basic functionality, no generics

metacircular.js

@@ -0,0 +1,31 @@
+import { getFnType } from "./function_registry.js";
+
+export const Type = Symbol('Type');
+export const Function = Symbol('Function');
+
+// Implementation of 'in' and 'out' functions,
+// to get input/output type of a function signature:
+export const getIn = fn => fn.in;
+export const getOut = fn => fn.out;
+
+// a module is just a set of typed objects
+// each 'typed object' is implicitly an instance of TypeLink (defined below)
+export const ModuleMetaCircular = [  
+  // TODO? maybe follow Lean so
+  //    Type.{0} : Type.{1}
+  //    Type.{1} : Type.{2}
+  //    ...
+  // see: https://lean-lang.org/functional_programming_in_lean/functor-applicative-monad/universes.html
+
+  // Type : Type
+  {i: Type, t: Type},
+
+  // Function : Type
+  {i: Function, t: Type},
+
+  // (Function -> Type) : Function
+  {i: getFnType(Function, Type), t: Function},
+
+  {i: getIn , t: getFnType(Function, Type)},
+  {i: getOut, t: getFnType(Function, Type)},
+];