xref: /vim-8.2.3635/src/vim9type.c (revision 8ea05de6)
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;
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)
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  */
256     static type_T *
257 typval2type_int(typval_T *tv, garray_T *type_gap)
258 {
259     type_T  *type;
260     type_T  *member_type = &t_any;
261     int	    argcount = 0;
262 
263     if (tv->v_type == VAR_NUMBER)
264 	return &t_number;
265     if (tv->v_type == VAR_BOOL)
266 	return &t_bool;
267     if (tv->v_type == VAR_STRING)
268 	return &t_string;
269 
270     if (tv->v_type == VAR_LIST)
271     {
272 	list_T	    *l = tv->vval.v_list;
273 	listitem_T  *li;
274 
275 	if (l == NULL || l->lv_first == NULL)
276 	    return &t_list_empty;
277 	if (l->lv_first == &range_list_item)
278 	    return &t_list_number;
279 
280 	// Use the common type of all members.
281 	member_type = typval2type(&l->lv_first->li_tv, type_gap);
282 	for (li = l->lv_first->li_next; li != NULL; li = li->li_next)
283 	    common_type(typval2type(&li->li_tv, type_gap),
284 					  member_type, &member_type, type_gap);
285 	return get_list_type(member_type, type_gap);
286     }
287 
288     if (tv->v_type == VAR_DICT)
289     {
290 	dict_iterator_T iter;
291 	typval_T	*value;
292 
293 	if (tv->vval.v_dict == NULL
294 				   || tv->vval.v_dict->dv_hashtab.ht_used == 0)
295 	    return &t_dict_empty;
296 
297 	// Use the common type of all values.
298 	dict_iterate_start(tv, &iter);
299 	dict_iterate_next(&iter, &value);
300 	member_type = typval2type(value, type_gap);
301 	while (dict_iterate_next(&iter, &value) != NULL)
302 	    common_type(typval2type(value, type_gap),
303 					  member_type, &member_type, type_gap);
304 	return get_dict_type(member_type, type_gap);
305     }
306 
307     if (tv->v_type == VAR_FUNC || tv->v_type == VAR_PARTIAL)
308     {
309 	char_u	*name = NULL;
310 	ufunc_T *ufunc = NULL;
311 
312 	if (tv->v_type == VAR_PARTIAL)
313 	{
314 	    if (tv->vval.v_partial->pt_func != NULL)
315 		ufunc = tv->vval.v_partial->pt_func;
316 	    else
317 		name = tv->vval.v_partial->pt_name;
318 	}
319 	else
320 	    name = tv->vval.v_string;
321 	if (name != NULL)
322 	{
323 	    int idx = find_internal_func(name);
324 
325 	    if (idx >= 0)
326 	    {
327 		// TODO: get actual arg count and types
328 		argcount = -1;
329 		member_type = internal_func_ret_type(idx, 0, NULL);
330 	    }
331 	    else
332 		ufunc = find_func(name, FALSE, NULL);
333 	}
334 	if (ufunc != NULL)
335 	{
336 	    // May need to get the argument types from default values by
337 	    // compiling the function.
338 	    if (ufunc->uf_def_status == UF_TO_BE_COMPILED
339 			    && compile_def_function(ufunc, TRUE, NULL) == FAIL)
340 		return NULL;
341 	    if (ufunc->uf_func_type != NULL)
342 		return ufunc->uf_func_type;
343 	}
344     }
345 
346     type = get_type_ptr(type_gap);
347     if (type == NULL)
348 	return NULL;
349     type->tt_type = tv->v_type;
350     type->tt_argcount = argcount;
351     type->tt_member = member_type;
352 
353     return type;
354 }
355 
356 /*
357  * Return TRUE if "tv" is not a bool but should be converted to bool.
358  */
359     int
360 need_convert_to_bool(type_T *type, typval_T *tv)
361 {
362     return type != NULL && type == &t_bool && tv->v_type != VAR_BOOL
363 	    && (tv->v_type == VAR_NUMBER
364 		       && (tv->vval.v_number == 0 || tv->vval.v_number == 1));
365 }
366 
367 /*
368  * Get a type_T for a typval_T.
369  * "type_list" is used to temporarily create types in.
