xref: /vim-8.2.3635/src/vim9type.c (revision 90df4b9d)
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 easily freed later.
26  */
27     type_T *
28 get_type_ptr(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 /*
52  * Take a type that is using entries in a growarray and turn it into a type
53  * with allocated entries.
54  */
55     type_T *
56 alloc_type(type_T *type)
57 {
58     type_T *ret;
59 
60     if (type == NULL)
61 	return NULL;
62 
63     // A fixed type never contains allocated types, return as-is.
64     if (type->tt_flags & TTFLAG_STATIC)
65 	return type;
66 
67     ret = ALLOC_ONE(type_T);
68     *ret = *type;
69 
70     if (ret->tt_member != NULL)
71 	ret->tt_member = alloc_type(ret->tt_member);
72     if (type->tt_args != NULL)
73     {
74 	int i;
75 
76 	ret->tt_args = ALLOC_MULT(type_T *, type->tt_argcount);
77 	if (ret->tt_args != NULL)
78 	    for (i = 0; i < type->tt_argcount; ++i)
79 		ret->tt_args[i] = alloc_type(type->tt_args[i]);
80     }
81 
82     return ret;
83 }
84 
85 /*
86  * Free a type that was created with alloc_type().
87  */
88     void
89 free_type(type_T *type)
90 {
91     int i;
92 
93     if (type == NULL || (type->tt_flags & TTFLAG_STATIC))
94 	return;
95     if (type->tt_args != NULL)
96     {
97 	for (i = 0; i < type->tt_argcount; ++i)
98 	    free_type(type->tt_args[i]);
99 	vim_free(type->tt_args);
100     }
101     free_type(type->tt_member);
102     vim_free(type);
103 }
104 
105     type_T *
106 get_list_type(type_T *member_type, garray_T *type_gap)
107 {
108     type_T *type;
109 
110     // recognize commonly used types
111     if (member_type == NULL || member_type->tt_type == VAR_ANY)
112 	return &t_list_any;
113     if (member_type->tt_type == VAR_VOID
114 	    || member_type->tt_type == VAR_UNKNOWN)
115 	return &t_list_empty;
116     if (member_type->tt_type == VAR_BOOL)
117 	return &t_list_bool;
118     if (member_type->tt_type == VAR_NUMBER)
119 	return &t_list_number;
120     if (member_type->tt_type == VAR_STRING)
121 	return &t_list_string;
122 
123     // Not a common type, create a new entry.
124     type = get_type_ptr(type_gap);
125     if (type == NULL)
126 	return &t_any;
127     type->tt_type = VAR_LIST;
128     type->tt_member = member_type;
129     type->tt_argcount = 0;
130     type->tt_args = NULL;
131     return type;
132 }
133 
134     type_T *
135 get_dict_type(type_T *member_type, garray_T *type_gap)
136 {
137     type_T *type;
138 
139     // recognize commonly used types
140     if (member_type == NULL || member_type->tt_type == VAR_ANY)
141 	return &t_dict_any;
142     if (member_type->tt_type == VAR_VOID
143 	    || member_type->tt_type == VAR_UNKNOWN)
144 	return &t_dict_empty;
145     if (member_type->tt_type == VAR_BOOL)
146 	return &t_dict_bool;
147     if (member_type->tt_type == VAR_NUMBER)
148 	return &t_dict_number;
149     if (member_type->tt_type == VAR_STRING)
150 	return &t_dict_string;
151 
152     // Not a common type, create a new entry.
153     type = get_type_ptr(type_gap);
154     if (type == NULL)
155 	return &t_any;
156     type->tt_type = VAR_DICT;
157     type->tt_member = member_type;
158     type->tt_argcount = 0;
159     type->tt_args = NULL;
160     return type;
161 }
162 
163 /*
164  * Allocate a new type for a function.
165  */
166     type_T *
167 alloc_func_type(type_T *ret_type, int argcount, garray_T *type_gap)
168 {
169     type_T *type = get_type_ptr(type_gap);
170 
171     if (type == NULL)
172 	return &t_any;
173     type->tt_type = VAR_FUNC;
174     type->tt_member = ret_type == NULL ? &t_unknown : ret_type;
175     type->tt_argcount = argcount;
176     type->tt_args = NULL;
177     return type;
178 }
179 
180 /*
181  * Get a function type, based on the return type "ret_type".
182  * If "argcount" is -1 or 0 a predefined type can be used.
183  * If "argcount" > 0 always create a new type, so that arguments can be added.
184  */
185     type_T *
186 get_func_type(type_T *ret_type, int argcount, garray_T *type_gap)
187 {
188     // recognize commonly used types
189     if (argcount <= 0)
190     {
191 	if (ret_type == &t_unknown || ret_type == NULL)
192 	{
193 	    // (argcount == 0) is not possible
194 	    return &t_func_unknown;
195 	}
196 	if (ret_type == &t_void)
197 	{
198 	    if (argcount == 0)
199 		return &t_func_0_void;
200 	    else
201 		return &t_func_void;
202 	}
203 	if (ret_type == &t_any)
204 	{
205 	    if (argcount == 0)
206 		return &t_func_0_any;
207 	    else
208 		return &t_func_any;
209 	}
210 	if (ret_type == &t_number)
211 	{
212 	    if (argcount == 0)
213 		return &t_func_0_number;
214 	    else
215 		return &t_func_number;
216 	}
217 	if (ret_type == &t_string)
218 	{
219 	    if (argcount == 0)
220 		return &t_func_0_string;
221 	    else
222 		return &t_func_string;
223 	}
224     }
225 
226     return alloc_func_type(ret_type, argcount, type_gap);
227 }
228 
229 /*
230  * For a function type, reserve space for "argcount" argument types (including
231  * vararg).
