argv[argc] should
493  * have type VAR_UNKNOWN.
494  */
495     varnumber_T
496 call_func_retnr(
497     char_u      *func,
498     int		argc,
499     typval_T	*argv)
500 {
501     typval_T	rettv;
502     varnumber_T	retval;
503 
504     if (call_vim_function(func, argc, argv, &rettv) == FAIL)
505 	return -1;
506 
507     retval = tv_get_number_chk(&rettv, NULL);
508     clear_tv(&rettv);
509     return retval;
510 }
511 
512 /*
513  * Call Vim script function "func" and return the result as a string.
514  * Returns NULL when calling the function fails.
515  * Uses argv[0] to argv[argc - 1] for the function arguments. argv[argc] should
516  * have type VAR_UNKNOWN.
517  */
518     void *
519 call_func_retstr(
520     char_u      *func,
521     int		argc,
522     typval_T	*argv)
523 {
524     typval_T	rettv;
525     char_u	*retval;
526 
527     if (call_vim_function(func, argc, argv, &rettv) == FAIL)
528 	return NULL;
529 
530     retval = vim_strsave(tv_get_string(&rettv));
531     clear_tv(&rettv);
532     return retval;
533 }
534 
535 /*
536  * Call Vim script function "func" and return the result as a List.
537  * Uses argv[0] to argv[argc - 1] for the function arguments. argv[argc] should
538  * have type VAR_UNKNOWN.
539  * Returns NULL when there is something wrong.
540  */
541     void *
542 call_func_retlist(
543     char_u      *func,
544     int		argc,
545     typval_T	*argv)
546 {
547     typval_T	rettv;
548 
549     if (call_vim_function(func, argc, argv, &rettv) == FAIL)
550 	return NULL;
551 
552     if (rettv.v_type != VAR_LIST)
553     {
554 	clear_tv(&rettv);
555 	return NULL;
556     }
557 
558     return rettv.vval.v_list;
559 }
560 
561 #ifdef FEAT_FOLDING
562 /*
563  * Evaluate 'foldexpr'.  Returns the foldlevel, and any character preceding
564  * it in "*cp".  Doesn't give error messages.
565  */
566     int
567 eval_foldexpr(char_u *arg, int *cp)
568 {
569     typval_T	tv;
570     varnumber_T	retval;
571     char_u	*s;
572     int		use_sandbox = was_set_insecurely((char_u *)"foldexpr",
573 								   OPT_LOCAL);
574 
575     ++emsg_off;
576     if (use_sandbox)
577 	++sandbox;
578     ++textlock;
579     *cp = NUL;
580     if (eval0(arg, &tv, NULL, TRUE) == FAIL)
581 	retval = 0;
582     else
583     {
584 	// If the result is a number, just return the number.
585 	if (tv.v_type == VAR_NUMBER)
586 	    retval = tv.vval.v_number;
587 	else if (tv.v_type != VAR_STRING || tv.vval.v_string == NULL)
588 	    retval = 0;
589 	else
590 	{
591 	    // If the result is a string, check if there is a non-digit before
592 	    // the number.
593 	    s = tv.vval.v_string;
594 	    if (!VIM_ISDIGIT(*s) && *s != '-')
595 		*cp = *s++;
596 	    retval = atol((char *)s);
597 	}
598 	clear_tv(&tv);
599     }
600     --emsg_off;
601     if (use_sandbox)
602 	--sandbox;
603     --textlock;
604 
605     return (int)retval;
606 }
607 #endif
608 
609 /*
610  * Get an lval: variable, Dict item or List item that can be assigned a value
611  * to: "name", "na{me}", "name[expr]", "name[expr:expr]", "name[expr][expr]",
612  * "name.key", "name.key[expr]" etc.
613  * Indexing only works if "name" is an existing List or Dictionary.
614  * "name" points to the start of the name.
615  * If "rettv" is not NULL it points to the value to be assigned.
616  * "unlet" is TRUE for ":unlet": slightly different behavior when something is
617  * wrong; must end in space or cmd separator.
618  *
619  * flags:
620  *  GLV_QUIET:       do not give error messages
621  *  GLV_READ_ONLY:   will not change the variable
622  *  GLV_NO_AUTOLOAD: do not use script autoloading
623  *
624  * Returns a pointer to just after the name, including indexes.
625  * When an evaluation error occurs "lp->ll_name" is NULL;
626  * Returns NULL for a parsing error.  Still need to free items in "lp"!
627  */
628     char_u *
629 get_lval(
630     char_u	*name,
631     typval_T	*rettv,
632     lval_T	*lp,
633     int		unlet,
634     int		skip,
635     int		flags,	    // GLV_ values
636     int		fne_flags)  // flags for find_name_end()
637 {
638     char_u	*p;
639     char_u	*expr_start, *expr_end;
640     int		cc;
641     dictitem_T	*v;
642     typval_T	var1;
643     typval_T	var2;
644     int		empty1 = FALSE;
645     listitem_T	*ni;
646     char_u	*key = NULL;
647     int		len;
648     hashtab_T	*ht;
649     int		quiet = flags & GLV_QUIET;
650 
651     // Clear everything in "lp".
652     vim_memset(lp, 0, sizeof(lval_T));
653 
654     if (skip)
655     {
656 	// When skipping just find the end of the name.
657 	lp->ll_name = name;
658 	return find_name_end(name, NULL, NULL, FNE_INCL_BR | fne_flags);
659     }
660 
661     // Find the end of the name.
662     p = find_name_end(name, &expr_start, &expr_end, fne_flags);
663     lp->ll_name_end = p;
664     if (expr_start != NULL)
665     {
666 	// Don't expand the name when we already know there is an error.
667 	if (unlet && !VIM_ISWHITE(*p) && !ends_excmd(*p)
668 						    && *p != '[' && *p != '.')
669 	{
670 	    emsg(_(e_trailing));
671 	    return NULL;
672 	}
673 
674 	lp->ll_exp_name = make_expanded_name(name, expr_start, expr_end, p);
675 	if (lp->ll_exp_name == NULL)
676 	{
677 	    // Report an invalid expression in braces, unless the
678 	    // expression evaluation has been cancelled due to an
679 	    // aborting error, an interrupt, or an exception.
680 	    if (!aborting() && !quiet)
681 	    {
682 		emsg_severe = TRUE;
683 		semsg(_(e_invarg2), name);
684 		return NULL;
685 	    }
686 	}
687 	lp->ll_name = lp->ll_exp_name;
688     }
689     else
690     {
691 	lp->ll_name = name;
692 
693 	if (current_sctx.sc_version == SCRIPT_VERSION_VIM9 && *p == ':')
694 	{
695 	    scriptitem_T *si = SCRIPT_ITEM(current_sctx.sc_sid);
696 	    char_u	 *tp = skipwhite(p + 1);
697 
698 	    // parse the type after the name
699 	    lp->ll_type = parse_type(&tp, &si->sn_type_list);
700 	    lp->ll_name_end = tp;
701 	}
702     }
703 
704     // Without [idx] or .key we are done.
705     if ((*p != '[' && *p != '.') || lp->ll_name == NULL)
706 	return p;
707 
708     cc = *p;
709     *p = NUL;
710     // Only pass &ht when we would write to the variable, it prevents autoload
711     // as well.
712     v = find_var(lp->ll_name, (flags & GLV_READ_ONLY) ? NULL : &ht,
713 						      flags & GLV_NO_AUTOLOAD);
714     if (v == NULL && !quiet)
715 	semsg(_(e_undefvar), lp->ll_name);
716     *p = cc;
717     if (v == NULL)
718 	return NULL;
719 
720     /*
721      * Loop until no more [idx] or .key is following.
722      */
723     lp->ll_tv = &v->di_tv;
724     var1.v_type = VAR_UNKNOWN;
725     var2.v_type = VAR_UNKNOWN;
726     while (*p == '[' || (*p == '.' && lp->ll_tv->v_type == VAR_DICT))
727     {
728 	if (!(lp->ll_tv->v_type == VAR_LIST && lp->ll_tv->vval.v_list != NULL)
729 		&& !(lp->ll_tv->v_type == VAR_DICT
730 					   && lp->ll_tv->vval.v_dict != NULL)
731 		&& !(lp->ll_tv->v_type == VAR_BLOB
732 					   && lp->ll_tv->vval.v_blob != NULL))
733 	{
734 	    if (!quiet)
735 		emsg(_("E689: Can only index a List, Dictionary or Blob"));
736 	    return NULL;
737 	}
738 	if (lp->ll_range)
739 	{
740 	    if (!quiet)
741 		emsg(_("E708: [:] must come last"));
742 	    return NULL;
743 	}
744 
745 	len = -1;
746 	if (*p == '.')
747 	{
748 	    key = p + 1;
749 	    for (len = 0; ASCII_ISALNUM(key[len]) || key[len] == '_'; ++len)
750 		;
751 	    if (len == 0)
752 	    {
753 		if (!quiet)
754 		    emsg(_(e_emptykey));
755 		return NULL;
756 	    }
757 	    p = key + len;
758 	}
759 	else
760 	{
761 	    // Get the index [expr] or the first index [expr: ].
762 	    p = skipwhite(p + 1);
763 	    if (*p == ':')
764 		empty1 = TRUE;
765 	    else
766 	    {
767 		empty1 = FALSE;
768 		if (eval1(&p, &var1, TRUE) == FAIL)	// recursive!
769 		    return NULL;
770 		if (tv_get_string_chk(&var1) == NULL)
771 		{
772 		    // not a number or string
773 		    clear_tv(&var1);
774 		    return NULL;
775 		}
776 	    }
777 
778 	    // Optionally get the second index [ :expr].
779 	    if (*p == ':')
780 	    {
781 		if (lp->ll_tv->v_type == VAR_DICT)
782 		{
783 		    if (!quiet)
784 			emsg(_(e_dictrange));
785 		    clear_tv(&var1);
786 		    return NULL;
787 		}
788 		if (rettv != NULL
789 			&& !(rettv->v_type == VAR_LIST
790 						 && rettv->vval.v_list != NULL)
791 			&& !(rettv->v_type == VAR_BLOB
792 						&& rettv->vval.v_blob != NULL))
793 		{
794 		    if (!quiet)
795 			emsg(_("E709: [:] requires a List or Blob value"));
796 		    clear_tv(&var1);
797 		    return NULL;
798 		}
799 		p = skipwhite(p + 1);
800 		if (*p == ']')
801 		    lp->ll_empty2 = TRUE;
802 		else
803 		{
804 		    lp->ll_empty2 = FALSE;
805 		    if (eval1(&p, &var2, TRUE) == FAIL)	// recursive!
806 		    {
807 			clear_tv(&var1);
808 			return NULL;
809 		    }
810 		    if (tv_get_string_chk(&var2) == NULL)
811 		    {
812 			// not a number or string
813 			clear_tv(&var1);
814 			clear_tv(&var2);
815 			return NULL;
816 		    }
817 		}
818 		lp->ll_range = TRUE;
819 	    }
820 	    else
821 		lp->ll_range = FALSE;
822 
823 	    if (*p != ']')
824 	    {
825 		if (!quiet)
826 		    emsg(_(e_missbrac));
827 		clear_tv(&var1);
828 		clear_tv(&var2);
829 		return NULL;
830 	    }
831 
832 	    // Skip to past ']'.
833 	    ++p;
834 	}
835 
836 	if (lp->ll_tv->v_type == VAR_DICT)
837 	{
838 	    if (len == -1)
839 	    {
840 		// "[key]": get key from "var1"
841 		key = tv_get_string_chk(&var1);	// is number or string
842 		if (key == NULL)
843 		{
844 		    clear_tv(&var1);
845 		    return NULL;
846 		}
847 	    }
848 	    lp->ll_list = NULL;
849 	    lp->ll_dict = lp->ll_tv->vval.v_dict;
850 	    lp->ll_di = dict_find(lp->ll_dict, key, len);
851 
852 	    // When assigning to a scope dictionary check that a function and
853 	    // variable name is valid (only variable name unless it is l: or
854 	    // g: dictionary). Disallow overwriting a builtin function.
855 	    if (rettv != NULL && lp->ll_dict->dv_scope != 0)
856 	    {
857 		int prevval;
858 		int wrong;
859 
860 		if (len != -1)
861 		{
862 		    prevval = key[len];
863 		    key[len] = NUL;
864 		}
865 		else
866 		    prevval = 0; // avoid compiler warning
867 		wrong = (lp->ll_dict->dv_scope == VAR_DEF_SCOPE
868 			       && rettv->v_type == VAR_FUNC
869 			       && var_check_func_name(key, lp->ll_di == NULL))
870 			|| !valid_varname(key);
871 		if (len != -1)
872 		    key[len] = prevval;
873 		if (wrong)
874 		    return NULL;
875 	    }
876 
877 	    if (lp->ll_di == NULL)
878 	    {
879 		// Can't add "v:" or "a:" variable.
880 		if (lp->ll_dict == get_vimvar_dict()
881 			 || &lp->ll_dict->dv_hashtab == get_funccal_args_ht())
882 		{
883 		    semsg(_(e_illvar), name);
884 		    clear_tv(&var1);
885 		    return NULL;
886 		}
887 
888 		// Key does not exist in dict: may need to add it.
889 		if (*p == '[' || *p == '.' || unlet)
890 		{
891 		    if (!quiet)
892 			semsg(_(e_dictkey), key);
893 		    clear_tv(&var1);
894 		    return NULL;
895 		}
896 		if (len == -1)
897 		    lp->ll_newkey = vim_strsave(key);
898 		else
899 		    lp->ll_newkey = vim_strnsave(key, len);
900 		clear_tv(&var1);
901 		if (lp->ll_newkey == NULL)
902 		    p = NULL;
903 		break;
904 	    }
905 	    // existing variable, need to check if it can be changed
906 	    else if ((flags & GLV_READ_ONLY) == 0
907 			     && var_check_ro(lp->ll_di->di_flags, name, FALSE))
908 	    {
909 		clear_tv(&var1);
910 		return NULL;
911 	    }
912 
913 	    clear_tv(&var1);
914 	    lp->ll_tv = &lp->ll_di->di_tv;
915 	}
916 	else if (lp->ll_tv->v_type == VAR_BLOB)
917 	{
918 	    long bloblen = blob_len(lp->ll_tv->vval.v_blob);
919 
920 	    /*
921 	     * Get the number and item for the only or first index of the List.
922 	     */
923 	    if (empty1)
924 		lp->ll_n1 = 0;
925 	    else
926 		// is number or string
927 		lp->ll_n1 = (long)tv_get_number(&var1);
928 	    clear_tv(&var1);
929 
930 	    if (lp->ll_n1 < 0
931 		    || lp->ll_n1 > bloblen
932 		    || (lp->ll_range && lp->ll_n1 == bloblen))
933 	    {
934 		if (!quiet)
935 		    semsg(_(e_blobidx), lp->ll_n1);
936 		clear_tv(&var2);
937 		return NULL;
938 	    }
939 	    if (lp->ll_range && !lp->ll_empty2)
940 	    {
941 		lp->ll_n2 = (long)tv_get_number(&var2);
942 		clear_tv(&var2);
943 		if (lp->ll_n2 < 0
944 			|| lp->ll_n2 >= bloblen
945 			|| lp->ll_n2 < lp->ll_n1)
946 		{
947 		    if (!quiet)
948 			semsg(_(e_blobidx), lp->ll_n2);
949 		    return NULL;
950 		}
951 	    }
952 	    lp->ll_blob = lp->ll_tv->vval.v_blob;
953 	    lp->ll_tv = NULL;
954 	    break;
955 	}
956 	else
957 	{
958 	    /*
959 	     * Get the number and item for the only or first index of the List.
960 	     */
961 	    if (empty1)
962 		lp->ll_n1 = 0;
963 	    else
964 		// is number or string
965 		lp->ll_n1 = (long)tv_get_number(&var1);
966 	    clear_tv(&var1);
967 
968 	    lp->ll_dict = NULL;
969 	    lp->ll_list = lp->ll_tv->vval.v_list;
970 	    lp->ll_li = list_find(lp->ll_list, lp->ll_n1);
971 	    if (lp->ll_li == NULL)
972 	    {
973 		if (lp->ll_n1 < 0)
974 		{
975 		    lp->ll_n1 = 0;
976 		    lp->ll_li = list_find(lp->ll_list, lp->ll_n1);
977 		}
978 	    }
979 	    if (lp->ll_li == NULL)
980 	    {
981 		clear_tv(&var2);
982 		if (!quiet)
983 		    semsg(_(e_listidx), lp->ll_n1);
984 		return NULL;
985 	    }
986 
987 	    /*
988 	     * May need to find the item or absolute index for the second
989 	     * index of a range.
990 	     * When no index given: "lp->ll_empty2" is TRUE.
991 	     * Otherwise "lp->ll_n2" is set to the second index.
992 	     */
993 	    if (lp->ll_range && !lp->ll_empty2)
994 	    {
995 		lp->ll_n2 = (long)tv_get_number(&var2);
996 						    // is number or string
997 		clear_tv(&var2);
998 		if (lp->ll_n2 < 0)
999 		{
1000 		    ni = list_find(lp->ll_list, lp->ll_n2);
1001 		    if (ni == NULL)
1002 		    {
1003 			if (!quiet)
1004 			    semsg(_(e_listidx), lp->ll_n2);
1005 			return NULL;
1006 		    }
1007 		    lp->ll_n2 = list_idx_of_item(lp->ll_list, ni);
1008 		}
1009 
1010 		// Check that lp->ll_n2 isn't before lp->ll_n1.
1011 		if (lp->ll_n1 < 0)
1012 		    lp->ll_n1 = list_idx_of_item(lp->ll_list, lp->ll_li);
1013 		if (lp->ll_n2 < lp->ll_n1)
1014 		{
1015 		    if (!quiet)
1016 			semsg(_(e_listidx), lp->ll_n2);
1017 		    return NULL;
1018 		}
1019 	    }
1020 
1021 	    lp->ll_tv = &lp->ll_li->li_tv;
1022 	}
1023     }
1024 
1025     clear_tv(&var1);
1026     lp->ll_name_end = p;
1027     return p;
1028 }
1029 
1030 /*
1031  * Clear lval "lp" that was filled by get_lval().
1032  */
1033     void
1034 clear_lval(lval_T *lp)
1035 {
1036     vim_free(lp->ll_exp_name);
1037     vim_free(lp->ll_newkey);
1038 }
1039 
1040 /*
1041  * Set a variable that was parsed by get_lval() to "rettv".
1042  * "endp" points to just after the parsed name.
1043  * "op" is NULL, "+" for "+=", "-" for "-=", "*" for "*=", "/" for "/=",
1044  * "%" for "%=", "." for ".=" or "=" for "=".
1045  */
1046     void
1047 set_var_lval(
1048     lval_T	*lp,
1049     char_u	*endp,
1050     typval_T	*rettv,
1051     int		copy,
1052     int		flags,    // LET_IS_CONST and/or LET_NO_COMMAND
1053     char_u	*op)
1054 {
1055     int		cc;
1056     listitem_T	*ri;
1057     dictitem_T	*di;
1058 
1059     if (lp->ll_tv == NULL)
1060     {
1061 	cc = *endp;
1062 	*endp = NUL;
1063 	if (lp->ll_blob != NULL)
1064 	{
1065 	    int	    error = FALSE, val;
1066 
1067 	    if (op != NULL && *op != '=')
1068 	    {
1069 		semsg(_(e_letwrong), op);
1070 		return;
1071 	    }
1072 
1073 	    if (lp->ll_range && rettv->v_type == VAR_BLOB)
1074 	    {
1075 		int	il, ir;
1076 
1077 		if (lp->ll_empty2)
1078 		    lp->ll_n2 = blob_len(lp->ll_blob) - 1;
1079 
1080 		if (lp->ll_n2 - lp->ll_n1 + 1 != blob_len(rettv->vval.v_blob))
1081 		{
1082 		    emsg(_("E972: Blob value does not have the right number of bytes"));
1083 		    return;
1084 		}
1085 		if (lp->ll_empty2)
1086 		    lp->ll_n2 = blob_len(lp->ll_blob);
1087 
1088 		ir = 0;
1089 		for (il = lp->ll_n1; il <= lp->ll_n2; il++)
1090 		    blob_set(lp->ll_blob, il,
1091 			    blob_get(rettv->vval.v_blob, ir++));
1092 	    }
1093 	    else
1094 	    {
1095 		val = (int)tv_get_number_chk(rettv, &error);
1096 		if (!error)
1097 		{
1098 		    garray_T *gap = &lp->ll_blob->bv_ga;
1099 
1100 		    // Allow for appending a byte.  Setting a byte beyond
1101 		    // the end is an error otherwise.
1102 		    if (lp->ll_n1 < gap->ga_len
1103 			    || (lp->ll_n1 == gap->ga_len
1104 				&& ga_grow(&lp->ll_blob->bv_ga, 1) == OK))
1105 		    {
1106 			blob_set(lp->ll_blob, lp->ll_n1, val);
1107 			if (lp->ll_n1 == gap->ga_len)
1108 			    ++gap->ga_len;
1109 		    }
1110 		    // error for invalid range was already given in get_lval()
1111 		}
1112 	    }
1113 	}
1114 	else if (op != NULL && *op != '=')
1115 	{
1116 	    typval_T tv;
1117 
1118 	    if (flags & LET_IS_CONST)
1119 	    {
1120 		emsg(_(e_cannot_mod));
1121 		*endp = cc;
1122 		return;
1123 	    }
1124 
1125 	    // handle +=, -=, *=, /=, %= and .=
1126 	    di = NULL;
1127 	    if (get_var_tv(lp->ll_name, (int)STRLEN(lp->ll_name),
1128 					     &tv, &di, TRUE, FALSE) == OK)
1129 	    {
1130 		if ((di == NULL
1131 			 || (!var_check_ro(di->di_flags, lp->ll_name, FALSE)
1132 			   && !tv_check_lock(&di->di_tv, lp->ll_name, FALSE)))
1133 			&& tv_op(&tv, rettv, op) == OK)
1134 		    set_var(lp->ll_name, &tv, FALSE);
1135 		clear_tv(&tv);
1136 	    }
1137 	}
1138 	else
1139 	    set_var_const(lp->ll_name, lp->ll_type, rettv, copy, flags);
1140 	*endp = cc;
1141     }
1142     else if (var_check_lock(lp->ll_newkey == NULL
1143 		? lp->ll_tv->v_lock
1144 		: lp->ll_tv->vval.v_dict->dv_lock, lp->ll_name, FALSE))
1145 	;
1146     else if (lp->ll_range)
1147     {
1148 	listitem_T *ll_li = lp->ll_li;
1149 	int	    ll_n1 = lp->ll_n1;
1150 
1151 	if (flags & LET_IS_CONST)
1152 	{
1153 	    emsg(_("E996: Cannot lock a range"));
1154 	    return;
1155 	}
1156 
1157 	/*
1158 	 * Check whether any of the list items is locked
1159 	 */
1160 	for (ri = rettv->vval.v_list->lv_first; ri != NULL && ll_li != NULL; )
1161 	{
1162 	    if (var_check_lock(ll_li->li_tv.v_lock, lp->ll_name, FALSE))
1163 		return;
1164 	    ri = ri->li_next;
1165 	    if (ri == NULL || (!lp->ll_empty2 && lp->ll_n2 == ll_n1))
1166 		break;
1167 	    ll_li = ll_li->li_next;
1168 	    ++ll_n1;
1169 	}
1170 
1171 	/*
1172 	 * Assign the List values to the list items.
1173 	 */
1174 	for (ri = rettv->vval.v_list->lv_first; ri != NULL; )
1175 	{
1176 	    if (op != NULL && *op != '=')
1177 		tv_op(&lp->ll_li->li_tv, &ri->li_tv, op);
1178 	    else
1179 	    {
1180 		clear_tv(&lp->ll_li->li_tv);
1181 		copy_tv(&ri->li_tv, &lp->ll_li->li_tv);
1182 	    }
1183 	    ri = ri->li_next;
1184 	    if (ri == NULL || (!lp->ll_empty2 && lp->ll_n2 == lp->ll_n1))
1185 		break;
1186 	    if (lp->ll_li->li_next == NULL)
1187 	    {
1188 		// Need to add an empty item.
1189 		if (list_append_number(lp->ll_list, 0) == FAIL)
1190 		{
1191 		    ri = NULL;
1192 		    break;
1193 		}
1194 	    }
1195 	    lp->ll_li = lp->ll_li->li_next;
1196 	    ++lp->ll_n1;
1197 	}
1198 	if (ri != NULL)
1199 	    emsg(_("E710: List value has more items than target"));
1200 	else if (lp->ll_empty2
1201 		? (lp->ll_li != NULL && lp->ll_li->li_next != NULL)
1202 		: lp->ll_n1 != lp->ll_n2)
1203 	    emsg(_("E711: List value has not enough items"));
1204     }
1205     else
1206     {
1207 	/*
1208 	 * Assign to a List or Dictionary item.
1209 	 */
1210 	if (flags & LET_IS_CONST)
1211 	{
1212 	    emsg(_("E996: Cannot lock a list or dict"));
1213 	    return;
1214 	}
1215 	if (lp->ll_newkey != NULL)
1216 	{
1217 	    if (op != NULL && *op != '=')
1218 	    {
1219 		semsg(_(e_letwrong), op);
1220 		return;
1221 	    }
1222 
1223 	    // Need to add an item to the Dictionary.
1224 	    di = dictitem_alloc(lp->ll_newkey);
1225 	    if (di == NULL)
1226 		return;
1227 	    if (dict_add(lp->ll_tv->vval.v_dict, di) == FAIL)
1228 	    {
1229 		vim_free(di);
1230 		return;
1231 	    }
1232 	    lp->ll_tv = &di->di_tv;
1233 	}
1234 	else if (op != NULL && *op != '=')
1235 	{
1236 	    tv_op(lp->ll_tv, rettv, op);
1237 	    return;
1238 	}
1239 	else
1240 	    clear_tv(lp->ll_tv);
1241 
1242 	/*
1243 	 * Assign the value to the variable or list item.
1244 	 */
1245 	if (copy)
1246 	    copy_tv(rettv, lp->ll_tv);
1247 	else
1248 	{
1249 	    *lp->ll_tv = *rettv;
1250 	    lp->ll_tv->v_lock = 0;
1251 	    init_tv(rettv);
1252 	}
1253     }
1254 }
1255 
1256 /*
1257  * Handle "tv1 += tv2", "tv1 -= tv2", "tv1 *= tv2", "tv1 /= tv2", "tv1 %= tv2"
1258  * and "tv1 .= tv2"
1259  * Returns OK or FAIL.
