xref: /vim-8.2.3635/src/vim9type.c (revision 4f33bc20)
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     if (tv->v_type == VAR_PARTIAL && tv->vval.v_partial->pt_argc > 0)
382     {
383 	type->tt_argcount -= tv->vval.v_partial->pt_argc;
384 	type->tt_min_argcount -= tv->vval.v_partial->pt_argc;
385     }
386     type->tt_member = member_type;
387 
388     return type;
389 }
390 
391 /*
392  * Return TRUE if "tv" is not a bool but should be converted to bool.
393  */
394     int
395 need_convert_to_bool(type_T *type, typval_T *tv)
396 {
397     return type != NULL && type == &t_bool && tv->v_type != VAR_BOOL
398 	    && (tv->v_type == VAR_NUMBER
399 		       && (tv->vval.v_number == 0 || tv->vval.v_number == 1));
400 }
401 
402 /*
403  * Get a type_T for a typval_T.
404  * "type_list" is used to temporarily create types in.
405  * When "do_member" is TRUE also get the member type, otherwise use "any".
406  */
407     type_T *
408 typval2type(typval_T *tv, int copyID, garray_T *type_gap, int do_member)
409 {
410     type_T *type = typval2type_int(tv, copyID, type_gap, do_member);
411 
412     if (type != NULL && type != &t_bool
413 	    && (tv->v_type == VAR_NUMBER
414 		    && (tv->vval.v_number == 0 || tv->vval.v_number == 1)))
415 	// Number 0 and 1 and expression with "&&" or "||" can also be used for
416 	// bool.
417 	type = &t_number_bool;
418     return type;
419 }
420 
421 /*
422  * Get a type_T for a typval_T, used for v: variables.
423  * "type_list" is used to temporarily create types in.
424  */
425     type_T *
426 typval2type_vimvar(typval_T *tv, garray_T *type_gap)
427 {
428     if (tv->v_type == VAR_LIST)  // e.g. for v:oldfiles
429 	return &t_list_string;
430     if (tv->v_type == VAR_DICT)  // e.g. for v:completed_item
431 	return &t_dict_any;
432     return typval2type(tv, get_copyID(), type_gap, TRUE);
433 }
434 
435     int
436 check_typval_arg_type(
437 	type_T	    *expected,
438 	typval_T    *actual_tv,
439 	char	    *func_name,
440 	int	    arg_idx)
441 {
442     where_T	where = WHERE_INIT;
443 
444     where.wt_index = arg_idx;
445     where.wt_func_name = func_name;
446     return check_typval_type(expected, actual_tv, where);
447 }
448 
449 /*
450  * Return FAIL if "expected" and "actual" don't match.
451  * When "argidx" > 0 it is included in the error message.
452  */
453     int
454 check_typval_type(type_T *expected, typval_T *actual_tv, where_T where)
455 {
456     garray_T	type_list;
457     type_T	*actual_type;
458     int		res = FAIL;
459 
460     ga_init2(&type_list, sizeof(type_T *), 10);
461     actual_type = typval2type(actual_tv, get_copyID(), &type_list, TRUE);
462     if (actual_type != NULL)
463 	res = check_type(expected, actual_type, TRUE, where);
464     clear_type_list(&type_list);
465     return res;
466 }
467 
468     void
469 type_mismatch(type_T *expected, type_T *actual)
470 {
471     arg_type_mismatch(expected, actual, 0);
472 }
473 
474     void
475 arg_type_mismatch(type_T *expected, type_T *actual, int arg_idx)
476 {
477     where_T	where = WHERE_INIT;
478 
479     where.wt_index = arg_idx;
480     type_mismatch_where(expected, actual, where);
481 }
482 
483     void
484 type_mismatch_where(type_T *expected, type_T *actual, where_T where)
485 {
486     char *tofree1, *tofree2;
487     char *typename1 = type_name(expected, &tofree1);
488     char *typename2 = type_name(actual, &tofree2);
489 
490     if (where.wt_index > 0)
491     {
492 	if (where.wt_func_name == NULL)
493 	    semsg(_(where.wt_variable
494 			 ? e_variable_nr_type_mismatch_expected_str_but_got_str
495 		       : e_argument_nr_type_mismatch_expected_str_but_got_str),
496 					 where.wt_index, typename1, typename2);
497 	else
498 	    semsg(_(where.wt_variable
499 		  ? e_variable_nr_type_mismatch_expected_str_but_got_str_in_str
500 		: e_argument_nr_type_mismatch_expected_str_but_got_str_in_str),
501 		     where.wt_index, typename1, typename2, where.wt_func_name);
502     }
503     else if (where.wt_func_name == NULL)
504 	semsg(_(e_type_mismatch_expected_str_but_got_str),
505 							 typename1, typename2);
506     else
507 	semsg(_(e_type_mismatch_expected_str_but_got_str_in_str),
508 				     typename1, typename2, where.wt_func_name);
509     vim_free(tofree1);
510     vim_free(tofree2);
511 }
512 
513 /*
514  * Check if the expected and actual types match.
