testdo.ts

import * as _Maybe from "./maybe"
import {maybe} from "./maybe"
import {Do} from "./syntax"
import Maybe = _Maybe.Maybe

type Person = {
    name: string
    age: number
}

type Id = string

const getName = (id: Id): Maybe<string> =>
    (id === "foo") ? _Maybe.just("Foo") : _Maybe.nothing()

const getAge = (id: Id): Maybe<number> =>
    (id === "foo") ? _Maybe.just(34) : _Maybe.nothing()

// doesn't compile : cannot reconcile HKT<"Maybe", { string, number}> with Maybe<Person>
const mbPers: Maybe<Person> = Do._(maybe

    , () => getName("foo")

    , _ => getAge("foo")

    , (name, age) => _Maybe.just({ name: name, age: age}))