1260  */
1261     static int
1262 tv_op(typval_T *tv1, typval_T *tv2, char_u *op)
1263 {
1264     varnumber_T	n;
1265     char_u	numbuf[NUMBUFLEN];
1266     char_u	*s;
1267 
1268     // Can't do anything with a Funcref, Dict, v:true on the right.
1269     if (tv2->v_type != VAR_FUNC && tv2->v_type != VAR_DICT
1270 		      && tv2->v_type != VAR_BOOL && tv2->v_type != VAR_SPECIAL)
1271     {
1272 	switch (tv1->v_type)
1273 	{
1274 	    case VAR_UNKNOWN:
1275 	    case VAR_ANY:
1276 	    case VAR_VOID:
1277 	    case VAR_DICT:
1278 	    case VAR_FUNC:
1279 	    case VAR_PARTIAL:
1280 	    case VAR_BOOL:
1281 	    case VAR_SPECIAL:
1282 	    case VAR_JOB:
1283 	    case VAR_CHANNEL:
1284 		break;
1285 
1286 	    case VAR_BLOB:
1287 		if (*op != '+' || tv2->v_type != VAR_BLOB)
1288 		    break;
1289 		// BLOB += BLOB
1290 		if (tv1->vval.v_blob != NULL && tv2->vval.v_blob != NULL)
1291 		{
1292 		    blob_T  *b1 = tv1->vval.v_blob;
1293 		    blob_T  *b2 = tv2->vval.v_blob;
1294 		    int	i, len = blob_len(b2);
1295 		    for (i = 0; i < len; i++)
1296 			ga_append(&b1->bv_ga, blob_get(b2, i));
1297 		}
1298 		return OK;
1299 
1300 	    case VAR_LIST:
1301 		if (*op != '+' || tv2->v_type != VAR_LIST)
1302 		    break;
1303 		// List += List
1304 		if (tv1->vval.v_list != NULL && tv2->vval.v_list != NULL)
1305 		    list_extend(tv1->vval.v_list, tv2->vval.v_list, NULL);
1306 		return OK;
1307 
1308 	    case VAR_NUMBER:
1309 	    case VAR_STRING:
1310 		if (tv2->v_type == VAR_LIST)
1311 		    break;
1312 		if (vim_strchr((char_u *)"+-*/%", *op) != NULL)
1313 		{
1314 		    // nr += nr , nr -= nr , nr *=nr , nr /= nr , nr %= nr
1315 		    n = tv_get_number(tv1);
1316 #ifdef FEAT_FLOAT
1317 		    if (tv2->v_type == VAR_FLOAT)
1318 		    {
1319 			float_T f = n;
1320 
1321 			if (*op == '%')
1322 			    break;
1323 			switch (*op)
1324 			{
1325 			    case '+': f += tv2->vval.v_float; break;
1326 			    case '-': f -= tv2->vval.v_float; break;
1327 			    case '*': f *= tv2->vval.v_float; break;
1328 			    case '/': f /= tv2->vval.v_float; break;
1329 			}
1330 			clear_tv(tv1);
1331 			tv1->v_type = VAR_FLOAT;
1332 			tv1->vval.v_float = f;
1333 		    }
1334 		    else
1335 #endif
1336 		    {
1337 			switch (*op)
1338 			{
1339 			    case '+': n += tv_get_number(tv2); break;
1340 			    case '-': n -= tv_get_number(tv2); break;
1341 			    case '*': n *= tv_get_number(tv2); break;
1342 			    case '/': n = num_divide(n, tv_get_number(tv2)); break;
1343 			    case '%': n = num_modulus(n, tv_get_number(tv2)); break;
1344 			}
1345 			clear_tv(tv1);
1346 			tv1->v_type = VAR_NUMBER;
1347 			tv1->vval.v_number = n;
1348 		    }
1349 		}
1350 		else
1351 		{
1352 		    if (tv2->v_type == VAR_FLOAT)
1353 			break;
1354 
1355 		    // str .= str
1356 		    s = tv_get_string(tv1);
1357 		    s = concat_str(s, tv_get_string_buf(tv2, numbuf));
1358 		    clear_tv(tv1);
1359 		    tv1->v_type = VAR_STRING;
1360 		    tv1->vval.v_string = s;
1361 		}
1362 		return OK;
1363 
1364 	    case VAR_FLOAT:
1365 #ifdef FEAT_FLOAT
1366 		{
1367 		    float_T f;
1368 
1369 		    if (*op == '%' || *op == '.'
1370 				   || (tv2->v_type != VAR_FLOAT
1371 				    && tv2->v_type != VAR_NUMBER
1372 				    && tv2->v_type != VAR_STRING))
1373 			break;
1374 		    if (tv2->v_type == VAR_FLOAT)
1375 			f = tv2->vval.v_float;
1376 		    else
1377 			f = tv_get_number(tv2);
1378 		    switch (*op)
1379 		    {
1380 			case '+': tv1->vval.v_float += f; break;
1381 			case '-': tv1->vval.v_float -= f; break;
1382 			case '*': tv1->vval.v_float *= f; break;
1383 			case '/': tv1->vval.v_float /= f; break;
1384 		    }
1385 		}
1386 #endif
1387 		return OK;
1388 	}
1389     }
1390 
1391     semsg(_(e_letwrong), op);
1392     return FAIL;
1393 }
1394 
1395 /*
1396  * Evaluate the expression used in a ":for var in expr" command.
1397  * "arg" points to "var".
1398  * Set "*errp" to TRUE for an error, FALSE otherwise;
1399  * Return a pointer that holds the info.  Null when there is an error.
1400  */
1401     void *
1402 eval_for_line(
1403     char_u	*arg,
1404     int		*errp,
1405     char_u	**nextcmdp,
1406     int		skip)
1407 {
1408     forinfo_T	*fi;
1409     char_u	*expr;
1410     typval_T	tv;
1411     list_T	*l;
1412 
1413     *errp = TRUE;	// default: there is an error
1414 
1415     fi = ALLOC_CLEAR_ONE(forinfo_T);
1416     if (fi == NULL)
1417 	return NULL;
1418 
1419     expr = skip_var_list(arg, TRUE, &fi->fi_varcount, &fi->fi_semicolon);
1420     if (expr == NULL)
1421 	return fi;
1422 
1423     expr = skipwhite(expr);
1424     if (expr[0] != 'i' || expr[1] != 'n' || !VIM_ISWHITE(expr[2]))
1425     {
1426 	emsg(_(e_missing_in));
1427 	return fi;
1428     }
1429 
1430     if (skip)
1431 	++emsg_skip;
1432     if (eval0(skipwhite(expr + 2), &tv, nextcmdp, !skip) == OK)
1433     {
1434 	*errp = FALSE;
1435 	if (!skip)
1436 	{
1437 	    if (tv.v_type == VAR_LIST)
1438 	    {
1439 		l = tv.vval.v_list;
1440 		if (l == NULL)
1441 		{
1442 		    // a null list is like an empty list: do nothing
1443 		    clear_tv(&tv);
1444 		}
1445 		else
1446 		{
1447 		    // Need a real list here.
1448 		    range_list_materialize(l);
1449 
1450 		    // No need to increment the refcount, it's already set for
1451 		    // the list being used in "tv".
1452 		    fi->fi_list = l;
1453 		    list_add_watch(l, &fi->fi_lw);
1454 		    fi->fi_lw.lw_item = l->lv_first;
1455 		}
1456 	    }
1457 	    else if (tv.v_type == VAR_BLOB)
1458 	    {
1459 		fi->fi_bi = 0;
1460 		if (tv.vval.v_blob != NULL)
1461 		{
1462 		    typval_T btv;
1463 
1464 		    // Make a copy, so that the iteration still works when the
1465 		    // blob is changed.
1466 		    blob_copy(tv.vval.v_blob, &btv);
1467 		    fi->fi_blob = btv.vval.v_blob;
1468 		}
1469 		clear_tv(&tv);
1470 	    }
1471 	    else
1472 	    {
1473 		emsg(_(e_listreq));
1474 		clear_tv(&tv);
1475 	    }
1476 	}
1477     }
1478     if (skip)
1479 	--emsg_skip;
1480 
1481     return fi;
1482 }
1483 
1484 /*
1485  * Use the first item in a ":for" list.  Advance to the next.
1486  * Assign the values to the variable (list).  "arg" points to the first one.
1487  * Return TRUE when a valid item was found, FALSE when at end of list or
1488  * something wrong.
1489  */
1490     int
1491 next_for_item(void *fi_void, char_u *arg)
1492 {
1493     forinfo_T	*fi = (forinfo_T *)fi_void;
1494     int		result;
1495     int		flag = current_sctx.sc_version == SCRIPT_VERSION_VIM9 ?
1496 							LET_NO_COMMAND : 0;
1497     listitem_T	*item;
1498 
1499     if (fi->fi_blob != NULL)
1500     {
1501 	typval_T	tv;
1502 
1503 	if (fi->fi_bi >= blob_len(fi->fi_blob))
1504 	    return FALSE;
1505 	tv.v_type = VAR_NUMBER;
1506 	tv.v_lock = VAR_FIXED;
1507 	tv.vval.v_number = blob_get(fi->fi_blob, fi->fi_bi);
1508 	++fi->fi_bi;
1509 	return ex_let_vars(arg, &tv, TRUE, fi->fi_semicolon,
1510 				       fi->fi_varcount, flag, NULL) == OK;
1511     }
1512 
1513     item = fi->fi_lw.lw_item;
1514     if (item == NULL)
1515 	result = FALSE;
1516     else
1517     {
1518 	fi->fi_lw.lw_item = item->li_next;
1519 	result = (ex_let_vars(arg, &item->li_tv, TRUE, fi->fi_semicolon,
1520 				      fi->fi_varcount, flag, NULL) == OK);
1521     }
1522     return result;
1523 }
1524 
1525 /*
1526  * Free the structure used to store info used by ":for".
1527  */
1528     void
1529 free_for_info(void *fi_void)
1530 {
1531     forinfo_T    *fi = (forinfo_T *)fi_void;
1532 
1533     if (fi != NULL && fi->fi_list != NULL)
1534     {
1535 	list_rem_watch(fi->fi_list, &fi->fi_lw);
1536 	list_unref(fi->fi_list);
1537     }
1538     if (fi != NULL && fi->fi_blob != NULL)
1539 	blob_unref(fi->fi_blob);
1540     vim_free(fi);
1541 }
1542 
1543     void
1544 set_context_for_expression(
1545     expand_T	*xp,
1546     char_u	*arg,
1547     cmdidx_T	cmdidx)
1548 {
1549     int		got_eq = FALSE;
1550     int		c;
1551     char_u	*p;
1552 
1553     if (cmdidx == CMD_let || cmdidx == CMD_const)
1554     {
1555 	xp->xp_context = EXPAND_USER_VARS;
1556 	if (vim_strpbrk(arg, (char_u *)"\"'+-*/%.=!?~|&$([<>,#") == NULL)
1557 	{
1558 	    // ":let var1 var2 ...": find last space.
1559 	    for (p = arg + STRLEN(arg); p >= arg; )
1560 	    {
1561 		xp->xp_pattern = p;
1562 		MB_PTR_BACK(arg, p);
1563 		if (VIM_ISWHITE(*p))
1564 		    break;
1565 	    }
1566 	    return;
1567 	}
1568     }
1569     else
1570 	xp->xp_context = cmdidx == CMD_call ? EXPAND_FUNCTIONS
1571 							  : EXPAND_EXPRESSION;
1572     while ((xp->xp_pattern = vim_strpbrk(arg,
1573 				  (char_u *)"\"'+-*/%.=!?~|&$([<>,#")) != NULL)
1574     {
1575 	c = *xp->xp_pattern;
1576 	if (c == '&')
1577 	{
1578 	    c = xp->xp_pattern[1];
1579 	    if (c == '&')
1580 	    {
1581 		++xp->xp_pattern;
1582 		xp->xp_context = cmdidx != CMD_let || got_eq
1583 					 ? EXPAND_EXPRESSION : EXPAND_NOTHING;
1584 	    }
1585 	    else if (c != ' ')
1586 	    {
1587 		xp->xp_context = EXPAND_SETTINGS;
1588 		if ((c == 'l' || c == 'g') && xp->xp_pattern[2] == ':')
1589 		    xp->xp_pattern += 2;
1590 
1591 	    }
1592 	}
1593 	else if (c == '$')
1594 	{
1595 	    // environment variable
1596 	    xp->xp_context = EXPAND_ENV_VARS;
1597 	}
1598 	else if (c == '=')
1599 	{
1600 	    got_eq = TRUE;
1601 	    xp->xp_context = EXPAND_EXPRESSION;
1602 	}
1603 	else if (c == '#'
1604 		&& xp->xp_context == EXPAND_EXPRESSION)
1605 	{
1606 	    // Autoload function/variable contains '#'.
1607 	    break;
1608 	}
1609 	else if ((c == '<' || c == '#')
1610 		&& xp->xp_context == EXPAND_FUNCTIONS
1611 		&& vim_strchr(xp->xp_pattern, '(') == NULL)
1612 	{
1613 	    // Function name can start with "<SNR>" and contain '#'.
1614 	    break;
1615 	}
1616 	else if (cmdidx != CMD_let || got_eq)
1617 	{
1618 	    if (c == '"')	    // string
1619 	    {
1620 		while ((c = *++xp->xp_pattern) != NUL && c != '"')
1621 		    if (c == '\\' && xp->xp_pattern[1] != NUL)
1622 			++xp->xp_pattern;
1623 		xp->xp_context = EXPAND_NOTHING;
1624 	    }
1625 	    else if (c == '\'')	    // literal string
1626 	    {
1627 		// Trick: '' is like stopping and starting a literal string.
1628 		while ((c = *++xp->xp_pattern) != NUL && c != '\'')
1629 		    /* skip */ ;
1630 		xp->xp_context = EXPAND_NOTHING;
1631 	    }
1632 	    else if (c == '|')
1633 	    {
1634 		if (xp->xp_pattern[1] == '|')
1635 		{
1636 		    ++xp->xp_pattern;
1637 		    xp->xp_context = EXPAND_EXPRESSION;
1638 		}
1639 		else
1640 		    xp->xp_context = EXPAND_COMMANDS;
1641 	    }
1642 	    else
1643 		xp->xp_context = EXPAND_EXPRESSION;
1644 	}
1645 	else
1646 	    // Doesn't look like something valid, expand as an expression
1647 	    // anyway.
1648 	    xp->xp_context = EXPAND_EXPRESSION;
1649 	arg = xp->xp_pattern;
1650 	if (*arg != NUL)
1651 	    while ((c = *++arg) != NUL && (c == ' ' || c == '\t'))
1652 		/* skip */ ;
1653     }
1654     xp->xp_pattern = arg;
1655 }
1656 
1657 /*
1658  * Return TRUE if "pat" matches "text".
1659  * Does not use 'cpo' and always uses 'magic'.
1660  */
1661     int
1662 pattern_match(char_u *pat, char_u *text, int ic)
1663 {
1664     int		matches = FALSE;
1665     char_u	*save_cpo;
1666     regmatch_T	regmatch;
1667 
1668     // avoid 'l' flag in 'cpoptions'
1669     save_cpo = p_cpo;
1670     p_cpo = (char_u *)"";
1671     regmatch.regprog = vim_regcomp(pat, RE_MAGIC + RE_STRING);
1672     if (regmatch.regprog != NULL)
1673     {
1674 	regmatch.rm_ic = ic;
1675 	matches = vim_regexec_nl(&regmatch, text, (colnr_T)0);
1676 	vim_regfree(regmatch.regprog);
1677     }
1678     p_cpo = save_cpo;
1679     return matches;
1680 }
1681 
1682 /*
1683  * Handle a name followed by "(".  Both for just "name(arg)" and for
1684  * "expr->name(arg)".
1685  * Returns OK or FAIL.
1686  */
1687     static int
1688 eval_func(
1689 	char_u	    **arg,	// points to "(", will be advanced
1690 	char_u	    *name,
1691 	int	    name_len,
1692 	typval_T    *rettv,
1693 	int	    evaluate,
1694 	typval_T    *basetv)	// "expr" for "expr->name(arg)"
1695 {
1696     char_u	*s = name;
1697     int		len = name_len;
1698     partial_T	*partial;
1699     int		ret = OK;
1700 
1701     if (!evaluate)
1702 	check_vars(s, len);
1703 
1704     // If "s" is the name of a variable of type VAR_FUNC
1705     // use its contents.
1706     s = deref_func_name(s, &len, &partial, !evaluate);
1707 
1708     // Need to make a copy, in case evaluating the arguments makes
1709     // the name invalid.
1710     s = vim_strsave(s);
1711     if (s == NULL)
1712 	ret = FAIL;
1713     else
1714     {
1715 	funcexe_T funcexe;
1716 
1717 	// Invoke the function.
1718 	vim_memset(&funcexe, 0, sizeof(funcexe));
1719 	funcexe.firstline = curwin->w_cursor.lnum;
1720 	funcexe.lastline = curwin->w_cursor.lnum;
1721 	funcexe.evaluate = evaluate;
1722 	funcexe.partial = partial;
1723 	funcexe.basetv = basetv;
1724 	ret = get_func_tv(s, len, rettv, arg, &funcexe);
1725     }
1726     vim_free(s);
1727 
1728     // If evaluate is FALSE rettv->v_type was not set in
1729     // get_func_tv, but it's needed in handle_subscript() to parse
1730     // what follows. So set it here.
1731     if (rettv->v_type == VAR_UNKNOWN && !evaluate && **arg == '(')
1732     {
1733 	rettv->vval.v_string = NULL;
1734 	rettv->v_type = VAR_FUNC;
1735     }
1736 
1737     // Stop the expression evaluation when immediately
1738     // aborting on error, or when an interrupt occurred or
1739     // an exception was thrown but not caught.
1740     if (evaluate && aborting())
1741     {
1742 	if (ret == OK)
1743 	    clear_tv(rettv);
1744 	ret = FAIL;
1745     }
1746     return ret;
1747 }
1748 
1749 /*
1750  * The "evaluate" argument: When FALSE, the argument is only parsed but not
1751  * executed.  The function may return OK, but the rettv will be of type
1752  * VAR_UNKNOWN.  The function still returns FAIL for a syntax error.
1753  */
1754 
1755 /*
1756  * Handle zero level expression.
1757  * This calls eval1() and handles error message and nextcmd.
1758  * Put the result in "rettv" when returning OK and "evaluate" is TRUE.
1759  * Note: "rettv.v_lock" is not set.
1760  * Return OK or FAIL.
1761  */
1762     int
1763 eval0(
1764     char_u	*arg,
1765     typval_T	*rettv,
1766     char_u	**nextcmd,
1767     int		evaluate)
1768 {
1769     int		ret;
1770     char_u	*p;
1771     int		did_emsg_before = did_emsg;
1772     int		called_emsg_before = called_emsg;
1773 
1774     p = skipwhite(arg);
1775     ret = eval1(&p, rettv, evaluate);
1776     if (ret == FAIL || !ends_excmd(*p))
1777     {
1778 	if (ret != FAIL)
1779 	    clear_tv(rettv);
1780 	/*
1781 	 * Report the invalid expression unless the expression evaluation has
1782 	 * been cancelled due to an aborting error, an interrupt, or an
1783 	 * exception, or we already gave a more specific error.
1784 	 * Also check called_emsg for when using assert_fails().
1785 	 */
1786 	if (!aborting() && did_emsg == did_emsg_before
1787 					  && called_emsg == called_emsg_before)
1788 	    semsg(_(e_invexpr2), arg);
1789 	ret = FAIL;
1790     }
1791     if (nextcmd != NULL)
1792 	*nextcmd = check_nextcmd(p);
1793 
1794     return ret;
1795 }
1796 
1797 /*
1798  * Handle top level expression:
1799  *	expr2 ? expr1 : expr1
1800  *
1801  * "arg" must point to the first non-white of the expression.
1802  * "arg" is advanced to the next non-white after the recognized expression.
1803  *
1804  * Note: "rettv.v_lock" is not set.
1805  *
1806  * Return OK or FAIL.
1807  */
1808     int
1809 eval1(char_u **arg, typval_T *rettv, int evaluate)
1810 {
1811     int		result;
1812     typval_T	var2;
1813 
1814     /*
1815      * Get the first variable.
1816      */
1817     if (eval2(arg, rettv, evaluate) == FAIL)
1818 	return FAIL;
1819 
1820     if ((*arg)[0] == '?')
1821     {
1822 	result = FALSE;
1823 	if (evaluate)
1824 	{
1825 	    int		error = FALSE;
1826 
1827 	    if (tv_get_number_chk(rettv, &error) != 0)
1828 		result = TRUE;
1829 	    clear_tv(rettv);
1830 	    if (error)
1831 		return FAIL;
1832 	}
1833 
1834 	/*
1835 	 * Get the second variable.
1836 	 */
1837 	*arg = skipwhite(*arg + 1);
1838 	if (eval1(arg, rettv, evaluate && result) == FAIL) // recursive!
1839 	    return FAIL;
1840 
1841 	/*
1842 	 * Check for the ":".
1843 	 */
1844 	if ((*arg)[0] != ':')
1845 	{
1846 	    emsg(_(e_missing_colon));
1847 	    if (evaluate && result)
1848 		clear_tv(rettv);
1849 	    return FAIL;
1850 	}
1851 
1852 	/*
1853 	 * Get the third variable.
1854 	 */
1855 	*arg = skipwhite(*arg + 1);
1856 	if (eval1(arg, &var2, evaluate && !result) == FAIL) // recursive!
1857 	{
1858 	    if (evaluate && result)
1859 		clear_tv(rettv);
1860 	    return FAIL;
1861 	}
1862 	if (evaluate && !result)
1863 	    *rettv = var2;
1864     }
1865 
1866     return OK;
1867 }
1868 
1869 /*
1870  * Handle first level expression:
1871  *	expr2 || expr2 || expr2	    logical OR
1872  *
1873  * "arg" must point to the first non-white of the expression.
1874  * "arg" is advanced to the next non-white after the recognized expression.
1875  *
1876  * Return OK or FAIL.
1877  */
1878     static int
1879 eval2(char_u **arg, typval_T *rettv, int evaluate)
1880 {
1881     typval_T	var2;
1882     long	result;
1883     int		first;
1884     int		error = FALSE;
1885 
1886     /*
1887      * Get the first variable.
1888      */
1889     if (eval3(arg, rettv, evaluate) == FAIL)
1890 	return FAIL;
1891 
1892     /*
1893      * Repeat until there is no following "||".
1894      */
1895     first = TRUE;
1896     result = FALSE;
1897     while ((*arg)[0] == '|' && (*arg)[1] == '|')
1898     {
1899 	if (evaluate && first)
1900 	{
1901 	    if (tv_get_number_chk(rettv, &error) != 0)
1902 		result = TRUE;
1903 	    clear_tv(rettv);
1904 	    if (error)
1905 		return FAIL;
1906 	    first = FALSE;
1907 	}
1908 
1909 	/*
1910 	 * Get the second variable.
1911 	 */
1912 	*arg = skipwhite(*arg + 2);
1913 	if (eval3(arg, &var2, evaluate && !result) == FAIL)
1914 	    return FAIL;
1915 
1916 	/*
1917 	 * Compute the result.
1918 	 */
1919 	if (evaluate && !result)
1920 	{
1921 	    if (tv_get_number_chk(&var2, &error) != 0)
1922 		result = TRUE;
1923 	    clear_tv(&var2);
1924 	    if (error)
1925 		return FAIL;
1926 	}
1927 	if (evaluate)
1928 	{
1929 	    rettv->v_type = VAR_NUMBER;
1930 	    rettv->vval.v_number = result;
1931 	}
1932     }
1933 
1934     return OK;
1935 }
1936 
1937 /*
1938  * Handle second level expression:
1939  *	expr3 && expr3 && expr3	    logical AND
1940  *
1941  * "arg" must point to the first non-white of the expression.
1942  * "arg" is advanced to the next non-white after the recognized expression.
1943  *
1944  * Return OK or FAIL.
1945  */
1946     static int
1947 eval3(char_u **arg, typval_T *rettv, int evaluate)
1948 {
1949     typval_T	var2;
1950     long	result;
1951     int		first;
1952     int		error = FALSE;
1953 
1954     /*
1955      * Get the first variable.
1956      */
1957     if (eval4(arg, rettv, evaluate) == FAIL)
1958 	return FAIL;
1959 
1960     /*
1961      * Repeat until there is no following "&&".
1962      */
1963     first = TRUE;
1964     result = TRUE;
1965     while ((*arg)[0] == '&' && (*arg)[1] == '&')
1966     {
1967 	if (evaluate && first)
1968 	{
1969 	    if (tv_get_number_chk(rettv, &error) == 0)
1970 		result = FALSE;
1971 	    clear_tv(rettv);
1972 	    if (error)
1973 		return FAIL;
1974 	    first = FALSE;
1975 	}
1976 
1977 	/*
1978 	 * Get the second variable.
1979 	 */
1980 	*arg = skipwhite(*arg + 2);
1981 	if (eval4(arg, &var2, evaluate && result) == FAIL)
1982 	    return FAIL;
1983 
1984 	/*
1985 	 * Compute the result.
1986 	 */
1987 	if (evaluate && result)
1988 	{
1989 	    if (tv_get_number_chk(&var2, &error) == 0)
1990 		result = FALSE;
1991 	    clear_tv(&var2);
1992 	    if (error)
1993 		return FAIL;
1994 	}
1995 	if (evaluate)
1996 	{
1997 	    rettv->v_type = VAR_NUMBER;
1998 	    rettv->vval.v_number = result;
1999 	}
2000     }
2001 
2002     return OK;
2003 }
2004 
2005 /*
2006  * Handle third level expression:
2007  *	var1 == var2
2008  *	var1 =~ var2
2009  *	var1 != var2
2010  *	var1 !~ var2
2011  *	var1 > var2
2012  *	var1 >= var2
2013  *	var1 < var2
2014  *	var1 <= var2
2015  *	var1 is var2
2016  *	var1 isnot var2
2017  *
2018  * "arg" must point to the first non-white of the expression.
2019  * "arg" is advanced to the next non-white after the recognized expression.
2020  *
2021  * Return OK or FAIL.
