xref: /vim-8.2.3635/src/vim9type.c (revision be7529e8)
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  * vim9type.c: handling of types
12  */
13 
14 #define USING_FLOAT_STUFF
15 #include "vim.h"
16 
17 #if defined(FEAT_EVAL) || defined(PROTO)
18 
19 #ifdef VMS
20 # include <float.h>
21 #endif
22 
23 /*
24  * Allocate memory for a type_T and add the pointer to type_gap, so that it can
25  * be freed later.
26  */
27     static type_T *
28 alloc_type(garray_T *type_gap)
29 {
30     type_T *type;
31 
32     if (ga_grow(type_gap, 1) == FAIL)
33 	return NULL;
34     type = ALLOC_CLEAR_ONE(type_T);
35     if (type != NULL)
36     {
37 	((type_T **)type_gap->ga_data)[type_gap->ga_len] = type;
38 	++type_gap->ga_len;
39     }
40     return type;
41 }
42 
43     void
44 clear_type_list(garray_T *gap)
45 {
46     while (gap->ga_len > 0)
47 	vim_free(((type_T **)gap->ga_data)[--gap->ga_len]);
48     ga_clear(gap);
49 }
50 
51     type_T *
52 get_list_type(type_T *member_type, garray_T *type_gap)
53 {
54     type_T *type;
55 
56     // recognize commonly used types
57     if (member_type->tt_type == VAR_ANY)
58 	return &t_list_any;
59     if (member_type->tt_type == VAR_VOID
60 	    || member_type->tt_type == VAR_UNKNOWN)
61 	return &t_list_empty;
62     if (member_type->tt_type == VAR_BOOL)
63 	return &t_list_bool;
64     if (member_type->tt_type == VAR_NUMBER)
65 	return &t_list_number;
66     if (member_type->tt_type == VAR_STRING)
67 	return &t_list_string;
68 
69     // Not a common type, create a new entry.
70     type = alloc_type(type_gap);
71     if (type == NULL)
72 	return &t_any;
73     type->tt_type = VAR_LIST;
74     type->tt_member = member_type;
75     type->tt_argcount = 0;
76     type->tt_args = NULL;
77     return type;
78 }
79 
80     type_T *
81 get_dict_type(type_T *member_type, garray_T *type_gap)
82 {
83     type_T *type;
84 
85     // recognize commonly used types
86     if (member_type->tt_type == VAR_ANY)
87 	return &t_dict_any;
88     if (member_type->tt_type == VAR_VOID
89 	    || member_type->tt_type == VAR_UNKNOWN)
90 	return &t_dict_empty;
91     if (member_type->tt_type == VAR_BOOL)
92 	return &t_dict_bool;
93     if (member_type->tt_type == VAR_NUMBER)
94 	return &t_dict_number;
95     if (member_type->tt_type == VAR_STRING)
96 	return &t_dict_string;
97 
98     // Not a common type, create a new entry.
99     type = alloc_type(type_gap);
100     if (type == NULL)
101 	return &t_any;
102     type->tt_type = VAR_DICT;
103     type->tt_member = member_type;
104     type->tt_argcount = 0;
105     type->tt_args = NULL;
106     return type;
107 }
108 
109 /*
110  * Allocate a new type for a function.
111  */
112     type_T *
113 alloc_func_type(type_T *ret_type, int argcount, garray_T *type_gap)
114 {
115     type_T *type = alloc_type(type_gap);
116 
117     if (type == NULL)
118 	return &t_any;
119     type->tt_type = VAR_FUNC;
120     type->tt_member = ret_type;
121     type->tt_argcount = argcount;
122     type->tt_args = NULL;
123     return type;
124 }
125 
126 /*
127  * Get a function type, based on the return type "ret_type".
128  * If "argcount" is -1 or 0 a predefined type can be used.
129  * If "argcount" > 0 always create a new type, so that arguments can be added.