370  */
371     type_T *
372 typval2type(typval_T *tv, garray_T *type_gap)
373 {
374     type_T *type = typval2type_int(tv, type_gap);
375 
376     if (type != NULL && type != &t_bool
377 	    && (tv->v_type == VAR_NUMBER
378 		    && (tv->vval.v_number == 0 || tv->vval.v_number == 1)))
379     {
380 	type_T *newtype = get_type_ptr(type_gap);
381 
382 	// Number 0 and 1 and expression with "&&" or "||" can also be used
383 	// for bool.
384 	if (newtype != NULL)
385 	{
386 	    *newtype = *type;
387 	    newtype->tt_flags = TTFLAG_BOOL_OK;
388 	    type = newtype;
389 	}
390     }
391     return type;
392 }
393 
394 /*
395  * Get a type_T for a typval_T, used for v: variables.
396  * "type_list" is used to temporarily create types in.
397  */
398     type_T *
399 typval2type_vimvar(typval_T *tv, garray_T *type_gap)
400 {
401     if (tv->v_type == VAR_LIST)  // e.g. for v:oldfiles
402 	return &t_list_string;
403     if (tv->v_type == VAR_DICT)  // e.g. for v:completed_item
404 	return &t_dict_any;
405     return typval2type(tv, type_gap);
406 }
407 
408 
409 /*
410  * Return FAIL if "expected" and "actual" don't match.
411  * When "argidx" > 0 it is included in the error message.
412  */
413     int
414 check_typval_type(type_T *expected, typval_T *actual_tv, int argidx)
415 {
416     garray_T	type_list;
417     type_T	*actual_type;
418     int		res = FAIL;
419 
420     ga_init2(&type_list, sizeof(type_T *), 10);
421     actual_type = typval2type(actual_tv, &type_list);
422     if (actual_type != NULL)
423 	res = check_type(expected, actual_type, TRUE, argidx);
424     clear_type_list(&type_list);
425     return res;
426 }
427 
428     void
429 type_mismatch(type_T *expected, type_T *actual)
430 {
431     arg_type_mismatch(expected, actual, 0);
432 }
433 
434     void
435 arg_type_mismatch(type_T *expected, type_T *actual, int argidx)
436 {
437     char *tofree1, *tofree2;
438     char *typename1 = type_name(expected, &tofree1);
439     char *typename2 = type_name(actual, &tofree2);
440 
441     if (argidx > 0)
442 	semsg(_(e_argument_nr_type_mismatch_expected_str_but_got_str),
443 						 argidx, typename1, typename2);
444     else
445 	semsg(_(e_type_mismatch_expected_str_but_got_str),
446 							 typename1, typename2);
447     vim_free(tofree1);
448     vim_free(tofree2);
449 }
450 
451 /*
452  * Check if the expected and actual types match.
453  * Does not allow for assigning "any" to a specific type.
454  * When "argidx" > 0 it is included in the error message.
455  */
456     int
457 check_type(type_T *expected, type_T *actual, int give_msg, int argidx)
458 {
459     int ret = OK;
460 
461     // When expected is "unknown" we accept any actual type.
462     // When expected is "any" we accept any actual type except "void".
463     if (expected->tt_type != VAR_UNKNOWN
464 	    && !(expected->tt_type == VAR_ANY && actual->tt_type != VAR_VOID))
465 
466     {
467 	// tt_type should match, except that a "partial" can be assigned to a
468 	// variable with type "func".
469 	if (!(expected->tt_type == actual->tt_type
470 		    || (expected->tt_type == VAR_FUNC
471 					   && actual->tt_type == VAR_PARTIAL)))
472 	{
473 	    if (expected->tt_type == VAR_BOOL
474 					&& (actual->tt_flags & TTFLAG_BOOL_OK))
475 		// Using number 0 or 1 for bool is OK.
