add nominal types for 2D points

structures/nominal_type.js

@@ -0,0 +1,14 @@
+import { Type } from "../metacircular.js";
+import { Int } from "../primitives/symbols.js";
+import { prodType } from "../type_registry.js";
+import { makeProductType } from "./product.js";
+
+export const NominalType = prodType(Int, Type);
+
+export const ModuleNominalType = makeProductType(Int, Type);
+
+export const nominalType = x => {
+  const result = ModuleNominalType.l[5].i(x); // dirty!!
+  result.__proto__.toString = () => "HEY";
+  return result;
+}