130  */
131     type_T *
132 get_func_type(type_T *ret_type, int argcount, garray_T *type_gap)
133 {
134     // recognize commonly used types
135     if (argcount <= 0)
136     {
137 	if (ret_type == &t_unknown)
138 	{
139 	    // (argcount == 0) is not possible
140 	    return &t_func_unknown;
141 	}
142 	if (ret_type == &t_void)
143 	{
144 	    if (argcount == 0)
145 		return &t_func_0_void;
146 	    else
147 		return &t_func_void;
148 	}
149 	if (ret_type == &t_any)
150 	{
151 	    if (argcount == 0)
152 		return &t_func_0_any;
153 	    else
154 		return &t_func_any;
155 	}
156 	if (ret_type == &t_number)
157 	{
158 	    if (argcount == 0)
159 		return &t_func_0_number;
160 	    else
161 		return &t_func_number;
162 	}
163 	if (ret_type == &t_string)
164 	{
165 	    if (argcount == 0)
166 		return &t_func_0_string;
167 	    else
168 		return &t_func_string;
169 	}
170     }
171 
172     return alloc_func_type(ret_type, argcount, type_gap);
173 }
174 
175 /*
176  * For a function type, reserve space for "argcount" argument types (including
177  * vararg).
178  */
179     int
180 func_type_add_arg_types(
181 	type_T	    *functype,
182 	int	    argcount,
183 	garray_T    *type_gap)
184 {
185     // To make it easy to free the space needed for the argument types, add the
186     // pointer to type_gap.
187     if (ga_grow(type_gap, 1) == FAIL)
188 	return FAIL;
189     functype->tt_args = ALLOC_CLEAR_MULT(type_T *, argcount);
190     if (functype->tt_args == NULL)
191 	return FAIL;
192     ((type_T **)type_gap->ga_data)[type_gap->ga_len] =
193 						     (void *)functype->tt_args;
194     ++type_gap->ga_len;
195     return OK;
196 }
197 
198 /*
199  * Get a type_T for a typval_T.
200  * "type_list" is used to temporarily create types in.
201  */
202     type_T *
203 typval2type(typval_T *tv, garray_T *type_gap)
204 {
205     type_T  *actual;
206     type_T  *member_type;
207 
208     if (tv->v_type == VAR_NUMBER)
209 	return &t_number;
210     if (tv->v_type == VAR_BOOL)
211 	return &t_bool;  // not used
212     if (tv->v_type == VAR_STRING)
213 	return &t_string;
214 
215     if (tv->v_type == VAR_LIST)
216     {
217 	if (tv->vval.v_list == NULL || tv->vval.v_list->lv_first == NULL)
218 	    return &t_list_empty;
219 
220 	// Use the type of the first member, it is the most specific.
221 	member_type = typval2type(&tv->vval.v_list->lv_first->li_tv, type_gap);
222 	return get_list_type(member_type, type_gap);
223     }
224 
225     if (tv->v_type == VAR_DICT)
226     {
227 	dict_iterator_T iter;
228 	typval_T	*value;
229 
230 	if (tv->vval.v_dict == NULL
231 				   || tv->vval.v_dict->dv_hashtab.ht_used == 0)
232 	    return &t_dict_empty;
233 
234 	// Use the type of the first value, it is the most specific.
235 	dict_iterate_start(tv, &iter);
236 	dict_iterate_next(&iter, &value);
237 	member_type = typval2type(value, type_gap);
238 	return get_dict_type(member_type, type_gap);
239     }
240 
241     if (tv->v_type == VAR_FUNC || tv->v_type == VAR_PARTIAL)
242     {
243 	char_u	*name = NULL;
244 	ufunc_T *ufunc = NULL;
245 
246 	if (tv->v_type == VAR_PARTIAL)
247 	{
248 	    if (tv->vval.v_partial->pt_func != NULL)
249 		ufunc = tv->vval.v_partial->pt_func;
250 	    else
251 		name = tv->vval.v_partial->pt_name;
252 	}
253 	else
254 	    name = tv->vval.v_string;
255 	if (name != NULL)
256 	    // TODO: how about a builtin function?