2022  */
2023     static int
2024 eval4(char_u **arg, typval_T *rettv, int evaluate)
2025 {
2026     typval_T	var2;
2027     char_u	*p;
2028     int		i;
2029     exptype_T	type = EXPR_UNKNOWN;
2030     int		len = 2;
2031     int		ic;
2032 
2033     /*
2034      * Get the first variable.
2035      */
2036     if (eval5(arg, rettv, evaluate) == FAIL)
2037 	return FAIL;
2038 
2039     p = *arg;
2040     switch (p[0])
2041     {
2042 	case '=':   if (p[1] == '=')
2043 			type = EXPR_EQUAL;
2044 		    else if (p[1] == '~')
2045 			type = EXPR_MATCH;
2046 		    break;
2047 	case '!':   if (p[1] == '=')
2048 			type = EXPR_NEQUAL;
2049 		    else if (p[1] == '~')
2050 			type = EXPR_NOMATCH;
2051 		    break;
2052 	case '>':   if (p[1] != '=')
2053 		    {
2054 			type = EXPR_GREATER;
2055 			len = 1;
2056 		    }
2057 		    else
2058 			type = EXPR_GEQUAL;
2059 		    break;
2060 	case '<':   if (p[1] != '=')
2061 		    {
2062 			type = EXPR_SMALLER;
2063 			len = 1;
2064 		    }
2065 		    else
2066 			type = EXPR_SEQUAL;
2067 		    break;
2068 	case 'i':   if (p[1] == 's')
2069 		    {
2070 			if (p[2] == 'n' && p[3] == 'o' && p[4] == 't')
2071 			    len = 5;
2072 			i = p[len];
2073 			if (!isalnum(i) && i != '_')
2074 			    type = len == 2 ? EXPR_IS : EXPR_ISNOT;
2075 		    }
2076 		    break;
2077     }
2078 
2079     /*
2080      * If there is a comparative operator, use it.
2081      */
2082     if (type != EXPR_UNKNOWN)
2083     {
2084 	// extra question mark appended: ignore case
2085 	if (p[len] == '?')
2086 	{
2087 	    ic = TRUE;
2088 	    ++len;
2089 	}
2090 	// extra '#' appended: match case
2091 	else if (p[len] == '#')
2092 	{
2093 	    ic = FALSE;
2094 	    ++len;
2095 	}
2096 	// nothing appended: use 'ignorecase'
2097 	else
2098 	    ic = p_ic;
2099 
2100 	/*
2101 	 * Get the second variable.
2102 	 */
2103 	*arg = skipwhite(p + len);
2104 	if (eval5(arg, &var2, evaluate) == FAIL)
2105 	{
2106 	    clear_tv(rettv);
2107 	    return FAIL;
2108 	}
2109 	if (evaluate)
2110 	{
2111 	    int ret = typval_compare(rettv, &var2, type, ic);
2112 
2113 	    clear_tv(&var2);
2114 	    return ret;
2115 	}
2116     }
2117 
2118     return OK;
2119 }
2120 
2121     void
2122 eval_addblob(typval_T *tv1, typval_T *tv2)
2123 {
2124     blob_T  *b1 = tv1->vval.v_blob;
2125     blob_T  *b2 = tv2->vval.v_blob;
2126     blob_T  *b = blob_alloc();
2127     int	    i;
2128 
2129     if (b != NULL)
2130     {
2131 	for (i = 0; i < blob_len(b1); i++)
2132 	    ga_append(&b->bv_ga, blob_get(b1, i));
2133 	for (i = 0; i < blob_len(b2); i++)
2134 	    ga_append(&b->bv_ga, blob_get(b2, i));
2135 
2136 	clear_tv(tv1);
2137 	rettv_blob_set(tv1, b);
2138     }
2139 }
2140 
2141     int
2142 eval_addlist(typval_T *tv1, typval_T *tv2)
2143 {
2144     typval_T var3;
2145 
2146     // concatenate Lists
2147     if (list_concat(tv1->vval.v_list, tv2->vval.v_list, &var3) == FAIL)
2148     {
2149 	clear_tv(tv1);
2150 	clear_tv(tv2);
2151 	return FAIL;
2152     }
2153     clear_tv(tv1);
2154     *tv1 = var3;
2155     return OK;
2156 }
2157 
2158 /*
2159  * Handle fourth level expression:
2160  *	+	number addition
2161  *	-	number subtraction
2162  *	.	string concatenation (if script version is 1)
2163  *	..	string concatenation
2164  *
2165  * "arg" must point to the first non-white of the expression.
2166  * "arg" is advanced to the next non-white after the recognized expression.
2167  *
2168  * Return OK or FAIL.
2169  */
2170     static int
2171 eval5(char_u **arg, typval_T *rettv, int evaluate)
2172 {
2173     typval_T	var2;
2174     int		op;
2175     varnumber_T	n1, n2;
2176 #ifdef FEAT_FLOAT
2177     float_T	f1 = 0, f2 = 0;
2178 #endif
2179     char_u	*s1, *s2;
2180     char_u	buf1[NUMBUFLEN], buf2[NUMBUFLEN];
2181     char_u	*p;
2182     int		concat;
2183 
2184     /*
2185      * Get the first variable.
2186      */
2187     if (eval6(arg, rettv, evaluate, FALSE) == FAIL)
2188 	return FAIL;
2189 
2190     /*
2191      * Repeat computing, until no '+', '-' or '.' is following.
2192      */
2193     for (;;)
2194     {
2195 	// "." is only string concatenation when scriptversion is 1
2196 	op = **arg;
2197 	concat = op == '.'
2198 			&& (*(*arg + 1) == '.' || current_sctx.sc_version < 2);
2199 	if (op != '+' && op != '-' && !concat)
2200 	    break;
2201 
2202 	if ((op != '+' || (rettv->v_type != VAR_LIST
2203 						 && rettv->v_type != VAR_BLOB))
2204 #ifdef FEAT_FLOAT
2205 		&& (op == '.' || rettv->v_type != VAR_FLOAT)
2206 #endif
2207 		)
2208 	{
2209 	    // For "list + ...", an illegal use of the first operand as
2210 	    // a number cannot be determined before evaluating the 2nd
2211 	    // operand: if this is also a list, all is ok.
2212 	    // For "something . ...", "something - ..." or "non-list + ...",
2213 	    // we know that the first operand needs to be a string or number
2214 	    // without evaluating the 2nd operand.  So check before to avoid
2215 	    // side effects after an error.
2216 	    if (evaluate && tv_get_string_chk(rettv) == NULL)
2217 	    {
2218 		clear_tv(rettv);
2219 		return FAIL;
2220 	    }
2221 	}
2222 
2223 	/*
2224 	 * Get the second variable.
2225 	 */
2226 	if (op == '.' && *(*arg + 1) == '.')  // .. string concatenation
2227 	    ++*arg;
2228 	*arg = skipwhite(*arg + 1);
2229 	if (eval6(arg, &var2, evaluate, op == '.') == FAIL)
2230 	{
2231 	    clear_tv(rettv);
2232 	    return FAIL;
2233 	}
2234 
2235 	if (evaluate)
2236 	{
2237 	    /*
2238 	     * Compute the result.
2239 	     */
2240 	    if (op == '.')
2241 	    {
2242 		s1 = tv_get_string_buf(rettv, buf1);	// already checked
2243 		s2 = tv_get_string_buf_chk(&var2, buf2);
2244 		if (s2 == NULL)		// type error ?
2245 		{
2246 		    clear_tv(rettv);
2247 		    clear_tv(&var2);
2248 		    return FAIL;
2249 		}
2250 		p = concat_str(s1, s2);
2251 		clear_tv(rettv);
2252 		rettv->v_type = VAR_STRING;
2253 		rettv->vval.v_string = p;
2254 	    }
2255 	    else if (op == '+' && rettv->v_type == VAR_BLOB
2256 						   && var2.v_type == VAR_BLOB)
2257 		eval_addblob(rettv, &var2);
2258 	    else if (op == '+' && rettv->v_type == VAR_LIST
2259 						   && var2.v_type == VAR_LIST)
2260 	    {
2261 		if (eval_addlist(rettv, &var2) == FAIL)
2262 		    return FAIL;
2263 	    }
2264 	    else
2265 	    {
2266 		int	    error = FALSE;
2267 
2268 #ifdef FEAT_FLOAT
2269 		if (rettv->v_type == VAR_FLOAT)
2270 		{
2271 		    f1 = rettv->vval.v_float;
2272 		    n1 = 0;
2273 		}
2274 		else
2275 #endif
2276 		{
2277 		    n1 = tv_get_number_chk(rettv, &error);
2278 		    if (error)
2279 		    {
2280 			// This can only happen for "list + non-list".  For
2281 			// "non-list + ..." or "something - ...", we returned
2282 			// before evaluating the 2nd operand.
2283 			clear_tv(rettv);
2284 			return FAIL;
2285 		    }
2286 #ifdef FEAT_FLOAT
2287 		    if (var2.v_type == VAR_FLOAT)
2288 			f1 = n1;
2289 #endif
2290 		}
2291 #ifdef FEAT_FLOAT
2292 		if (var2.v_type == VAR_FLOAT)
2293 		{
2294 		    f2 = var2.vval.v_float;
2295 		    n2 = 0;
2296 		}
2297 		else
2298 #endif
2299 		{
2300 		    n2 = tv_get_number_chk(&var2, &error);
2301 		    if (error)
2302 		    {
2303 			clear_tv(rettv);
2304 			clear_tv(&var2);
2305 			return FAIL;
2306 		    }
2307 #ifdef FEAT_FLOAT
2308 		    if (rettv->v_type == VAR_FLOAT)
2309 			f2 = n2;
2310 #endif
2311 		}
2312 		clear_tv(rettv);
2313 
2314 #ifdef FEAT_FLOAT
2315 		// If there is a float on either side the result is a float.
2316 		if (rettv->v_type == VAR_FLOAT || var2.v_type == VAR_FLOAT)
2317 		{
2318 		    if (op == '+')
2319 			f1 = f1 + f2;
2320 		    else
2321 			f1 = f1 - f2;
2322 		    rettv->v_type = VAR_FLOAT;
2323 		    rettv->vval.v_float = f1;
2324 		}
2325 		else
2326 #endif
2327 		{
2328 		    if (op == '+')
2329 			n1 = n1 + n2;
2330 		    else
2331 			n1 = n1 - n2;
2332 		    rettv->v_type = VAR_NUMBER;
2333 		    rettv->vval.v_number = n1;
2334 		}
2335 	    }
2336 	    clear_tv(&var2);
2337 	}
2338     }
2339     return OK;
2340 }
2341 
2342 /*
2343  * Handle fifth level expression:
2344  *	*	number multiplication
2345  *	/	number division
2346  *	%	number modulo
2347  *
2348  * "arg" must point to the first non-white of the expression.
2349  * "arg" is advanced to the next non-white after the recognized expression.
2350  *
2351  * Return OK or FAIL.
2352  */
2353     static int
2354 eval6(
2355     char_u	**arg,
2356     typval_T	*rettv,
2357     int		evaluate,
2358     int		want_string)  // after "." operator
2359 {
2360     typval_T	var2;
2361     int		op;
2362     varnumber_T	n1, n2;
2363 #ifdef FEAT_FLOAT
2364     int		use_float = FALSE;
2365     float_T	f1 = 0, f2 = 0;
2366 #endif
2367     int		error = FALSE;
2368 
2369     /*
2370      * Get the first variable.
2371      */
2372     if (eval7(arg, rettv, evaluate, want_string) == FAIL)
2373 	return FAIL;
2374 
2375     /*
2376      * Repeat computing, until no '*', '/' or '%' is following.
2377      */
2378     for (;;)
2379     {
2380 	op = **arg;
2381 	if (op != '*' && op != '/' && op != '%')
2382 	    break;
2383 
2384 	if (evaluate)
2385 	{
2386 #ifdef FEAT_FLOAT
2387 	    if (rettv->v_type == VAR_FLOAT)
2388 	    {
2389 		f1 = rettv->vval.v_float;
2390 		use_float = TRUE;
2391 		n1 = 0;
2392 	    }
2393 	    else
2394 #endif
2395 		n1 = tv_get_number_chk(rettv, &error);
2396 	    clear_tv(rettv);
2397 	    if (error)
2398 		return FAIL;
2399 	}
2400 	else
2401 	    n1 = 0;
2402 
2403 	/*
2404 	 * Get the second variable.
2405 	 */
2406 	*arg = skipwhite(*arg + 1);
2407 	if (eval7(arg, &var2, evaluate, FALSE) == FAIL)
2408 	    return FAIL;
2409 
2410 	if (evaluate)
2411 	{
2412 #ifdef FEAT_FLOAT
2413 	    if (var2.v_type == VAR_FLOAT)
2414 	    {
2415 		if (!use_float)
2416 		{
2417 		    f1 = n1;
2418 		    use_float = TRUE;
2419 		}
2420 		f2 = var2.vval.v_float;
2421 		n2 = 0;
2422 	    }
2423 	    else
2424 #endif
2425 	    {
2426 		n2 = tv_get_number_chk(&var2, &error);
2427 		clear_tv(&var2);
2428 		if (error)
2429 		    return FAIL;
2430 #ifdef FEAT_FLOAT
2431 		if (use_float)
2432 		    f2 = n2;
2433 #endif
2434 	    }
2435 
2436 	    /*
2437 	     * Compute the result.
2438 	     * When either side is a float the result is a float.
2439 	     */
2440 #ifdef FEAT_FLOAT
2441 	    if (use_float)
2442 	    {
2443 		if (op == '*')
2444 		    f1 = f1 * f2;
2445 		else if (op == '/')
2446 		{
2447 # ifdef VMS
2448 		    // VMS crashes on divide by zero, work around it
2449 		    if (f2 == 0.0)
2450 		    {
2451 			if (f1 == 0)
2452 			    f1 = -1 * __F_FLT_MAX - 1L;   // similar to NaN
2453 			else if (f1 < 0)
2454 			    f1 = -1 * __F_FLT_MAX;
2455 			else
2456 			    f1 = __F_FLT_MAX;
2457 		    }
2458 		    else
2459 			f1 = f1 / f2;
2460 # else
2461 		    // We rely on the floating point library to handle divide
2462 		    // by zero to result in "inf" and not a crash.
2463 		    f1 = f1 / f2;
2464 # endif
2465 		}
2466 		else
2467 		{
2468 		    emsg(_(e_modulus));
2469 		    return FAIL;
2470 		}
2471 		rettv->v_type = VAR_FLOAT;
2472 		rettv->vval.v_float = f1;
2473 	    }
2474 	    else
2475 #endif
2476 	    {
2477 		if (op == '*')
2478 		    n1 = n1 * n2;
2479 		else if (op == '/')
2480 		    n1 = num_divide(n1, n2);
2481 		else
2482 		    n1 = num_modulus(n1, n2);
2483 
2484 		rettv->v_type = VAR_NUMBER;
2485 		rettv->vval.v_number = n1;
2486 	    }
2487 	}
2488     }
2489 
2490     return OK;
2491 }
2492 
2493 /*
2494  * Handle sixth level expression:
2495  *  number		number constant
2496  *  0zFFFFFFFF		Blob constant
2497  *  "string"		string constant
2498  *  'string'		literal string constant
2499  *  &option-name	option value
2500  *  @r			register contents
2501  *  identifier		variable value
2502  *  function()		function call
2503  *  $VAR		environment variable
2504  *  (expression)	nested expression
2505  *  [expr, expr]	List
2506  *  {arg, arg -> expr}	Lambda
2507  *  {key: val, key: val}   Dictionary
2508  *  #{key: val, key: val}  Dictionary with literal keys
2509  *
2510  *  Also handle:
2511  *  ! in front		logical NOT
2512  *  - in front		unary minus
2513  *  + in front		unary plus (ignored)
2514  *  trailing []		subscript in String or List
2515  *  trailing .name	entry in Dictionary
2516  *  trailing ->name()	method call
2517  *
2518  * "arg" must point to the first non-white of the expression.
2519  * "arg" is advanced to the next non-white after the recognized expression.
2520  *
2521  * Return OK or FAIL.
2522  */
2523     static int
2524 eval7(
2525     char_u	**arg,
2526     typval_T	*rettv,
2527     int		evaluate,
2528     int		want_string)	// after "." operator
2529 {
2530     int		len;
2531     char_u	*s;
2532     char_u	*start_leader, *end_leader;
2533     int		ret = OK;
2534     char_u	*alias;
2535 
2536     /*
2537      * Initialise variable so that clear_tv() can't mistake this for a
2538      * string and free a string that isn't there.
2539      */
2540     rettv->v_type = VAR_UNKNOWN;
2541 
2542     /*
2543      * Skip '!', '-' and '+' characters.  They are handled later.
2544      */
2545     start_leader = *arg;
2546     while (**arg == '!' || **arg == '-' || **arg == '+')
2547 	*arg = skipwhite(*arg + 1);
2548     end_leader = *arg;
2549 
2550     if (**arg == '.' && (!isdigit(*(*arg + 1))
2551 #ifdef FEAT_FLOAT
2552 	    || current_sctx.sc_version < 2
2553 #endif
2554 	    ))
2555     {
2556 	semsg(_(e_invexpr2), *arg);
2557 	++*arg;
2558 	return FAIL;
2559     }
2560 
2561     switch (**arg)
2562     {
2563     /*
2564      * Number constant.
2565      */
2566     case '0':
2567     case '1':
2568     case '2':
2569     case '3':
2570     case '4':
2571     case '5':
2572     case '6':
2573     case '7':
2574     case '8':
2575     case '9':
2576     case '.':	ret = get_number_tv(arg, rettv, evaluate, want_string);
2577 		break;
2578 
2579     /*
2580      * String constant: "string".
2581      */
2582     case '"':	ret = get_string_tv(arg, rettv, evaluate);
2583 		break;
2584 
2585     /*
2586      * Literal string constant: 'str''ing'.
2587      */
2588     case '\'':	ret = get_lit_string_tv(arg, rettv, evaluate);
2589 		break;
2590 
2591     /*
2592      * List: [expr, expr]
2593      */
2594     case '[':	ret = get_list_tv(arg, rettv, evaluate, TRUE);
2595 		break;
2596 
2597     /*
2598      * Dictionary: #{key: val, key: val}
2599      */
2600     case '#':	if ((*arg)[1] == '{')
2601 		{
2602 		    ++*arg;
2603 		    ret = eval_dict(arg, rettv, evaluate, TRUE);
2604 		}
2605 		else
2606 		    ret = NOTDONE;
2607 		break;
2608 
2609     /*
2610      * Lambda: {arg, arg -> expr}
2611      * Dictionary: {'key': val, 'key': val}
2612      */
2613     case '{':	ret = get_lambda_tv(arg, rettv, evaluate);
2614 		if (ret == NOTDONE)
2615 		    ret = eval_dict(arg, rettv, evaluate, FALSE);
2616 		break;
2617 
2618     /*
2619      * Option value: &name
2620      */
2621     case '&':	ret = get_option_tv(arg, rettv, evaluate);
2622 		break;
2623 
2624     /*
2625      * Environment variable: $VAR.
2626      */
2627     case '$':	ret = get_env_tv(arg, rettv, evaluate);
2628 		break;
2629 
2630     /*
2631      * Register contents: @r.
2632      */
2633     case '@':	++*arg;
2634 		if (evaluate)
2635 		{
2636 		    rettv->v_type = VAR_STRING;
2637 		    rettv->vval.v_string = get_reg_contents(**arg,
2638 							    GREG_EXPR_SRC);
2639 		}
2640 		if (**arg != NUL)
2641 		    ++*arg;
2642 		break;
2643 
2644     /*
2645      * nested expression: (expression).
2646      */
2647     case '(':	*arg = skipwhite(*arg + 1);
2648 		ret = eval1(arg, rettv, evaluate);	// recursive!
2649 		if (**arg == ')')
2650 		    ++*arg;
2651 		else if (ret == OK)
2652 		{
2653 		    emsg(_(e_missing_close));
2654 		    clear_tv(rettv);
2655 		    ret = FAIL;
2656 		}
2657 		break;
2658 
2659     default:	ret = NOTDONE;
2660 		break;
2661     }
2662 
2663     if (ret == NOTDONE)
2664     {
2665 	/*
2666 	 * Must be a variable or function name.
2667 	 * Can also be a curly-braces kind of name: {expr}.
2668 	 */
2669 	s = *arg;
2670 	len = get_name_len(arg, &alias, evaluate, TRUE);
2671 	if (alias != NULL)
2672 	    s = alias;
2673 
2674 	if (len <= 0)
2675 	    ret = FAIL;
2676 	else
2677 	{
2678 	    if (**arg == '(')		// recursive!
2679 		ret = eval_func(arg, s, len, rettv, evaluate, NULL);
2680 	    else if (evaluate)
2681 		ret = get_var_tv(s, len, rettv, NULL, TRUE, FALSE);
2682 	    else
2683 	    {
2684 		check_vars(s, len);
2685 		ret = OK;
2686 	    }
2687 	}
2688 	vim_free(alias);
2689     }
2690 
2691     *arg = skipwhite(*arg);
2692 
2693     // Handle following '[', '(' and '.' for expr[expr], expr.name,
2694     // expr(expr), expr->name(expr)
2695     if (ret == OK)
2696 	ret = handle_subscript(arg, rettv, evaluate, TRUE,
2697 						    start_leader, &end_leader);
2698 
2699     /*
2700      * Apply logical NOT and unary '-', from right to left, ignore '+'.
2701      */
2702     if (ret == OK && evaluate && end_leader > start_leader)
2703 	ret = eval7_leader(rettv, start_leader, &end_leader);
2704     return ret;
2705 }
2706 
2707 /*
2708  * Apply the leading "!" and "-" before an eval7 expression to "rettv".
2709  * Adjusts "end_leaderp" until it is at "start_leader".
2710  */
2711     static int
2712 eval7_leader(typval_T *rettv, char_u *start_leader, char_u **end_leaderp)
2713 {
2714     char_u	*end_leader = *end_leaderp;
2715     int		ret = OK;
2716     int		error = FALSE;
2717     varnumber_T val = 0;
2718 #ifdef FEAT_FLOAT
2719     float_T	    f = 0.0;
2720 
2721     if (rettv->v_type == VAR_FLOAT)
2722 	f = rettv->vval.v_float;
2723     else
2724 #endif
2725 	val = tv_get_number_chk(rettv, &error);
2726     if (error)
2727     {
2728 	clear_tv(rettv);
2729 	ret = FAIL;
2730     }
2731     else
2732     {
2733 	while (end_leader > start_leader)
2734 	{
2735 	    --end_leader;
2736 	    if (*end_leader == '!')
2737 	    {
2738 #ifdef FEAT_FLOAT
2739 		if (rettv->v_type == VAR_FLOAT)
2740 		    f = !f;
2741 		else
2742 #endif
2743 		    val = !val;
2744 	    }
2745 	    else if (*end_leader == '-')
2746 	    {
2747 #ifdef FEAT_FLOAT
2748 		if (rettv->v_type == VAR_FLOAT)
2749 		    f = -f;
2750 		else
2751 #endif
2752 		    val = -val;
2753 	    }
2754 	}
2755 #ifdef FEAT_FLOAT
2756 	if (rettv->v_type == VAR_FLOAT)
2757 	{
2758 	    clear_tv(rettv);
2759 	    rettv->vval.v_float = f;
2760 	}
2761 	else
2762 #endif
2763 	{
2764 	    clear_tv(rettv);
2765 	    rettv->v_type = VAR_NUMBER;
2766 	    rettv->vval.v_number = val;
2767 	}
2768     }
2769     *end_leaderp = end_leader;
2770     return ret;
2771 }
2772 
2773 /*
2774  * Call the function referred to in "rettv".
2775  */
2776     static int
2777 call_func_rettv(
2778 	char_u	    **arg,
2779 	typval_T    *rettv,
2780 	int	    evaluate,
2781 	dict_T	    *selfdict,
2782 	typval_T    *basetv)
2783 {
2784     partial_T	*pt = NULL;
2785     funcexe_T	funcexe;
2786     typval_T	functv;
2787     char_u	*s;
2788     int		ret;
2789 
2790     // need to copy the funcref so that we can clear rettv
2791     if (evaluate)
2792     {
2793 	functv = *rettv;
2794 	rettv->v_type = VAR_UNKNOWN;
2795 
2796 	// Invoke the function.  Recursive!
2797 	if (functv.v_type == VAR_PARTIAL)
2798 	{
2799 	    pt = functv.vval.v_partial;
2800 	    s = partial_name(pt);
2801 	}
2802 	else
2803 	    s = functv.vval.v_string;
2804     }
2805     else
2806 	s = (char_u *)"";
2807 
2808     vim_memset(&funcexe, 0, sizeof(funcexe));
2809     funcexe.firstline = curwin->w_cursor.lnum;
2810     funcexe.lastline = curwin->w_cursor.lnum;
2811     funcexe.evaluate = evaluate;
2812     funcexe.partial = pt;
2813     funcexe.selfdict = selfdict;
2814     funcexe.basetv = basetv;
2815     ret = get_func_tv(s, -1, rettv, arg, &funcexe);
2816 
2817     // Clear the funcref afterwards, so that deleting it while
2818     // evaluating the arguments is possible (see test55).
2819     if (evaluate)
2820 	clear_tv(&functv);
2821 
2822     return ret;
2823 }
2824 
2825 /*
2826  * Evaluate "->method()".
2827  * "*arg" points to the '-'.
2828  * Returns FAIL or OK. "*arg" is advanced to after the ')'.
2829  */
2830     static int
2831 eval_lambda(
2832     char_u	**arg,
2833     typval_T	*rettv,
2834     int		evaluate,
2835     int		verbose)	// give error messages
2836 {
2837     typval_T	base = *rettv;
2838     int		ret;
2839 
2840     // Skip over the ->.
2841     *arg += 2;
2842     rettv->v_type = VAR_UNKNOWN;
2843 
2844     ret = get_lambda_tv(arg, rettv, evaluate);
2845     if (ret != OK)
2846 	return FAIL;
2847     else if (**arg != '(')
2848     {
2849 	if (verbose)
2850 	{
2851 	    if (*skipwhite(*arg) == '(')
2852 		emsg(_(e_nowhitespace));
2853 	    else
2854 		semsg(_(e_missing_paren), "lambda");
2855 	}
2856 	clear_tv(rettv);
2857 	ret = FAIL;
2858     }
2859     else
2860 	ret = call_func_rettv(arg, rettv, evaluate, NULL, &base);
2861 
2862     // Clear the funcref afterwards, so that deleting it while
2863     // evaluating the arguments is possible (see test55).
