test

vlib/v/tests/comptime_generic_ret_test.v

@@ -0,0 +1,48 @@
+struct Parent {
+pub mut:
+	id    int
+	name  string
+	child Child
+	other Other
+}
+
+struct Child {
+pub mut:
+	id  int
+	age int
+}
+
+struct Other {
+pub mut:
+	id   int
+	name string
+}
+
+interface IdInterface {
+mut:
+	id int
+}
+
+fn insert_ids[T](val T) !T {
+	mut clone := val
+
+	$for field in T.fields {
+		$if field.typ is $struct {
+			clone.$(field.name) = insert_ids(val.$(field.name))!
+		}
+	}
+	$if T is IdInterface {
+		clone.id = 1
+	} $else {
+		return error('${T.name} does not have an id field!')
+	}
+	return clone
+}
+
+fn test_main() {
+	inserted := insert_ids(Parent{
+		name: 'test'
+	})!
+	assert inserted.child.id == 1
+	assert inserted.other.id == 1
+}