232  */
233     int
234 func_type_add_arg_types(
235 	type_T	    *functype,
236 	int	    argcount,
237 	garray_T    *type_gap)
238 {
239     // To make it easy to free the space needed for the argument types, add the
240     // pointer to type_gap.
241     if (ga_grow(type_gap, 1) == FAIL)
242 	return FAIL;
243     functype->tt_args = ALLOC_CLEAR_MULT(type_T *, argcount);
244     if (functype->tt_args == NULL)
245 	return FAIL;
246     ((type_T **)type_gap->ga_data)[type_gap->ga_len] =
247 						     (void *)functype->tt_args;
248     ++type_gap->ga_len;
249     return OK;
250 }
251 
252 /*
253  * Get a type_T for a typval_T.
254  * "type_gap" is used to temporarily create types in.
255  * When "do_member" is TRUE also get the member type, otherwise use "any".
256  */
257     static type_T *
258 typval2type_int(typval_T *tv, int copyID, garray_T *type_gap, int do_member)
259 {
260     type_T  *type;
261     type_T  *member_type = &t_any;
262     int	    argcount = 0;
263     int	    min_argcount = 0;
264 
265     if (tv->v_type == VAR_NUMBER)
266 	return &t_number;
267     if (tv->v_type == VAR_BOOL)
268 	return &t_bool;
269     if (tv->v_type == VAR_STRING)
270 	return &t_string;
271 
272     if (tv->v_type == VAR_LIST)
273     {
274 	list_T	    *l = tv->vval.v_list;
275 	listitem_T  *li;
276 
277 	if (l == NULL || l->lv_first == NULL)
278 	    return &t_list_empty;
279 	if (!do_member)
280 	    return &t_list_any;
281 	if (l->lv_first == &range_list_item)
282 	    return &t_list_number;
283 	if (l->lv_copyID == copyID)
284 	    // avoid recursion
285 	    return &t_list_any;
286 	l->lv_copyID = copyID;
287 
288 	// Use the common type of all members.
289 	member_type = typval2type(&l->lv_first->li_tv, copyID, type_gap, TRUE);
290 	for (li = l->lv_first->li_next; li != NULL; li = li->li_next)
291 	    common_type(typval2type(&li->li_tv, copyID, type_gap, TRUE),
292 					  member_type, &member_type, type_gap);
293 	return get_list_type(member_type, type_gap);
294     }
295 
296     if (tv->v_type == VAR_DICT)
297     {
298 	dict_iterator_T iter;
299 	typval_T	*value;
300 	dict_T		*d = tv->vval.v_dict;
301 
302 	if (d == NULL || d->dv_hashtab.ht_used == 0)
303 	    return &t_dict_empty;
304 	if (!do_member)
305 	    return &t_dict_any;
306 	if (d->dv_copyID == copyID)
307 	    // avoid recursion
308 	    return &t_dict_any;
309 	d->dv_copyID = copyID;
310 
311 	// Use the common type of all values.
312 	dict_iterate_start(tv, &iter);
313 	dict_iterate_next(&iter, &value);
314 	member_type = typval2type(value, copyID, type_gap, TRUE);
315 	while (dict_iterate_next(&iter, &value) != NULL)
316 	    common_type(typval2type(value, copyID, type_gap, TRUE),
317 					  member_type, &member_type, type_gap);
318 	return get_dict_type(member_type, type_gap);
319     }
320 
321     if (tv->v_type == VAR_FUNC || tv->v_type == VAR_PARTIAL)
322     {
323 	char_u	*name = NULL;
324 	ufunc_T *ufunc = NULL;
325 
326 	if (tv->v_type == VAR_PARTIAL)
327 	{
328 	    if (tv->vval.v_partial->pt_func != NULL)
329 		ufunc = tv->vval.v_partial->pt_func;
330 	    else
331 		name = tv->vval.v_partial->pt_name;
332 	}
333 	else
334 	    name = tv->vval.v_string;
335 	if (name != NULL)
336 	{
337 	    int idx = find_internal_func(name);
338 
339 	    if (idx >= 0)
340 	    {
341 		internal_func_get_argcount(idx, &argcount, &min_argcount);
342 		member_type = internal_func_ret_type(idx, 0, NULL);
343 	    }
344 	    else
345 		ufunc = find_func(name, FALSE, NULL);
346 	}
347 	if (ufunc != NULL)
348 	{
349 	    // May need to get the argument types from default values by
350 	    // compiling the function.