257 	    ufunc = find_func(name, FALSE, NULL);
258 	if (ufunc != NULL)
259 	{
260 	    // May need to get the argument types from default values by
261 	    // compiling the function.
262 	    if (ufunc->uf_def_status == UF_TO_BE_COMPILED
263 			    && compile_def_function(ufunc, TRUE, NULL) == FAIL)
264 		return NULL;
265 	    if (ufunc->uf_func_type != NULL)
266 		return ufunc->uf_func_type;
267 	}
268     }
269 
270     actual = alloc_type(type_gap);
271     if (actual == NULL)
272 	return NULL;
273     actual->tt_type = tv->v_type;
274     actual->tt_member = &t_any;
275 
276     return actual;
277 }
278 
279 /*
280  * Get a type_T for a typval_T, used for v: variables.
281  * "type_list" is used to temporarily create types in.
282  */
283     type_T *
284 typval2type_vimvar(typval_T *tv, garray_T *type_gap)
285 {
286     if (tv->v_type == VAR_LIST)  // e.g. for v:oldfiles
287 	return &t_list_string;
288     if (tv->v_type == VAR_DICT)  // e.g. for v:completed_item
289 	return &t_dict_any;
290     return typval2type(tv, type_gap);
291 }
292 
293 
294 /*
295  * Return FAIL if "expected" and "actual" don't match.
296  */
297     int
298 check_typval_type(type_T *expected, typval_T *actual_tv)
299 {
300     garray_T	type_list;
301     type_T	*actual_type;
302     int		res = FAIL;
303 
304     ga_init2(&type_list, sizeof(type_T *), 10);
305     actual_type = typval2type(actual_tv, &type_list);
306     if (actual_type != NULL)
307 	res = check_type(expected, actual_type, TRUE);
308     clear_type_list(&type_list);
309     return res;
310 }
311 
312     void
313 type_mismatch(type_T *expected, type_T *actual)
314 {
315     char *tofree1, *tofree2;
316 
317     semsg(_("E1013: type mismatch, expected %s but got %s"),
318 		   type_name(expected, &tofree1), type_name(actual, &tofree2));
319     vim_free(tofree1);
320     vim_free(tofree2);
321 }
322 
323     void
324 arg_type_mismatch(type_T *expected, type_T *actual, int argidx)
325 {
326     char *tofree1, *tofree2;
327 
328     semsg(_("E1013: argument %d: type mismatch, expected %s but got %s"),
329 	    argidx,
330 	    type_name(expected, &tofree1), type_name(actual, &tofree2));
331     vim_free(tofree1);
332     vim_free(tofree2);
333 }
334 
335 /*
336  * Check if the expected and actual types match.
337  * Does not allow for assigning "any" to a specific type.
338  */
339     int
340 check_type(type_T *expected, type_T *actual, int give_msg)
341 {
342     int ret = OK;
343 
344     // When expected is "unknown" we accept any actual type.
345     // When expected is "any" we accept any actual type except "void".
346     if (expected->tt_type != VAR_UNKNOWN
347 	    && !(expected->tt_type == VAR_ANY && actual->tt_type != VAR_VOID))
348 
349     {
350 	if (expected->tt_type != actual->tt_type)
351 	{
352 	    if (give_msg)
353 		type_mismatch(expected, actual);
354 	    return FAIL;
355 	}
356 	if (expected->tt_type == VAR_DICT || expected->tt_type == VAR_LIST)
357 	{
358 	    // "unknown" is used for an empty list or dict
359 	    if (actual->tt_member != &t_unknown)
360 		ret = check_type(expected->tt_member, actual->tt_member, FALSE);
361 	}
362 	else if (expected->tt_type == VAR_FUNC)
363 	{
364 	    if (expected->tt_member != &t_unknown)
365 		ret = check_type(expected->tt_member, actual->tt_member, FALSE);
366 	    if (ret == OK && expected->tt_argcount != -1
367 		    && (actual->tt_argcount < expected->tt_min_argcount
368 			|| actual->tt_argcount > expected->tt_argcount))
369 		    ret = FAIL;
370 	    if (expected->tt_args != NULL && actual->tt_args != NULL)
371 	    {
372 		int i;
373 
374 		for (i = 0; i < expected->tt_argcount; ++i)
375 		    // Allow for using "any" argument type, lambda's have them.
