commit ec3cebbd2b6b7583d2f683f5e66345163ec122aa
author Yegappan Lakshmanan <yegappan@yahoo.com> Fri Oct 27 19:35:26 2023 +0200
committer Christian Brabandt <cb@256bit.org> Fri Oct 27 19:35:26 2023 +0200
tree 66f0c9b69e88fa4a0d35ae738f687b5679bc56e0
parent 4bca4897a12dfb91b3b27e3083fd5f370bd857d1

patch 9.0.2076: Vim9: No support for type aliases

Problem:  Vim9: No support for type aliases
Solution: Implement :type command

A type definition is giving a name to a type specification.  This also known
type alias.

	:type ListOfStrings = list<string>

The type alias can be used wherever a built-in type can be used.  The type
alias name must start with an upper case character.

closes: #13407

Signed-off-by: Christian Brabandt <cb@256bit.org>
Signed-off-by: Yegappan Lakshmanan <yegappan@yahoo.com>

src/eval.c

diff --git a/src/eval.c b/src/eval.c
index e888fec..ce98122 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -1883,6 +1883,14 @@
 	    if (eval_variable(lp->ll_name, (int)STRLEN(lp->ll_name),
 				 lp->ll_sid, &tv, &di, EVAL_VAR_VERBOSE) == OK)
 	    {
+		if (di != NULL && di->di_tv.v_type == VAR_TYPEALIAS)
+		{
+		    semsg(_(e_using_typealias_as_variable),
+					di->di_tv.vval.v_typealias->ta_name);
+		    clear_tv(&tv);
+		    return;
+		}
+
 		if ((di == NULL
 			 || (!var_check_ro(di->di_flags, lp->ll_name, FALSE)
 			   && !tv_check_lock(&di->di_tv, lp->ll_name, FALSE)))
@@ -2013,6 +2021,7 @@
 	    case VAR_INSTR:
 	    case VAR_CLASS:
 	    case VAR_OBJECT:
+	    case VAR_TYPEALIAS:
 		break;
 
 	    case VAR_BLOB:
@@ -5004,6 +5013,7 @@
 	case VAR_INSTR:
 	case VAR_CLASS:
 	case VAR_OBJECT:
+	case VAR_TYPEALIAS:
 	    if (verbose)
 		emsg(_(e_cannot_index_special_variable));
 	    return FAIL;
@@ -5109,6 +5119,7 @@
 	case VAR_INSTR:
 	case VAR_CLASS:
 	case VAR_OBJECT:
+	case VAR_TYPEALIAS:
 	    break; // not evaluating, skipping over subscript
 
 	case VAR_NUMBER:
@@ -6046,6 +6057,7 @@
 	case VAR_FLOAT:
 	case VAR_STRING:
 	case VAR_BLOB:
+	case VAR_TYPEALIAS:
 	case VAR_INSTR:
 	    // Types that do not contain any other item
 	    break;
@@ -6329,6 +6341,13 @@
 	    *tofree = NULL;
 	    r = (char_u *)get_var_special_name(tv->vval.v_number);
 	    break;
+
+	case VAR_TYPEALIAS:
+	    *tofree = vim_strsave(tv->vval.v_typealias->ta_name);
+	    r = *tofree;
+	    if (r == NULL)
+		r = (char_u *)"";
+	    break;
     }
 
     if (--recurse == 0)
@@ -7201,6 +7220,7 @@
 	case VAR_INSTR:
 	case VAR_CLASS:
 	case VAR_OBJECT:
+	case VAR_TYPEALIAS:
 	    copy_tv(from, to);
 	    break;
 	case VAR_LIST: