comptime: implement field.is_enum (#16920)

vlib/builtin/builtin.v

@@ -125,6 +125,7 @@ pub:
 	is_array  bool // `f []string` , TODO
 	is_map    bool // `f map[string]int` , TODO
 	is_chan   bool // `f chan int` , TODO
+	is_enum   bool // `f Enum` where Enum is an enum
 	is_struct bool // `f Abc` where Abc is a struct , TODO
 	is_alias  bool // `f MyInt` where `type MyInt = int`, TODO
 	//

vlib/v/checker/comptime.v

@@ -766,7 +766,7 @@ fn (mut c Checker) check_comptime_is_field_selector(node ast.SelectorExpr) bool
 fn (mut c Checker) check_comptime_is_field_selector_bool(node ast.SelectorExpr) bool {
 	if c.check_comptime_is_field_selector(node) {
 		return node.field_name in ['is_mut', 'is_pub', 'is_shared', 'is_atomic', 'is_option',
-			'is_array', 'is_map', 'is_chan', 'is_struct', 'is_alias']
+			'is_array', 'is_map', 'is_chan', 'is_struct', 'is_alias', 'is_enum']
 	}
 	return false
 }
@@ -787,6 +787,7 @@ fn (mut c Checker) get_comptime_selector_bool_field(field_name string) bool {
 		'is_chan' { return field_sym.kind == .chan }
 		'is_struct' { return field_sym.kind == .struct_ }
 		'is_alias' { return field_sym.kind == .alias }
+		'is_enum' { return field_sym.kind == .enum_ }
 		else { return false }
 	}
 }

vlib/v/gen/c/comptime.v

@@ -42,6 +42,7 @@ fn (mut g Gen) get_comptime_selector_bool_field(field_name string) bool {
 		'is_chan' { return field_sym.kind == .chan }
 		'is_struct' { return field_sym.kind == .struct_ }
 		'is_alias' { return field_sym.kind == .alias }
+		'is_enum' { return field_sym.kind == .enum_ }
 		else { return false }
 	}
 }
@@ -571,7 +572,7 @@ fn (mut g Gen) comptime_if_cond(cond ast.Expr, pkg_exist bool) (bool, bool) {
 		}
 		ast.SelectorExpr {
 			if g.inside_comptime_for_field && cond.expr is ast.Ident
-				&& (cond.expr as ast.Ident).name == g.comptime_for_field_var && cond.field_name in ['is_mut', 'is_pub', 'is_shared', 'is_atomic', 'is_option', 'is_array', 'is_map', 'is_chan', 'is_struct', 'is_alias'] {
+				&& (cond.expr as ast.Ident).name == g.comptime_for_field_var && cond.field_name in ['is_mut', 'is_pub', 'is_shared', 'is_atomic', 'is_option', 'is_array', 'is_map', 'is_chan', 'is_struct', 'is_alias', 'is_enum'] {
 				ret_bool := g.get_comptime_selector_bool_field(cond.field_name)
 				g.write(ret_bool.str())
 				return ret_bool, true
@@ -744,6 +745,7 @@ fn (mut g Gen) comptime_for(node ast.ComptimeFor) {
 				g.writeln('\t${node.val_var}.is_chan = ${field_sym.kind == .chan};')
 				g.writeln('\t${node.val_var}.is_struct = ${field_sym.kind == .struct_};')
 				g.writeln('\t${node.val_var}.is_alias = ${field_sym.kind == .alias};')
+				g.writeln('\t${node.val_var}.is_enum = ${field_sym.kind == .enum_};')
 				//
 				g.writeln('\t${node.val_var}.indirections = ${field.typ.nr_muls()};')
 				//

vlib/v/tests/comptime_for_in_fields_FieldData_test.v

@@ -6,6 +6,12 @@ struct Abc {
 	name string
 }
 
+enum JobTitle {
+	manager
+	executive
+	worker
+}
+
 struct Complex {
 	s        string
 	i        int
@@ -35,6 +41,7 @@ struct Complex {
 	o_map_i            ?map[int]int
 	o_my_struct        ?Abc
 	o_my_struct_shared ?shared Abc
+	jobtitle_enum      JobTitle
 }
 
 fn test_is_shared() {
@@ -117,6 +124,16 @@ fn test_is_alias() {
 	}
 }
 
+fn test_is_enum() {
+	$for f in Complex.fields {
+		if f.name.contains('_enum') {
+			assert f.is_enum, 'Complex.${f.name} should have f.is_enum set'
+		} else {
+			assert !f.is_enum, 'Complex.${f.name} should NOT have f.is_enum set'
+		}
+	}
+}
+
 fn test_indirections() {
 	$for f in Complex.fields {
 		if f.name.contains('pointer') || f.name in ['my_struct_shared', 'o_my_struct_shared'] {