376 		    if (actual->tt_args[i] != &t_any && check_type(
377 			       expected->tt_args[i], actual->tt_args[i], FALSE)
378 								       == FAIL)
379 		    {
380 			ret = FAIL;
381 			break;
382 		    }
383 	    }
384 	}
385 	if (ret == FAIL && give_msg)
386 	    type_mismatch(expected, actual);
387     }
388     return ret;
389 }
390 
391 /*
392  * Skip over a type definition and return a pointer to just after it.
393  * When "optional" is TRUE then a leading "?" is accepted.
394  */
395     char_u *
396 skip_type(char_u *start, int optional)
397 {
398     char_u *p = start;
399 
400     if (optional && *p == '?')
401 	++p;
402     while (ASCII_ISALNUM(*p) || *p == '_')
403 	++p;
404 
405     // Skip over "<type>"; this is permissive about white space.
406     if (*skipwhite(p) == '<')
407     {
408 	p = skipwhite(p);
409 	p = skip_type(skipwhite(p + 1), FALSE);
410 	p = skipwhite(p);
411 	if (*p == '>')
412 	    ++p;
413     }
414     else if ((*p == '(' || (*p == ':' && VIM_ISWHITE(p[1])))
415 					     && STRNCMP("func", start, 4) == 0)
416     {
417 	if (*p == '(')
418 	{
419 	    // handle func(args): type
420 	    ++p;
421 	    while (*p != ')' && *p != NUL)
422 	    {
423 		char_u *sp = p;
424 
425 		if (STRNCMP(p, "...", 3) == 0)
426 		    p += 3;
427 		p = skip_type(p, TRUE);
428 		if (p == sp)
429 		    return p;  // syntax error
430 		if (*p == ',')
431 		    p = skipwhite(p + 1);
432 	    }
433 	    if (*p == ')')
434 	    {
435 		if (p[1] == ':')
436 		    p = skip_type(skipwhite(p + 2), FALSE);
437 		else
438 		    ++p;
439 	    }
440 	}
441 	else
442 	{
443 	    // handle func: return_type
444 	    p = skip_type(skipwhite(p + 1), FALSE);
445 	}
446     }
447 
448     return p;
449 }
450 
451 /*
452  * Parse the member type: "<type>" and return "type" with the member set.
453  * Use "type_gap" if a new type needs to be added.
454  * Returns NULL in case of failure.
455  */
456     static type_T *
457 parse_type_member(char_u **arg, type_T *type, garray_T *type_gap)
458 {
459     type_T  *member_type;
460     int	    prev_called_emsg = called_emsg;
461 
462     if (**arg != '<')
463     {
464 	if (*skipwhite(*arg) == '<')
465 	    semsg(_(e_no_white_before), "<");
466 	else
467 	    emsg(_("E1008: Missing <type>"));
468 	return type;
469     }
470     *arg = skipwhite(*arg + 1);
471 
472     member_type = parse_type(arg, type_gap);
473 
474     *arg = skipwhite(*arg);
475     if (**arg != '>' && called_emsg == prev_called_emsg)
476     {
477 	emsg(_("E1009: Missing > after type"));
478 	return type;
479     }
480     ++*arg;
481 
482     if (type->tt_type == VAR_LIST)
483 	return get_list_type(member_type, type_gap);
484     return get_dict_type(member_type, type_gap);
485 }
486 
487 /*
488  * Parse a type at "arg" and advance over it.
