import { fnType } 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: fnType({in: Function, out: Type}), t: Function},

  {i: getIn , t: fnType({in: Function, out: Type})},
  {i: getOut, t: fnType({in: Function, out: Type})},
];