2864     if (evaluate)
2865 	clear_tv(&base);
2866 
2867     return ret;
2868 }
2869 
2870 /*
2871  * Evaluate "->method()".
2872  * "*arg" points to the '-'.
2873  * Returns FAIL or OK. "*arg" is advanced to after the ')'.
2874  */
2875     static int
2876 eval_method(
2877     char_u	**arg,
2878     typval_T	*rettv,
2879     int		evaluate,
2880     int		verbose)	// give error messages
2881 {
2882     char_u	*name;
2883     long	len;
2884     char_u	*alias;
2885     typval_T	base = *rettv;
2886     int		ret;
2887 
2888     // Skip over the ->.
2889     *arg += 2;
2890     rettv->v_type = VAR_UNKNOWN;
2891 
2892     name = *arg;
2893     len = get_name_len(arg, &alias, evaluate, TRUE);
2894     if (alias != NULL)
2895 	name = alias;
2896 
2897     if (len <= 0)
2898     {
2899 	if (verbose)
2900 	    emsg(_("E260: Missing name after ->"));
2901 	ret = FAIL;
2902     }
2903     else
2904     {
2905 	if (**arg != '(')
2906 	{
2907 	    if (verbose)
2908 		semsg(_(e_missing_paren), name);
2909 	    ret = FAIL;
2910 	}
2911 	else if (VIM_ISWHITE((*arg)[-1]))
2912 	{
2913 	    if (verbose)
2914 		emsg(_(e_nowhitespace));
2915 	    ret = FAIL;
2916 	}
2917 	else
2918 	    ret = eval_func(arg, name, len, rettv, evaluate, &base);
2919     }
2920 
2921     // Clear the funcref afterwards, so that deleting it while
2922     // evaluating the arguments is possible (see test55).
2923     if (evaluate)
2924 	clear_tv(&base);
2925 
2926     return ret;
2927 }
2928 
2929 /*
2930  * Evaluate an "[expr]" or "[expr:expr]" index.  Also "dict.key".
2931  * "*arg" points to the '[' or '.'.
2932  * Returns FAIL or OK. "*arg" is advanced to after the ']'.
2933  */
2934     static int
2935 eval_index(
2936     char_u	**arg,
2937     typval_T	*rettv,
2938     int		evaluate,
2939     int		verbose)	// give error messages
2940 {
2941     int		empty1 = FALSE, empty2 = FALSE;
2942     typval_T	var1, var2;
2943     long	i;
2944     long	n1, n2 = 0;
2945     long	len = -1;
2946     int		range = FALSE;
2947     char_u	*s;
2948     char_u	*key = NULL;
2949 
2950     switch (rettv->v_type)
2951     {
2952 	case VAR_FUNC:
2953 	case VAR_PARTIAL:
2954 	    if (verbose)
2955 		emsg(_("E695: Cannot index a Funcref"));
2956 	    return FAIL;
2957 	case VAR_FLOAT:
2958 #ifdef FEAT_FLOAT
2959 	    if (verbose)
2960 		emsg(_(e_float_as_string));
2961 	    return FAIL;
2962 #endif
2963 	case VAR_BOOL:
2964 	case VAR_SPECIAL:
2965 	case VAR_JOB:
2966 	case VAR_CHANNEL:
2967 	    if (verbose)
2968 		emsg(_("E909: Cannot index a special variable"));
2969 	    return FAIL;
2970 	case VAR_UNKNOWN:
2971 	case VAR_ANY:
2972 	case VAR_VOID:
2973 	    if (evaluate)
2974 		return FAIL;
2975 	    // FALLTHROUGH
2976 
2977 	case VAR_STRING:
2978 	case VAR_NUMBER:
2979 	case VAR_LIST:
2980 	case VAR_DICT:
2981 	case VAR_BLOB:
2982 	    break;
2983     }
2984 
2985     init_tv(&var1);
2986     init_tv(&var2);
2987     if (**arg == '.')
2988     {
2989 	/*
2990 	 * dict.name
2991 	 */
2992 	key = *arg + 1;
2993 	for (len = 0; ASCII_ISALNUM(key[len]) || key[len] == '_'; ++len)
2994 	    ;
2995 	if (len == 0)
2996 	    return FAIL;
2997 	*arg = skipwhite(key + len);
2998     }
2999     else
3000     {
3001 	/*
3002 	 * something[idx]
3003 	 *
3004 	 * Get the (first) variable from inside the [].
3005 	 */
3006 	*arg = skipwhite(*arg + 1);
3007 	if (**arg == ':')
3008 	    empty1 = TRUE;
3009 	else if (eval1(arg, &var1, evaluate) == FAIL)	// recursive!
3010 	    return FAIL;
3011 	else if (evaluate && tv_get_string_chk(&var1) == NULL)
3012 	{
3013 	    // not a number or string
3014 	    clear_tv(&var1);
3015 	    return FAIL;
3016 	}
3017 
3018 	/*
3019 	 * Get the second variable from inside the [:].
3020 	 */
3021 	if (**arg == ':')
3022 	{
3023 	    range = TRUE;
3024 	    *arg = skipwhite(*arg + 1);
3025 	    if (**arg == ']')
3026 		empty2 = TRUE;
3027 	    else if (eval1(arg, &var2, evaluate) == FAIL)	// recursive!
3028 	    {
3029 		if (!empty1)
3030 		    clear_tv(&var1);
3031 		return FAIL;
3032 	    }
3033 	    else if (evaluate && tv_get_string_chk(&var2) == NULL)
3034 	    {
3035 		// not a number or string
3036 		if (!empty1)
3037 		    clear_tv(&var1);
3038 		clear_tv(&var2);
3039 		return FAIL;
3040 	    }
3041 	}
3042 
3043 	// Check for the ']'.
3044 	if (**arg != ']')
3045 	{
3046 	    if (verbose)
3047 		emsg(_(e_missbrac));
3048 	    clear_tv(&var1);
3049 	    if (range)
3050 		clear_tv(&var2);
3051 	    return FAIL;
3052 	}
3053 	*arg = skipwhite(*arg + 1);	// skip the ']'
3054     }
3055 
3056     if (evaluate)
3057     {
3058 	n1 = 0;
3059 	if (!empty1 && rettv->v_type != VAR_DICT)
3060 	{
3061 	    n1 = tv_get_number(&var1);
3062 	    clear_tv(&var1);
3063 	}
3064 	if (range)
3065 	{
3066 	    if (empty2)
3067 		n2 = -1;
3068 	    else
3069 	    {
3070 		n2 = tv_get_number(&var2);
3071 		clear_tv(&var2);
3072 	    }
3073 	}
3074 
3075 	switch (rettv->v_type)
3076 	{
3077 	    case VAR_UNKNOWN:
3078 	    case VAR_ANY:
3079 	    case VAR_VOID:
3080 	    case VAR_FUNC:
3081 	    case VAR_PARTIAL:
3082 	    case VAR_FLOAT:
3083 	    case VAR_BOOL:
3084 	    case VAR_SPECIAL:
3085 	    case VAR_JOB:
3086 	    case VAR_CHANNEL:
3087 		break; // not evaluating, skipping over subscript
3088 
3089 	    case VAR_NUMBER:
3090 	    case VAR_STRING:
3091 		s = tv_get_string(rettv);
3092 		len = (long)STRLEN(s);
3093 		if (range)
3094 		{
3095 		    // The resulting variable is a substring.  If the indexes
3096 		    // are out of range the result is empty.
3097 		    if (n1 < 0)
3098 		    {
3099 			n1 = len + n1;
3100 			if (n1 < 0)
3101 			    n1 = 0;
3102 		    }
3103 		    if (n2 < 0)
3104 			n2 = len + n2;
3105 		    else if (n2 >= len)
3106 			n2 = len;
3107 		    if (n1 >= len || n2 < 0 || n1 > n2)
3108 			s = NULL;
3109 		    else
3110 			s = vim_strnsave(s + n1, (int)(n2 - n1 + 1));
3111 		}
3112 		else
3113 		{
3114 		    // The resulting variable is a string of a single
3115 		    // character.  If the index is too big or negative the
3116 		    // result is empty.
3117 		    if (n1 >= len || n1 < 0)
3118 			s = NULL;
3119 		    else
3120 			s = vim_strnsave(s + n1, 1);
3121 		}
3122 		clear_tv(rettv);
3123 		rettv->v_type = VAR_STRING;
3124 		rettv->vval.v_string = s;
3125 		break;
3126 
3127 	    case VAR_BLOB:
3128 		len = blob_len(rettv->vval.v_blob);
3129 		if (range)
3130 		{
3131 		    // The resulting variable is a sub-blob.  If the indexes
3132 		    // are out of range the result is empty.
3133 		    if (n1 < 0)
3134 		    {
3135 			n1 = len + n1;
3136 			if (n1 < 0)
3137 			    n1 = 0;
3138 		    }
3139 		    if (n2 < 0)
3140 			n2 = len + n2;
3141 		    else if (n2 >= len)
3142 			n2 = len - 1;
3143 		    if (n1 >= len || n2 < 0 || n1 > n2)
3144 		    {
3145 			clear_tv(rettv);
3146 			rettv->v_type = VAR_BLOB;
3147 			rettv->vval.v_blob = NULL;
3148 		    }
3149 		    else
3150 		    {
3151 			blob_T  *blob = blob_alloc();
3152 
3153 			if (blob != NULL)
3154 			{
3155 			    if (ga_grow(&blob->bv_ga, n2 - n1 + 1) == FAIL)
3156 			    {
3157 				blob_free(blob);
3158 				return FAIL;
3159 			    }
3160 			    blob->bv_ga.ga_len = n2 - n1 + 1;
3161 			    for (i = n1; i <= n2; i++)
3162 				blob_set(blob, i - n1,
3163 					      blob_get(rettv->vval.v_blob, i));
3164 
3165 			    clear_tv(rettv);
3166 			    rettv_blob_set(rettv, blob);
3167 			}
3168 		    }
3169 		}
3170 		else
3171 		{
3172 		    // The resulting variable is a byte value.
3173 		    // If the index is too big or negative that is an error.
3174 		    if (n1 < 0)
3175 			n1 = len + n1;
3176 		    if (n1 < len && n1 >= 0)
3177 		    {
3178 			int v = blob_get(rettv->vval.v_blob, n1);
3179 
3180 			clear_tv(rettv);
3181 			rettv->v_type = VAR_NUMBER;
3182 			rettv->vval.v_number = v;
3183 		    }
3184 		    else
3185 			semsg(_(e_blobidx), n1);
3186 		}
3187 		break;
3188 
3189 	    case VAR_LIST:
3190 		len = list_len(rettv->vval.v_list);
3191 		if (n1 < 0)
3192 		    n1 = len + n1;
3193 		if (!empty1 && (n1 < 0 || n1 >= len))
3194 		{
3195 		    // For a range we allow invalid values and return an empty
3196 		    // list.  A list index out of range is an error.
3197 		    if (!range)
3198 		    {
3199 			if (verbose)
3200 			    semsg(_(e_listidx), n1);
3201 			return FAIL;
3202 		    }
3203 		    n1 = len;
3204 		}
3205 		if (range)
3206 		{
3207 		    list_T	*l;
3208 		    listitem_T	*item;
3209 
3210 		    if (n2 < 0)
3211 			n2 = len + n2;
3212 		    else if (n2 >= len)
3213 			n2 = len - 1;
3214 		    if (!empty2 && (n2 < 0 || n2 + 1 < n1))
3215 			n2 = -1;
3216 		    l = list_alloc();
3217 		    if (l == NULL)
3218 			return FAIL;
3219 		    for (item = list_find(rettv->vval.v_list, n1);
3220 							       n1 <= n2; ++n1)
3221 		    {
3222 			if (list_append_tv(l, &item->li_tv) == FAIL)
3223 			{
3224 			    list_free(l);
3225 			    return FAIL;
3226 			}
3227 			item = item->li_next;
3228 		    }
3229 		    clear_tv(rettv);
3230 		    rettv_list_set(rettv, l);
3231 		}
3232 		else
3233 		{
3234 		    copy_tv(&list_find(rettv->vval.v_list, n1)->li_tv, &var1);
3235 		    clear_tv(rettv);
3236 		    *rettv = var1;
3237 		}
3238 		break;
3239 
3240 	    case VAR_DICT:
3241 		if (range)
3242 		{
3243 		    if (verbose)
3244 			emsg(_(e_dictrange));
3245 		    if (len == -1)
3246 			clear_tv(&var1);
3247 		    return FAIL;
3248 		}
3249 		{
3250 		    dictitem_T	*item;
3251 
3252 		    if (len == -1)
3253 		    {
3254 			key = tv_get_string_chk(&var1);
3255 			if (key == NULL)
3256 			{
3257 			    clear_tv(&var1);
3258 			    return FAIL;
3259 			}
3260 		    }
3261 
3262 		    item = dict_find(rettv->vval.v_dict, key, (int)len);
3263 
3264 		    if (item == NULL && verbose)
3265 			semsg(_(e_dictkey), key);
3266 		    if (len == -1)
3267 			clear_tv(&var1);
3268 		    if (item == NULL)
3269 			return FAIL;
3270 
3271 		    copy_tv(&item->di_tv, &var1);
3272 		    clear_tv(rettv);
3273 		    *rettv = var1;
3274 		}
3275 		break;
3276 	}
3277     }
3278 
3279     return OK;
3280 }
3281 
3282 /*
3283  * Get an option value.
3284  * "arg" points to the '&' or '+' before the option name.
3285  * "arg" is advanced to character after the option name.
3286  * Return OK or FAIL.
3287  */
3288     int
3289 get_option_tv(
3290     char_u	**arg,
3291     typval_T	*rettv,	// when NULL, only check if option exists
3292     int		evaluate)
3293 {
3294     char_u	*option_end;
3295     long	numval;
3296     char_u	*stringval;
3297     int		opt_type;
3298     int		c;
3299     int		working = (**arg == '+');    // has("+option")
3300     int		ret = OK;
3301     int		opt_flags;
3302 
3303     /*
3304      * Isolate the option name and find its value.
3305      */
3306     option_end = find_option_end(arg, &opt_flags);
3307     if (option_end == NULL)
3308     {
3309 	if (rettv != NULL)
3310 	    semsg(_("E112: Option name missing: %s"), *arg);
3311 	return FAIL;
3312     }
3313 
3314     if (!evaluate)
3315     {
3316 	*arg = option_end;
3317 	return OK;
3318     }
3319 
3320     c = *option_end;
3321     *option_end = NUL;
3322     opt_type = get_option_value(*arg, &numval,
3323 			       rettv == NULL ? NULL : &stringval, opt_flags);
3324 
3325     if (opt_type == -3)			// invalid name
3326     {
3327 	if (rettv != NULL)
3328 	    semsg(_(e_unknown_option), *arg);
3329 	ret = FAIL;
3330     }
3331     else if (rettv != NULL)
3332     {
3333 	if (opt_type == -2)		// hidden string option
3334 	{
3335 	    rettv->v_type = VAR_STRING;
3336 	    rettv->vval.v_string = NULL;
3337 	}
3338 	else if (opt_type == -1)	// hidden number option
3339 	{
3340 	    rettv->v_type = VAR_NUMBER;
3341 	    rettv->vval.v_number = 0;
3342 	}
3343 	else if (opt_type == 1)		// number option
3344 	{
3345 	    rettv->v_type = VAR_NUMBER;
3346 	    rettv->vval.v_number = numval;
3347 	}
3348 	else				// string option
3349 	{
3350 	    rettv->v_type = VAR_STRING;
3351 	    rettv->vval.v_string = stringval;
3352 	}
3353     }
3354     else if (working && (opt_type == -2 || opt_type == -1))
3355 	ret = FAIL;
3356 
3357     *option_end = c;		    // put back for error messages
3358     *arg = option_end;
3359 
3360     return ret;
3361 }
3362 
3363 /*
3364  * Allocate a variable for a number constant.  Also deals with "0z" for blob.
3365  * Return OK or FAIL.
3366  */
3367     int
3368 get_number_tv(
3369 	char_u	    **arg,
3370 	typval_T    *rettv,
3371 	int	    evaluate,
3372 	int	    want_string UNUSED)
3373 {
3374     int		len;
3375 #ifdef FEAT_FLOAT
3376     char_u	*p;
3377     int		get_float = FALSE;
3378 
3379     // We accept a float when the format matches
3380     // "[0-9]\+\.[0-9]\+\([eE][+-]\?[0-9]\+\)\?".  This is very
3381     // strict to avoid backwards compatibility problems.
3382     // With script version 2 and later the leading digit can be
3383     // omitted.
3384     // Don't look for a float after the "." operator, so that
3385     // ":let vers = 1.2.3" doesn't fail.
3386     if (**arg == '.')
3387 	p = *arg;
3388     else
3389 	p = skipdigits(*arg + 1);
3390     if (!want_string && p[0] == '.' && vim_isdigit(p[1]))
3391     {
3392 	get_float = TRUE;
3393 	p = skipdigits(p + 2);
3394 	if (*p == 'e' || *p == 'E')
3395 	{
3396 	    ++p;
3397 	    if (*p == '-' || *p == '+')
3398 		++p;
3399 	    if (!vim_isdigit(*p))
3400 		get_float = FALSE;
3401 	    else
3402 		p = skipdigits(p + 1);
3403 	}
3404 	if (ASCII_ISALPHA(*p) || *p == '.')
3405 	    get_float = FALSE;
3406     }
3407     if (get_float)
3408     {
3409 	float_T	f;
3410 
3411 	*arg += string2float(*arg, &f);
3412 	if (evaluate)
3413 	{
3414 	    rettv->v_type = VAR_FLOAT;
3415 	    rettv->vval.v_float = f;
3416 	}
3417     }
3418     else
3419 #endif
3420     if (**arg == '0' && ((*arg)[1] == 'z' || (*arg)[1] == 'Z'))
3421     {
3422 	char_u  *bp;
3423 	blob_T  *blob = NULL;  // init for gcc
3424 
3425 	// Blob constant: 0z0123456789abcdef
3426 	if (evaluate)
3427 	    blob = blob_alloc();
3428 	for (bp = *arg + 2; vim_isxdigit(bp[0]); bp += 2)
3429 	{
3430 	    if (!vim_isxdigit(bp[1]))
3431 	    {
3432 		if (blob != NULL)
3433 		{
3434 		    emsg(_("E973: Blob literal should have an even number of hex characters"));
3435 		    ga_clear(&blob->bv_ga);
3436 		    VIM_CLEAR(blob);
3437 		}
3438 		return FAIL;
3439 	    }
3440 	    if (blob != NULL)
3441 		ga_append(&blob->bv_ga,
3442 			     (hex2nr(*bp) << 4) + hex2nr(*(bp+1)));
3443 	    if (bp[2] == '.' && vim_isxdigit(bp[3]))
3444 		++bp;
3445 	}
3446 	if (blob != NULL)
3447 	    rettv_blob_set(rettv, blob);
3448 	*arg = bp;
3449     }
3450     else
3451     {
3452 	varnumber_T	n;
3453 
3454 	// decimal, hex or octal number
3455 	vim_str2nr(*arg, NULL, &len, current_sctx.sc_version >= 4
3456 		      ? STR2NR_NO_OCT + STR2NR_QUOTE
3457 		      : STR2NR_ALL, &n, NULL, 0, TRUE);
3458 	if (len == 0)
3459 	{
3460 	    semsg(_(e_invexpr2), *arg);
3461 	    return FAIL;
3462 	}
3463 	*arg += len;
3464 	if (evaluate)
3465 	{
3466 	    rettv->v_type = VAR_NUMBER;
3467 	    rettv->vval.v_number = n;
3468 	}
3469     }
3470     return OK;
3471 }
3472 
3473 /*
3474  * Allocate a variable for a string constant.
3475  * Return OK or FAIL.
3476  */
3477     int
3478 get_string_tv(char_u **arg, typval_T *rettv, int evaluate)
3479 {
3480     char_u	*p;
3481     char_u	*name;
3482     int		extra = 0;
3483 
3484     /*
3485      * Find the end of the string, skipping backslashed characters.
3486      */
3487     for (p = *arg + 1; *p != NUL && *p != '"'; MB_PTR_ADV(p))
3488     {
3489 	if (*p == '\\' && p[1] != NUL)
3490 	{
3491 	    ++p;
3492 	    // A "\<x>" form occupies at least 4 characters, and produces up
3493 	    // to 6 characters: reserve space for 2 extra
3494 	    if (*p == '<')
3495 		extra += 2;
3496 	}
3497     }
3498 
3499     if (*p != '"')
3500     {
3501 	semsg(_("E114: Missing quote: %s"), *arg);
3502 	return FAIL;
3503     }
3504 
3505     // If only parsing, set *arg and return here
3506     if (!evaluate)
3507     {
3508 	*arg = p + 1;
3509 	return OK;
3510     }
3511 
3512     /*
3513      * Copy the string into allocated memory, handling backslashed
3514      * characters.
3515      */
3516     name = alloc(p - *arg + extra);
3517     if (name == NULL)
3518 	return FAIL;
3519     rettv->v_type = VAR_STRING;
3520     rettv->vval.v_string = name;
3521 
3522     for (p = *arg + 1; *p != NUL && *p != '"'; )
3523     {
3524 	if (*p == '\\')
3525 	{
3526 	    switch (*++p)
3527 	    {
3528 		case 'b': *name++ = BS; ++p; break;
3529 		case 'e': *name++ = ESC; ++p; break;
3530 		case 'f': *name++ = FF; ++p; break;
3531 		case 'n': *name++ = NL; ++p; break;
3532 		case 'r': *name++ = CAR; ++p; break;
3533 		case 't': *name++ = TAB; ++p; break;
3534 
3535 		case 'X': // hex: "\x1", "\x12"
3536 		case 'x':
3537 		case 'u': // Unicode: "\u0023"
3538 		case 'U':
3539 			  if (vim_isxdigit(p[1]))
3540 			  {
3541 			      int	n, nr;
3542 			      int	c = toupper(*p);
3543 
3544 			      if (c == 'X')
3545 				  n = 2;
3546 			      else if (*p == 'u')
3547 				  n = 4;
3548 			      else
3549 				  n = 8;
3550 			      nr = 0;
3551 			      while (--n >= 0 && vim_isxdigit(p[1]))
3552 			      {
3553 				  ++p;
3554 				  nr = (nr << 4) + hex2nr(*p);
3555 			      }
3556 			      ++p;
3557 			      // For "\u" store the number according to
3558 			      // 'encoding'.
3559 			      if (c != 'X')
3560 				  name += (*mb_char2bytes)(nr, name);
3561 			      else
3562 				  *name++ = nr;
3563 			  }
3564 			  break;
3565 
3566 			  // octal: "\1", "\12", "\123"
3567 		case '0':
3568 		case '1':
3569 		case '2':
3570 		case '3':
3571 		case '4':
3572 		case '5':
3573 		case '6':
3574 		case '7': *name = *p++ - '0';
3575 			  if (*p >= '0' && *p <= '7')
3576 			  {
3577 			      *name = (*name << 3) + *p++ - '0';
3578 			      if (*p >= '0' && *p <= '7')
3579 				  *name = (*name << 3) + *p++ - '0';
3580 			  }
3581 			  ++name;
3582 			  break;
3583 
3584 			    // Special key, e.g.: "\<C-W>"
3585 		case '<': extra = trans_special(&p, name, TRUE, TRUE,
3586 								   TRUE, NULL);
3587 			  if (extra != 0)
3588 			  {
3589 			      name += extra;
3590 			      break;
3591 			  }
3592 			  // FALLTHROUGH
3593 
3594 		default:  MB_COPY_CHAR(p, name);
3595 			  break;
3596 	    }
3597 	}
3598 	else
3599 	    MB_COPY_CHAR(p, name);
3600 
3601     }
3602     *name = NUL;
3603     if (*p != NUL) // just in case
3604 	++p;
3605     *arg = p;
3606 
3607     return OK;
3608 }
3609 
3610 /*
3611  * Allocate a variable for a 'str''ing' constant.
3612  * Return OK or FAIL.
3613  */
3614     int
3615 get_lit_string_tv(char_u **arg, typval_T *rettv, int evaluate)
3616 {
3617     char_u	*p;
3618     char_u	*str;
3619     int		reduce = 0;
3620 
3621     /*
3622      * Find the end of the string, skipping ''.
3623      */
3624     for (p = *arg + 1; *p != NUL; MB_PTR_ADV(p))
3625     {
3626 	if (*p == '\'')
3627 	{
3628 	    if (p[1] != '\'')
3629 		break;
3630 	    ++reduce;
3631 	    ++p;
3632 	}
3633     }
3634 
3635     if (*p != '\'')
3636     {
3637 	semsg(_("E115: Missing quote: %s"), *arg);
3638 	return FAIL;
3639     }
3640 
3641     // If only parsing return after setting "*arg"
3642     if (!evaluate)
3643     {
3644 	*arg = p + 1;
3645 	return OK;
3646     }
3647 
3648     /*
3649      * Copy the string into allocated memory, handling '' to ' reduction.
3650      */
3651     str = alloc((p - *arg) - reduce);
3652     if (str == NULL)
3653 	return FAIL;
3654     rettv->v_type = VAR_STRING;
3655     rettv->vval.v_string = str;
3656 
3657     for (p = *arg + 1; *p != NUL; )
3658     {
3659 	if (*p == '\'')
3660 	{
3661 	    if (p[1] != '\'')
3662 		break;
3663 	    ++p;
3664 	}
3665 	MB_COPY_CHAR(p, str);
3666     }
3667     *str = NUL;
3668     *arg = p + 1;
3669 
3670     return OK;
3671 }
3672 
3673 /*
3674  * Return the function name of partial "pt".
3675  */
3676     char_u *
3677 partial_name(partial_T *pt)
3678 {
3679     if (pt->pt_name != NULL)
3680 	return pt->pt_name;
3681     return pt->pt_func->uf_name;
3682 }
3683 
3684     static void
3685 partial_free(partial_T *pt)
3686 {
3687     int i;
3688 
3689     for (i = 0; i < pt->pt_argc; ++i)
3690 	clear_tv(&pt->pt_argv[i]);
3691     vim_free(pt->pt_argv);
3692     dict_unref(pt->pt_dict);
3693     if (pt->pt_name != NULL)
3694     {
3695 	func_unref(pt->pt_name);
3696 	vim_free(pt->pt_name);
3697     }
3698     else
3699 	func_ptr_unref(pt->pt_func);
3700     vim_free(pt);
3701 }
3702 
3703 /*
3704  * Unreference a closure: decrement the reference count and free it when it
3705  * becomes zero.