489  * Return &t_any for failure.
490  */
491     type_T *
492 parse_type(char_u **arg, garray_T *type_gap)
493 {
494     char_u  *p = *arg;
495     size_t  len;
496 
497     // skip over the first word
498     while (ASCII_ISALNUM(*p) || *p == '_')
499 	++p;
500     len = p - *arg;
501 
502     switch (**arg)
503     {
504 	case 'a':
505 	    if (len == 3 && STRNCMP(*arg, "any", len) == 0)
506 	    {
507 		*arg += len;
508 		return &t_any;
509 	    }
510 	    break;
511 	case 'b':
512 	    if (len == 4 && STRNCMP(*arg, "bool", len) == 0)
513 	    {
514 		*arg += len;
515 		return &t_bool;
516 	    }
517 	    if (len == 4 && STRNCMP(*arg, "blob", len) == 0)
518 	    {
519 		*arg += len;
520 		return &t_blob;
521 	    }
522 	    break;
523 	case 'c':
524 	    if (len == 7 && STRNCMP(*arg, "channel", len) == 0)
525 	    {
526 		*arg += len;
527 		return &t_channel;
528 	    }
529 	    break;
530 	case 'd':
531 	    if (len == 4 && STRNCMP(*arg, "dict", len) == 0)
532 	    {
533 		*arg += len;
534 		return parse_type_member(arg, &t_dict_any, type_gap);
535 	    }
536 	    break;
537 	case 'f':
538 	    if (len == 5 && STRNCMP(*arg, "float", len) == 0)
539 	    {
540 #ifdef FEAT_FLOAT
541 		*arg += len;
542 		return &t_float;
543 #else
544 		emsg(_("E1076: This Vim is not compiled with float support"));
545 		return &t_any;
546 #endif
547 	    }
548 	    if (len == 4 && STRNCMP(*arg, "func", len) == 0)
549 	    {
550 		type_T  *type;
551 		type_T  *ret_type = &t_unknown;
552 		int	argcount = -1;
553 		int	flags = 0;
554 		int	first_optional = -1;
555 		type_T	*arg_type[MAX_FUNC_ARGS + 1];
556 
557 		// func({type}, ...{type}): {type}
558 		*arg += len;
559 		if (**arg == '(')
560 		{
561 		    // "func" may or may not return a value, "func()" does
562 		    // not return a value.
563 		    ret_type = &t_void;
564 
565 		    p = ++*arg;
566 		    argcount = 0;
567 		    while (*p != NUL && *p != ')')
568 		    {
569 			if (*p == '?')
570 			{
571 			    if (first_optional == -1)
572 				first_optional = argcount;
573 			    ++p;
574 			}
575 			else if (STRNCMP(p, "...", 3) == 0)
576 			{
577 			    flags |= TTFLAG_VARARGS;
578 			    p += 3;
579 			}
580 			else if (first_optional != -1)
581 			{
582 			    emsg(_("E1007: mandatory argument after optional argument"));
583 			    return &t_any;
584 			}
585 
586 			arg_type[argcount++] = parse_type(&p, type_gap);
587 
588 			// Nothing comes after "...{type}".