351 	    if (ufunc->uf_def_status == UF_TO_BE_COMPILED
352 			    && compile_def_function(ufunc, TRUE, CT_NONE, NULL)
353 								       == FAIL)
354 		return NULL;
355 	    if (ufunc->uf_func_type == NULL)
356 		set_function_type(ufunc);
357 	    if (ufunc->uf_func_type != NULL)
358 	    {
359 		if (tv->v_type == VAR_PARTIAL
360 					    && tv->vval.v_partial->pt_argc > 0)
361 		{
362 		    type = get_type_ptr(type_gap);
363 		    if (type == NULL)
364 			return NULL;
365 		    *type = *ufunc->uf_func_type;
366 		    type->tt_argcount -= tv->vval.v_partial->pt_argc;
367 		    type->tt_min_argcount -= tv->vval.v_partial->pt_argc;
368 		    return type;
369 		}
370 		return ufunc->uf_func_type;
371 	    }
372 	}
373     }
374 
375     type = get_type_ptr(type_gap);
376     if (type == NULL)
377 	return NULL;
378     type->tt_type = tv->v_type;
379     type->tt_argcount = argcount;
380     type->tt_min_argcount = min_argcount;
381     type->tt_member = member_type;
382 
383     return type;
384 }
385 
386 /*
387  * Return TRUE if "tv" is not a bool but should be converted to bool.
388  */
389     int
390 need_convert_to_bool(type_T *type, typval_T *tv)
391 {
392     return type != NULL && type == &t_bool && tv->v_type != VAR_BOOL
393 	    && (tv->v_type == VAR_NUMBER
394 		       && (tv->vval.v_number == 0 || tv->vval.v_number == 1));
395 }
396 
397 /*
398  * Get a type_T for a typval_T.
399  * "type_list" is used to temporarily create types in.
400  * When "do_member" is TRUE also get the member type, otherwise use "any".
401  */
402     type_T *
403 typval2type(typval_T *tv, int copyID, garray_T *type_gap, int do_member)
404 {
405     type_T *type = typval2type_int(tv, copyID, type_gap, do_member);
406 
407     if (type != NULL && type != &t_bool
408 	    && (tv->v_type == VAR_NUMBER
409 		    && (tv->vval.v_number == 0 || tv->vval.v_number == 1)))
410 	// Number 0 and 1 and expression with "&&" or "||" can also be used for
411 	// bool.
412 	type = &t_number_bool;
413     return type;
414 }
415 
416 /*
417  * Get a type_T for a typval_T, used for v: variables.
418  * "type_list" is used to temporarily create types in.
419  */
420     type_T *
421 typval2type_vimvar(typval_T *tv, garray_T *type_gap)
422 {
423     if (tv->v_type == VAR_LIST)  // e.g. for v:oldfiles
424 	return &t_list_string;
425     if (tv->v_type == VAR_DICT)  // e.g. for v:completed_item
426 	return &t_dict_any;
427     return typval2type(tv, get_copyID(), type_gap, TRUE);
428 }
429 
430     int
431 check_typval_arg_type(type_T *expected, typval_T *actual_tv, int arg_idx)
432 {
433     where_T	where;
434 
435     where.wt_index = arg_idx;
436     where.wt_variable = FALSE;
437     return check_typval_type(expected, actual_tv, where);
438 }
439 
440 /*
441  * Return FAIL if "expected" and "actual" don't match.
442  * When "argidx" > 0 it is included in the error message.
443  */
444     int
445 check_typval_type(type_T *expected, typval_T *actual_tv, where_T where)
446 {
447     garray_T	type_list;
448     type_T	*actual_type;
449     int		res = FAIL;
450 
451     ga_init2(&type_list, sizeof(type_T *), 10);
452     actual_type = typval2type(actual_tv, get_copyID(), &type_list, TRUE);
453     if (actual_type != NULL)
454 	res = check_type(expected, actual_type, TRUE, where);
455     clear_type_list(&type_list);
456     return res;
457 }
458 
459     void
460 type_mismatch(type_T *expected, type_T *actual)
461 {
462     arg_type_mismatch(expected, actual, 0);
463 }
464 
465     void
466 arg_type_mismatch(type_T *expected, type_T *actual, int arg_idx)
467 {
468     where_T	where;
469 
470     where.wt_index = arg_idx;
471     where.wt_variable = FALSE;
472     type_mismatch_where(expected, actual, where);
473 }
474 
475     void
476 type_mismatch_where(type_T *expected, type_T *actual, where_T where)
477 {
478     char *tofree1, *tofree2;
479     char *typename1 = type_name(expected, &tofree1);
480     char *typename2 = type_name(actual, &tofree2);
481 
482     if (where.wt_index > 0)
483     {
484 	semsg(_(where.wt_variable
485 			? e_variable_nr_type_mismatch_expected_str_but_got_str
486 			: e_argument_nr_type_mismatch_expected_str_but_got_str),
487 					 where.wt_index, typename1, typename2);
488     }
489     else
490 	semsg(_(e_type_mismatch_expected_str_but_got_str),
491 							 typename1, typename2);
492     vim_free(tofree1);
493     vim_free(tofree2);
494 }
495 
496 /*
497  * Check if the expected and actual types match.
498  * Does not allow for assigning "any" to a specific type.