3706  */
3707     void
3708 partial_unref(partial_T *pt)
3709 {
3710     if (pt != NULL && --pt->pt_refcount <= 0)
3711 	partial_free(pt);
3712 }
3713 
3714 static int tv_equal_recurse_limit;
3715 
3716     static int
3717 func_equal(
3718     typval_T *tv1,
3719     typval_T *tv2,
3720     int	     ic)	    // ignore case
3721 {
3722     char_u	*s1, *s2;
3723     dict_T	*d1, *d2;
3724     int		a1, a2;
3725     int		i;
3726 
3727     // empty and NULL function name considered the same
3728     s1 = tv1->v_type == VAR_FUNC ? tv1->vval.v_string
3729 					   : partial_name(tv1->vval.v_partial);
3730     if (s1 != NULL && *s1 == NUL)
3731 	s1 = NULL;
3732     s2 = tv2->v_type == VAR_FUNC ? tv2->vval.v_string
3733 					   : partial_name(tv2->vval.v_partial);
3734     if (s2 != NULL && *s2 == NUL)
3735 	s2 = NULL;
3736     if (s1 == NULL || s2 == NULL)
3737     {
3738 	if (s1 != s2)
3739 	    return FALSE;
3740     }
3741     else if (STRCMP(s1, s2) != 0)
3742 	return FALSE;
3743 
3744     // empty dict and NULL dict is different
3745     d1 = tv1->v_type == VAR_FUNC ? NULL : tv1->vval.v_partial->pt_dict;
3746     d2 = tv2->v_type == VAR_FUNC ? NULL : tv2->vval.v_partial->pt_dict;
3747     if (d1 == NULL || d2 == NULL)
3748     {
3749 	if (d1 != d2)
3750 	    return FALSE;
3751     }
3752     else if (!dict_equal(d1, d2, ic, TRUE))
3753 	return FALSE;
3754 
3755     // empty list and no list considered the same
3756     a1 = tv1->v_type == VAR_FUNC ? 0 : tv1->vval.v_partial->pt_argc;
3757     a2 = tv2->v_type == VAR_FUNC ? 0 : tv2->vval.v_partial->pt_argc;
3758     if (a1 != a2)
3759 	return FALSE;
3760     for (i = 0; i < a1; ++i)
3761 	if (!tv_equal(tv1->vval.v_partial->pt_argv + i,
3762 		      tv2->vval.v_partial->pt_argv + i, ic, TRUE))
3763 	    return FALSE;
3764 
3765     return TRUE;
3766 }
3767 
3768 /*
3769  * Return TRUE if "tv1" and "tv2" have the same value.
3770  * Compares the items just like "==" would compare them, but strings and
3771  * numbers are different.  Floats and numbers are also different.
3772  */
3773     int
3774 tv_equal(
3775     typval_T *tv1,
3776     typval_T *tv2,
3777     int	     ic,	    // ignore case
3778     int	     recursive)	    // TRUE when used recursively
3779 {
3780     char_u	buf1[NUMBUFLEN], buf2[NUMBUFLEN];
3781     char_u	*s1, *s2;
3782     static int  recursive_cnt = 0;	    // catch recursive loops
3783     int		r;
3784 
3785     // Catch lists and dicts that have an endless loop by limiting
3786     // recursiveness to a limit.  We guess they are equal then.
3787     // A fixed limit has the problem of still taking an awful long time.
3788     // Reduce the limit every time running into it. That should work fine for
3789     // deeply linked structures that are not recursively linked and catch
3790     // recursiveness quickly.
3791     if (!recursive)
3792 	tv_equal_recurse_limit = 1000;
3793     if (recursive_cnt >= tv_equal_recurse_limit)
3794     {
3795 	--tv_equal_recurse_limit;
3796 	return TRUE;
3797     }
3798 
3799     // For VAR_FUNC and VAR_PARTIAL compare the function name, bound dict and
3800     // arguments.
3801     if ((tv1->v_type == VAR_FUNC
3802 		|| (tv1->v_type == VAR_PARTIAL && tv1->vval.v_partial != NULL))
3803 	    && (tv2->v_type == VAR_FUNC
3804 		|| (tv2->v_type == VAR_PARTIAL && tv2->vval.v_partial != NULL)))
3805     {
3806 	++recursive_cnt;
3807 	r = func_equal(tv1, tv2, ic);
3808 	--recursive_cnt;
3809 	return r;
3810     }
3811 
3812     if (tv1->v_type != tv2->v_type)
3813 	return FALSE;
3814 
3815     switch (tv1->v_type)
3816     {
3817 	case VAR_LIST:
3818 	    ++recursive_cnt;
3819 	    r = list_equal(tv1->vval.v_list, tv2->vval.v_list, ic, TRUE);
3820 	    --recursive_cnt;
3821 	    return r;
3822 
3823 	case VAR_DICT:
3824 	    ++recursive_cnt;
3825 	    r = dict_equal(tv1->vval.v_dict, tv2->vval.v_dict, ic, TRUE);
3826 	    --recursive_cnt;
3827 	    return r;
3828 
3829 	case VAR_BLOB:
3830 	    return blob_equal(tv1->vval.v_blob, tv2->vval.v_blob);
3831 
3832 	case VAR_NUMBER:
3833 	case VAR_BOOL:
3834 	case VAR_SPECIAL:
3835 	    return tv1->vval.v_number == tv2->vval.v_number;
3836 
3837 	case VAR_STRING:
3838 	    s1 = tv_get_string_buf(tv1, buf1);
3839 	    s2 = tv_get_string_buf(tv2, buf2);
3840 	    return ((ic ? MB_STRICMP(s1, s2) : STRCMP(s1, s2)) == 0);
3841 
3842 	case VAR_FLOAT:
3843 #ifdef FEAT_FLOAT
3844 	    return tv1->vval.v_float == tv2->vval.v_float;
3845 #endif
3846 	case VAR_JOB:
3847 #ifdef FEAT_JOB_CHANNEL
3848 	    return tv1->vval.v_job == tv2->vval.v_job;
3849 #endif
3850 	case VAR_CHANNEL:
3851 #ifdef FEAT_JOB_CHANNEL
3852 	    return tv1->vval.v_channel == tv2->vval.v_channel;
3853 #endif
3854 
3855 	case VAR_PARTIAL:
3856 	    return tv1->vval.v_partial == tv2->vval.v_partial;
3857 
3858 	case VAR_FUNC:
3859 	    return tv1->vval.v_string == tv2->vval.v_string;
3860 
3861 	case VAR_UNKNOWN:
3862 	case VAR_ANY:
3863 	case VAR_VOID:
3864 	    break;
3865     }
3866 
3867     // VAR_UNKNOWN can be the result of a invalid expression, let's say it
3868     // does not equal anything, not even itself.
3869     return FALSE;
3870 }
3871 
3872 /*
3873  * Return the next (unique) copy ID.
3874  * Used for serializing nested structures.
3875  */
3876     int
3877 get_copyID(void)
3878 {
3879     current_copyID += COPYID_INC;
3880     return current_copyID;
3881 }
3882 
3883 /*
3884  * Garbage collection for lists and dictionaries.
3885  *
3886  * We use reference counts to be able to free most items right away when they
3887  * are no longer used.  But for composite items it's possible that it becomes
3888  * unused while the reference count is > 0: When there is a recursive
3889  * reference.  Example:
3890  *	:let l = [1, 2, 3]
3891  *	:let d = {9: l}
3892  *	:let l[1] = d
3893  *
3894  * Since this is quite unusual we handle this with garbage collection: every
3895  * once in a while find out which lists and dicts are not referenced from any
3896  * variable.
3897  *
3898  * Here is a good reference text about garbage collection (refers to Python
3899  * but it applies to all reference-counting mechanisms):
3900  *	http://python.ca/nas/python/gc/
3901  */
3902 
3903 /*
3904  * Do garbage collection for lists and dicts.
3905  * When "testing" is TRUE this is called from test_garbagecollect_now().
3906  * Return TRUE if some memory was freed.
3907  */
3908     int
3909 garbage_collect(int testing)
3910 {
3911     int		copyID;
3912     int		abort = FALSE;
3913     buf_T	*buf;
3914     win_T	*wp;
3915     int		did_free = FALSE;
3916     tabpage_T	*tp;
3917 
3918     if (!testing)
3919     {
3920 	// Only do this once.
3921 	want_garbage_collect = FALSE;
3922 	may_garbage_collect = FALSE;
3923 	garbage_collect_at_exit = FALSE;
3924     }
3925 
3926     // The execution stack can grow big, limit the size.
3927     if (exestack.ga_maxlen - exestack.ga_len > 500)
3928     {
3929 	size_t	new_len;
3930 	char_u	*pp;
3931 	int	n;
3932 
3933 	// Keep 150% of the current size, with a minimum of the growth size.
3934 	n = exestack.ga_len / 2;
3935 	if (n < exestack.ga_growsize)
3936 	    n = exestack.ga_growsize;
3937 
3938 	// Don't make it bigger though.
3939 	if (exestack.ga_len + n < exestack.ga_maxlen)
3940 	{
3941 	    new_len = exestack.ga_itemsize * (exestack.ga_len + n);
3942 	    pp = vim_realloc(exestack.ga_data, new_len);
3943 	    if (pp == NULL)
3944 		return FAIL;
3945 	    exestack.ga_maxlen = exestack.ga_len + n;
3946 	    exestack.ga_data = pp;
3947 	}
3948     }
3949 
3950     // We advance by two because we add one for items referenced through
3951     // previous_funccal.
3952     copyID = get_copyID();
3953 
3954     /*
3955      * 1. Go through all accessible variables and mark all lists and dicts
3956      *    with copyID.
3957      */
3958 
3959     // Don't free variables in the previous_funccal list unless they are only
3960     // referenced through previous_funccal.  This must be first, because if
3961     // the item is referenced elsewhere the funccal must not be freed.
3962     abort = abort || set_ref_in_previous_funccal(copyID);
3963 
3964     // script-local variables
3965     abort = abort || garbage_collect_scriptvars(copyID);
3966 
3967     // buffer-local variables
3968     FOR_ALL_BUFFERS(buf)
3969 	abort = abort || set_ref_in_item(&buf->b_bufvar.di_tv, copyID,
3970 								  NULL, NULL);
3971 
3972     // window-local variables
3973     FOR_ALL_TAB_WINDOWS(tp, wp)
3974 	abort = abort || set_ref_in_item(&wp->w_winvar.di_tv, copyID,
3975 								  NULL, NULL);
3976     if (aucmd_win != NULL)
3977 	abort = abort || set_ref_in_item(&aucmd_win->w_winvar.di_tv, copyID,
3978 								  NULL, NULL);
3979 #ifdef FEAT_PROP_POPUP
3980     FOR_ALL_POPUPWINS(wp)
3981 	abort = abort || set_ref_in_item(&wp->w_winvar.di_tv, copyID,
3982 								  NULL, NULL);
3983     FOR_ALL_TABPAGES(tp)
3984 	FOR_ALL_POPUPWINS_IN_TAB(tp, wp)
3985 		abort = abort || set_ref_in_item(&wp->w_winvar.di_tv, copyID,
3986 								  NULL, NULL);
3987 #endif
3988 
3989     // tabpage-local variables
3990     FOR_ALL_TABPAGES(tp)
3991 	abort = abort || set_ref_in_item(&tp->tp_winvar.di_tv, copyID,
3992 								  NULL, NULL);
3993     // global variables
3994     abort = abort || garbage_collect_globvars(copyID);
3995 
3996     // function-local variables
3997     abort = abort || set_ref_in_call_stack(copyID);
3998 
3999     // named functions (matters for closures)
4000     abort = abort || set_ref_in_functions(copyID);
4001 
4002     // function call arguments, if v:testing is set.
4003     abort = abort || set_ref_in_func_args(copyID);
4004 
4005     // v: vars
4006     abort = abort || garbage_collect_vimvars(copyID);
4007 
4008     // callbacks in buffers
4009     abort = abort || set_ref_in_buffers(copyID);
4010 
4011 #ifdef FEAT_LUA
4012     abort = abort || set_ref_in_lua(copyID);
4013 #endif
4014 
4015 #ifdef FEAT_PYTHON
4016     abort = abort || set_ref_in_python(copyID);
4017 #endif
4018 
4019 #ifdef FEAT_PYTHON3
4020     abort = abort || set_ref_in_python3(copyID);
4021 #endif
4022 
4023 #ifdef FEAT_JOB_CHANNEL
4024     abort = abort || set_ref_in_channel(copyID);
4025     abort = abort || set_ref_in_job(copyID);
4026 #endif
4027 #ifdef FEAT_NETBEANS_INTG
4028     abort = abort || set_ref_in_nb_channel(copyID);
4029 #endif
4030 
4031 #ifdef FEAT_TIMERS
4032     abort = abort || set_ref_in_timer(copyID);
4033 #endif
4034 
4035 #ifdef FEAT_QUICKFIX
4036     abort = abort || set_ref_in_quickfix(copyID);
4037 #endif
4038 
4039 #ifdef FEAT_TERMINAL
4040     abort = abort || set_ref_in_term(copyID);
4041 #endif
4042 
4043 #ifdef FEAT_PROP_POPUP
4044     abort = abort || set_ref_in_popups(copyID);
4045 #endif
4046 
4047     if (!abort)
4048     {
4049 	/*
4050 	 * 2. Free lists and dictionaries that are not referenced.
4051 	 */
4052 	did_free = free_unref_items(copyID);
4053 
4054 	/*
4055 	 * 3. Check if any funccal can be freed now.
4056 	 *    This may call us back recursively.
4057 	 */
4058 	free_unref_funccal(copyID, testing);
4059     }
4060     else if (p_verbose > 0)
4061     {
4062 	verb_msg(_("Not enough memory to set references, garbage collection aborted!"));
4063     }
4064 
4065     return did_free;
4066 }
4067 
4068 /*
4069  * Free lists, dictionaries, channels and jobs that are no longer referenced.
4070  */
4071     static int
4072 free_unref_items(int copyID)
4073 {
4074     int		did_free = FALSE;
4075 
4076     // Let all "free" functions know that we are here.  This means no
4077     // dictionaries, lists, channels or jobs are to be freed, because we will
4078     // do that here.
4079     in_free_unref_items = TRUE;
4080 
4081     /*
4082      * PASS 1: free the contents of the items.  We don't free the items
4083      * themselves yet, so that it is possible to decrement refcount counters
4084      */
4085 
4086     // Go through the list of dicts and free items without the copyID.
4087     did_free |= dict_free_nonref(copyID);
4088 
4089     // Go through the list of lists and free items without the copyID.
4090     did_free |= list_free_nonref(copyID);
4091 
4092 #ifdef FEAT_JOB_CHANNEL
4093     // Go through the list of jobs and free items without the copyID. This
4094     // must happen before doing channels, because jobs refer to channels, but
4095     // the reference from the channel to the job isn't tracked.
4096     did_free |= free_unused_jobs_contents(copyID, COPYID_MASK);
4097 
4098     // Go through the list of channels and free items without the copyID.
4099     did_free |= free_unused_channels_contents(copyID, COPYID_MASK);
4100 #endif
4101 
4102     /*
4103      * PASS 2: free the items themselves.
4104      */
4105     dict_free_items(copyID);
4106     list_free_items(copyID);
4107 
4108 #ifdef FEAT_JOB_CHANNEL
4109     // Go through the list of jobs and free items without the copyID. This
4110     // must happen before doing channels, because jobs refer to channels, but
4111     // the reference from the channel to the job isn't tracked.
4112     free_unused_jobs(copyID, COPYID_MASK);
4113 
4114     // Go through the list of channels and free items without the copyID.
4115     free_unused_channels(copyID, COPYID_MASK);
4116 #endif
4117 
4118     in_free_unref_items = FALSE;
4119 
4120     return did_free;
4121 }
4122 
4123 /*
4124  * Mark all lists and dicts referenced through hashtab "ht" with "copyID".
4125  * "list_stack" is used to add lists to be marked.  Can be NULL.
4126  *
4127  * Returns TRUE if setting references failed somehow.
4128  */
4129     int
4130 set_ref_in_ht(hashtab_T *ht, int copyID, list_stack_T **list_stack)
4131 {
4132     int		todo;
4133     int		abort = FALSE;
4134     hashitem_T	*hi;
4135     hashtab_T	*cur_ht;
4136     ht_stack_T	*ht_stack = NULL;
4137     ht_stack_T	*tempitem;
4138 
4139     cur_ht = ht;
4140     for (;;)
4141     {
4142 	if (!abort)
4143 	{
4144 	    // Mark each item in the hashtab.  If the item contains a hashtab
4145 	    // it is added to ht_stack, if it contains a list it is added to
4146 	    // list_stack.
4147 	    todo = (int)cur_ht->ht_used;
4148 	    for (hi = cur_ht->ht_array; todo > 0; ++hi)
4149 		if (!HASHITEM_EMPTY(hi))
4150 		{
4151 		    --todo;
4152 		    abort = abort || set_ref_in_item(&HI2DI(hi)->di_tv, copyID,
4153 						       &ht_stack, list_stack);
4154 		}
4155 	}
4156 
4157 	if (ht_stack == NULL)
4158 	    break;
4159 
4160 	// take an item from the stack
4161 	cur_ht = ht_stack->ht;
4162 	tempitem = ht_stack;
4163 	ht_stack = ht_stack->prev;
4164 	free(tempitem);
4165     }
4166 
4167     return abort;
4168 }
4169 
4170 /*
4171  * Mark a dict and its items with "copyID".
4172  * Returns TRUE if setting references failed somehow.
4173  */
4174     int
4175 set_ref_in_dict(dict_T *d, int copyID)
4176 {
4177     if (d != NULL && d->dv_copyID != copyID)
4178     {
4179 	d->dv_copyID = copyID;
4180 	return set_ref_in_ht(&d->dv_hashtab, copyID, NULL);
4181     }
4182     return FALSE;
4183 }
4184 
4185 /*
4186  * Mark a list and its items with "copyID".
4187  * Returns TRUE if setting references failed somehow.
4188  */
4189     int
4190 set_ref_in_list(list_T *ll, int copyID)
4191 {
4192     if (ll != NULL && ll->lv_copyID != copyID)
4193     {
4194 	ll->lv_copyID = copyID;
4195 	return set_ref_in_list_items(ll, copyID, NULL);
4196     }
4197     return FALSE;
4198 }
4199 
4200 /*
4201  * Mark all lists and dicts referenced through list "l" with "copyID".
4202  * "ht_stack" is used to add hashtabs to be marked.  Can be NULL.
4203  *
4204  * Returns TRUE if setting references failed somehow.
4205  */
4206     int
4207 set_ref_in_list_items(list_T *l, int copyID, ht_stack_T **ht_stack)
4208 {
4209     listitem_T	 *li;
4210     int		 abort = FALSE;
4211     list_T	 *cur_l;
4212     list_stack_T *list_stack = NULL;
4213     list_stack_T *tempitem;
4214 
4215     cur_l = l;
4216     for (;;)
4217     {
4218 	if (!abort && cur_l->lv_first != &range_list_item)
4219 	    // Mark each item in the list.  If the item contains a hashtab
4220 	    // it is added to ht_stack, if it contains a list it is added to
4221 	    // list_stack.
4222 	    for (li = cur_l->lv_first; !abort && li != NULL; li = li->li_next)
4223 		abort = abort || set_ref_in_item(&li->li_tv, copyID,
4224 						       ht_stack, &list_stack);
4225 	if (list_stack == NULL)
4226 	    break;
4227 
4228 	// take an item from the stack
4229 	cur_l = list_stack->list;
4230 	tempitem = list_stack;
4231 	list_stack = list_stack->prev;
4232 	free(tempitem);
4233     }
4234 
4235     return abort;
4236 }
4237 
4238 /*
4239  * Mark all lists and dicts referenced through typval "tv" with "copyID".
4240  * "list_stack" is used to add lists to be marked.  Can be NULL.
4241  * "ht_stack" is used to add hashtabs to be marked.  Can be NULL.
4242  *
4243  * Returns TRUE if setting references failed somehow.
4244  */
4245     int
4246 set_ref_in_item(
4247     typval_T	    *tv,
4248     int		    copyID,
4249     ht_stack_T	    **ht_stack,
4250     list_stack_T    **list_stack)
4251 {
4252     int		abort = FALSE;
4253 
4254     if (tv->v_type == VAR_DICT)
4255     {
4256 	dict_T	*dd = tv->vval.v_dict;
4257 
4258 	if (dd != NULL && dd->dv_copyID != copyID)
4259 	{
4260 	    // Didn't see this dict yet.
4261 	    dd->dv_copyID = copyID;
4262 	    if (ht_stack == NULL)
4263 	    {
4264 		abort = set_ref_in_ht(&dd->dv_hashtab, copyID, list_stack);
4265 	    }
4266 	    else
4267 	    {
4268 		ht_stack_T *newitem = (ht_stack_T*)malloc(sizeof(ht_stack_T));
4269 		if (newitem == NULL)
4270 		    abort = TRUE;
4271 		else
4272 		{
4273 		    newitem->ht = &dd->dv_hashtab;
4274 		    newitem->prev = *ht_stack;
4275 		    *ht_stack = newitem;
4276 		}
4277 	    }
4278 	}
4279     }
4280     else if (tv->v_type == VAR_LIST)
4281     {
4282 	list_T	*ll = tv->vval.v_list;
4283 
4284 	if (ll != NULL && ll->lv_copyID != copyID)
4285 	{
4286 	    // Didn't see this list yet.
4287 	    ll->lv_copyID = copyID;
4288 	    if (list_stack == NULL)
4289 	    {
4290 		abort = set_ref_in_list_items(ll, copyID, ht_stack);
4291 	    }
4292 	    else
4293 	    {
4294 		list_stack_T *newitem = (list_stack_T*)malloc(
4295 							sizeof(list_stack_T));
4296 		if (newitem == NULL)
4297 		    abort = TRUE;
4298 		else
4299 		{
4300 		    newitem->list = ll;
4301 		    newitem->prev = *list_stack;
4302 		    *list_stack = newitem;
4303 		}
4304 	    }
4305 	}
4306     }
4307     else if (tv->v_type == VAR_FUNC)
4308     {
4309 	abort = set_ref_in_func(tv->vval.v_string, NULL, copyID);
4310     }
4311     else if (tv->v_type == VAR_PARTIAL)
4312     {
4313 	partial_T	*pt = tv->vval.v_partial;
4314 	int		i;
4315 
4316 	// A partial does not have a copyID, because it cannot contain itself.
4317 	if (pt != NULL)
4318 	{
4319 	    abort = set_ref_in_func(pt->pt_name, pt->pt_func, copyID);
4320 
4321 	    if (pt->pt_dict != NULL)
4322 	    {
4323 		typval_T dtv;
4324 
4325 		dtv.v_type = VAR_DICT;
4326 		dtv.vval.v_dict = pt->pt_dict;
4327 		set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
4328 	    }
4329 
4330 	    for (i = 0; i < pt->pt_argc; ++i)
4331 		abort = abort || set_ref_in_item(&pt->pt_argv[i], copyID,
4332 							ht_stack, list_stack);
4333 	}
4334     }
4335 #ifdef FEAT_JOB_CHANNEL
4336     else if (tv->v_type == VAR_JOB)
4337     {
4338 	job_T	    *job = tv->vval.v_job;
4339 	typval_T    dtv;
4340 
4341 	if (job != NULL && job->jv_copyID != copyID)
4342 	{
4343 	    job->jv_copyID = copyID;
4344 	    if (job->jv_channel != NULL)
4345 	    {
4346 		dtv.v_type = VAR_CHANNEL;
4347 		dtv.vval.v_channel = job->jv_channel;
4348 		set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
4349 	    }
4350 	    if (job->jv_exit_cb.cb_partial != NULL)
4351 	    {
4352 		dtv.v_type = VAR_PARTIAL;
4353 		dtv.vval.v_partial = job->jv_exit_cb.cb_partial;
4354 		set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
4355 	    }
4356 	}
4357     }
4358     else if (tv->v_type == VAR_CHANNEL)
4359     {
4360 	channel_T   *ch =tv->vval.v_channel;
4361 	ch_part_T   part;
4362 	typval_T    dtv;
4363 	jsonq_T	    *jq;
4364 	cbq_T	    *cq;
4365 
4366 	if (ch != NULL && ch->ch_copyID != copyID)
4367 	{
4368 	    ch->ch_copyID = copyID;
4369 	    for (part = PART_SOCK; part < PART_COUNT; ++part)
4370 	    {
4371 		for (jq = ch->ch_part[part].ch_json_head.jq_next; jq != NULL;
4372 							     jq = jq->jq_next)
4373 		    set_ref_in_item(jq->jq_value, copyID, ht_stack, list_stack);
4374 		for (cq = ch->ch_part[part].ch_cb_head.cq_next; cq != NULL;
4375 							     cq = cq->cq_next)
4376 		    if (cq->cq_callback.cb_partial != NULL)
4377 		    {
4378 			dtv.v_type = VAR_PARTIAL;
4379 			dtv.vval.v_partial = cq->cq_callback.cb_partial;
4380 			set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
4381 		    }
4382 		if (ch->ch_part[part].ch_callback.cb_partial != NULL)
4383 		{
4384 		    dtv.v_type = VAR_PARTIAL;
4385 		    dtv.vval.v_partial =
4386 				      ch->ch_part[part].ch_callback.cb_partial;
4387 		    set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
4388 		}
4389 	    }
4390 	    if (ch->ch_callback.cb_partial != NULL)
4391 	    {
4392 		dtv.v_type = VAR_PARTIAL;
4393 		dtv.vval.v_partial = ch->ch_callback.cb_partial;
4394 		set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
4395 	    }
4396 	    if (ch->ch_close_cb.cb_partial != NULL)
4397 	    {
4398 		dtv.v_type = VAR_PARTIAL;
4399 		dtv.vval.v_partial = ch->ch_close_cb.cb_partial;
4400 		set_ref_in_item(&dtv, copyID, ht_stack, list_stack);
4401 	    }
4402 	}
4403     }
4404 #endif
4405     return abort;
4406 }
4407 
4408 /*
4409  * Return a string with the string representation of a variable.
4410  * If the memory is allocated "tofree" is set to it, otherwise NULL.
4411  * "numbuf" is used for a number.
4412  * When "copyID" is not NULL replace recursive lists and dicts with "...".
4413  * When both "echo_style" and "composite_val" are FALSE, put quotes around
4414  * stings as "string()", otherwise does not put quotes around strings, as
4415  * ":echo" displays values.
