anandabits

// This example shows how higher-kinded types can be emulated in Swift today.
// It acheives correct typing at the cost of some boilerplate, manual lifting and an existential representation.
// The technique below was directly inspired by the paper Lightweight Higher-Kinded Polymorphism
// by Jeremy Yallop and Leo White found at http://ocamllabs.io/higher/lightweight-higher-kinded-polymorphism.pdf

/// `ConstructorTag` represents a type constructor.
/// `Argument` represents an argument to the type constructor.
struct Apply<ConstructorTag, Argument> {
    /// An existential containing a value of `Constructor<Argument>`
    /// Where `Constructor` is the type constructor represented by `ConstructorTag`

raveclassic

import { right, either, left } from 'fp-ts/lib/Either'
import { HKTAs, HKT2As, HKT2, HKTS, HKT, HKT2S } from 'fp-ts/lib/HKT'
import { Monad } from 'fp-ts/lib/Monad'
import { option, some } from 'fp-ts/lib/Option'

function Do<M extends HKT2S>(m: Monad<M>): <L, A>(generator: () => Iterator<HKT2<M, L, A>>) => HKT2As<M, L, A>
function Do<M extends HKTS>(m: Monad<M>): <A>(generator: () => Iterator<HKT<M, A>>) => HKTAs<M, A>
function Do<M extends HKTS>(m: Monad<M>): <A>(generator: () => Iterator<HKT<M, A>>) => HKT<M, A> {
  return <A>(generator: () => Iterator<HKT<M, A>>): HKT<M, A> => {
    const iterator = generator()

NicolasT

[1 of 1] Compiling IO               ( io.hs, io.o )

8 Lets floated to top level; 0 Lets floated elsewhere; from 11 Lambda groups

8 Lets floated to top level; 0 Lets floated elsewhere; from 8 Lambda groups

Total ticks:     507

107 PreInlineUnconditionally
    2 eta_B1