476 		return OK;
477 	    if (give_msg)
478 		arg_type_mismatch(expected, actual, argidx);
479 	    return FAIL;
480 	}
481 	if (expected->tt_type == VAR_DICT || expected->tt_type == VAR_LIST)
482 	{
483 	    // "unknown" is used for an empty list or dict
484 	    if (actual->tt_member != &t_unknown)
485 		ret = check_type(expected->tt_member, actual->tt_member,
486 								     FALSE, 0);
487 	}
488 	else if (expected->tt_type == VAR_FUNC)
489 	{
490 	    if (expected->tt_member != &t_unknown)
491 		ret = check_type(expected->tt_member, actual->tt_member,
492 								     FALSE, 0);
493 	    if (ret == OK && expected->tt_argcount != -1
494 		    && actual->tt_argcount != -1
495 		    && (actual->tt_argcount < expected->tt_min_argcount
496 			|| actual->tt_argcount > expected->tt_argcount))
497 		    ret = FAIL;
498 	    if (expected->tt_args != NULL && actual->tt_args != NULL)
499 	    {
500 		int i;
501 
502 		for (i = 0; i < expected->tt_argcount; ++i)
503 		    // Allow for using "any" argument type, lambda's have them.
504 		    if (actual->tt_args[i] != &t_any && check_type(
505 			    expected->tt_args[i], actual->tt_args[i], FALSE, 0)
506 								       == FAIL)
507 		    {
508 			ret = FAIL;
509 			break;
510 		    }
511 	    }
512 	}
513 	if (ret == FAIL && give_msg)
514 	    arg_type_mismatch(expected, actual, argidx);
515     }
516     return ret;
517 }
518 
519 /*
520  * Like check_type() but also allow for a runtime type check. E.g. "any" can be
521  * used for "number".
522  */
523     int
524 check_arg_type(type_T *expected, type_T *actual, int argidx)
525 {
526     if (check_type(expected, actual, FALSE, 0) == OK
527 					    || use_typecheck(actual, expected))
528 	return OK;
529     // TODO: should generate a TYPECHECK instruction.
530     return check_type(expected, actual, TRUE, argidx);
531 }
532 
533 /*
534  * Skip over a type definition and return a pointer to just after it.
535  * When "optional" is TRUE then a leading "?" is accepted.
536  */
537     char_u *
538 skip_type(char_u *start, int optional)
539 {
540     char_u *p = start;
541 
542     if (optional && *p == '?')
543 	++p;
544     while (ASCII_ISALNUM(*p) || *p == '_')
545 	++p;
546 
547     // Skip over "<type>"; this is permissive about white space.
548     if (*skipwhite(p) == '<')
549     {
550 	p = skipwhite(p);
551 	p = skip_type(skipwhite(p + 1), FALSE);
552 	p = skipwhite(p);
553 	if (*p == '>')
554 	    ++p;
555     }
556     else if ((*p == '(' || (*p == ':' && VIM_ISWHITE(p[1])))
557 					     && STRNCMP("func", start, 4) == 0)
558     {
559 	if (*p == '(')
560 	{
561 	    // handle func(args): type
562 	    ++p;
563 	    while (*p != ')' && *p != NUL)
564 	    {
565 		char_u *sp = p;
566 
567 		if (STRNCMP(p, "...", 3) == 0)
568 		    p += 3;
569 		p = skip_type(p, TRUE);
570 		if (p == sp)
571 		    return p;  // syntax error
572 		if (*p == ',')
573 		    p = skipwhite(p + 1);
574 	    }
575 	    if (*p == ')')
576 	    {
577 		if (p[1] == ':')
578 		    p = skip_type(skipwhite(p + 2), FALSE);
579 		else
580 		    ++p;
581 	    }
582 	}
583 	else
584 	{
585 	    // handle func: return_type
586 	    p = skip_type(skipwhite(p + 1), FALSE);
587 	}
588     }
589 
590     return p;
591 }
592 
593 /*
594  * Parse the member type: "<type>" and return "type" with the member set.
595  * Use "type_gap" if a new type needs to be added.
596  * Returns NULL in case of failure.