515  * Does not allow for assigning "any" to a specific type.
516  * When "argidx" > 0 it is included in the error message.
517  */
518     int
519 check_type(type_T *expected, type_T *actual, int give_msg, where_T where)
520 {
521     int ret = OK;
522 
523     // When expected is "unknown" we accept any actual type.
524     // When expected is "any" we accept any actual type except "void".
525     if (expected->tt_type != VAR_UNKNOWN
526 	    && !(expected->tt_type == VAR_ANY && actual->tt_type != VAR_VOID))
527 
528     {
529 	// tt_type should match, except that a "partial" can be assigned to a
530 	// variable with type "func".
531 	if (!(expected->tt_type == actual->tt_type
532 		    || (expected->tt_type == VAR_FUNC
533 					   && actual->tt_type == VAR_PARTIAL)))
534 	{
535 	    if (expected->tt_type == VAR_BOOL
536 					&& (actual->tt_flags & TTFLAG_BOOL_OK))
537 		// Using number 0 or 1 for bool is OK.
538 		return OK;
539 	    if (give_msg)
540 		type_mismatch_where(expected, actual, where);
541 	    return FAIL;
542 	}
543 	if (expected->tt_type == VAR_DICT || expected->tt_type == VAR_LIST)
544 	{
545 	    // "unknown" is used for an empty list or dict
546 	    if (actual->tt_member != &t_unknown)
547 		ret = check_type(expected->tt_member, actual->tt_member,
548 								 FALSE, where);
549 	}
550 	else if (expected->tt_type == VAR_FUNC)
551 	{
552 	    // If the return type is unknown it can be anything, including
553 	    // nothing, thus there is no point in checking.
554 	    if (expected->tt_member != &t_unknown
555 					    && actual->tt_member != &t_unknown)
556 		ret = check_type(expected->tt_member, actual->tt_member,
557 								 FALSE, where);
558 	    if (ret == OK && expected->tt_argcount != -1
559 		    && actual->tt_min_argcount != -1
560 		    && (actual->tt_argcount == -1
561 			|| (actual->tt_argcount < expected->tt_min_argcount
562 			    || actual->tt_argcount > expected->tt_argcount)))
563 		ret = FAIL;
564 	    if (ret == OK && expected->tt_args != NULL
565 						    && actual->tt_args != NULL)
566 	    {
567 		int i;
568 
569 		for (i = 0; i < expected->tt_argcount; ++i)
570 		    // Allow for using "any" argument type, lambda's have them.
571 		    if (actual->tt_args[i] != &t_any && check_type(
572 			    expected->tt_args[i], actual->tt_args[i], FALSE,
573 								where) == FAIL)
574 		    {
575 			ret = FAIL;
576 			break;
577 		    }
578 	    }
579 	}
580 	if (ret == FAIL && give_msg)
581 	    type_mismatch_where(expected, actual, where);
582     }
583     return ret;
584 }
585 
586 /*
587  * Check that the arguments of "type" match "argvars[argcount]".