589 			if (flags & TTFLAG_VARARGS)
590 			    break;
591 
592 			if (*p != ',' && *skipwhite(p) == ',')
593 			{
594 			    semsg(_(e_no_white_before), ",");
595 			    return &t_any;
596 			}
597 			if (*p == ',')
598 			{
599 			    ++p;
600 			    if (!VIM_ISWHITE(*p))
601 			    {
602 				semsg(_(e_white_after), ",");
603 				return &t_any;
604 			    }
605 			}
606 			p = skipwhite(p);
607 			if (argcount == MAX_FUNC_ARGS)
608 			{
609 			    emsg(_("E740: Too many argument types"));
610 			    return &t_any;
611 			}
612 		    }
613 
614 		    p = skipwhite(p);
615 		    if (*p != ')')
616 		    {
617 			emsg(_(e_missing_close));
618 			return &t_any;
619 		    }
620 		    *arg = p + 1;
621 		}
622 		if (**arg == ':')
623 		{
624 		    // parse return type
625 		    ++*arg;
626 		    if (!VIM_ISWHITE(**arg))
627 			semsg(_(e_white_after), ":");
628 		    *arg = skipwhite(*arg);
629 		    ret_type = parse_type(arg, type_gap);
630 		}
631 		if (flags == 0 && first_optional == -1 && argcount <= 0)
632 		    type = get_func_type(ret_type, argcount, type_gap);
633 		else
634 		{
635 		    type = alloc_func_type(ret_type, argcount, type_gap);
636 		    type->tt_flags = flags;
637 		    if (argcount > 0)
638 		    {
639 			type->tt_argcount = argcount;
640 			type->tt_min_argcount = first_optional == -1
641 						   ? argcount : first_optional;
642 			if (func_type_add_arg_types(type, argcount,
643 							     type_gap) == FAIL)
644 			    return &t_any;
645 			mch_memmove(type->tt_args, arg_type,
646 						  sizeof(type_T *) * argcount);
647 		    }
648 		}
649 		return type;
650 	    }
651 	    break;
652 	case 'j':
653 	    if (len == 3 && STRNCMP(*arg, "job", len) == 0)
654 	    {
655 		*arg += len;
656 		return &t_job;
657 	    }
658 	    break;
659 	case 'l':
660 	    if (len == 4 && STRNCMP(*arg, "list", len) == 0)
661 	    {
662 		*arg += len;
663 		return parse_type_member(arg, &t_list_any, type_gap);
664 	    }
665 	    break;
666 	case 'n':
667 	    if (len == 6 && STRNCMP(*arg, "number", len) == 0)
668 	    {
669 		*arg += len;
670 		return &t_number;
671 	    }
672 	    break;
673 	case 's':
674 	    if (len == 6 && STRNCMP(*arg, "string", len) == 0)
675 	    {
676 		*arg += len;
677 		return &t_string;
678 	    }
679 	    break;
680 	case 'v':
681 	    if (len == 4 && STRNCMP(*arg, "void", len) == 0)
682 	    {
683 		*arg += len;
684 		return &t_void;
685 	    }
686 	    break;
687     }
688 
689     semsg(_("E1010: Type not recognized: %s"), *arg);
690     return &t_any;
691 }
692 
693 /*
694  * Check if "type1" and "type2" are exactly the same.
695  */
696     static int
697 equal_type(type_T *type1, type_T *type2)
698 {
699     int i;
700 
701     if (type1->tt_type != type2->tt_type)
702 	return FALSE;
703     switch (type1->tt_type)
704     {
705 	case VAR_UNKNOWN:
706 	case VAR_ANY:
707 	case VAR_VOID:
708 	case VAR_SPECIAL:
709 	case VAR_BOOL:
710 	case VAR_NUMBER:
711 	case VAR_FLOAT:
712 	case VAR_STRING:
713 	case VAR_BLOB:
714 	case VAR_JOB:
715 	case VAR_CHANNEL:
716 	    break;  // not composite is always OK
717 	case VAR_LIST:
718 	case VAR_DICT:
719 	    return equal_type(type1->tt_member, type2->tt_member);
720 	case VAR_FUNC:
721 	case VAR_PARTIAL:
722 	    if (!equal_type(type1->tt_member, type2->tt_member)
723 		    || type1->tt_argcount != type2->tt_argcount)
724 		return FALSE;
725 	    if (type1->tt_argcount < 0
726 			   || type1->tt_args == NULL || type2->tt_args == NULL)
727 		return TRUE;
728 	    for (i = 0; i < type1->tt_argcount; ++i)
729 		if (!equal_type(type1->tt_args[i], type2->tt_args[i]))
730 		    return FALSE;
731 	    return TRUE;
732     }
733     return TRUE;
734 }
735 
736 /*
737  * Find the common type of "type1" and "type2" and put it in "dest".
