MiloXia

import scala.language.higherKinds

object Conditions {
  //based on: An Introduction to Functional Programming Through Lambda Calculus
  trait BOOL {
    type body[e1 <: E, e2 <: E, E] <: E //select: (E, E) => E
  }
  trait TRUE extends BOOL {
    type body[e1 <: E, e2 <: E, E] = e1 //true = select_first
  }

MiloXia

import scala.language.higherKinds

import shapeless._
import shapeless.ops.coproduct.IsCCons
import shapeless.ops.hlist.IsHCons

object PolyFunctor extends App {
  trait TypeFunctor[F[_]] {
    def map[A, B](fa: F[A])(f: A => B): F[B]
    def pure[A](a: A): F[A] //for debug & test

MiloXia

import scala.language.higherKinds
import scalaz._, Scalaz._


object F_Algebra {
  //### F-Algebra
  //Fixed point of type constructor
  case class Fix[F[_]](f: F[Fix[F]])

  type Algebra[F[_], A] = Function[F[A], A] //a morphism from F(A) to A