4416  * When "restore_copyID" is FALSE, repeated items in dictionaries and lists
4417  * are replaced with "...".
4418  * May return NULL.
4419  */
4420     char_u *
4421 echo_string_core(
4422     typval_T	*tv,
4423     char_u	**tofree,
4424     char_u	*numbuf,
4425     int		copyID,
4426     int		echo_style,
4427     int		restore_copyID,
4428     int		composite_val)
4429 {
4430     static int	recurse = 0;
4431     char_u	*r = NULL;
4432 
4433     if (recurse >= DICT_MAXNEST)
4434     {
4435 	if (!did_echo_string_emsg)
4436 	{
4437 	    // Only give this message once for a recursive call to avoid
4438 	    // flooding the user with errors.  And stop iterating over lists
4439 	    // and dicts.
4440 	    did_echo_string_emsg = TRUE;
4441 	    emsg(_("E724: variable nested too deep for displaying"));
4442 	}
4443 	*tofree = NULL;
4444 	return (char_u *)"{E724}";
4445     }
4446     ++recurse;
4447 
4448     switch (tv->v_type)
4449     {
4450 	case VAR_STRING:
4451 	    if (echo_style && !composite_val)
4452 	    {
4453 		*tofree = NULL;
4454 		r = tv->vval.v_string;
4455 		if (r == NULL)
4456 		    r = (char_u *)"";
4457 	    }
4458 	    else
4459 	    {
4460 		*tofree = string_quote(tv->vval.v_string, FALSE);
4461 		r = *tofree;
4462 	    }
4463 	    break;
4464 
4465 	case VAR_FUNC:
4466 	    if (echo_style)
4467 	    {
4468 		*tofree = NULL;
4469 		r = tv->vval.v_string;
4470 	    }
4471 	    else
4472 	    {
4473 		*tofree = string_quote(tv->vval.v_string, TRUE);
4474 		r = *tofree;
4475 	    }
4476 	    break;
4477 
4478 	case VAR_PARTIAL:
4479 	    {
4480 		partial_T   *pt = tv->vval.v_partial;
4481 		char_u	    *fname = string_quote(pt == NULL ? NULL
4482 						    : partial_name(pt), FALSE);
4483 		garray_T    ga;
4484 		int	    i;
4485 		char_u	    *tf;
4486 
4487 		ga_init2(&ga, 1, 100);
4488 		ga_concat(&ga, (char_u *)"function(");
4489 		if (fname != NULL)
4490 		{
4491 		    ga_concat(&ga, fname);
4492 		    vim_free(fname);
4493 		}
4494 		if (pt != NULL && pt->pt_argc > 0)
4495 		{
4496 		    ga_concat(&ga, (char_u *)", [");
4497 		    for (i = 0; i < pt->pt_argc; ++i)
4498 		    {
4499 			if (i > 0)
4500 			    ga_concat(&ga, (char_u *)", ");
4501 			ga_concat(&ga,
4502 			     tv2string(&pt->pt_argv[i], &tf, numbuf, copyID));
4503 			vim_free(tf);
4504 		    }
4505 		    ga_concat(&ga, (char_u *)"]");
4506 		}
4507 		if (pt != NULL && pt->pt_dict != NULL)
4508 		{
4509 		    typval_T dtv;
4510 
4511 		    ga_concat(&ga, (char_u *)", ");
4512 		    dtv.v_type = VAR_DICT;
4513 		    dtv.vval.v_dict = pt->pt_dict;
4514 		    ga_concat(&ga, tv2string(&dtv, &tf, numbuf, copyID));
4515 		    vim_free(tf);
4516 		}
4517 		ga_concat(&ga, (char_u *)")");
4518 
4519 		*tofree = ga.ga_data;
4520 		r = *tofree;
4521 		break;
4522 	    }
4523 
4524 	case VAR_BLOB:
4525 	    r = blob2string(tv->vval.v_blob, tofree, numbuf);
4526 	    break;
4527 
4528 	case VAR_LIST:
4529 	    if (tv->vval.v_list == NULL)
4530 	    {
4531 		*tofree = NULL;
4532 		r = NULL;
4533 	    }
4534 	    else if (copyID != 0 && tv->vval.v_list->lv_copyID == copyID
4535 		    && tv->vval.v_list->lv_len > 0)
4536 	    {
4537 		*tofree = NULL;
4538 		r = (char_u *)"[...]";
4539 	    }
4540 	    else
4541 	    {
4542 		int old_copyID = tv->vval.v_list->lv_copyID;
4543 
4544 		tv->vval.v_list->lv_copyID = copyID;
4545 		*tofree = list2string(tv, copyID, restore_copyID);
4546 		if (restore_copyID)
4547 		    tv->vval.v_list->lv_copyID = old_copyID;
4548 		r = *tofree;
4549 	    }
4550 	    break;
4551 
4552 	case VAR_DICT:
4553 	    if (tv->vval.v_dict == NULL)
4554 	    {
4555 		*tofree = NULL;
4556 		r = NULL;
4557 	    }
4558 	    else if (copyID != 0 && tv->vval.v_dict->dv_copyID == copyID
4559 		    && tv->vval.v_dict->dv_hashtab.ht_used != 0)
4560 	    {
4561 		*tofree = NULL;
4562 		r = (char_u *)"{...}";
4563 	    }
4564 	    else
4565 	    {
4566 		int old_copyID = tv->vval.v_dict->dv_copyID;
4567 		tv->vval.v_dict->dv_copyID = copyID;
4568 		*tofree = dict2string(tv, copyID, restore_copyID);
4569 		if (restore_copyID)
4570 		    tv->vval.v_dict->dv_copyID = old_copyID;
4571 		r = *tofree;
4572 	    }
4573 	    break;
4574 
4575 	case VAR_NUMBER:
4576 	case VAR_UNKNOWN:
4577 	case VAR_ANY:
4578 	case VAR_VOID:
4579 	    *tofree = NULL;
4580 	    r = tv_get_string_buf(tv, numbuf);
4581 	    break;
4582 
4583 	case VAR_JOB:
4584 	case VAR_CHANNEL:
4585 	    *tofree = NULL;
4586 	    r = tv_get_string_buf(tv, numbuf);
4587 	    if (composite_val)
4588 	    {
4589 		*tofree = string_quote(r, FALSE);
4590 		r = *tofree;
4591 	    }
4592 	    break;
4593 
4594 	case VAR_FLOAT:
4595 #ifdef FEAT_FLOAT
4596 	    *tofree = NULL;
4597 	    vim_snprintf((char *)numbuf, NUMBUFLEN, "%g", tv->vval.v_float);
4598 	    r = numbuf;
4599 	    break;
4600 #endif
4601 
4602 	case VAR_BOOL:
4603 	case VAR_SPECIAL:
4604 	    *tofree = NULL;
4605 	    r = (char_u *)get_var_special_name(tv->vval.v_number);
4606 	    break;
4607     }
4608 
4609     if (--recurse == 0)
4610 	did_echo_string_emsg = FALSE;
4611     return r;
4612 }
4613 
4614 /*
4615  * Return a string with the string representation of a variable.
4616  * If the memory is allocated "tofree" is set to it, otherwise NULL.
4617  * "numbuf" is used for a number.
4618  * Does not put quotes around strings, as ":echo" displays values.
4619  * When "copyID" is not NULL replace recursive lists and dicts with "...".
4620  * May return NULL.
4621  */
4622     char_u *
4623 echo_string(
4624     typval_T	*tv,
4625     char_u	**tofree,
4626     char_u	*numbuf,
4627     int		copyID)
4628 {
4629     return echo_string_core(tv, tofree, numbuf, copyID, TRUE, FALSE, FALSE);
4630 }
4631 
4632 /*
4633  * Return a string with the string representation of a variable.
4634  * If the memory is allocated "tofree" is set to it, otherwise NULL.
4635  * "numbuf" is used for a number.
4636  * Puts quotes around strings, so that they can be parsed back by eval().
4637  * May return NULL.
4638  */
4639     char_u *
4640 tv2string(
4641     typval_T	*tv,
4642     char_u	**tofree,
4643     char_u	*numbuf,
4644     int		copyID)
4645 {
4646     return echo_string_core(tv, tofree, numbuf, copyID, FALSE, TRUE, FALSE);
4647 }
4648 
4649 /*
4650  * Return string "str" in ' quotes, doubling ' characters.
4651  * If "str" is NULL an empty string is assumed.
4652  * If "function" is TRUE make it function('string').
4653  */
4654     char_u *
4655 string_quote(char_u *str, int function)
4656 {
4657     unsigned	len;
4658     char_u	*p, *r, *s;
4659 
4660     len = (function ? 13 : 3);
4661     if (str != NULL)
4662     {
4663 	len += (unsigned)STRLEN(str);
4664 	for (p = str; *p != NUL; MB_PTR_ADV(p))
4665 	    if (*p == '\'')
4666 		++len;
4667     }
4668     s = r = alloc(len);
4669     if (r != NULL)
4670     {
4671 	if (function)
4672 	{
4673 	    STRCPY(r, "function('");
4674 	    r += 10;
4675 	}
4676 	else
4677 	    *r++ = '\'';
4678 	if (str != NULL)
4679 	    for (p = str; *p != NUL; )
4680 	    {
4681 		if (*p == '\'')
4682 		    *r++ = '\'';
4683 		MB_COPY_CHAR(p, r);
4684 	    }
4685 	*r++ = '\'';
4686 	if (function)
4687 	    *r++ = ')';
4688 	*r++ = NUL;
4689     }
4690     return s;
4691 }
4692 
4693 #if defined(FEAT_FLOAT) || defined(PROTO)
4694 /*
4695  * Convert the string "text" to a floating point number.
4696  * This uses strtod().  setlocale(LC_NUMERIC, "C") has been used to make sure
4697  * this always uses a decimal point.
4698  * Returns the length of the text that was consumed.
4699  */
4700     int
4701 string2float(
4702     char_u	*text,
4703     float_T	*value)	    // result stored here
4704 {
4705     char	*s = (char *)text;
4706     float_T	f;
4707 
4708     // MS-Windows does not deal with "inf" and "nan" properly.
4709     if (STRNICMP(text, "inf", 3) == 0)
4710     {
4711 	*value = INFINITY;
4712 	return 3;
4713     }
4714     if (STRNICMP(text, "-inf", 3) == 0)
4715     {
4716 	*value = -INFINITY;
4717 	return 4;
4718     }
4719     if (STRNICMP(text, "nan", 3) == 0)
4720     {
4721 	*value = NAN;
4722 	return 3;
4723     }
4724     f = strtod(s, &s);
4725     *value = f;
4726     return (int)((char_u *)s - text);
4727 }
4728 #endif
4729 
4730 /*
4731  * Get the value of an environment variable.
4732  * "arg" is pointing to the '$'.  It is advanced to after the name.
4733  * If the environment variable was not set, silently assume it is empty.
4734  * Return FAIL if the name is invalid.
4735  */
4736     int
4737 get_env_tv(char_u **arg, typval_T *rettv, int evaluate)
4738 {
4739     char_u	*string = NULL;
4740     int		len;
4741     int		cc;
4742     char_u	*name;
4743     int		mustfree = FALSE;
4744 
4745     ++*arg;
4746     name = *arg;
4747     len = get_env_len(arg);
4748     if (evaluate)
4749     {
4750 	if (len == 0)
4751 	    return FAIL; // invalid empty name
4752 
4753 	cc = name[len];
4754 	name[len] = NUL;
4755 	// first try vim_getenv(), fast for normal environment vars
4756 	string = vim_getenv(name, &mustfree);
4757 	if (string != NULL && *string != NUL)
4758 	{
4759 	    if (!mustfree)
4760 		string = vim_strsave(string);
4761 	}
4762 	else
4763 	{
4764 	    if (mustfree)
4765 		vim_free(string);
4766 
4767 	    // next try expanding things like $VIM and ${HOME}
4768 	    string = expand_env_save(name - 1);
4769 	    if (string != NULL && *string == '$')
4770 		VIM_CLEAR(string);
4771 	}
4772 	name[len] = cc;
4773 
4774 	rettv->v_type = VAR_STRING;
4775 	rettv->vval.v_string = string;
4776     }
4777 
4778     return OK;
4779 }
4780 
4781 /*
4782  * Translate a String variable into a position.
4783  * Returns NULL when there is an error.
4784  */
4785     pos_T *
4786 var2fpos(
4787     typval_T	*varp,
4788     int		dollar_lnum,	// TRUE when $ is last line
4789     int		*fnum)		// set to fnum for '0, 'A, etc.
4790 {
4791     char_u		*name;
4792     static pos_T	pos;
4793     pos_T		*pp;
4794 
4795     // Argument can be [lnum, col, coladd].
4796     if (varp->v_type == VAR_LIST)
4797     {
4798 	list_T		*l;
4799 	int		len;
4800 	int		error = FALSE;
4801 	listitem_T	*li;
4802 
4803 	l = varp->vval.v_list;
4804 	if (l == NULL)
4805 	    return NULL;
4806 
4807 	// Get the line number
4808 	pos.lnum = list_find_nr(l, 0L, &error);
4809 	if (error || pos.lnum <= 0 || pos.lnum > curbuf->b_ml.ml_line_count)
4810 	    return NULL;	// invalid line number
4811 
4812 	// Get the column number
4813 	pos.col = list_find_nr(l, 1L, &error);
4814 	if (error)
4815 	    return NULL;
4816 	len = (long)STRLEN(ml_get(pos.lnum));
4817 
4818 	// We accept "$" for the column number: last column.
4819 	li = list_find(l, 1L);
4820 	if (li != NULL && li->li_tv.v_type == VAR_STRING
4821 		&& li->li_tv.vval.v_string != NULL
4822 		&& STRCMP(li->li_tv.vval.v_string, "$") == 0)
4823 	    pos.col = len + 1;
4824 
4825 	// Accept a position up to the NUL after the line.
4826 	if (pos.col == 0 || (int)pos.col > len + 1)
4827 	    return NULL;	// invalid column number
4828 	--pos.col;
4829 
4830 	// Get the virtual offset.  Defaults to zero.
4831 	pos.coladd = list_find_nr(l, 2L, &error);
4832 	if (error)
4833 	    pos.coladd = 0;
4834 
4835 	return &pos;
4836     }
4837 
4838     name = tv_get_string_chk(varp);
4839     if (name == NULL)
4840 	return NULL;
4841     if (name[0] == '.')				// cursor
4842 	return &curwin->w_cursor;
4843     if (name[0] == 'v' && name[1] == NUL)	// Visual start
4844     {
4845 	if (VIsual_active)
4846 	    return &VIsual;
4847 	return &curwin->w_cursor;
4848     }
4849     if (name[0] == '\'')			// mark
4850     {
4851 	pp = getmark_buf_fnum(curbuf, name[1], FALSE, fnum);
4852 	if (pp == NULL || pp == (pos_T *)-1 || pp->lnum <= 0)
4853 	    return NULL;
4854 	return pp;
4855     }
4856 
4857     pos.coladd = 0;
4858 
4859     if (name[0] == 'w' && dollar_lnum)
4860     {
4861 	pos.col = 0;
4862 	if (name[1] == '0')		// "w0": first visible line
4863 	{
4864 	    update_topline();
4865 	    // In silent Ex mode topline is zero, but that's not a valid line
4866 	    // number; use one instead.
4867 	    pos.lnum = curwin->w_topline > 0 ? curwin->w_topline : 1;
4868 	    return &pos;
4869 	}
4870 	else if (name[1] == '$')	// "w$": last visible line
4871 	{
4872 	    validate_botline();
4873 	    // In silent Ex mode botline is zero, return zero then.
4874 	    pos.lnum = curwin->w_botline > 0 ? curwin->w_botline - 1 : 0;
4875 	    return &pos;
4876 	}
4877     }
4878     else if (name[0] == '$')		// last column or line
4879     {
4880 	if (dollar_lnum)
4881 	{
4882 	    pos.lnum = curbuf->b_ml.ml_line_count;
4883 	    pos.col = 0;
4884 	}
4885 	else
4886 	{
4887 	    pos.lnum = curwin->w_cursor.lnum;
4888 	    pos.col = (colnr_T)STRLEN(ml_get_curline());
4889 	}
4890 	return &pos;
4891     }
4892     return NULL;
4893 }
4894 
4895 /*
4896  * Convert list in "arg" into a position and optional file number.
4897  * When "fnump" is NULL there is no file number, only 3 items.
4898  * Note that the column is passed on as-is, the caller may want to decrement
4899  * it to use 1 for the first column.
4900  * Return FAIL when conversion is not possible, doesn't check the position for
4901  * validity.
4902  */
4903     int
4904 list2fpos(
4905     typval_T	*arg,
4906     pos_T	*posp,
4907     int		*fnump,
4908     colnr_T	*curswantp)
4909 {
4910     list_T	*l = arg->vval.v_list;
4911     long	i = 0;
4912     long	n;
4913 
4914     // List must be: [fnum, lnum, col, coladd, curswant], where "fnum" is only
4915     // there when "fnump" isn't NULL; "coladd" and "curswant" are optional.
4916     if (arg->v_type != VAR_LIST
4917 	    || l == NULL
4918 	    || l->lv_len < (fnump == NULL ? 2 : 3)
4919 	    || l->lv_len > (fnump == NULL ? 4 : 5))
4920 	return FAIL;
4921 
4922     if (fnump != NULL)
4923     {
4924 	n = list_find_nr(l, i++, NULL);	// fnum
4925 	if (n < 0)
4926 	    return FAIL;
4927 	if (n == 0)
4928 	    n = curbuf->b_fnum;		// current buffer
4929 	*fnump = n;
4930     }
4931 
4932     n = list_find_nr(l, i++, NULL);	// lnum
4933     if (n < 0)
4934 	return FAIL;
4935     posp->lnum = n;
4936 
4937     n = list_find_nr(l, i++, NULL);	// col
4938     if (n < 0)
4939 	return FAIL;
4940     posp->col = n;
4941 
4942     n = list_find_nr(l, i, NULL);	// off
4943     if (n < 0)
4944 	posp->coladd = 0;
4945     else
4946 	posp->coladd = n;
4947 
4948     if (curswantp != NULL)
4949 	*curswantp = list_find_nr(l, i + 1, NULL);  // curswant
4950 
4951     return OK;
4952 }
4953 
4954 /*
4955  * Get the length of an environment variable name.
4956  * Advance "arg" to the first character after the name.
4957  * Return 0 for error.
4958  */
4959     int
4960 get_env_len(char_u **arg)
4961 {
4962     char_u	*p;
4963     int		len;
4964 
4965     for (p = *arg; vim_isIDc(*p); ++p)
4966 	;
4967     if (p == *arg)	    // no name found
4968 	return 0;
4969 
4970     len = (int)(p - *arg);
4971     *arg = p;
4972     return len;
4973 }
4974 
4975 /*
4976  * Get the length of the name of a function or internal variable.
4977  * "arg" is advanced to the first non-white character after the name.
4978  * Return 0 if something is wrong.
4979  */
4980     int
4981 get_id_len(char_u **arg)
4982 {
4983     char_u	*p;
4984     int		len;
4985 
4986     // Find the end of the name.
4987     for (p = *arg; eval_isnamec(*p); ++p)
4988     {
4989 	if (*p == ':')
4990 	{
4991 	    // "s:" is start of "s:var", but "n:" is not and can be used in
4992 	    // slice "[n:]".  Also "xx:" is not a namespace.
4993 	    len = (int)(p - *arg);
4994 	    if ((len == 1 && vim_strchr(NAMESPACE_CHAR, **arg) == NULL)
4995 		    || len > 1)
4996 		break;
4997 	}
4998     }
4999     if (p == *arg)	    // no name found
5000 	return 0;
5001 
5002     len = (int)(p - *arg);
5003     *arg = skipwhite(p);
5004 
5005     return len;
5006 }
5007 
5008 /*
5009  * Get the length of the name of a variable or function.
5010  * Only the name is recognized, does not handle ".key" or "[idx]".
5011  * "arg" is advanced to the first non-white character after the name.
5012  * Return -1 if curly braces expansion failed.
5013  * Return 0 if something else is wrong.
5014  * If the name contains 'magic' {}'s, expand them and return the
5015  * expanded name in an allocated string via 'alias' - caller must free.
5016  */
5017     int
5018 get_name_len(
5019     char_u	**arg,
5020     char_u	**alias,
5021     int		evaluate,
5022     int		verbose)
5023 {
5024     int		len;
5025     char_u	*p;
5026     char_u	*expr_start;
5027     char_u	*expr_end;
5028 
5029     *alias = NULL;  // default to no alias
5030 
5031     if ((*arg)[0] == K_SPECIAL && (*arg)[1] == KS_EXTRA
5032 						  && (*arg)[2] == (int)KE_SNR)
5033     {
5034 	// hard coded <SNR>, already translated
5035 	*arg += 3;
5036 	return get_id_len(arg) + 3;
5037     }
5038     len = eval_fname_script(*arg);
5039     if (len > 0)
5040     {
5041 	// literal "<SID>", "s:" or "<SNR>"
5042 	*arg += len;
5043     }
5044 
5045     /*
5046      * Find the end of the name; check for {} construction.
5047      */
5048     p = find_name_end(*arg, &expr_start, &expr_end,
5049 					       len > 0 ? 0 : FNE_CHECK_START);
5050     if (expr_start != NULL)
5051     {
5052 	char_u	*temp_string;
5053 
5054 	if (!evaluate)
5055 	{
5056 	    len += (int)(p - *arg);
5057 	    *arg = skipwhite(p);
5058 	    return len;
5059 	}
5060 
5061 	/*
5062 	 * Include any <SID> etc in the expanded string:
5063 	 * Thus the -len here.
5064 	 */
5065 	temp_string = make_expanded_name(*arg - len, expr_start, expr_end, p);
5066 	if (temp_string == NULL)
5067 	    return -1;
5068 	*alias = temp_string;
5069 	*arg = skipwhite(p);
5070 	return (int)STRLEN(temp_string);
5071     }
5072 
5073     len += get_id_len(arg);
5074     // Only give an error when there is something, otherwise it will be
5075     // reported at a higher level.
5076     if (len == 0 && verbose && **arg != NUL)
5077 	semsg(_(e_invexpr2), *arg);
5078 
5079     return len;
5080 }
5081 
5082 /*
5083  * Find the end of a variable or function name, taking care of magic braces.
5084  * If "expr_start" is not NULL then "expr_start" and "expr_end" are set to the
5085  * start and end of the first magic braces item.
5086  * "flags" can have FNE_INCL_BR and FNE_CHECK_START.
5087  * Return a pointer to just after the name.  Equal to "arg" if there is no
5088  * valid name.
5089  */
5090     char_u *
5091 find_name_end(
5092     char_u	*arg,
5093     char_u	**expr_start,
5094     char_u	**expr_end,
5095     int		flags)
5096 {
5097     int		mb_nest = 0;
5098     int		br_nest = 0;
5099     char_u	*p;
5100     int		len;
5101 
5102     if (expr_start != NULL)
5103     {
5104 	*expr_start = NULL;
5105 	*expr_end = NULL;
5106     }
5107 
5108     // Quick check for valid starting character.
5109     if ((flags & FNE_CHECK_START) && !eval_isnamec1(*arg) && *arg != '{')
5110 	return arg;
5111 
5112     for (p = arg; *p != NUL
5113 		    && (eval_isnamec(*p)
5114 			|| *p == '{'
5115 			|| ((flags & FNE_INCL_BR) && (*p == '[' || *p == '.'))
5116 			|| mb_nest != 0
5117 			|| br_nest != 0); MB_PTR_ADV(p))
5118     {
5119 	if (*p == '\'')
5120 	{
5121 	    // skip over 'string' to avoid counting [ and ] inside it.
5122 	    for (p = p + 1; *p != NUL && *p != '\''; MB_PTR_ADV(p))
5123 		;
5124 	    if (*p == NUL)
5125 		break;
5126 	}
5127 	else if (*p == '"')
5128 	{
5129 	    // skip over "str\"ing" to avoid counting [ and ] inside it.
5130 	    for (p = p + 1; *p != NUL && *p != '"'; MB_PTR_ADV(p))
5131 		if (*p == '\\' && p[1] != NUL)
5132 		    ++p;
5133 	    if (*p == NUL)
5134 		break;
5135 	}
5136 	else if (br_nest == 0 && mb_nest == 0 && *p == ':')
5137 	{
5138 	    // "s:" is start of "s:var", but "n:" is not and can be used in
5139 	    // slice "[n:]".  Also "xx:" is not a namespace. But {ns}: is.
5140 	    len = (int)(p - arg);
5141 	    if ((len == 1 && vim_strchr(NAMESPACE_CHAR, *arg) == NULL)
5142 		    || (len > 1 && p[-1] != '}'))
5143 		break;
5144 	}
5145 
5146 	if (mb_nest == 0)
5147 	{
5148 	    if (*p == '[')
5149 		++br_nest;
5150 	    else if (*p == ']')
5151 		--br_nest;
5152 	}
5153 
5154 	if (br_nest == 0)
5155 	{
5156 	    if (*p == '{')
5157 	    {
5158 		mb_nest++;
5159 		if (expr_start != NULL && *expr_start == NULL)
5160 		    *expr_start = p;
5161 	    }
5162 	    else if (*p == '}')
5163 	    {
5164 		mb_nest--;
5165 		if (expr_start != NULL && mb_nest == 0 && *expr_end == NULL)
5166 		    *expr_end = p;
5167 	    }
5168 	}
5169     }
5170 
5171     return p;
5172 }
5173 
5174 /*
5175  * Expands out the 'magic' {}'s in a variable/function name.
5176  * Note that this can call itself recursively, to deal with
5177  * constructs like foo{bar}{baz}{bam}
5178  * The four pointer arguments point to "foo{expre}ss{ion}bar"
5179  *			"in_start"      ^
5180  *			"expr_start"	   ^
5181  *			"expr_end"		 ^
5182  *			"in_end"			    ^
5183  *
5184  * Returns a new allocated string, which the caller must free.
5185  * Returns NULL for failure.