499  * When "argidx" > 0 it is included in the error message.
500  */
501     int
502 check_type(type_T *expected, type_T *actual, int give_msg, where_T where)
503 {
504     int ret = OK;
505 
506     // When expected is "unknown" we accept any actual type.
507     // When expected is "any" we accept any actual type except "void".
508     if (expected->tt_type != VAR_UNKNOWN
509 	    && !(expected->tt_type == VAR_ANY && actual->tt_type != VAR_VOID))
510 
511     {
512 	// tt_type should match, except that a "partial" can be assigned to a
513 	// variable with type "func".
514 	if (!(expected->tt_type == actual->tt_type
515 		    || (expected->tt_type == VAR_FUNC
516 					   && actual->tt_type == VAR_PARTIAL)))
517 	{
518 	    if (expected->tt_type == VAR_BOOL
519 					&& (actual->tt_flags & TTFLAG_BOOL_OK))
520 		// Using number 0 or 1 for bool is OK.
521 		return OK;
522 	    if (give_msg)
523 		type_mismatch_where(expected, actual, where);
524 	    return FAIL;
525 	}
526 	if (expected->tt_type == VAR_DICT || expected->tt_type == VAR_LIST)
527 	{
528 	    // "unknown" is used for an empty list or dict
529 	    if (actual->tt_member != &t_unknown)
530 		ret = check_type(expected->tt_member, actual->tt_member,
531 								 FALSE, where);
532 	}
533 	else if (expected->tt_type == VAR_FUNC)
534 	{
535 	    // If the return type is unknown it can be anything, including
536 	    // nothing, thus there is no point in checking.
537 	    if (expected->tt_member != &t_unknown
538 					    && actual->tt_member != &t_unknown)
539 		ret = check_type(expected->tt_member, actual->tt_member,
540 								 FALSE, where);
541 	    if (ret == OK && expected->tt_argcount != -1
542 		    && actual->tt_min_argcount != -1
543 		    && (actual->tt_argcount == -1
544 			|| (actual->tt_argcount < expected->tt_min_argcount
545 			    || actual->tt_argcount > expected->tt_argcount)))
546 		ret = FAIL;
547 	    if (ret == OK && expected->tt_args != NULL
548 						    && actual->tt_args != NULL)
549 	    {
550 		int i;
551 
552 		for (i = 0; i < expected->tt_argcount; ++i)
553 		    // Allow for using "any" argument type, lambda's have them.
554 		    if (actual->tt_args[i] != &t_any && check_type(
555 			    expected->tt_args[i], actual->tt_args[i], FALSE,
556 								where) == FAIL)
557 		    {
558 			ret = FAIL;
559 			break;
560 		    }
561 	    }
562 	}
563 	if (ret == FAIL && give_msg)
564 	    type_mismatch_where(expected, actual, where);
565     }
566     return ret;
567 }
568 
569 /*
570  * Check that the arguments of "type" match "argvars[argcount]".
571  * Return OK/FAIL.
572  */
573     int
574 check_argument_types(
575 	type_T	    *type,
576 	typval_T    *argvars,
577 	int	    argcount,
578 	char_u	    *name)
579 {
580     int	    varargs = (type->tt_flags & TTFLAG_VARARGS) ? 1 : 0;
581     int	    i;
582 
583     if (type->tt_type != VAR_FUNC && type->tt_type != VAR_PARTIAL)
584 	return OK;  // just in case
585     if (argcount < type->tt_min_argcount - varargs)
586     {
587 	semsg(_(e_toofewarg), name);
588 	return FAIL;
589     }
590     if (!varargs && type->tt_argcount >= 0 && argcount > type->tt_argcount)
591     {
592 	semsg(_(e_toomanyarg), name);
593 	return FAIL;
594     }
595     if (type->tt_args == NULL)
596 	return OK;  // cannot check
597 
598 
599     for (i = 0; i < argcount; ++i)
600     {
601 	type_T	*expected;
602 
603 	if (varargs && i >= type->tt_argcount - 1)
604 	    expected = type->tt_args[type->tt_argcount - 1]->tt_member;
605 	else
606 	    expected = type->tt_args[i];
607 	if (check_typval_arg_type(expected, &argvars[i], i + 1) == FAIL)
608 	    return FAIL;
609     }
610     return OK;
611 }
612 
613 /*
614  * Skip over a type definition and return a pointer to just after it.
615  * When "optional" is TRUE then a leading "?" is accepted.
616  */
617     char_u *
618 skip_type(char_u *start, int optional)
619 {
620     char_u *p = start;
621 
622     if (optional && *p == '?')
623 	++p;
624     while (ASCII_ISALNUM(*p) || *p == '_')
625 	++p;
626 
627     // Skip over "<type>"; this is permissive about white space.
