jyrimatti

#! /usr/bin/env nix-shell
#! nix-shell -i runghc -p "haskellPackages.ghcWithPackages(p: with p; [type-level-sets])"
#! nix-shell -I nixpkgs=channel:nixos-18.03


{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE FlexibleInstances #-}

jyrimatti

#! /usr/bin/env nix-shell
#! nix-shell -i bash -p "haskellPackages.ghcWithPackages(p: with p; [profunctors mtl lens])"
ghci <<---EOF
:set +m
:set -XRank2Types
:set -XScopedTypeVariables

{-# LANGUAGE Rank2Types, ScopedTypeVariables #-}
import Data.Tuple (swap)
import Data.Monoid (First(..), getFirst, (<>))

jyrimatti

Verifying that +jyrimatti is my blockchain ID. https://onename.com/jyrimatti

jyrimatti

Keybase proof

I hereby claim:

• I am jyrimatti on github.
• I am jyrimatti (https://keybase.io/jyrimatti) on keybase.
• I have a public key whose fingerprint is 38E6 FC6A C104 7CEC 71CE 71E7 1959 B8A4 F22F EC94

To claim this, I am signing this object:

jyrimatti

{-# LANGUAGE TupleSections #-}
module Main where

-- hide the-dot to use it from Control.Category
import Prelude hiding ((.))
import Control.Category
import Control.Monad ((<=<))
import Control.Comonad.Env
import Control.Arrow
import Data.Profunctor

jyrimatti

-- build with cabal file:

-- name: aeson-ex
-- version: 0.1
-- build-type: Simple
-- 
-- executable aeson_ex
--   hs-source-dirs:  src
--   main-is:         Main.hs
--   build-depends:   base >= 4,

jyrimatti

38E6 FC6A C104 7CEC 71CE 71E7 1959 B8A4 F22F EC94

jyrimatti

// These should already exist in a standard library or similar
trait Showable[T] {
  val show: T => String
}
trait StandardShowables {
  implicit object StringIsShowable extends Showable[String] {
    val show = (a: String) => a
  }
  implicit object BooleanIsShowable extends Showable[Boolean] {
    val show = (a: Boolean) => a.toString