597  */
598     static type_T *
599 parse_type_member(char_u **arg, type_T *type, garray_T *type_gap)
600 {
601     type_T  *member_type;
602     int	    prev_called_emsg = called_emsg;
603 
604     if (**arg != '<')
605     {
606 	if (*skipwhite(*arg) == '<')
607 	    semsg(_(e_no_white_space_allowed_before_str), "<");
608 	else
609 	    emsg(_(e_missing_type));
610 	return type;
611     }
612     *arg = skipwhite(*arg + 1);
613 
614     member_type = parse_type(arg, type_gap);
615 
616     *arg = skipwhite(*arg);
617     if (**arg != '>' && called_emsg == prev_called_emsg)
618     {
619 	emsg(_(e_missing_gt_after_type));
620 	return type;
621     }
622     ++*arg;
623 
624     if (type->tt_type == VAR_LIST)
625 	return get_list_type(member_type, type_gap);
626     return get_dict_type(member_type, type_gap);
627 }
628 
629 /*
630  * Parse a type at "arg" and advance over it.
631  * Return &t_any for failure.
632  */
633     type_T *
634 parse_type(char_u **arg, garray_T *type_gap)
635 {
636     char_u  *p = *arg;
637     size_t  len;
638 
639     // skip over the first word
640     while (ASCII_ISALNUM(*p) || *p == '_')
641 	++p;
642     len = p - *arg;
643 
644     switch (**arg)
645     {
646 	case 'a':
647 	    if (len == 3 && STRNCMP(*arg, "any", len) == 0)
648 	    {
649 		*arg += len;
650 		return &t_any;
651 	    }
652 	    break;
653 	case 'b':
654 	    if (len == 4 && STRNCMP(*arg, "bool", len) == 0)
655 	    {
656 		*arg += len;
657 		return &t_bool;
658 	    }
659 	    if (len == 4 && STRNCMP(*arg, "blob", len) == 0)
660 	    {
661 		*arg += len;
662 		return &t_blob;
663 	    }
664 	    break;
665 	case 'c':
666 	    if (len == 7 && STRNCMP(*arg, "channel", len) == 0)
667 	    {
668 		*arg += len;
669 		return &t_channel;
670 	    }
671 	    break;
672 	case 'd':
673 	    if (len == 4 && STRNCMP(*arg, "dict", len) == 0)
674 	    {
675 		*arg += len;
676 		return parse_type_member(arg, &t_dict_any, type_gap);
677 	    }
678 	    break;
679 	case 'f':
680 	    if (len == 5 && STRNCMP(*arg, "float", len) == 0)
681 	    {
682 #ifdef FEAT_FLOAT
683 		*arg += len;
684 		return &t_float;
685 #else
686 		emsg(_(e_this_vim_is_not_compiled_with_float_support));
687 		return &t_any;
688 #endif
689 	    }
690 	    if (len == 4 && STRNCMP(*arg, "func", len) == 0)
691 	    {
692 		type_T  *type;
693 		type_T  *ret_type = &t_unknown;
694 		int	argcount = -1;
695 		int	flags = 0;
696 		int	first_optional = -1;
697 		type_T	*arg_type[MAX_FUNC_ARGS + 1];
698 
699 		// func({type}, ...{type}): {type}
700 		*arg += len;
701 		if (**arg == '(')
702 		{
703 		    // "func" may or may not return a value, "func()" does
704 		    // not return a value.
705 		    ret_type = &t_void;
706 
707 		    p = ++*arg;
708 		    argcount = 0;
709 		    while (*p != NUL && *p != ')')
710 		    {
711 			if (*p == '?')
712 			{
713 			    if (first_optional == -1)
714 				first_optional = argcount;
715 			    ++p;
716 			}
717 			else if (STRNCMP(p, "...", 3) == 0)
718 			{
719 			    flags |= TTFLAG_VARARGS;
720 			    p += 3;
721 			}
722 			else if (first_optional != -1)
723 			{
724 			    emsg(_(e_mandatory_argument_after_optional_argument));
725 			    return &t_any;
726 			}
727 
728 			arg_type[argcount++] = parse_type(&p, type_gap);
729 
730 			// Nothing comes after "...{type}".
