tonymorris

// see https://github.com/gseitz/Lensed

case class CoState[A, B](put: A => B, pos: A)

object CoState {
  type Store[A, B] = CoState[A, B]
}

// fused get/set
case class Lens[A, B](lens: A => CoState[B, A]) {

tonymorris

case class ReaderWriterStateT[R, W, S, F[_], A](
  run: (R, S) => F[(W, A, S)]
) {
  def map[B](f: A => B)(implicit F: Functor[F])
      : ReaderWriterStateT[R, W, S, F, B] =
    ReaderWriterStateT {
      case (r, s) => F.map(run(r, s)) {
        case (w, a, s) => (w, f(a), s)
      }
    }

tonymorris

class Functor f => Unzip f where
  unfzip ::
    f (a, b) 
    -> (f a, f b)

  unfzip3 ::
    f (a, b, c)
    -> (f a, f b, f c)
  unfzip3 x =
    let (a, bc) = unfzip (fmap (\(a', b', c') -> (a', (b', c'))) x)

tonymorris

trait Semigroup[A] {
  def op(a1: A, a2: A): A
}

trait Monoid[A] extends Semigroup[A] {
  def id: A
}

object EitherFilter {
  def filterR[A, B](e: Either[A, B])(p: B => Boolean)(implicit M: Monoid[B]): Either[A, B] =

tonymorris

case class Swizzler[A](swizzle: String => A) {
  def map[B](f: A => B): Swizzler[B] =
    Swizzler(f compose swizzle)

  def flatMap[B](f: A => Swizzler[B]): Swizzler[B] =
    Swizzler(s => f(swizzle(s)).swizzle(s))
}


object Swizzler {

tonymorris

trait Functor[F[_]] {
  def fmap[A, B](f: A => B): F[A] => F[B]
}

trait Extend[F[_]] extends Functor[F] {
  // coflatmap
  def extend[A, B](f: F[A] => B): F[A] => F[B]
}

trait Comonad[F[_]] extends Extend[F] {

tonymorris

trait Functor[F[_]] {
  def fmap[A, B](f: A => B): F[A] => F[B]
}

trait Extend[F[_]] extends Functor[F] {
  // coflatmap
  def extend[A, B](f: F[A] => B): F[A] => F[B]
}

trait Comonad[F[_]] extends Extend[F] {

tonymorris

class Semigroupoid cat where
  (<.>) ::
    cat a b
    -> cat b c
    -> cat a c

class Semigroupoid cat => Category cat where
  identity ::
    cat a a

tonymorris

case class Person(name: String, age: Int)

object Person

case class OtherPerson(name: String, age: Int)

object T {
  def ap[A, B, C](f: (A, B) => C)(a: A, b: B): C =
    f(a, b)

tonymorris

#!/bin/sh

set -e

# Base temporary work directory
TMP="/tmp"

# Glasgow Haskell Compiler version
GHCVERSION=7.0.4