628     if (*skipwhite(p) == '<')
629     {
630 	p = skipwhite(p);
631 	p = skip_type(skipwhite(p + 1), FALSE);
632 	p = skipwhite(p);
633 	if (*p == '>')
634 	    ++p;
635     }
636     else if ((*p == '(' || (*p == ':' && VIM_ISWHITE(p[1])))
637 					     && STRNCMP("func", start, 4) == 0)
638     {
639 	if (*p == '(')
640 	{
641 	    // handle func(args): type
642 	    ++p;
643 	    while (*p != ')' && *p != NUL)
644 	    {
645 		char_u *sp = p;
646 
647 		if (STRNCMP(p, "...", 3) == 0)
648 		    p += 3;
649 		p = skip_type(p, TRUE);
650 		if (p == sp)
651 		    return p;  // syntax error
652 		if (*p == ',')
653 		    p = skipwhite(p + 1);
654 	    }
655 	    if (*p == ')')
656 	    {
657 		if (p[1] == ':')
658 		    p = skip_type(skipwhite(p + 2), FALSE);
659 		else
660 		    ++p;
661 	    }
662 	}
663 	else
664 	{
665 	    // handle func: return_type
666 	    p = skip_type(skipwhite(p + 1), FALSE);
667 	}
668     }
669 
670     return p;
671 }
672 
673 /*
674  * Parse the member type: "<type>" and return "type" with the member set.
675  * Use "type_gap" if a new type needs to be added.
676  * Returns NULL in case of failure.
677  */
678     static type_T *
679 parse_type_member(
680 	char_u	    **arg,
681 	type_T	    *type,
682 	garray_T    *type_gap,
683 	int	    give_error)
684 {
685     type_T  *member_type;
686     int	    prev_called_emsg = called_emsg;
687 
688     if (**arg != '<')
689     {
690 	if (give_error)
691 	{
692 	    if (*skipwhite(*arg) == '<')
693 		semsg(_(e_no_white_space_allowed_before_str_str), "<", *arg);
694 	    else
695 		emsg(_(e_missing_type));
696 	}
697 	return NULL;
698     }
699     *arg = skipwhite(*arg + 1);
700 
701     member_type = parse_type(arg, type_gap, give_error);
702     if (member_type == NULL)
703 	return NULL;
704 
705     *arg = skipwhite(*arg);
706     if (**arg != '>' && called_emsg == prev_called_emsg)
707     {
708 	if (give_error)
709 	    emsg(_(e_missing_gt_after_type));
710 	return NULL;
711     }
712     ++*arg;
713 
714     if (type->tt_type == VAR_LIST)
715 	return get_list_type(member_type, type_gap);
716     return get_dict_type(member_type, type_gap);
717 }
718 
719 /*
720  * Parse a type at "arg" and advance over it.
721  * When "give_error" is TRUE give error messages, otherwise be quiet.
722  * Return NULL for failure.
723  */
724     type_T *
725 parse_type(char_u **arg, garray_T *type_gap, int give_error)
726 {
727     char_u  *p = *arg;
728     size_t  len;
729 
730     // skip over the first word
731     while (ASCII_ISALNUM(*p) || *p == '_')
732 	++p;
733     len = p - *arg;
734 
735     switch (**arg)
736     {
737 	case 'a':
738 	    if (len == 3 && STRNCMP(*arg, "any", len) == 0)
739 	    {
740 		*arg += len;
741 		return &t_any;
742 	    }
743 	    break;
744 	case 'b':
745 	    if (len == 4 && STRNCMP(*arg, "bool", len) == 0)
746 	    {
747 		*arg += len;
748 		return &t_bool;
749 	    }
750 	    if (len == 4 && STRNCMP(*arg, "blob", len) == 0)
751 	    {
752 		*arg += len;
753 		return &t_blob;
754 	    }
755 	    break;
756 	case 'c':
757 	    if (len == 7 && STRNCMP(*arg, "channel", len) == 0)
758 	    {
759 		*arg += len;
760 		return &t_channel;
761 	    }
762 	    break;
763 	case 'd':
764 	    if (len == 4 && STRNCMP(*arg, "dict", len) == 0)
765 	    {
766 		*arg += len;
767 		return parse_type_member(arg, &t_dict_any,
768 							 type_gap, give_error);
769 	    }
770 	    break;
771 	case 'f':
772 	    if (len == 5 && STRNCMP(*arg, "float", len) == 0)
773 	    {
774 #ifdef FEAT_FLOAT
775 		*arg += len;
776 		return &t_float;
777 #else
778 		if (give_error)
779 		    emsg(_(e_this_vim_is_not_compiled_with_float_support));
780 		return NULL;
781 #endif
782 	    }
783 	    if (len == 4 && STRNCMP(*arg, "func", len) == 0)
784 	    {
785 		type_T  *type;
786 		type_T  *ret_type = &t_unknown;
787 		int	argcount = -1;
788 		int	flags = 0;
789 		int	first_optional = -1;
790 		type_T	*arg_type[MAX_FUNC_ARGS + 1];
791 
792 		// func({type}, ...{type}): {type}
793 		*arg += len;
794 		if (**arg == '(')
795 		{
796 		    // "func" may or may not return a value, "func()" does
797 		    // not return a value.
798 		    ret_type = &t_void;
799 
800 		    p = ++*arg;
801 		    argcount = 0;
802 		    while (*p != NUL && *p != ')')
803 		    {
804 			if (*p == '?')