5186  */
5187     static char_u *
5188 make_expanded_name(
5189     char_u	*in_start,
5190     char_u	*expr_start,
5191     char_u	*expr_end,
5192     char_u	*in_end)
5193 {
5194     char_u	c1;
5195     char_u	*retval = NULL;
5196     char_u	*temp_result;
5197     char_u	*nextcmd = NULL;
5198 
5199     if (expr_end == NULL || in_end == NULL)
5200 	return NULL;
5201     *expr_start	= NUL;
5202     *expr_end = NUL;
5203     c1 = *in_end;
5204     *in_end = NUL;
5205 
5206     temp_result = eval_to_string(expr_start + 1, &nextcmd, FALSE);
5207     if (temp_result != NULL && nextcmd == NULL)
5208     {
5209 	retval = alloc(STRLEN(temp_result) + (expr_start - in_start)
5210 						   + (in_end - expr_end) + 1);
5211 	if (retval != NULL)
5212 	{
5213 	    STRCPY(retval, in_start);
5214 	    STRCAT(retval, temp_result);
5215 	    STRCAT(retval, expr_end + 1);
5216 	}
5217     }
5218     vim_free(temp_result);
5219 
5220     *in_end = c1;		// put char back for error messages
5221     *expr_start = '{';
5222     *expr_end = '}';
5223 
5224     if (retval != NULL)
5225     {
5226 	temp_result = find_name_end(retval, &expr_start, &expr_end, 0);
5227 	if (expr_start != NULL)
5228 	{
5229 	    // Further expansion!
5230 	    temp_result = make_expanded_name(retval, expr_start,
5231 						       expr_end, temp_result);
5232 	    vim_free(retval);
5233 	    retval = temp_result;
5234 	}
5235     }
5236 
5237     return retval;
5238 }
5239 
5240 /*
5241  * Return TRUE if character "c" can be used in a variable or function name.
5242  * Does not include '{' or '}' for magic braces.
5243  */
5244     int
5245 eval_isnamec(int c)
5246 {
5247     return (ASCII_ISALNUM(c) || c == '_' || c == ':' || c == AUTOLOAD_CHAR);
5248 }
5249 
5250 /*
5251  * Return TRUE if character "c" can be used as the first character in a
5252  * variable or function name (excluding '{' and '}').
5253  */
5254     int
5255 eval_isnamec1(int c)
5256 {
5257     return (ASCII_ISALPHA(c) || c == '_');
5258 }
5259 
5260 /*
5261  * Handle:
5262  * - expr[expr], expr[expr:expr] subscript
5263  * - ".name" lookup
5264  * - function call with Funcref variable: func(expr)
5265  * - method call: var->method()
5266  *
5267  * Can all be combined in any order: dict.func(expr)[idx]['func'](expr)->len()
5268  */
5269     int
5270 handle_subscript(
5271     char_u	**arg,
5272     typval_T	*rettv,
5273     int		evaluate,	// do more than finding the end
5274     int		verbose,	// give error messages
5275     char_u	*start_leader,	// start of '!' and '-' prefixes
5276     char_u	**end_leaderp)  // end of '!' and '-' prefixes
5277 {
5278     int		ret = OK;
5279     dict_T	*selfdict = NULL;
5280 
5281     // "." is ".name" lookup when we found a dict or when evaluating and
5282     // scriptversion is at least 2, where string concatenation is "..".
5283     while (ret == OK
5284 	    && (((**arg == '['
5285 		    || (**arg == '.' && (rettv->v_type == VAR_DICT
5286 			|| (!evaluate
5287 			    && (*arg)[1] != '.'
5288 			    && current_sctx.sc_version >= 2)))
5289 		    || (**arg == '(' && (!evaluate || rettv->v_type == VAR_FUNC
5290 					    || rettv->v_type == VAR_PARTIAL)))
5291 		&& !VIM_ISWHITE(*(*arg - 1)))
5292 	    || (**arg == '-' && (*arg)[1] == '>')))
5293     {
5294 	if (**arg == '(')
5295 	{
5296 	    ret = call_func_rettv(arg, rettv, evaluate, selfdict, NULL);
5297 
5298 	    // Stop the expression evaluation when immediately aborting on
5299 	    // error, or when an interrupt occurred or an exception was thrown
5300 	    // but not caught.
5301 	    if (aborting())
5302 	    {
5303 		if (ret == OK)
5304 		    clear_tv(rettv);
5305 		ret = FAIL;
5306 	    }
5307 	    dict_unref(selfdict);
5308 	    selfdict = NULL;
5309 	}
5310 	else if (**arg == '-')
5311 	{
5312 	    // Expression "-1.0->method()" applies the leader "-" before
5313 	    // applying ->.
5314 	    if (evaluate && *end_leaderp > start_leader)
5315 		ret = eval7_leader(rettv, start_leader, end_leaderp);
5316 	    if (ret == OK)
5317 	    {
5318 		if ((*arg)[2] == '{')
5319 		    // expr->{lambda}()
5320 		    ret = eval_lambda(arg, rettv, evaluate, verbose);
5321 		else
5322 		    // expr->name()
5323 		    ret = eval_method(arg, rettv, evaluate, verbose);
5324 	    }
5325 	}
5326 	else // **arg == '[' || **arg == '.'
5327 	{
5328 	    dict_unref(selfdict);
5329 	    if (rettv->v_type == VAR_DICT)
5330 	    {
5331 		selfdict = rettv->vval.v_dict;
5332 		if (selfdict != NULL)
5333 		    ++selfdict->dv_refcount;
5334 	    }
5335 	    else
5336 		selfdict = NULL;
5337 	    if (eval_index(arg, rettv, evaluate, verbose) == FAIL)
5338 	    {
5339 		clear_tv(rettv);
5340 		ret = FAIL;
5341 	    }
5342 	}
5343     }
5344 
5345     // Turn "dict.Func" into a partial for "Func" bound to "dict".
5346     // Don't do this when "Func" is already a partial that was bound
5347     // explicitly (pt_auto is FALSE).
5348     if (selfdict != NULL
5349 	    && (rettv->v_type == VAR_FUNC
5350 		|| (rettv->v_type == VAR_PARTIAL
5351 		    && (rettv->vval.v_partial->pt_auto
5352 			|| rettv->vval.v_partial->pt_dict == NULL))))
5353 	selfdict = make_partial(selfdict, rettv);
5354 
5355     dict_unref(selfdict);
5356     return ret;
5357 }
5358 
5359 /*
5360  * Allocate memory for a variable type-value, and make it empty (0 or NULL
5361  * value).
5362  */
5363     typval_T *
5364 alloc_tv(void)
5365 {
5366     return ALLOC_CLEAR_ONE(typval_T);
5367 }
5368 
5369 /*
5370  * Allocate memory for a variable type-value, and assign a string to it.
5371  * The string "s" must have been allocated, it is consumed.
5372  * Return NULL for out of memory, the variable otherwise.
5373  */
5374     typval_T *
5375 alloc_string_tv(char_u *s)
5376 {
5377     typval_T	*rettv;
5378 
5379     rettv = alloc_tv();
5380     if (rettv != NULL)
5381     {
5382 	rettv->v_type = VAR_STRING;
5383 	rettv->vval.v_string = s;
5384     }
5385     else
5386 	vim_free(s);
5387     return rettv;
5388 }
5389 
5390 /*
5391  * Free the memory for a variable type-value.
5392  */
5393     void
5394 free_tv(typval_T *varp)
5395 {
5396     if (varp != NULL)
5397     {
5398 	switch (varp->v_type)
5399 	{
5400 	    case VAR_FUNC:
5401 		func_unref(varp->vval.v_string);
5402 		// FALLTHROUGH
5403 	    case VAR_STRING:
5404 		vim_free(varp->vval.v_string);
5405 		break;
5406 	    case VAR_PARTIAL:
5407 		partial_unref(varp->vval.v_partial);
5408 		break;
5409 	    case VAR_BLOB:
5410 		blob_unref(varp->vval.v_blob);
5411 		break;
5412 	    case VAR_LIST:
5413 		list_unref(varp->vval.v_list);
5414 		break;
5415 	    case VAR_DICT:
5416 		dict_unref(varp->vval.v_dict);
5417 		break;
5418 	    case VAR_JOB:
5419 #ifdef FEAT_JOB_CHANNEL
5420 		job_unref(varp->vval.v_job);
5421 		break;
5422 #endif
5423 	    case VAR_CHANNEL:
5424 #ifdef FEAT_JOB_CHANNEL
5425 		channel_unref(varp->vval.v_channel);
5426 		break;
5427 #endif
5428 	    case VAR_NUMBER:
5429 	    case VAR_FLOAT:
5430 	    case VAR_ANY:
5431 	    case VAR_UNKNOWN:
5432 	    case VAR_VOID:
5433 	    case VAR_BOOL:
5434 	    case VAR_SPECIAL:
5435 		break;
5436 	}
5437 	vim_free(varp);
5438     }
5439 }
5440 
5441 /*
5442  * Free the memory for a variable value and set the value to NULL or 0.
5443  */
5444     void
5445 clear_tv(typval_T *varp)
5446 {
5447     if (varp != NULL)
5448     {
5449 	switch (varp->v_type)
5450 	{
5451 	    case VAR_FUNC:
5452 		func_unref(varp->vval.v_string);
5453 		// FALLTHROUGH
5454 	    case VAR_STRING:
5455 		VIM_CLEAR(varp->vval.v_string);
5456 		break;
5457 	    case VAR_PARTIAL:
5458 		partial_unref(varp->vval.v_partial);
5459 		varp->vval.v_partial = NULL;
5460 		break;
5461 	    case VAR_BLOB:
5462 		blob_unref(varp->vval.v_blob);
5463 		varp->vval.v_blob = NULL;
5464 		break;
5465 	    case VAR_LIST:
5466 		list_unref(varp->vval.v_list);
5467 		varp->vval.v_list = NULL;
5468 		break;
5469 	    case VAR_DICT:
5470 		dict_unref(varp->vval.v_dict);
5471 		varp->vval.v_dict = NULL;
5472 		break;
5473 	    case VAR_NUMBER:
5474 	    case VAR_BOOL:
5475 	    case VAR_SPECIAL:
5476 		varp->vval.v_number = 0;
5477 		break;
5478 	    case VAR_FLOAT:
5479 #ifdef FEAT_FLOAT
5480 		varp->vval.v_float = 0.0;
5481 		break;
5482 #endif
5483 	    case VAR_JOB:
5484 #ifdef FEAT_JOB_CHANNEL
5485 		job_unref(varp->vval.v_job);
5486 		varp->vval.v_job = NULL;
5487 #endif
5488 		break;
5489 	    case VAR_CHANNEL:
5490 #ifdef FEAT_JOB_CHANNEL
5491 		channel_unref(varp->vval.v_channel);
5492 		varp->vval.v_channel = NULL;
5493 #endif
5494 	    case VAR_UNKNOWN:
5495 	    case VAR_ANY:
5496 	    case VAR_VOID:
5497 		break;
5498 	}
5499 	varp->v_lock = 0;
5500     }
5501 }
5502 
5503 /*
5504  * Set the value of a variable to NULL without freeing items.
5505  */
5506     void
5507 init_tv(typval_T *varp)
5508 {
5509     if (varp != NULL)
5510 	vim_memset(varp, 0, sizeof(typval_T));
5511 }
5512 
5513 /*
5514  * Get the number value of a variable.
5515  * If it is a String variable, uses vim_str2nr().
5516  * For incompatible types, return 0.
5517  * tv_get_number_chk() is similar to tv_get_number(), but informs the
5518  * caller of incompatible types: it sets *denote to TRUE if "denote"
5519  * is not NULL or returns -1 otherwise.
5520  */
5521     varnumber_T
5522 tv_get_number(typval_T *varp)
5523 {
5524     int		error = FALSE;
5525 
5526     return tv_get_number_chk(varp, &error);	// return 0L on error
5527 }
5528 
5529     varnumber_T
5530 tv_get_number_chk(typval_T *varp, int *denote)
5531 {
5532     varnumber_T	n = 0L;
5533 
5534     switch (varp->v_type)
5535     {
5536 	case VAR_NUMBER:
5537 	    return varp->vval.v_number;
5538 	case VAR_FLOAT:
5539 #ifdef FEAT_FLOAT
5540 	    emsg(_("E805: Using a Float as a Number"));
5541 	    break;
5542 #endif
5543 	case VAR_FUNC:
5544 	case VAR_PARTIAL:
5545 	    emsg(_("E703: Using a Funcref as a Number"));
5546 	    break;
5547 	case VAR_STRING:
5548 	    if (varp->vval.v_string != NULL)
5549 		vim_str2nr(varp->vval.v_string, NULL, NULL,
5550 					    STR2NR_ALL, &n, NULL, 0, FALSE);
5551 	    return n;
5552 	case VAR_LIST:
5553 	    emsg(_("E745: Using a List as a Number"));
5554 	    break;
5555 	case VAR_DICT:
5556 	    emsg(_("E728: Using a Dictionary as a Number"));
5557 	    break;
5558 	case VAR_BOOL:
5559 	case VAR_SPECIAL:
5560 	    return varp->vval.v_number == VVAL_TRUE ? 1 : 0;
5561 	case VAR_JOB:
5562 #ifdef FEAT_JOB_CHANNEL
5563 	    emsg(_("E910: Using a Job as a Number"));
5564 	    break;
5565 #endif
5566 	case VAR_CHANNEL:
5567 #ifdef FEAT_JOB_CHANNEL
5568 	    emsg(_("E913: Using a Channel as a Number"));
5569 	    break;
5570 #endif
5571 	case VAR_BLOB:
5572 	    emsg(_("E974: Using a Blob as a Number"));
5573 	    break;
5574 	case VAR_UNKNOWN:
5575 	case VAR_ANY:
5576 	case VAR_VOID:
5577 	    internal_error_no_abort("tv_get_number(UNKNOWN)");
5578 	    break;
5579     }
5580     if (denote == NULL)		// useful for values that must be unsigned
5581 	n = -1;
5582     else
5583 	*denote = TRUE;
5584     return n;
5585 }
5586 
5587 #ifdef FEAT_FLOAT
5588     float_T
5589 tv_get_float(typval_T *varp)
5590 {
5591     switch (varp->v_type)
5592     {
5593 	case VAR_NUMBER:
5594 	    return (float_T)(varp->vval.v_number);
5595 	case VAR_FLOAT:
5596 	    return varp->vval.v_float;
5597 	case VAR_FUNC:
5598 	case VAR_PARTIAL:
5599 	    emsg(_("E891: Using a Funcref as a Float"));
5600 	    break;
5601 	case VAR_STRING:
5602 	    emsg(_("E892: Using a String as a Float"));
5603 	    break;
5604 	case VAR_LIST:
5605 	    emsg(_("E893: Using a List as a Float"));
5606 	    break;
5607 	case VAR_DICT:
5608 	    emsg(_("E894: Using a Dictionary as a Float"));
5609 	    break;
5610 	case VAR_BOOL:
5611 	    emsg(_("E362: Using a boolean value as a Float"));
5612 	    break;
5613 	case VAR_SPECIAL:
5614 	    emsg(_("E907: Using a special value as a Float"));
5615 	    break;
5616 	case VAR_JOB:
5617 # ifdef FEAT_JOB_CHANNEL
5618 	    emsg(_("E911: Using a Job as a Float"));
5619 	    break;
5620 # endif
5621 	case VAR_CHANNEL:
5622 # ifdef FEAT_JOB_CHANNEL
5623 	    emsg(_("E914: Using a Channel as a Float"));
5624 	    break;
5625 # endif
5626 	case VAR_BLOB:
5627 	    emsg(_("E975: Using a Blob as a Float"));
5628 	    break;
5629 	case VAR_UNKNOWN:
5630 	case VAR_ANY:
5631 	case VAR_VOID:
5632 	    internal_error_no_abort("tv_get_float(UNKNOWN)");
5633 	    break;
5634     }
5635     return 0;
5636 }
5637 #endif
5638 
5639 /*
5640  * Get the string value of a variable.
5641  * If it is a Number variable, the number is converted into a string.
5642  * tv_get_string() uses a single, static buffer.  YOU CAN ONLY USE IT ONCE!
5643  * tv_get_string_buf() uses a given buffer.
5644  * If the String variable has never been set, return an empty string.
5645  * Never returns NULL;
5646  * tv_get_string_chk() and tv_get_string_buf_chk() are similar, but return
5647  * NULL on error.
5648  */
5649     char_u *
5650 tv_get_string(typval_T *varp)
5651 {
5652     static char_u   mybuf[NUMBUFLEN];
5653 
5654     return tv_get_string_buf(varp, mybuf);
5655 }
5656 
5657     char_u *
5658 tv_get_string_buf(typval_T *varp, char_u *buf)
5659 {
5660     char_u	*res =  tv_get_string_buf_chk(varp, buf);
5661 
5662     return res != NULL ? res : (char_u *)"";
5663 }
5664 
5665 /*
5666  * Careful: This uses a single, static buffer.  YOU CAN ONLY USE IT ONCE!
5667  */
5668     char_u *
5669 tv_get_string_chk(typval_T *varp)
5670 {
5671     static char_u   mybuf[NUMBUFLEN];
5672 
5673     return tv_get_string_buf_chk(varp, mybuf);
5674 }
5675 
5676     char_u *
5677 tv_get_string_buf_chk(typval_T *varp, char_u *buf)
5678 {
5679     switch (varp->v_type)
5680     {
5681 	case VAR_NUMBER:
5682 	    vim_snprintf((char *)buf, NUMBUFLEN, "%lld",
5683 					    (varnumber_T)varp->vval.v_number);
5684 	    return buf;
5685 	case VAR_FUNC:
5686 	case VAR_PARTIAL:
5687 	    emsg(_("E729: using Funcref as a String"));
5688 	    break;
5689 	case VAR_LIST:
5690 	    emsg(_("E730: using List as a String"));
5691 	    break;
5692 	case VAR_DICT:
5693 	    emsg(_("E731: using Dictionary as a String"));
5694 	    break;
5695 	case VAR_FLOAT:
5696 #ifdef FEAT_FLOAT
5697 	    emsg(_(e_float_as_string));
5698 	    break;
5699 #endif
5700 	case VAR_STRING:
5701 	    if (varp->vval.v_string != NULL)
5702 		return varp->vval.v_string;
5703 	    return (char_u *)"";
5704 	case VAR_BOOL:
5705 	case VAR_SPECIAL:
5706 	    STRCPY(buf, get_var_special_name(varp->vval.v_number));
5707 	    return buf;
5708         case VAR_BLOB:
5709 	    emsg(_("E976: using Blob as a String"));
5710 	    break;
5711 	case VAR_JOB:
5712 #ifdef FEAT_JOB_CHANNEL
5713 	    {
5714 		job_T *job = varp->vval.v_job;
5715 		char  *status;
5716 
5717 		if (job == NULL)
5718 		    return (char_u *)"no process";
5719 		status = job->jv_status == JOB_FAILED ? "fail"
5720 				: job->jv_status >= JOB_ENDED ? "dead"
5721 				: "run";
5722 # ifdef UNIX
5723 		vim_snprintf((char *)buf, NUMBUFLEN,
5724 			    "process %ld %s", (long)job->jv_pid, status);
5725 # elif defined(MSWIN)
5726 		vim_snprintf((char *)buf, NUMBUFLEN,
5727 			    "process %ld %s",
5728 			    (long)job->jv_proc_info.dwProcessId,
5729 			    status);
5730 # else
5731 		// fall-back
5732 		vim_snprintf((char *)buf, NUMBUFLEN, "process ? %s", status);
5733 # endif
5734 		return buf;
5735 	    }
5736 #endif
5737 	    break;
5738 	case VAR_CHANNEL:
5739 #ifdef FEAT_JOB_CHANNEL
5740 	    {
5741 		channel_T *channel = varp->vval.v_channel;
5742 		char      *status = channel_status(channel, -1);
5743 
5744 		if (channel == NULL)
5745 		    vim_snprintf((char *)buf, NUMBUFLEN, "channel %s", status);
5746 		else
5747 		    vim_snprintf((char *)buf, NUMBUFLEN,
5748 				     "channel %d %s", channel->ch_id, status);
5749 		return buf;
5750 	    }
5751 #endif
5752 	    break;
5753 	case VAR_UNKNOWN:
5754 	case VAR_ANY:
5755 	case VAR_VOID:
5756 	    emsg(_(e_inval_string));
5757 	    break;
5758     }
5759     return NULL;
5760 }
5761 
5762 /*
5763  * Turn a typeval into a string.  Similar to tv_get_string_buf() but uses
5764  * string() on Dict, List, etc.
5765  */
5766     static char_u *
5767 tv_stringify(typval_T *varp, char_u *buf)
5768 {
5769     if (varp->v_type == VAR_LIST
5770 	    || varp->v_type == VAR_DICT
5771 	    || varp->v_type == VAR_BLOB
5772 	    || varp->v_type == VAR_FUNC
5773 	    || varp->v_type == VAR_PARTIAL
5774 	    || varp->v_type == VAR_FLOAT)
5775     {
5776 	typval_T tmp;
5777 
5778 	f_string(varp, &tmp);
5779 	tv_get_string_buf(&tmp, buf);
5780 	clear_tv(varp);
5781 	*varp = tmp;
5782 	return tmp.vval.v_string;
5783     }
5784     return tv_get_string_buf(varp, buf);
5785 }
5786 
5787 /*
5788  * Return TRUE if typeval "tv" and its value are set to be locked (immutable).
5789  * Also give an error message, using "name" or _("name") when use_gettext is
5790  * TRUE.
5791  */
5792     static int
5793 tv_check_lock(typval_T *tv, char_u *name, int use_gettext)
5794 {
5795     int	lock = 0;
5796 
5797     switch (tv->v_type)
5798     {
5799 	case VAR_BLOB:
5800 	    if (tv->vval.v_blob != NULL)
5801 		lock = tv->vval.v_blob->bv_lock;
5802 	    break;
5803 	case VAR_LIST:
5804 	    if (tv->vval.v_list != NULL)
5805 		lock = tv->vval.v_list->lv_lock;
5806 	    break;
5807 	case VAR_DICT:
5808 	    if (tv->vval.v_dict != NULL)
5809 		lock = tv->vval.v_dict->dv_lock;
5810 	    break;
5811 	default:
5812 	    break;
5813     }
5814     return var_check_lock(tv->v_lock, name, use_gettext)
5815 		    || (lock != 0 && var_check_lock(lock, name, use_gettext));
5816 }
5817 
5818 /*
5819  * Copy the values from typval_T "from" to typval_T "to".
5820  * When needed allocates string or increases reference count.
5821  * Does not make a copy of a list, blob or dict but copies the reference!
5822  * It is OK for "from" and "to" to point to the same item.  This is used to
5823  * make a copy later.
5824  */
5825     void
5826 copy_tv(typval_T *from, typval_T *to)
5827 {
5828     to->v_type = from->v_type;
5829     to->v_lock = 0;
5830     switch (from->v_type)
5831     {
5832 	case VAR_NUMBER:
5833 	case VAR_BOOL:
5834 	case VAR_SPECIAL:
5835 	    to->vval.v_number = from->vval.v_number;
5836 	    break;
5837 	case VAR_FLOAT:
5838 #ifdef FEAT_FLOAT
5839 	    to->vval.v_float = from->vval.v_float;
5840 	    break;
5841 #endif
5842 	case VAR_JOB:
5843 #ifdef FEAT_JOB_CHANNEL
5844 	    to->vval.v_job = from->vval.v_job;
5845 	    if (to->vval.v_job != NULL)
5846 		++to->vval.v_job->jv_refcount;
5847 	    break;
5848 #endif
5849 	case VAR_CHANNEL:
5850 #ifdef FEAT_JOB_CHANNEL
5851 	    to->vval.v_channel = from->vval.v_channel;
5852 	    if (to->vval.v_channel != NULL)
5853 		++to->vval.v_channel->ch_refcount;
5854 	    break;
5855 #endif
5856 	case VAR_STRING:
5857 	case VAR_FUNC:
5858 	    if (from->vval.v_string == NULL)
5859 		to->vval.v_string = NULL;
5860 	    else
5861 	    {
5862 		to->vval.v_string = vim_strsave(from->vval.v_string);
5863 		if (from->v_type == VAR_FUNC)
5864 		    func_ref(to->vval.v_string);
5865 	    }
5866 	    break;
5867 	case VAR_PARTIAL:
5868 	    if (from->vval.v_partial == NULL)
5869 		to->vval.v_partial = NULL;
5870 	    else
5871 	    {
5872 		to->vval.v_partial = from->vval.v_partial;
5873 		++to->vval.v_partial->pt_refcount;
5874 	    }
5875 	    break;
5876 	case VAR_BLOB:
5877 	    if (from->vval.v_blob == NULL)
5878 		to->vval.v_blob = NULL;
5879 	    else
5880 	    {
5881 		to->vval.v_blob = from->vval.v_blob;
5882 		++to->vval.v_blob->bv_refcount;
5883 	    }
5884 	    break;
5885 	case VAR_LIST:
5886 	    if (from->vval.v_list == NULL)
5887 		to->vval.v_list = NULL;
5888 	    else
5889 	    {
5890 		to->vval.v_list = from->vval.v_list;
5891 		++to->vval.v_list->lv_refcount;
5892 	    }
5893 	    break;
5894 	case VAR_DICT:
5895 	    if (from->vval.v_dict == NULL)
5896 		to->vval.v_dict = NULL;
5897 	    else
5898 	    {
5899 		to->vval.v_dict = from->vval.v_dict;
5900 		++to->vval.v_dict->dv_refcount;
5901 	    }
5902 	    break;
5903 	case VAR_UNKNOWN:
5904 	case VAR_ANY:
5905 	case VAR_VOID:
5906 	    internal_error_no_abort("copy_tv(UNKNOWN)");
5907 	    break;
5908     }
5909 }
5910 
5911 /*
5912  * Make a copy of an item.
5913  * Lists and Dictionaries are also copied.  A deep copy if "deep" is set.
5914  * For deepcopy() "copyID" is zero for a full copy or the ID for when a
5915  * reference to an already copied list/dict can be used.
5916  * Returns FAIL or OK.