731 			if (flags & TTFLAG_VARARGS)
732 			    break;
733 
734 			if (*p != ',' && *skipwhite(p) == ',')
735 			{
736 			    semsg(_(e_no_white_space_allowed_before_str), ",");
737 			    return &t_any;
738 			}
739 			if (*p == ',')
740 			{
741 			    ++p;
742 			    if (!VIM_ISWHITE(*p))
743 			    {
744 				semsg(_(e_white_space_required_after_str), ",");
745 				return &t_any;
746 			    }
747 			}
748 			p = skipwhite(p);
749 			if (argcount == MAX_FUNC_ARGS)
750 			{
751 			    emsg(_(e_too_many_argument_types));
752 			    return &t_any;
753 			}
754 		    }
755 
756 		    p = skipwhite(p);
757 		    if (*p != ')')
758 		    {
759 			emsg(_(e_missing_close));
760 			return &t_any;
761 		    }
762 		    *arg = p + 1;
763 		}
764 		if (**arg == ':')
765 		{
766 		    // parse return type
767 		    ++*arg;
768 		    if (!VIM_ISWHITE(**arg))
769 			semsg(_(e_white_space_required_after_str), ":");
770 		    *arg = skipwhite(*arg);
771 		    ret_type = parse_type(arg, type_gap);
772 		}
773 		if (flags == 0 && first_optional == -1 && argcount <= 0)
774 		    type = get_func_type(ret_type, argcount, type_gap);
775 		else
776 		{
777 		    type = alloc_func_type(ret_type, argcount, type_gap);
778 		    type->tt_flags = flags;
779 		    if (argcount > 0)
780 		    {
781 			type->tt_argcount = argcount;
782 			type->tt_min_argcount = first_optional == -1
783 						   ? argcount : first_optional;
784 			if (func_type_add_arg_types(type, argcount,
785 							     type_gap) == FAIL)
786 			    return &t_any;
787 			mch_memmove(type->tt_args, arg_type,
788 						  sizeof(type_T *) * argcount);
789 		    }
790 		}
791 		return type;
792 	    }
793 	    break;
794 	case 'j':
795 	    if (len == 3 && STRNCMP(*arg, "job", len) == 0)
796 	    {
797 		*arg += len;
798 		return &t_job;
799 	    }
800 	    break;
801 	case 'l':
802 	    if (len == 4 && STRNCMP(*arg, "list", len) == 0)
803 	    {
804 		*arg += len;
805 		return parse_type_member(arg, &t_list_any, type_gap);
806 	    }
807 	    break;
808 	case 'n':
809 	    if (len == 6 && STRNCMP(*arg, "number", len) == 0)
810 	    {
811 		*arg += len;
812 		return &t_number;
813 	    }
814 	    break;
815 	case 's':
816 	    if (len == 6 && STRNCMP(*arg, "string", len) == 0)
817 	    {
818 		*arg += len;
819 		return &t_string;
820 	    }
821 	    break;
822 	case 'v':
823 	    if (len == 4 && STRNCMP(*arg, "void", len) == 0)
824 	    {
825 		*arg += len;
826 		return &t_void;
827 	    }
828 	    break;
829     }
830 
831     semsg(_(e_type_not_recognized_str), *arg);
832     return &t_any;
833 }
834 
835 /*
836  * Check if "type1" and "type2" are exactly the same.
837  */
838     static int
839 equal_type(type_T *type1, type_T *type2)
840 {
841     int i;
842 
843     if (type1->tt_type != type2->tt_type)
844 	return FALSE;
845     switch (type1->tt_type)
846     {
847 	case VAR_UNKNOWN:
848 	case VAR_ANY:
849 	case VAR_VOID:
850 	case VAR_SPECIAL:
851 	case VAR_BOOL:
852 	case VAR_NUMBER:
853 	case VAR_FLOAT:
854 	case VAR_STRING:
855 	case VAR_BLOB:
856 	case VAR_JOB:
857 	case VAR_CHANNEL:
858 	    break;  // not composite is always OK
859 	case VAR_LIST:
860 	case VAR_DICT:
861 	    return equal_type(type1->tt_member, type2->tt_member);
862 	case VAR_FUNC:
863 	case VAR_PARTIAL:
864 	    if (!equal_type(type1->tt_member, type2->tt_member)
865 		    || type1->tt_argcount != type2->tt_argcount)
866 		return FALSE;
867 	    if (type1->tt_argcount < 0
868 			   || type1->tt_args == NULL || type2->tt_args == NULL)
869 		return TRUE;
870 	    for (i = 0; i < type1->tt_argcount; ++i)
871 		if (!equal_type(type1->tt_args[i], type2->tt_args[i]))
872 		    return FALSE;
873 	    return TRUE;
874     }
875     return TRUE;
876 }
877 
878 /*
879  * Find the common type of "type1" and "type2" and put it in "dest".