738  * "type2" and "dest" may be the same.
739  */
740     void
741 common_type(type_T *type1, type_T *type2, type_T **dest, garray_T *type_gap)
742 {
743     if (equal_type(type1, type2))
744     {
745 	*dest = type1;
746 	return;
747     }
748 
749     if (type1->tt_type == type2->tt_type)
750     {
751 	if (type1->tt_type == VAR_LIST || type2->tt_type == VAR_DICT)
752 	{
753 	    type_T *common;
754 
755 	    common_type(type1->tt_member, type2->tt_member, &common, type_gap);
756 	    if (type1->tt_type == VAR_LIST)
757 		*dest = get_list_type(common, type_gap);
758 	    else
759 		*dest = get_dict_type(common, type_gap);
760 	    return;
761 	}
762 	if (type1->tt_type == VAR_FUNC)
763 	{
764 	    type_T *common;
765 
766 	    common_type(type1->tt_member, type2->tt_member, &common, type_gap);
767 	    if (type1->tt_argcount == type2->tt_argcount
768 						    && type1->tt_argcount >= 0)
769 	    {
770 		int argcount = type1->tt_argcount;
771 		int i;
772 
773 		*dest = alloc_func_type(common, argcount, type_gap);
774 		if (type1->tt_args != NULL && type2->tt_args != NULL)
775 		{
776 		    if (func_type_add_arg_types(*dest, argcount,
777 							     type_gap) == OK)
778 			for (i = 0; i < argcount; ++i)
779 			    common_type(type1->tt_args[i], type2->tt_args[i],
780 					       &(*dest)->tt_args[i], type_gap);
781 		}
782 	    }
783 	    else
784 		*dest = alloc_func_type(common, -1, type_gap);
785 	    return;
786 	}
787     }
788 
789     *dest = &t_any;
790 }
791 
792 /*
793  * Get the member type of a dict or list from the items on the stack.
794  * "stack_top" points just after the last type on the type stack.
795  * For a list "skip" is 1, for a dict "skip" is 2, keys are skipped.
796  * Returns &t_void for an empty list or dict.
797  * Otherwise finds the common type of all items.
798  */
799     type_T *
800 get_member_type_from_stack(
801 	type_T	    **stack_top,
802 	int	    count,
803 	int	    skip,
804 	garray_T    *type_gap)
805 {
806     int	    i;
807     type_T  *result;
808     type_T  *type;
809 
810     // Use "any" for an empty list or dict.
811     if (count == 0)
812 	return &t_void;
813 
814     // Use the first value type for the list member type, then find the common
815     // type from following items.
816     result = *(stack_top -(count * skip) + skip - 1);
817     for (i = 1; i < count; ++i)
818     {
819 	if (result == &t_any)
820 	    break;  // won't get more common
821 	type = *(stack_top -((count - i) * skip) + skip - 1);
822 	common_type(type, result, &result, type_gap);
823     }
824 
825     return result;
826 }
827 
828     char *
829 vartype_name(vartype_T type)
830 {
831     switch (type)
832     {
833 	case VAR_UNKNOWN: break;
834 	case VAR_ANY: return "any";
835 	case VAR_VOID: return "void";
836 	case VAR_SPECIAL: return "special";
837 	case VAR_BOOL: return "bool";
838 	case VAR_NUMBER: return "number";
839 	case VAR_FLOAT: return "float";
840 	case VAR_STRING: return "string";
841 	case VAR_BLOB: return "blob";
842 	case VAR_JOB: return "job";
843 	case VAR_CHANNEL: return "channel";
844 	case VAR_LIST: return "list";
845 	case VAR_DICT: return "dict";
846 
847 	case VAR_FUNC:
848 	case VAR_PARTIAL: return "func";
849     }
850     return "unknown";
851 }
852 
853 /*
854  * Return the name of a type.
