| {-# LANGUAGE DataKinds #-} | |
| {-# LANGUAGE FlexibleContexts #-} | |
| {-# LANGUAGE GADTs #-} | |
| {-# LANGUAGE KindSignatures #-} | |
| {-# LANGUAGE LambdaCase #-} | |
| {-# LANGUAGE OverloadedStrings #-} | |
| {-# LANGUAGE RankNTypes #-} | |
| {-# LANGUAGE ScopedTypeVariables #-} | |
| {-# LANGUAGE TypeFamilies #-} | |
| {-# LANGUAGE TypeOperators #-} |
Disclaimer 1: Type classes are great but they are not the right tool for every job. Enjoy some balance and balance to your balance.
Disclaimer 2: I should tidy this up but probably won’t.
Disclaimer 3: Yeah called it, better to be realistic.
Type classes are a language of their own, this is an attempt to document features and give a name to them.
| This is my short-ish tutorial on how to implement closures in | |
| a simple functional language: Foo. | |
| First, some boilerplate. | |
| > {-# LANGUAGE DeriveFunctor, TypeFamilies #-} | |
| > import Control.Applicative | |
| > import Control.Monad.Gen | |
| > import Control.Monad.Writer | |
| > import Data.Functor.Foldable |