5917  */
5918     int
5919 item_copy(
5920     typval_T	*from,
5921     typval_T	*to,
5922     int		deep,
5923     int		copyID)
5924 {
5925     static int	recurse = 0;
5926     int		ret = OK;
5927 
5928     if (recurse >= DICT_MAXNEST)
5929     {
5930 	emsg(_("E698: variable nested too deep for making a copy"));
5931 	return FAIL;
5932     }
5933     ++recurse;
5934 
5935     switch (from->v_type)
5936     {
5937 	case VAR_NUMBER:
5938 	case VAR_FLOAT:
5939 	case VAR_STRING:
5940 	case VAR_FUNC:
5941 	case VAR_PARTIAL:
5942 	case VAR_BOOL:
5943 	case VAR_SPECIAL:
5944 	case VAR_JOB:
5945 	case VAR_CHANNEL:
5946 	    copy_tv(from, to);
5947 	    break;
5948 	case VAR_LIST:
5949 	    to->v_type = VAR_LIST;
5950 	    to->v_lock = 0;
5951 	    if (from->vval.v_list == NULL)
5952 		to->vval.v_list = NULL;
5953 	    else if (copyID != 0 && from->vval.v_list->lv_copyID == copyID)
5954 	    {
5955 		// use the copy made earlier
5956 		to->vval.v_list = from->vval.v_list->lv_copylist;
5957 		++to->vval.v_list->lv_refcount;
5958 	    }
5959 	    else
5960 		to->vval.v_list = list_copy(from->vval.v_list, deep, copyID);
5961 	    if (to->vval.v_list == NULL)
5962 		ret = FAIL;
5963 	    break;
5964 	case VAR_BLOB:
5965 	    ret = blob_copy(from->vval.v_blob, to);
5966 	    break;
5967 	case VAR_DICT:
5968 	    to->v_type = VAR_DICT;
5969 	    to->v_lock = 0;
5970 	    if (from->vval.v_dict == NULL)
5971 		to->vval.v_dict = NULL;
5972 	    else if (copyID != 0 && from->vval.v_dict->dv_copyID == copyID)
5973 	    {
5974 		// use the copy made earlier
5975 		to->vval.v_dict = from->vval.v_dict->dv_copydict;
5976 		++to->vval.v_dict->dv_refcount;
5977 	    }
5978 	    else
5979 		to->vval.v_dict = dict_copy(from->vval.v_dict, deep, copyID);
5980 	    if (to->vval.v_dict == NULL)
5981 		ret = FAIL;
5982 	    break;
5983 	case VAR_UNKNOWN:
5984 	case VAR_ANY:
5985 	case VAR_VOID:
5986 	    internal_error_no_abort("item_copy(UNKNOWN)");
5987 	    ret = FAIL;
5988     }
5989     --recurse;
5990     return ret;
5991 }
5992 
5993     void
5994 echo_one(typval_T *rettv, int with_space, int *atstart, int *needclr)
5995 {
5996     char_u	*tofree;
5997     char_u	numbuf[NUMBUFLEN];
5998     char_u	*p = echo_string(rettv, &tofree, numbuf, get_copyID());
5999 
6000     if (*atstart)
6001     {
6002 	*atstart = FALSE;
6003 	// Call msg_start() after eval1(), evaluating the expression
6004 	// may cause a message to appear.
6005 	if (with_space)
6006 	{
6007 	    // Mark the saved text as finishing the line, so that what
6008 	    // follows is displayed on a new line when scrolling back
6009 	    // at the more prompt.
6010 	    msg_sb_eol();
6011 	    msg_start();
6012 	}
6013     }
6014     else if (with_space)
6015 	msg_puts_attr(" ", echo_attr);
6016 
6017     if (p != NULL)
6018 	for ( ; *p != NUL && !got_int; ++p)
6019 	{
6020 	    if (*p == '\n' || *p == '\r' || *p == TAB)
6021 	    {
6022 		if (*p != TAB && *needclr)
6023 		{
6024 		    // remove any text still there from the command
6025 		    msg_clr_eos();
6026 		    *needclr = FALSE;
6027 		}
6028 		msg_putchar_attr(*p, echo_attr);
6029 	    }
6030 	    else
6031 	    {
6032 		if (has_mbyte)
6033 		{
6034 		    int i = (*mb_ptr2len)(p);
6035 
6036 		    (void)msg_outtrans_len_attr(p, i, echo_attr);
6037 		    p += i - 1;
6038 		}
6039 		else
6040 		    (void)msg_outtrans_len_attr(p, 1, echo_attr);
6041 	    }
6042 	}
6043     vim_free(tofree);
6044 }
6045 
6046 /*
6047  * ":echo expr1 ..."	print each argument separated with a space, add a
6048  *			newline at the end.
6049  * ":echon expr1 ..."	print each argument plain.
6050  */
6051     void
6052 ex_echo(exarg_T *eap)
6053 {
6054     char_u	*arg = eap->arg;
6055     typval_T	rettv;
6056     char_u	*p;
6057     int		needclr = TRUE;
6058     int		atstart = TRUE;
6059     int		did_emsg_before = did_emsg;
6060     int		called_emsg_before = called_emsg;
6061 
6062     if (eap->skip)
6063 	++emsg_skip;
6064     while (*arg != NUL && *arg != '|' && *arg != '\n' && !got_int)
6065     {
6066 	// If eval1() causes an error message the text from the command may
6067 	// still need to be cleared. E.g., "echo 22,44".
6068 	need_clr_eos = needclr;
6069 
6070 	p = arg;
6071 	if (eval1(&arg, &rettv, !eap->skip) == FAIL)
6072 	{
6073 	    /*
6074 	     * Report the invalid expression unless the expression evaluation
6075 	     * has been cancelled due to an aborting error, an interrupt, or an
6076 	     * exception.
6077 	     */
6078 	    if (!aborting() && did_emsg == did_emsg_before
6079 					  && called_emsg == called_emsg_before)
6080 		semsg(_(e_invexpr2), p);
6081 	    need_clr_eos = FALSE;
6082 	    break;
6083 	}
6084 	need_clr_eos = FALSE;
6085 
6086 	if (!eap->skip)
6087 	    echo_one(&rettv, eap->cmdidx == CMD_echo, &atstart, &needclr);
6088 
6089 	clear_tv(&rettv);
6090 	arg = skipwhite(arg);
6091     }
6092     eap->nextcmd = check_nextcmd(arg);
6093 
6094     if (eap->skip)
6095 	--emsg_skip;
6096     else
6097     {
6098 	// remove text that may still be there from the command
6099 	if (needclr)
6100 	    msg_clr_eos();
6101 	if (eap->cmdidx == CMD_echo)
6102 	    msg_end();
6103     }
6104 }
6105 
6106 /*
6107  * ":echohl {name}".
6108  */
6109     void
6110 ex_echohl(exarg_T *eap)
6111 {
6112     echo_attr = syn_name2attr(eap->arg);
6113 }
6114 
6115 /*
6116  * Returns the :echo attribute
6117  */
6118     int
6119 get_echo_attr(void)
6120 {
6121     return echo_attr;
6122 }
6123 
6124 /*
6125  * ":execute expr1 ..."	execute the result of an expression.
6126  * ":echomsg expr1 ..."	Print a message
6127  * ":echoerr expr1 ..."	Print an error
6128  * Each gets spaces around each argument and a newline at the end for
6129  * echo commands
6130  */
6131     void
6132 ex_execute(exarg_T *eap)
6133 {
6134     char_u	*arg = eap->arg;
6135     typval_T	rettv;
6136     int		ret = OK;
6137     char_u	*p;
6138     garray_T	ga;
6139     int		len;
6140     int		save_did_emsg;
6141 
6142     ga_init2(&ga, 1, 80);
6143 
6144     if (eap->skip)
6145 	++emsg_skip;
6146     while (*arg != NUL && *arg != '|' && *arg != '\n')
6147     {
6148 	ret = eval1_emsg(&arg, &rettv, !eap->skip);
6149 	if (ret == FAIL)
6150 	    break;
6151 
6152 	if (!eap->skip)
6153 	{
6154 	    char_u   buf[NUMBUFLEN];
6155 
6156 	    if (eap->cmdidx == CMD_execute)
6157 	    {
6158 		if (rettv.v_type == VAR_CHANNEL || rettv.v_type == VAR_JOB)
6159 		{
6160 		    emsg(_(e_inval_string));
6161 		    p = NULL;
6162 		}
6163 		else
6164 		    p = tv_get_string_buf(&rettv, buf);
6165 	    }
6166 	    else
6167 		p = tv_stringify(&rettv, buf);
6168 	    if (p == NULL)
6169 	    {
6170 		clear_tv(&rettv);
6171 		ret = FAIL;
6172 		break;
6173 	    }
6174 	    len = (int)STRLEN(p);
6175 	    if (ga_grow(&ga, len + 2) == FAIL)
6176 	    {
6177 		clear_tv(&rettv);
6178 		ret = FAIL;
6179 		break;
6180 	    }
6181 	    if (ga.ga_len)
6182 		((char_u *)(ga.ga_data))[ga.ga_len++] = ' ';
6183 	    STRCPY((char_u *)(ga.ga_data) + ga.ga_len, p);
6184 	    ga.ga_len += len;
6185 	}
6186 
6187 	clear_tv(&rettv);
6188 	arg = skipwhite(arg);
6189     }
6190 
6191     if (ret != FAIL && ga.ga_data != NULL)
6192     {
6193 	if (eap->cmdidx == CMD_echomsg || eap->cmdidx == CMD_echoerr)
6194 	{
6195 	    // Mark the already saved text as finishing the line, so that what
6196 	    // follows is displayed on a new line when scrolling back at the
6197 	    // more prompt.
6198 	    msg_sb_eol();
6199 	}
6200 
6201 	if (eap->cmdidx == CMD_echomsg)
6202 	{
6203 	    msg_attr(ga.ga_data, echo_attr);
6204 	    out_flush();
6205 	}
6206 	else if (eap->cmdidx == CMD_echoerr)
6207 	{
6208 	    // We don't want to abort following commands, restore did_emsg.
6209 	    save_did_emsg = did_emsg;
6210 	    emsg(ga.ga_data);
6211 	    if (!force_abort)
6212 		did_emsg = save_did_emsg;
6213 	}
6214 	else if (eap->cmdidx == CMD_execute)
6215 	    do_cmdline((char_u *)ga.ga_data,
6216 		       eap->getline, eap->cookie, DOCMD_NOWAIT|DOCMD_VERBOSE);
6217     }
6218 
6219     ga_clear(&ga);
6220 
6221     if (eap->skip)
6222 	--emsg_skip;
6223 
6224     eap->nextcmd = check_nextcmd(arg);
6225 }
6226 
6227 /*
6228  * Skip over the name of an option: "&option", "&g:option" or "&l:option".
6229  * "arg" points to the "&" or '+' when called, to "option" when returning.
6230  * Returns NULL when no option name found.  Otherwise pointer to the char
6231  * after the option name.
6232  */
6233     char_u *
6234 find_option_end(char_u **arg, int *opt_flags)
6235 {
6236     char_u	*p = *arg;
6237 
6238     ++p;
6239     if (*p == 'g' && p[1] == ':')
6240     {
6241 	*opt_flags = OPT_GLOBAL;
6242 	p += 2;
6243     }
6244     else if (*p == 'l' && p[1] == ':')
6245     {
6246 	*opt_flags = OPT_LOCAL;
6247 	p += 2;
6248     }
6249     else
6250 	*opt_flags = 0;
6251 
6252     if (!ASCII_ISALPHA(*p))
6253 	return NULL;
6254     *arg = p;
6255 
6256     if (p[0] == 't' && p[1] == '_' && p[2] != NUL && p[3] != NUL)
6257 	p += 4;	    // termcap option
6258     else
6259 	while (ASCII_ISALPHA(*p))
6260 	    ++p;
6261     return p;
6262 }
6263 
6264 /*
6265  * Display script name where an item was last set.
6266  * Should only be invoked when 'verbose' is non-zero.
6267  */
6268     void
6269 last_set_msg(sctx_T script_ctx)
6270 {
6271     char_u *p;
6272 
6273     if (script_ctx.sc_sid != 0)
6274     {
6275 	p = home_replace_save(NULL, get_scriptname(script_ctx.sc_sid));
6276 	if (p != NULL)
6277 	{
6278 	    verbose_enter();
6279 	    msg_puts(_("\n\tLast set from "));
6280 	    msg_puts((char *)p);
6281 	    if (script_ctx.sc_lnum > 0)
6282 	    {
6283 		msg_puts(_(line_msg));
6284 		msg_outnum((long)script_ctx.sc_lnum);
6285 	    }
6286 	    verbose_leave();
6287 	    vim_free(p);
6288 	}
6289     }
6290 }
6291 
6292 /*
6293  * Compare "typ1" and "typ2".  Put the result in "typ1".
6294  */
6295     int
6296 typval_compare(
6297     typval_T	*typ1,   // first operand
6298     typval_T	*typ2,   // second operand
6299     exptype_T	type,    // operator
6300     int		ic)      // ignore case
6301 {
6302     int		i;
6303     varnumber_T	n1, n2;
6304     char_u	*s1, *s2;
6305     char_u	buf1[NUMBUFLEN], buf2[NUMBUFLEN];
6306     int		type_is = type == EXPR_IS || type == EXPR_ISNOT;
6307 
6308     if (type_is && typ1->v_type != typ2->v_type)
6309     {
6310 	// For "is" a different type always means FALSE, for "notis"
6311 	// it means TRUE.
6312 	n1 = (type == EXPR_ISNOT);
6313     }
6314     else if (typ1->v_type == VAR_BLOB || typ2->v_type == VAR_BLOB)
6315     {
6316 	if (type_is)
6317 	{
6318 	    n1 = (typ1->v_type == typ2->v_type
6319 			    && typ1->vval.v_blob == typ2->vval.v_blob);
6320 	    if (type == EXPR_ISNOT)
6321 		n1 = !n1;
6322 	}
6323 	else if (typ1->v_type != typ2->v_type
6324 		|| (type != EXPR_EQUAL && type != EXPR_NEQUAL))
6325 	{
6326 	    if (typ1->v_type != typ2->v_type)
6327 		emsg(_("E977: Can only compare Blob with Blob"));
6328 	    else
6329 		emsg(_(e_invalblob));
6330 	    clear_tv(typ1);
6331 	    return FAIL;
6332 	}
6333 	else
6334 	{
6335 	    // Compare two Blobs for being equal or unequal.
6336 	    n1 = blob_equal(typ1->vval.v_blob, typ2->vval.v_blob);
6337 	    if (type == EXPR_NEQUAL)
6338 		n1 = !n1;
6339 	}
6340     }
6341     else if (typ1->v_type == VAR_LIST || typ2->v_type == VAR_LIST)
6342     {
6343 	if (type_is)
6344 	{
6345 	    n1 = (typ1->v_type == typ2->v_type
6346 			    && typ1->vval.v_list == typ2->vval.v_list);
6347 	    if (type == EXPR_ISNOT)
6348 		n1 = !n1;
6349 	}
6350 	else if (typ1->v_type != typ2->v_type
6351 		|| (type != EXPR_EQUAL && type != EXPR_NEQUAL))
6352 	{
6353 	    if (typ1->v_type != typ2->v_type)
6354 		emsg(_("E691: Can only compare List with List"));
6355 	    else
6356 		emsg(_("E692: Invalid operation for List"));
6357 	    clear_tv(typ1);
6358 	    return FAIL;
6359 	}
6360 	else
6361 	{
6362 	    // Compare two Lists for being equal or unequal.
6363 	    n1 = list_equal(typ1->vval.v_list, typ2->vval.v_list,
6364 							    ic, FALSE);
6365 	    if (type == EXPR_NEQUAL)
6366 		n1 = !n1;
6367 	}
6368     }
6369 
6370     else if (typ1->v_type == VAR_DICT || typ2->v_type == VAR_DICT)
6371     {
6372 	if (type_is)
6373 	{
6374 	    n1 = (typ1->v_type == typ2->v_type
6375 			    && typ1->vval.v_dict == typ2->vval.v_dict);
6376 	    if (type == EXPR_ISNOT)
6377 		n1 = !n1;
6378 	}
6379 	else if (typ1->v_type != typ2->v_type
6380 		|| (type != EXPR_EQUAL && type != EXPR_NEQUAL))
6381 	{
6382 	    if (typ1->v_type != typ2->v_type)
6383 		emsg(_("E735: Can only compare Dictionary with Dictionary"));
6384 	    else
6385 		emsg(_("E736: Invalid operation for Dictionary"));
6386 	    clear_tv(typ1);
6387 	    return FAIL;
6388 	}
6389 	else
6390 	{
6391 	    // Compare two Dictionaries for being equal or unequal.
6392 	    n1 = dict_equal(typ1->vval.v_dict, typ2->vval.v_dict,
6393 							    ic, FALSE);
6394 	    if (type == EXPR_NEQUAL)
6395 		n1 = !n1;
6396 	}
6397     }
6398 
6399     else if (typ1->v_type == VAR_FUNC || typ2->v_type == VAR_FUNC
6400 	|| typ1->v_type == VAR_PARTIAL || typ2->v_type == VAR_PARTIAL)
6401     {
6402 	if (type != EXPR_EQUAL && type != EXPR_NEQUAL
6403 		&& type != EXPR_IS && type != EXPR_ISNOT)
6404 	{
6405 	    emsg(_("E694: Invalid operation for Funcrefs"));
6406 	    clear_tv(typ1);
6407 	    return FAIL;
6408 	}
6409 	if ((typ1->v_type == VAR_PARTIAL
6410 					&& typ1->vval.v_partial == NULL)
6411 		|| (typ2->v_type == VAR_PARTIAL
6412 					&& typ2->vval.v_partial == NULL))
6413 	    // when a partial is NULL assume not equal
6414 	    n1 = FALSE;
6415 	else if (type_is)
6416 	{
6417 	    if (typ1->v_type == VAR_FUNC && typ2->v_type == VAR_FUNC)
6418 		// strings are considered the same if their value is
6419 		// the same
6420 		n1 = tv_equal(typ1, typ2, ic, FALSE);
6421 	    else if (typ1->v_type == VAR_PARTIAL
6422 					&& typ2->v_type == VAR_PARTIAL)
6423 		n1 = (typ1->vval.v_partial == typ2->vval.v_partial);
6424 	    else
6425 		n1 = FALSE;
6426 	}
6427 	else
6428 	    n1 = tv_equal(typ1, typ2, ic, FALSE);
6429 	if (type == EXPR_NEQUAL || type == EXPR_ISNOT)
6430 	    n1 = !n1;
6431     }
6432 
6433 #ifdef FEAT_FLOAT
6434     /*
6435 	* If one of the two variables is a float, compare as a float.
6436 	* When using "=~" or "!~", always compare as string.
6437 	*/
6438     else if ((typ1->v_type == VAR_FLOAT || typ2->v_type == VAR_FLOAT)
6439 	    && type != EXPR_MATCH && type != EXPR_NOMATCH)
6440     {
6441 	float_T f1, f2;
6442 
6443 	f1 = tv_get_float(typ1);
6444 	f2 = tv_get_float(typ2);
6445 	n1 = FALSE;
6446 	switch (type)
6447 	{
6448 	    case EXPR_IS:
6449 	    case EXPR_EQUAL:    n1 = (f1 == f2); break;
6450 	    case EXPR_ISNOT:
6451 	    case EXPR_NEQUAL:   n1 = (f1 != f2); break;
6452 	    case EXPR_GREATER:  n1 = (f1 > f2); break;
6453 	    case EXPR_GEQUAL:   n1 = (f1 >= f2); break;
6454 	    case EXPR_SMALLER:  n1 = (f1 < f2); break;
6455 	    case EXPR_SEQUAL:   n1 = (f1 <= f2); break;
6456 	    case EXPR_UNKNOWN:
6457 	    case EXPR_MATCH:
6458 	    default:  break;  // avoid gcc warning
6459 	}
6460     }
6461 #endif
6462 
6463     /*
6464      * If one of the two variables is a number, compare as a number.
6465      * When using "=~" or "!~", always compare as string.
6466      */
6467     else if ((typ1->v_type == VAR_NUMBER || typ2->v_type == VAR_NUMBER)
6468 	    && type != EXPR_MATCH && type != EXPR_NOMATCH)
6469     {
6470 	n1 = tv_get_number(typ1);
6471 	n2 = tv_get_number(typ2);
6472 	switch (type)
6473 	{
6474 	    case EXPR_IS:
6475 	    case EXPR_EQUAL:    n1 = (n1 == n2); break;
6476 	    case EXPR_ISNOT:
6477 	    case EXPR_NEQUAL:   n1 = (n1 != n2); break;
6478 	    case EXPR_GREATER:  n1 = (n1 > n2); break;
6479 	    case EXPR_GEQUAL:   n1 = (n1 >= n2); break;
6480 	    case EXPR_SMALLER:  n1 = (n1 < n2); break;
6481 	    case EXPR_SEQUAL:   n1 = (n1 <= n2); break;
6482 	    case EXPR_UNKNOWN:
6483 	    case EXPR_MATCH:
6484 	    default:  break;  // avoid gcc warning
6485 	}
6486     }
6487     else
6488     {
6489 	s1 = tv_get_string_buf(typ1, buf1);
6490 	s2 = tv_get_string_buf(typ2, buf2);
6491 	if (type != EXPR_MATCH && type != EXPR_NOMATCH)
6492 	    i = ic ? MB_STRICMP(s1, s2) : STRCMP(s1, s2);
6493 	else
6494 	    i = 0;
6495 	n1 = FALSE;
6496 	switch (type)
6497 	{
6498 	    case EXPR_IS:
6499 	    case EXPR_EQUAL:    n1 = (i == 0); break;
6500 	    case EXPR_ISNOT:
6501 	    case EXPR_NEQUAL:   n1 = (i != 0); break;
6502 	    case EXPR_GREATER:  n1 = (i > 0); break;
6503 	    case EXPR_GEQUAL:   n1 = (i >= 0); break;
6504 	    case EXPR_SMALLER:  n1 = (i < 0); break;
6505 	    case EXPR_SEQUAL:   n1 = (i <= 0); break;
6506 
6507 	    case EXPR_MATCH:
6508 	    case EXPR_NOMATCH:
6509 		    n1 = pattern_match(s2, s1, ic);
6510 		    if (type == EXPR_NOMATCH)
6511 			n1 = !n1;
6512 		    break;
6513 
6514 	    default:  break;  // avoid gcc warning
6515 	}
6516     }
6517     clear_tv(typ1);
6518     typ1->v_type = VAR_NUMBER;
6519     typ1->vval.v_number = n1;
6520 
6521     return OK;
6522 }
6523 
6524     char_u *
6525 typval_tostring(typval_T *arg)
6526 {
6527     char_u	*tofree;
6528     char_u	numbuf[NUMBUFLEN];
6529     char_u	*ret = NULL;
6530 
6531     if (arg == NULL)
6532 	return vim_strsave((char_u *)"(does not exist)");
6533     ret = tv2string(arg, &tofree, numbuf, 0);
6534     // Make a copy if we have a value but it's not in allocated memory.
6535     if (ret != NULL && tofree == NULL)
6536 	ret = vim_strsave(ret);
6537     return ret;
6538 }
6539 
6540 #endif // FEAT_EVAL
6541 
6542 /*
6543  * Perform a substitution on "str" with pattern "pat" and substitute "sub".
6544  * When "sub" is NULL "expr" is used, must be a VAR_FUNC or VAR_PARTIAL.
6545  * "flags" can be "g" to do a global substitute.
6546  * Returns an allocated string, NULL for error.
6547  */
6548     char_u *
6549 do_string_sub(
6550     char_u	*str,
6551     char_u	*pat,
6552     char_u	*sub,
6553     typval_T	*expr,
6554     char_u	*flags)
6555 {
6556     int		sublen;
6557     regmatch_T	regmatch;
6558     int		i;
6559     int		do_all;
6560     char_u	*tail;
6561     char_u	*end;
6562     garray_T	ga;
6563     char_u	*ret;
6564     char_u	*save_cpo;
6565     char_u	*zero_width = NULL;
6566 
6567     // Make 'cpoptions' empty, so that the 'l' flag doesn't work here
6568     save_cpo = p_cpo;
6569     p_cpo = empty_option;
6570 
6571     ga_init2(&ga, 1, 200);
6572 
6573     do_all = (flags[0] == 'g');
6574 
6575     regmatch.rm_ic = p_ic;
6576     regmatch.regprog = vim_regcomp(pat, RE_MAGIC + RE_STRING);
6577     if (regmatch.regprog != NULL)
6578     {
6579 	tail = str;
6580 	end = str + STRLEN(str);
6581 	while (vim_regexec_nl(&regmatch, str, (colnr_T)(tail - str)))
6582 	{
6583 	    // Skip empty match except for first match.
6584 	    if (regmatch.startp[0] == regmatch.endp[0])
6585 	    {
6586 		if (zero_width == regmatch.startp[0])
6587 		{
6588 		    // avoid getting stuck on a match with an empty string
6589 		    i = mb_ptr2len(tail);
6590 		    mch_memmove((char_u *)ga.ga_data + ga.ga_len, tail,
6591 								   (size_t)i);
6592 		    ga.ga_len += i;
6593 		    tail += i;
6594 		    continue;
6595 		}
6596 		zero_width = regmatch.startp[0];
6597 	    }
6598 
6599 	    /*
6600 	     * Get some space for a temporary buffer to do the substitution
6601 	     * into.  It will contain:
6602 	     * - The text up to where the match is.
6603 	     * - The substituted text.
6604 	     * - The text after the match.
6605 	     */
6606 	    sublen = vim_regsub(&regmatch, sub, expr, tail, FALSE, TRUE, FALSE);
6607 	    if (ga_grow(&ga, (int)((end - tail) + sublen -
6608 			    (regmatch.endp[0] - regmatch.startp[0]))) == FAIL)
6609 	    {
6610 		ga_clear(&ga);
6611 		break;
6612 	    }
6613 
6614 	    // copy the text up to where the match is
6615 	    i = (int)(regmatch.startp[0] - tail);
6616 	    mch_memmove((char_u *)ga.ga_data + ga.ga_len, tail, (size_t)i);
6617 	    // add the substituted text
6618 	    (void)vim_regsub(&regmatch, sub, expr, (char_u *)ga.ga_data
6619 					  + ga.ga_len + i, TRUE, TRUE, FALSE);
6620 	    ga.ga_len += i + sublen - 1;
6621 	    tail = regmatch.endp[0];
6622 	    if (*tail == NUL)
6623 		break;
6624 	    if (!do_all)
6625 		break;
6626 	}
6627 
6628 	if (ga.ga_data != NULL)
6629 	    STRCPY((char *)ga.ga_data + ga.ga_len, tail);
6630 
6631 	vim_regfree(regmatch.regprog);
6632     }
6633 
6634     ret = vim_strsave(ga.ga_data == NULL ? str : (char_u *)ga.ga_data);
6635     ga_clear(&ga);
6636     if (p_cpo == empty_option)
6637 	p_cpo = save_cpo;
6638     else
6639 	// Darn, evaluating {sub} expression or {expr} changed the value.
6640 	free_string_option(save_cpo);
6641 
6642     return ret;
6643 }
6644