588  * Return OK/FAIL.
589  */
590     int
591 check_argument_types(
592 	type_T	    *type,
593 	typval_T    *argvars,
594 	int	    argcount,
595 	char_u	    *name)
596 {
597     int	    varargs = (type->tt_flags & TTFLAG_VARARGS) ? 1 : 0;
598     int	    i;
599 
600     if (type->tt_type != VAR_FUNC && type->tt_type != VAR_PARTIAL)
601 	return OK;  // just in case
602     if (argcount < type->tt_min_argcount - varargs)
603     {
604 	semsg(_(e_toofewarg), name);
605 	return FAIL;
606     }
607     if (!varargs && type->tt_argcount >= 0 && argcount > type->tt_argcount)
608     {
609 	semsg(_(e_toomanyarg), name);
610 	return FAIL;
611     }
612     if (type->tt_args == NULL)
613 	return OK;  // cannot check
614 
615 
616     for (i = 0; i < argcount; ++i)
617     {
618 	type_T	*expected;
619 
620 	if (varargs && i >= type->tt_argcount - 1)
621 	    expected = type->tt_args[type->tt_argcount - 1]->tt_member;
622 	else
623 	    expected = type->tt_args[i];
624 	if (check_typval_arg_type(expected, &argvars[i], NULL, i + 1) == FAIL)
625 	    return FAIL;
626     }
627     return OK;
628 }
629 
630 /*
631  * Skip over a type definition and return a pointer to just after it.
632  * When "optional" is TRUE then a leading "?" is accepted.
633  */
634     char_u *
635 skip_type(char_u *start, int optional)
636 {
637     char_u *p = start;
638 
639     if (optional && *p == '?')
640 	++p;
641     while (ASCII_ISALNUM(*p) || *p == '_')
642 	++p;
643 
644     // Skip over "<type>"; this is permissive about white space.
645     if (*skipwhite(p) == '<')
646     {
647 	p = skipwhite(p);
648 	p = skip_type(skipwhite(p + 1), FALSE);
649 	p = skipwhite(p);
650 	if (*p == '>')
651 	    ++p;
652     }
653     else if ((*p == '(' || (*p == ':' && VIM_ISWHITE(p[1])))
654 					     && STRNCMP("func", start, 4) == 0)
655     {
656 	if (*p == '(')
657 	{
658 	    // handle func(args): type
659 	    ++p;
660 	    while (*p != ')' && *p != NUL)
661 	    {
662 		char_u *sp = p;
663 
664 		if (STRNCMP(p, "...", 3) == 0)
665 		    p += 3;
666 		p = skip_type(p, TRUE);
667 		if (p == sp)
668 		    return p;  // syntax error
669 		if (*p == ',')
670 		    p = skipwhite(p + 1);
671 	    }
672 	    if (*p == ')')
673 	    {
674 		if (p[1] == ':')
675 		    p = skip_type(skipwhite(p + 2), FALSE);
676 		else
677 		    ++p;
678 	    }
679 	}
680 	else
681 	{
682 	    // handle func: return_type
683 	    p = skip_type(skipwhite(p + 1), FALSE);
684 	}
685     }
686 
687     return p;
688 }
689 
690 /*
691  * Parse the member type: "<type>" and return "type" with the member set.
692  * Use "type_gap" if a new type needs to be added.
693  * Returns NULL in case of failure.