880  * "type2" and "dest" may be the same.
881  */
882     void
883 common_type(type_T *type1, type_T *type2, type_T **dest, garray_T *type_gap)
884 {
885     if (equal_type(type1, type2))
886     {
887 	*dest = type1;
888 	return;
889     }
890 
891     // If either is VAR_UNKNOWN use the other type.  An empty list/dict has no
892     // specific type.
893     if (type1->tt_type == VAR_UNKNOWN)
894     {
895 	*dest = type2;
896 	return;
897     }
898     if (type2->tt_type == VAR_UNKNOWN)
899     {
900 	*dest = type1;
901 	return;
902     }
903 
904     if (type1->tt_type == type2->tt_type)
905     {
906 	if (type1->tt_type == VAR_LIST || type2->tt_type == VAR_DICT)
907 	{
908 	    type_T *common;
909 
910 	    common_type(type1->tt_member, type2->tt_member, &common, type_gap);
911 	    if (type1->tt_type == VAR_LIST)
912 		*dest = get_list_type(common, type_gap);
913 	    else
914 		*dest = get_dict_type(common, type_gap);
915 	    return;
916 	}
917 	if (type1->tt_type == VAR_FUNC)
918 	{
919 	    type_T *common;
920 
921 	    common_type(type1->tt_member, type2->tt_member, &common, type_gap);
922 	    if (type1->tt_argcount == type2->tt_argcount
923 						    && type1->tt_argcount >= 0)
924 	    {
925 		int argcount = type1->tt_argcount;
926 		int i;
927 
928 		*dest = alloc_func_type(common, argcount, type_gap);
929 		if (type1->tt_args != NULL && type2->tt_args != NULL)
930 		{
931 		    if (func_type_add_arg_types(*dest, argcount,
932 							     type_gap) == OK)
933 			for (i = 0; i < argcount; ++i)
934 			    common_type(type1->tt_args[i], type2->tt_args[i],
935 					       &(*dest)->tt_args[i], type_gap);
936 		}
937 	    }
938 	    else
939 		*dest = alloc_func_type(common, -1, type_gap);
940 	    // Use the minimum of min_argcount.
941 	    (*dest)->tt_min_argcount =
942 			type1->tt_min_argcount < type2->tt_min_argcount
943 			     ? type1->tt_min_argcount : type2->tt_min_argcount;
944 	    return;
945 	}
946     }
947 
948     *dest = &t_any;
949 }
950 
951 /*
952  * Get the member type of a dict or list from the items on the stack.
953  * "stack_top" points just after the last type on the type stack.
954  * For a list "skip" is 1, for a dict "skip" is 2, keys are skipped.
955  * Returns &t_void for an empty list or dict.
956  * Otherwise finds the common type of all items.
957  */
958     type_T *
959 get_member_type_from_stack(
960 	type_T	    **stack_top,
961 	int	    count,
962 	int	    skip,
963 	garray_T    *type_gap)
964 {
965     int	    i;
966     type_T  *result;
967     type_T  *type;
968 
969     // Use "any" for an empty list or dict.
970     if (count == 0)
971 	return &t_unknown;
972 
973     // Use the first value type for the list member type, then find the common
974     // type from following items.
975     result = *(stack_top -(count * skip) + skip - 1);
976     for (i = 1; i < count; ++i)
977     {
978 	if (result == &t_any)
979 	    break;  // won't get more common
980 	type = *(stack_top -((count - i) * skip) + skip - 1);
981 	common_type(type, result, &result, type_gap);
982     }
983 
984     return result;
985 }
986 
987     char *
988 vartype_name(vartype_T type)
989 {
990     switch (type)
991     {
992 	case VAR_UNKNOWN: break;
993 	case VAR_ANY: return "any";
994 	case VAR_VOID: return "void";
995 	case VAR_SPECIAL: return "special";
996 	case VAR_BOOL: return "bool";
997 	case VAR_NUMBER: return "number";
998 	case VAR_FLOAT: return "float";
999 	case VAR_STRING: return "string";
1000 	case VAR_BLOB: return "blob";
1001 	case VAR_JOB: return "job";
1002 	case VAR_CHANNEL: return "channel";
1003 	case VAR_LIST: return "list";
1004 	case VAR_DICT: return "dict";
1005 
1006 	case VAR_FUNC:
1007 	case VAR_PARTIAL: return "func";
1008     }
1009     return "unknown";
1010 }
1011 
1012 /*
1013  * Return the name of a type.