805 			{
806 			    if (first_optional == -1)
807 				first_optional = argcount;
808 			    ++p;
809 			}
810 			else if (STRNCMP(p, "...", 3) == 0)
811 			{
812 			    flags |= TTFLAG_VARARGS;
813 			    p += 3;
814 			}
815 			else if (first_optional != -1)
816 			{
817 			    if (give_error)
818 				emsg(_(e_mandatory_argument_after_optional_argument));
819 			    return NULL;
820 			}
821 
822 			type = parse_type(&p, type_gap, give_error);
823 			if (type == NULL)
824 			    return NULL;
825 			arg_type[argcount++] = type;
826 
827 			// Nothing comes after "...{type}".
828 			if (flags & TTFLAG_VARARGS)
829 			    break;
830 
831 			if (*p != ',' && *skipwhite(p) == ',')
832 			{
833 			    if (give_error)
834 				semsg(_(e_no_white_space_allowed_before_str_str),
835 								       ",", p);
836 			    return NULL;
837 			}
838 			if (*p == ',')
839 			{
840 			    ++p;
841 			    if (!VIM_ISWHITE(*p))
842 			    {
843 				if (give_error)
844 				    semsg(_(e_white_space_required_after_str_str),
845 								   ",", p - 1);
846 				return NULL;
847 			    }
848 			}
849 			p = skipwhite(p);
850 			if (argcount == MAX_FUNC_ARGS)
851 			{
852 			    if (give_error)
853 				emsg(_(e_too_many_argument_types));
854 			    return NULL;
855 			}
856 		    }
857 
858 		    p = skipwhite(p);
859 		    if (*p != ')')
860 		    {
861 			if (give_error)
862 			    emsg(_(e_missing_close));
863 			return NULL;
864 		    }
865 		    *arg = p + 1;
866 		}
867 		if (**arg == ':')
868 		{
869 		    // parse return type
870 		    ++*arg;
871 		    if (!VIM_ISWHITE(**arg) && give_error)
872 			semsg(_(e_white_space_required_after_str_str),
873 								":", *arg - 1);
874 		    *arg = skipwhite(*arg);
875 		    ret_type = parse_type(arg, type_gap, give_error);
876 		    if (ret_type == NULL)
877 			return NULL;
878 		}
879 		if (flags == 0 && first_optional == -1 && argcount <= 0)
880 		    type = get_func_type(ret_type, argcount, type_gap);
881 		else
882 		{
883 		    type = alloc_func_type(ret_type, argcount, type_gap);
884 		    type->tt_flags = flags;
885 		    if (argcount > 0)
886 		    {
887 			type->tt_argcount = argcount;
888 			type->tt_min_argcount = first_optional == -1
889 						   ? argcount : first_optional;
890 			if (func_type_add_arg_types(type, argcount,
891 							     type_gap) == FAIL)
892 			    return NULL;
893 			mch_memmove(type->tt_args, arg_type,
894 						  sizeof(type_T *) * argcount);
895 		    }
896 		}
897 		return type;
898 	    }
899 	    break;
900 	case 'j':
901 	    if (len == 3 && STRNCMP(*arg, "job", len) == 0)
902 	    {
903 		*arg += len;
904 		return &t_job;
905 	    }
906 	    break;
907 	case 'l':
908 	    if (len == 4 && STRNCMP(*arg, "list", len) == 0)
909 	    {
910 		*arg += len;
911 		return parse_type_member(arg, &t_list_any,
912 							 type_gap, give_error);
913 	    }
914 	    break;
915 	case 'n':
916 	    if (len == 6 && STRNCMP(*arg, "number", len) == 0)
917 	    {
918 		*arg += len;
919 		return &t_number;
920 	    }
921 	    break;
922 	case 's':
923 	    if (len == 6 && STRNCMP(*arg, "string", len) == 0)
924 	    {
925 		*arg += len;
926 		return &t_string;
927 	    }
928 	    break;
929 	case 'v':
930 	    if (len == 4 && STRNCMP(*arg, "void", len) == 0)
931 	    {
932 		*arg += len;
933 		return &t_void;
934 	    }
935 	    break;
936     }
937 
938     if (give_error)
939 	semsg(_(e_type_not_recognized_str), *arg);
940     return NULL;
941 }
942 
943 /*
944  * Check if "type1" and "type2" are exactly the same.
945  */
946     int
947 equal_type(type_T *type1, type_T *type2)
948 {
949     int i;
950 
951     if (type1 == NULL || type2 == NULL)
952 	return FALSE;
953     if (type1->tt_type != type2->tt_type)
954 	return FALSE;
955     switch (type1->tt_type)
956     {
957 	case VAR_UNKNOWN:
958 	case VAR_ANY:
959 	case VAR_VOID:
960 	case VAR_SPECIAL:
961 	case VAR_BOOL:
962 	case VAR_NUMBER:
963 	case VAR_FLOAT:
964 	case VAR_STRING:
965 	case VAR_BLOB:
966 	case VAR_JOB:
967 	case VAR_CHANNEL:
968 	case VAR_INSTR:
969 	    break;  // not composite is always OK
970 	case VAR_LIST:
971 	case VAR_DICT:
972 	    return equal_type(type1->tt_member, type2->tt_member);
973 	case VAR_FUNC:
974 	case VAR_PARTIAL:
975 	    if (!equal_type(type1->tt_member, type2->tt_member)
976 		    || type1->tt_argcount != type2->tt_argcount)
977 		return FALSE;
978 	    if (type1->tt_argcount < 0
979 			   || type1->tt_args == NULL || type2->tt_args == NULL)
980 		return TRUE;
981 	    for (i = 0; i < type1->tt_argcount; ++i)
982 		if (!equal_type(type1->tt_args[i], type2->tt_args[i]))
983 		    return FALSE;
984 	    return TRUE;
985     }
986     return TRUE;
987 }
988 
989 /*
990  * Find the common type of "type1" and "type2" and put it in "dest".