694  */
695     static type_T *
696 parse_type_member(
697 	char_u	    **arg,
698 	type_T	    *type,
699 	garray_T    *type_gap,
700 	int	    give_error)
701 {
702     type_T  *member_type;
703     int	    prev_called_emsg = called_emsg;
704 
705     if (**arg != '<')
706     {
707 	if (give_error)
708 	{
709 	    if (*skipwhite(*arg) == '<')
710 		semsg(_(e_no_white_space_allowed_before_str_str), "<", *arg);
711 	    else
712 		emsg(_(e_missing_type));
713 	}
714 	return NULL;
715     }
716     *arg = skipwhite(*arg + 1);
717 
718     member_type = parse_type(arg, type_gap, give_error);
719     if (member_type == NULL)
720 	return NULL;
721 
722     *arg = skipwhite(*arg);
723     if (**arg != '>' && called_emsg == prev_called_emsg)
724     {
725 	if (give_error)
726 	    emsg(_(e_missing_gt_after_type));
727 	return NULL;
728     }
729     ++*arg;
730 
731     if (type->tt_type == VAR_LIST)
732 	return get_list_type(member_type, type_gap);
733     return get_dict_type(member_type, type_gap);
734 }
735 
736 /*
737  * Parse a type at "arg" and advance over it.
738  * When "give_error" is TRUE give error messages, otherwise be quiet.
739  * Return NULL for failure.
740  */
741     type_T *
742 parse_type(char_u **arg, garray_T *type_gap, int give_error)
743 {
744     char_u  *p = *arg;
745     size_t  len;
746 
747     // skip over the first word
748     while (ASCII_ISALNUM(*p) || *p == '_')
749 	++p;
750     len = p - *arg;
751 
752     switch (**arg)
753     {
754 	case 'a':
755 	    if (len == 3 && STRNCMP(*arg, "any", len) == 0)
756 	    {
757 		*arg += len;
758 		return &t_any;
759 	    }
760 	    break;
761 	case 'b':
762 	    if (len == 4 && STRNCMP(*arg, "bool", len) == 0)
763 	    {
764 		*arg += len;
765 		return &t_bool;
766 	    }
767 	    if (len == 4 && STRNCMP(*arg, "blob", len) == 0)
768 	    {
769 		*arg += len;
770 		return &t_blob;
771 	    }
772 	    break;
773 	case 'c':
774 	    if (len == 7 && STRNCMP(*arg, "channel", len) == 0)
775 	    {
776 		*arg += len;
777 		return &t_channel;
778 	    }
779 	    break;
780 	case 'd':
781 	    if (len == 4 && STRNCMP(*arg, "dict", len) == 0)
782 	    {
783 		*arg += len;
784 		return parse_type_member(arg, &t_dict_any,
785 							 type_gap, give_error);
786 	    }
787 	    break;
788 	case 'f':
789 	    if (len == 5 && STRNCMP(*arg, "float", len) == 0)
790 	    {
791 #ifdef FEAT_FLOAT
792 		*arg += len;
793 		return &t_float;
794 #else
795 		if (give_error)
796 		    emsg(_(e_this_vim_is_not_compiled_with_float_support));
797 		return NULL;
798 #endif
799 	    }
800 	    if (len == 4 && STRNCMP(*arg, "func", len) == 0)
801 	    {
802 		type_T  *type;
803 		type_T  *ret_type = &t_unknown;
804 		int	argcount = -1;
805 		int	flags = 0;
806 		int	first_optional = -1;
807 		type_T	*arg_type[MAX_FUNC_ARGS + 1];
808 
809 		// func({type}, ...{type}): {type}
810 		*arg += len;
811 		if (**arg == '(')
812 		{
813 		    // "func" may or may not return a value, "func()" does
814 		    // not return a value.
815 		    ret_type = &t_void;
816 
817 		    p = ++*arg;
818 		    argcount = 0;
819 		    while (*p != NUL && *p != ')')
820 		    {
821 			if (*p == '?')
