Initial project import

tools/v/vlib/builtin/string_d_ownership.v

@@ -0,0 +1,18 @@
+// Ownership extensions for strings.
+// Only included when -ownership flag is passed (via -d ownership).
+// Provides .to_owned() which creates an owned string with move semantics.
+module builtin
+
+// IClone marks values that provide explicit clone semantics in ownership mode.
+//
+// This is a marker interface. Concrete types still define their own `clone()`
+// methods with concrete return types.
+pub interface IClone {}
+
+// to_owned creates an owned copy of the string.
+// When ownership checking is enabled, owned strings have move semantics:
+// assigning an owned string to another variable moves ownership,
+// making the original variable invalid.
+pub fn (s string) to_owned() string {
+	return s.clone()
+}