1014  * The result may be in allocated memory, in which case "tofree" is set.
1015  */
1016     char *
1017 type_name(type_T *type, char **tofree)
1018 {
1019     char *name = vartype_name(type->tt_type);
1020 
1021     *tofree = NULL;
1022     if (type->tt_type == VAR_LIST || type->tt_type == VAR_DICT)
1023     {
1024 	char *member_free;
1025 	char *member_name = type_name(type->tt_member, &member_free);
1026 	size_t len;
1027 
1028 	len = STRLEN(name) + STRLEN(member_name) + 3;
1029 	*tofree = alloc(len);
1030 	if (*tofree != NULL)
1031 	{
1032 	    vim_snprintf(*tofree, len, "%s<%s>", name, member_name);
1033 	    vim_free(member_free);
1034 	    return *tofree;
1035 	}
1036     }
1037     if (type->tt_type == VAR_FUNC)
1038     {
1039 	garray_T    ga;
1040 	int	    i;
1041 	int	    varargs = (type->tt_flags & TTFLAG_VARARGS) ? 1 : 0;
1042 
1043 	ga_init2(&ga, 1, 100);
1044 	if (ga_grow(&ga, 20) == FAIL)
1045 	    return "[unknown]";
1046 	STRCPY(ga.ga_data, "func(");
1047 	ga.ga_len += 5;
1048 
1049 	for (i = 0; i < type->tt_argcount; ++i)
1050 	{
1051 	    char *arg_free;
1052 	    char *arg_type;
1053 	    int  len;
1054 
1055 	    if (type->tt_args == NULL)
1056 		arg_type = "[unknown]";
1057 	    else
1058 		arg_type = type_name(type->tt_args[i], &arg_free);
1059 	    if (i > 0)
1060 	    {
1061 		STRCPY((char *)ga.ga_data + ga.ga_len, ", ");
1062 		ga.ga_len += 2;
1063 	    }
1064 	    len = (int)STRLEN(arg_type);
1065 	    if (ga_grow(&ga, len + 8) == FAIL)
1066 	    {
1067 		vim_free(arg_free);
1068 		ga_clear(&ga);
1069 		return "[unknown]";
1070 	    }
1071 	    if (varargs && i == type->tt_argcount - 1)
1072 		ga_concat(&ga, (char_u *)"...");
1073 	    else if (i >= type->tt_min_argcount)
1074 		*((char *)ga.ga_data + ga.ga_len++) = '?';
1075 	    ga_concat(&ga, (char_u *)arg_type);
1076 	    vim_free(arg_free);
1077 	}
1078 	if (type->tt_argcount < 0)
1079 	    // any number of arguments
1080 	    ga_concat(&ga, (char_u *)"...");
1081 
1082 	if (type->tt_member == &t_void)
1083 	    STRCPY((char *)ga.ga_data + ga.ga_len, ")");
1084 	else
1085 	{
1086 	    char *ret_free;
1087 	    char *ret_name = type_name(type->tt_member, &ret_free);
1088 	    int  len;
1089 
1090 	    len = (int)STRLEN(ret_name) + 4;
1091 	    if (ga_grow(&ga, len) == FAIL)
1092 	    {
1093 		vim_free(ret_free);
1094 		ga_clear(&ga);
1095 		return "[unknown]";
1096 	    }
1097 	    STRCPY((char *)ga.ga_data + ga.ga_len, "): ");
1098 	    STRCPY((char *)ga.ga_data + ga.ga_len + 3, ret_name);
1099 	    vim_free(ret_free);
1100 	}
1101 	*tofree = ga.ga_data;
1102 	return ga.ga_data;
1103     }
1104 
1105     return name;
1106 }
1107 
1108 #endif // FEAT_EVAL
1109