822 			{
823 			    if (first_optional == -1)
824 				first_optional = argcount;
825 			    ++p;
826 			}
827 			else if (STRNCMP(p, "...", 3) == 0)
828 			{
829 			    flags |= TTFLAG_VARARGS;
830 			    p += 3;
831 			}
832 			else if (first_optional != -1)
833 			{
834 			    if (give_error)
835 				emsg(_(e_mandatory_argument_after_optional_argument));
836 			    return NULL;
837 			}
838 
839 			type = parse_type(&p, type_gap, give_error);
840 			if (type == NULL)
841 			    return NULL;
842 			arg_type[argcount++] = type;
843 
844 			// Nothing comes after "...{type}".
845 			if (flags & TTFLAG_VARARGS)
846 			    break;
847 
848 			if (*p != ',' && *skipwhite(p) == ',')
849 			{
850 			    if (give_error)
851 				semsg(_(e_no_white_space_allowed_before_str_str),
852 								       ",", p);
853 			    return NULL;
854 			}
855 			if (*p == ',')
856 			{
857 			    ++p;
858 			    if (!VIM_ISWHITE(*p))
859 			    {
860 				if (give_error)
861 				    semsg(_(e_white_space_required_after_str_str),
862 								   ",", p - 1);
863 				return NULL;
864 			    }
865 			}
866 			p = skipwhite(p);
867 			if (argcount == MAX_FUNC_ARGS)
868 			{
869 			    if (give_error)
870 				emsg(_(e_too_many_argument_types));
871 			    return NULL;
872 			}
873 		    }
874 
875 		    p = skipwhite(p);
876 		    if (*p != ')')
877 		    {
878 			if (give_error)
879 			    emsg(_(e_missing_close));
880 			return NULL;
881 		    }
882 		    *arg = p + 1;
883 		}
884 		if (**arg == ':')
885 		{
886 		    // parse return type
887 		    ++*arg;
888 		    if (!VIM_ISWHITE(**arg) && give_error)
889 			semsg(_(e_white_space_required_after_str_str),
890 								":", *arg - 1);
891 		    *arg = skipwhite(*arg);
892 		    ret_type = parse_type(arg, type_gap, give_error);
893 		    if (ret_type == NULL)
894 			return NULL;
895 		}
896 		if (flags == 0 && first_optional == -1 && argcount <= 0)
897 		    type = get_func_type(ret_type, argcount, type_gap);
898 		else
899 		{
900 		    type = alloc_func_type(ret_type, argcount, type_gap);
901 		    type->tt_flags = flags;
902 		    if (argcount > 0)
903 		    {
904 			type->tt_argcount = argcount;
905 			type->tt_min_argcount = first_optional == -1
906 						   ? argcount : first_optional;
907 			if (func_type_add_arg_types(type, argcount,
908 							     type_gap) == FAIL)
909 			    return NULL;
910 			mch_memmove(type->tt_args, arg_type,
911 						  sizeof(type_T *) * argcount);
912 		    }
913 		}
914 		return type;
915 	    }
916 	    break;
917 	case 'j':
918 	    if (len == 3 && STRNCMP(*arg, "job", len) == 0)
919 	    {
920 		*arg += len;
921 		return &t_job;
922 	    }
923 	    break;
924 	case 'l':
925 	    if (len == 4 && STRNCMP(*arg, "list", len) == 0)
926 	    {
927 		*arg += len;
928 		return parse_type_member(arg, &t_list_any,
929 							 type_gap, give_error);
930 	    }
931 	    break;
932 	case 'n':
933 	    if (len == 6 && STRNCMP(*arg, "number", len) == 0)
934 	    {
935 		*arg += len;
936 		return &t_number;
937 	    }
938 	    break;
939 	case 's':
940 	    if (len == 6 && STRNCMP(*arg, "string", len) == 0)
941 	    {
942 		*arg += len;
943 		return &t_string;
944 	    }
945 	    break;
946 	case 'v':
947 	    if (len == 4 && STRNCMP(*arg, "void", len) == 0)
948 	    {
949 		*arg += len;
950 		return &t_void;
951 	    }
952 	    break;
953     }
954 
955     if (give_error)
956 	semsg(_(e_type_not_recognized_str), *arg);
957     return NULL;
958 }
959 
960 /*
961  * Check if "type1" and "type2" are exactly the same.