991  * "type2" and "dest" may be the same.
992  */
993     void
994 common_type(type_T *type1, type_T *type2, type_T **dest, garray_T *type_gap)
995 {
996     if (equal_type(type1, type2))
997     {
998 	*dest = type1;
999 	return;
1000     }
1001 
1002     // If either is VAR_UNKNOWN use the other type.  An empty list/dict has no
1003     // specific type.
1004     if (type1 == NULL || type1->tt_type == VAR_UNKNOWN)
1005     {
1006 	*dest = type2;
1007 	return;
1008     }
1009     if (type2 == NULL || type2->tt_type == VAR_UNKNOWN)
1010     {
1011 	*dest = type1;
1012 	return;
1013     }
1014 
1015     if (type1->tt_type == type2->tt_type)
1016     {
1017 	if (type1->tt_type == VAR_LIST || type2->tt_type == VAR_DICT)
1018 	{
1019 	    type_T *common;
1020 
1021 	    common_type(type1->tt_member, type2->tt_member, &common, type_gap);
1022 	    if (type1->tt_type == VAR_LIST)
1023 		*dest = get_list_type(common, type_gap);
1024 	    else
1025 		*dest = get_dict_type(common, type_gap);
1026 	    return;
1027 	}
1028 	if (type1->tt_type == VAR_FUNC)
1029 	{
1030 	    type_T *common;
1031 
1032 	    common_type(type1->tt_member, type2->tt_member, &common, type_gap);
1033 	    if (type1->tt_argcount == type2->tt_argcount
1034 						    && type1->tt_argcount >= 0)
1035 	    {
1036 		int argcount = type1->tt_argcount;
1037 		int i;
1038 
1039 		*dest = alloc_func_type(common, argcount, type_gap);
1040 		if (type1->tt_args != NULL && type2->tt_args != NULL)
1041 		{
1042 		    if (func_type_add_arg_types(*dest, argcount,
1043 							     type_gap) == OK)
1044 			for (i = 0; i < argcount; ++i)
1045 			    common_type(type1->tt_args[i], type2->tt_args[i],
1046 					       &(*dest)->tt_args[i], type_gap);
1047 		}
1048 	    }
1049 	    else
1050 		// Use -1 for "tt_argcount" to indicate an unknown number of
1051 		// arguments.
1052 		*dest = alloc_func_type(common, -1, type_gap);
1053 
1054 	    // Use the minimum of min_argcount.
1055 	    (*dest)->tt_min_argcount =
1056 			type1->tt_min_argcount < type2->tt_min_argcount
1057 			     ? type1->tt_min_argcount : type2->tt_min_argcount;
1058 	    return;
1059 	}
1060     }
1061 
1062     *dest = &t_any;
1063 }
1064 
1065 /*
1066  * Get the member type of a dict or list from the items on the stack.
1067  * "stack_top" points just after the last type on the type stack.
1068  * For a list "skip" is 1, for a dict "skip" is 2, keys are skipped.
1069  * Returns &t_void for an empty list or dict.
1070  * Otherwise finds the common type of all items.
1071  */
1072     type_T *
1073 get_member_type_from_stack(
1074 	type_T	    **stack_top,
1075 	int	    count,
1076 	int	    skip,
1077 	garray_T    *type_gap)
1078 {
1079     int	    i;
1080     type_T  *result;
1081     type_T  *type;
1082 
1083     // Use "any" for an empty list or dict.
1084     if (count == 0)
1085 	return &t_unknown;
1086 
1087     // Use the first value type for the list member type, then find the common
1088     // type from following items.
1089     result = *(stack_top -(count * skip) + skip - 1);
1090     for (i = 1; i < count; ++i)
1091     {
1092 	if (result == &t_any)
1093 	    break;  // won't get more common
1094 	type = *(stack_top -((count - i) * skip) + skip - 1);
1095 	common_type(type, result, &result, type_gap);
1096     }
1097 
1098     return result;
1099 }
1100 
1101     char *
1102 vartype_name(vartype_T type)
1103 {
1104     switch (type)
1105     {
1106 	case VAR_UNKNOWN: break;
1107 	case VAR_ANY: return "any";
1108 	case VAR_VOID: return "void";
1109 	case VAR_SPECIAL: return "special";
1110 	case VAR_BOOL: return "bool";
1111 	case VAR_NUMBER: return "number";
1112 	case VAR_FLOAT: return "float";
1113 	case VAR_STRING: return "string";
1114 	case VAR_BLOB: return "blob";
1115 	case VAR_JOB: return "job";
1116 	case VAR_CHANNEL: return "channel";
1117 	case VAR_LIST: return "list";
1118 	case VAR_DICT: return "dict";
1119 	case VAR_INSTR: return "instr";
1120 
1121 	case VAR_FUNC:
1122 	case VAR_PARTIAL: return "func";
1123     }
1124     return "unknown";
1125 }
1126 
1127 /*
1128  * Return the name of a type.
