import { Bool, Int } from "../primitives/symbols.js";
import { fnType, lsType } from "../type_registry.js";
import { assign, makeGeneric, matchConcrete, matchGeneric } from "./generics.js";

// a -> Int
const a_to_Int = makeGeneric(a => fnType({in: a, out: Int}));
// Bool -> Int
const Bool_to_Int = fnType({in: lsType(Bool), out: Int});
// should be: Bool -> Int
console.log(matchConcrete(a_to_Int, Bool_to_Int));

// (a -> a) -> b
const fnType2 = makeGeneric((a,b) => fnType({in: fnType({in: a, out: a}), out: b}));
// (Bool -> Bool) -> a
const fnType3 = makeGeneric(a => fnType({in: fnType({in: Bool, out: Bool}), out: a}));
// should be: (Bool -> Bool) -> a
console.log(matchGeneric(fnType2, fnType3));

// (a -> b) -> [a] -> [b]
const mapFnType = makeGeneric((a,b) =>
  fnType({
    in: fnType({in: a, out: b}),
    out: fnType({in: lsType(a), out: lsType(b)}),
  }));
// a -> a
const idFnType = makeGeneric(a =>
  fnType({in: a, out: a}));
// should be: [a] -> [a]
console.log(assign(mapFnType, idFnType));