855  * The result may be in allocated memory, in which case "tofree" is set.
856  */
857     char *
858 type_name(type_T *type, char **tofree)
859 {
860     char *name = vartype_name(type->tt_type);
861 
862     *tofree = NULL;
863     if (type->tt_type == VAR_LIST || type->tt_type == VAR_DICT)
864     {
865 	char *member_free;
866 	char *member_name = type_name(type->tt_member, &member_free);
867 	size_t len;
868 
869 	len = STRLEN(name) + STRLEN(member_name) + 3;
870 	*tofree = alloc(len);
871 	if (*tofree != NULL)
872 	{
873 	    vim_snprintf(*tofree, len, "%s<%s>", name, member_name);
874 	    vim_free(member_free);
875 	    return *tofree;
876 	}
877     }
878     if (type->tt_type == VAR_FUNC)
879     {
880 	garray_T    ga;
881 	int	    i;
882 	int	    varargs = (type->tt_flags & TTFLAG_VARARGS) ? 1 : 0;
883 
884 	ga_init2(&ga, 1, 100);
885 	if (ga_grow(&ga, 20) == FAIL)
886 	    return "[unknown]";
887 	*tofree = ga.ga_data;
888 	STRCPY(ga.ga_data, "func(");
889 	ga.ga_len += 5;
890 
891 	for (i = 0; i < type->tt_argcount; ++i)
892 	{
893 	    char *arg_free;
894 	    char *arg_type;
895 	    int  len;
896 
897 	    if (type->tt_args == NULL)
898 		arg_type = "[unknown]";
899 	    else
900 		arg_type = type_name(type->tt_args[i], &arg_free);
901 	    if (i > 0)
902 	    {
903 		STRCPY((char *)ga.ga_data + ga.ga_len, ", ");
904 		ga.ga_len += 2;
905 	    }
906 	    len = (int)STRLEN(arg_type);
907 	    if (ga_grow(&ga, len + 8) == FAIL)
908 	    {
909 		vim_free(arg_free);
910 		return "[unknown]";
911 	    }
912 	    *tofree = ga.ga_data;
913 	    if (varargs && i == type->tt_argcount - 1)
914 	    {
915 		STRCPY((char *)ga.ga_data + ga.ga_len, "...");
916 		ga.ga_len += 3;
917 	    }
918 	    else if (i >= type->tt_min_argcount)
919 		*((char *)ga.ga_data + ga.ga_len++) = '?';
920 	    STRCPY((char *)ga.ga_data + ga.ga_len, arg_type);
921 	    ga.ga_len += len;
922 	    vim_free(arg_free);
923 	}
924 
925 	if (type->tt_member == &t_void)
926 	    STRCPY((char *)ga.ga_data + ga.ga_len, ")");
927 	else
928 	{
929 	    char *ret_free;
930 	    char *ret_name = type_name(type->tt_member, &ret_free);
931 	    int  len;
932 
933 	    len = (int)STRLEN(ret_name) + 4;
934 	    if (ga_grow(&ga, len) == FAIL)
935 	    {
936 		vim_free(ret_free);
937 		return "[unknown]";
938 	    }
939 	    *tofree = ga.ga_data;
940 	    STRCPY((char *)ga.ga_data + ga.ga_len, "): ");
941 	    STRCPY((char *)ga.ga_data + ga.ga_len + 3, ret_name);
942 	    vim_free(ret_free);
943 	}
944 	return ga.ga_data;
945     }
946 
947     return name;
948 }
949 
950 
951 #endif // FEAT_EVAL
952