962  * "flags" can have ETYPE_ARG_UNKNOWN, which means that an unknown argument
963  * type in "type1" is accepted.
964  */
965     int
966 equal_type(type_T *type1, type_T *type2, int flags)
967 {
968     int i;
969 
970     if (type1 == NULL || type2 == NULL)
971 	return FALSE;
972     if (type1->tt_type != type2->tt_type)
973 	return FALSE;
974     switch (type1->tt_type)
975     {
976 	case VAR_UNKNOWN:
977 	case VAR_ANY:
978 	case VAR_VOID:
979 	case VAR_SPECIAL:
980 	case VAR_BOOL:
981 	case VAR_NUMBER:
982 	case VAR_FLOAT:
983 	case VAR_STRING:
984 	case VAR_BLOB:
985 	case VAR_JOB:
986 	case VAR_CHANNEL:
987 	case VAR_INSTR:
988 	    break;  // not composite is always OK
989 	case VAR_LIST:
990 	case VAR_DICT:
991 	    return equal_type(type1->tt_member, type2->tt_member, flags);
992 	case VAR_FUNC:
993 	case VAR_PARTIAL:
994 	    if (!equal_type(type1->tt_member, type2->tt_member, flags)
995 		    || type1->tt_argcount != type2->tt_argcount)
996 		return FALSE;
997 	    if (type1->tt_argcount < 0
998 			   || type1->tt_args == NULL || type2->tt_args == NULL)
999 		return TRUE;
1000 	    for (i = 0; i < type1->tt_argcount; ++i)
1001 		if ((flags & ETYPE_ARG_UNKNOWN) == 0
1002 			&& !equal_type(type1->tt_args[i], type2->tt_args[i],
1003 									flags))
1004 		    return FALSE;
1005 	    return TRUE;
1006     }
1007     return TRUE;
1008 }
1009 
1010 /*
1011  * Find the common type of "type1" and "type2" and put it in "dest".
1012  * "type2" and "dest" may be the same.
1013  */
1014     void
1015 common_type(type_T *type1, type_T *type2, type_T **dest, garray_T *type_gap)
1016 {
1017     if (equal_type(type1, type2, 0))
1018     {
1019 	*dest = type1;
1020 	return;
1021     }
1022 
1023     // If either is VAR_UNKNOWN use the other type.  An empty list/dict has no
1024     // specific type.
1025     if (type1 == NULL || type1->tt_type == VAR_UNKNOWN)
1026     {
1027 	*dest = type2;
1028 	return;
1029     }
1030     if (type2 == NULL || type2->tt_type == VAR_UNKNOWN)
1031     {
1032 	*dest = type1;
1033 	return;
1034     }
1035 
1036     if (type1->tt_type == type2->tt_type)
1037     {
1038 	if (type1->tt_type == VAR_LIST || type2->tt_type == VAR_DICT)
1039 	{
1040 	    type_T *common;
1041 
1042 	    common_type(type1->tt_member, type2->tt_member, &common, type_gap);
1043 	    if (type1->tt_type == VAR_LIST)
1044 		*dest = get_list_type(common, type_gap);
1045 	    else
1046 		*dest = get_dict_type(common, type_gap);
1047 	    return;
1048 	}
1049 	if (type1->tt_type == VAR_FUNC)
1050 	{
1051 	    type_T *common;
1052 
1053 	    common_type(type1->tt_member, type2->tt_member, &common, type_gap);
1054 	    if (type1->tt_argcount == type2->tt_argcount
1055 						    && type1->tt_argcount >= 0)
1056 	    {
1057 		int argcount = type1->tt_argcount;
1058 		int i;
1059 
1060 		*dest = alloc_func_type(common, argcount, type_gap);
1061 		if (type1->tt_args != NULL && type2->tt_args != NULL)
1062 		{
1063 		    if (func_type_add_arg_types(*dest, argcount,
1064 							     type_gap) == OK)
1065 			for (i = 0; i < argcount; ++i)
1066 			    common_type(type1->tt_args[i], type2->tt_args[i],
1067 					       &(*dest)->tt_args[i], type_gap);
1068 		}
1069 	    }
1070 	    else
1071 		// Use -1 for "tt_argcount" to indicate an unknown number of
1072 		// arguments.