1129  * The result may be in allocated memory, in which case "tofree" is set.
1130  */
1131     char *
1132 type_name(type_T *type, char **tofree)
1133 {
1134     char *name;
1135 
1136     *tofree = NULL;
1137     if (type == NULL)
1138 	return "[unknown]";
1139     name = vartype_name(type->tt_type);
1140     if (type->tt_type == VAR_LIST || type->tt_type == VAR_DICT)
1141     {
1142 	char *member_free;
1143 	char *member_name = type_name(type->tt_member, &member_free);
1144 	size_t len;
1145 
1146 	len = STRLEN(name) + STRLEN(member_name) + 3;
1147 	*tofree = alloc(len);
1148 	if (*tofree != NULL)
1149 	{
1150 	    vim_snprintf(*tofree, len, "%s<%s>", name, member_name);
1151 	    vim_free(member_free);
1152 	    return *tofree;
1153 	}
1154     }
1155     if (type->tt_type == VAR_FUNC)
1156     {
1157 	garray_T    ga;
1158 	int	    i;
1159 	int	    varargs = (type->tt_flags & TTFLAG_VARARGS) ? 1 : 0;
1160 
1161 	ga_init2(&ga, 1, 100);
1162 	if (ga_grow(&ga, 20) == FAIL)
1163 	    return "[unknown]";
1164 	STRCPY(ga.ga_data, "func(");
1165 	ga.ga_len += 5;
1166 
1167 	for (i = 0; i < type->tt_argcount; ++i)
1168 	{
1169 	    char *arg_free;
1170 	    char *arg_type;
1171 	    int  len;
1172 
1173 	    if (type->tt_args == NULL)
1174 		arg_type = "[unknown]";
1175 	    else
1176 		arg_type = type_name(type->tt_args[i], &arg_free);
1177 	    if (i > 0)
1178 	    {
1179 		STRCPY((char *)ga.ga_data + ga.ga_len, ", ");
1180 		ga.ga_len += 2;
1181 	    }
1182 	    len = (int)STRLEN(arg_type);
1183 	    if (ga_grow(&ga, len + 8) == FAIL)
1184 	    {
1185 		vim_free(arg_free);
1186 		ga_clear(&ga);
1187 		return "[unknown]";
1188 	    }
1189 	    if (varargs && i == type->tt_argcount - 1)
1190 		ga_concat(&ga, (char_u *)"...");
1191 	    else if (i >= type->tt_min_argcount)
1192 		*((char *)ga.ga_data + ga.ga_len++) = '?';
1193 	    ga_concat(&ga, (char_u *)arg_type);
1194 	    vim_free(arg_free);
1195 	}
1196 	if (type->tt_argcount < 0)
1197 	    // any number of arguments
1198 	    ga_concat(&ga, (char_u *)"...");
1199 
1200 	if (type->tt_member == &t_void)
1201 	    STRCPY((char *)ga.ga_data + ga.ga_len, ")");
1202 	else
1203 	{
1204 	    char *ret_free;
1205 	    char *ret_name = type_name(type->tt_member, &ret_free);
1206 	    int  len;
1207 
1208 	    len = (int)STRLEN(ret_name) + 4;
1209 	    if (ga_grow(&ga, len) == FAIL)
1210 	    {
1211 		vim_free(ret_free);
1212 		ga_clear(&ga);
1213 		return "[unknown]";
1214 	    }
1215 	    STRCPY((char *)ga.ga_data + ga.ga_len, "): ");
1216 	    STRCPY((char *)ga.ga_data + ga.ga_len + 3, ret_name);
1217 	    vim_free(ret_free);
1218 	}
1219 	*tofree = ga.ga_data;
1220 	return ga.ga_data;
1221     }
1222 
1223     return name;
1224 }
1225 
1226 /*
1227  * "typename(expr)" function
1228  */
1229     void
1230 f_typename(typval_T *argvars, typval_T *rettv)
1231 {
1232     garray_T	type_list;
1233     type_T	*type;
1234     char	*tofree;
1235     char	*name;
1236 
1237     rettv->v_type = VAR_STRING;
1238     ga_init2(&type_list, sizeof(type_T *), 10);
1239     type = typval2type(argvars, get_copyID(), &type_list, TRUE);
1240     name = type_name(type, &tofree);
1241     if (tofree != NULL)
1242 	rettv->vval.v_string = (char_u *)tofree;
1243     else
1244     {
1245 	rettv->vval.v_string = vim_strsave((char_u *)name);
1246 	vim_free(tofree);
1247     }
1248     clear_type_list(&type_list);
1249 }
1250 
1251 #endif // FEAT_EVAL
1252