1073 		*dest = alloc_func_type(common, -1, type_gap);
1074 
1075 	    // Use the minimum of min_argcount.
1076 	    (*dest)->tt_min_argcount =
1077 			type1->tt_min_argcount < type2->tt_min_argcount
1078 			     ? type1->tt_min_argcount : type2->tt_min_argcount;
1079 	    return;
1080 	}
1081     }
1082 
1083     *dest = &t_any;
1084 }
1085 
1086 /*
1087  * Get the member type of a dict or list from the items on the stack.
1088  * "stack_top" points just after the last type on the type stack.
1089  * For a list "skip" is 1, for a dict "skip" is 2, keys are skipped.
1090  * Returns &t_void for an empty list or dict.
1091  * Otherwise finds the common type of all items.
1092  */
1093     type_T *
1094 get_member_type_from_stack(
1095 	type_T	    **stack_top,
1096 	int	    count,
1097 	int	    skip,
1098 	garray_T    *type_gap)
1099 {
1100     int	    i;
1101     type_T  *result;
1102     type_T  *type;
1103 
1104     // Use "any" for an empty list or dict.
1105     if (count == 0)
1106 	return &t_unknown;
1107 
1108     // Use the first value type for the list member type, then find the common
1109     // type from following items.
1110     result = *(stack_top -(count * skip) + skip - 1);
1111     for (i = 1; i < count; ++i)
1112     {
1113 	if (result == &t_any)
1114 	    break;  // won't get more common
1115 	type = *(stack_top -((count - i) * skip) + skip - 1);
1116 	common_type(type, result, &result, type_gap);
1117     }
1118 
1119     return result;
1120 }
1121 
1122     char *
1123 vartype_name(vartype_T type)
1124 {
1125     switch (type)
1126     {
1127 	case VAR_UNKNOWN: break;
1128 	case VAR_ANY: return "any";
1129 	case VAR_VOID: return "void";
1130 	case VAR_SPECIAL: return "special";
1131 	case VAR_BOOL: return "bool";
1132 	case VAR_NUMBER: return "number";
1133 	case VAR_FLOAT: return "float";
1134 	case VAR_STRING: return "string";
1135 	case VAR_BLOB: return "blob";
1136 	case VAR_JOB: return "job";
1137 	case VAR_CHANNEL: return "channel";
1138 	case VAR_LIST: return "list";
1139 	case VAR_DICT: return "dict";
1140 	case VAR_INSTR: return "instr";
1141 
1142 	case VAR_FUNC:
1143 	case VAR_PARTIAL: return "func";
1144     }
1145     return "unknown";
1146 }
1147 
1148 /*
1149  * Return the name of a type.
1150  * The result may be in allocated memory, in which case "tofree" is set.
1151  */
1152     char *
1153 type_name(type_T *type, char **tofree)
1154 {
1155     char *name;
1156 
1157     *tofree = NULL;
1158     if (type == NULL)
1159 	return "[unknown]";
1160     name = vartype_name(type->tt_type);
1161     if (type->tt_type == VAR_LIST || type->tt_type == VAR_DICT)
1162     {
1163 	char *member_free;
1164 	char *member_name = type_name(type->tt_member, &member_free);
1165 	size_t len;
1166 
1167 	len = STRLEN(name) + STRLEN(member_name) + 3;
1168 	*tofree = alloc(len);
1169 	if (*tofree != NULL)
1170 	{
1171 	    vim_snprintf(*tofree, len, "%s<%s>", name, member_name);
1172 	    vim_free(member_free);
1173 	    return *tofree;
1174 	}
1175     }
1176     if (type->tt_type == VAR_FUNC)
1177     {
1178 	garray_T    ga;
1179 	int	    i;
1180 	int	    varargs = (type->tt_flags & TTFLAG_VARARGS) ? 1 : 0;
1181 
1182 	ga_init2(&ga, 1, 100);
1183 	if (ga_grow(&ga, 20) == FAIL)
1184 	    return "[unknown]";
1185 	STRCPY(ga.ga_data, "func(");
1186 	ga.ga_len += 5;
1187 
1188 	for (i = 0; i < type->tt_argcount; ++i)
1189 	{
1190 	    char *arg_free = NULL;
1191 	    char *arg_type;
1192 	    int  len;
1193 
1194 	    if (type->tt_args == NULL)
1195 		arg_type = "[unknown]";
1196 	    else
1197 		arg_type = type_name(type->tt_args[i], &arg_free);
1198 	    if (i > 0)
1199 	    {
1200 		STRCPY((char *)ga.ga_data + ga.ga_len, ", ");
1201 		ga.ga_len += 2;
1202 	    }
1203 	    len = (int)STRLEN(arg_type);
1204 	    if (ga_grow(&ga, len + 8) == FAIL)
1205 	    {
1206 		vim_free(arg_free);
1207 		ga_clear(&ga);
1208 		return "[unknown]";
1209 	    }
1210 	    if (varargs && i == type->tt_argcount - 1)
1211 		ga_concat(&ga, (char_u *)"...");
1212 	    else if (i >= type->tt_min_argcount)
1213 		*((char *)ga.ga_data + ga.ga_len++) = '?';
1214 	    ga_concat(&ga, (char_u *)arg_type);
1215 	    vim_free(arg_free);
1216 	}
1217 	if (type->tt_argcount < 0)
1218 	    // any number of arguments
1219 	    ga_concat(&ga, (char_u *)"...");
1220 
1221 	if (type->tt_member == &t_void)
1222 	    STRCPY((char *)ga.ga_data + ga.ga_len, ")");
1223 	else
1224 	{
1225 	    char *ret_free;
1226 	    char *ret_name = type_name(type->tt_member, &ret_free);
1227 	    int  len;
1228 
1229 	    len = (int)STRLEN(ret_name) + 4;
1230 	    if (ga_grow(&ga, len) == FAIL)
1231 	    {
1232 		vim_free(ret_free);
1233 		ga_clear(&ga);
1234 		return "[unknown]";
1235 	    }
1236 	    STRCPY((char *)ga.ga_data + ga.ga_len, "): ");
1237 	    STRCPY((char *)ga.ga_data + ga.ga_len + 3, ret_name);
1238 	    vim_free(ret_free);
1239 	}
1240 	*tofree = ga.ga_data;
1241 	return ga.ga_data;
1242     }
1243 
1244     return name;
1245 }
1246 
1247 /*
1248  * "typename(expr)" function
1249  */
1250     void
1251 f_typename(typval_T *argvars, typval_T *rettv)
1252 {
1253     garray_T	type_list;
1254     type_T	*type;
1255     char	*tofree;
1256     char	*name;
1257 
1258     rettv->v_type = VAR_STRING;
1259     ga_init2(&type_list, sizeof(type_T *), 10);
1260     type = typval2type(argvars, get_copyID(), &type_list, TRUE);
1261     name = type_name(type, &tofree);
1262     if (tofree != NULL)
1263 	rettv->vval.v_string = (char_u *)tofree;
1264     else
1265     {
1266 	rettv->vval.v_string = vim_strsave((char_u *)name);
1267 	vim_free(tofree);
1268     }
1269     clear_type_list(&type_list);
1270 }
1271 
1272 #endif // FEAT_EVAL
1273