yasuabe

package fp_tdd

import cats.Apply
import cats.syntax.apply._
import org.scalacheck.Prop.forAll
import org.scalacheck.{Arbitrary, Gen, Properties}

object Chapter14 extends Properties("Ch14") {
  // ======== TODO ========
  // $5 + 10 CHF = $10 if rate is 2:1

yasuabe

package fp_tdd

import cats.Apply
import cats.syntax.apply._
import org.scalacheck.Prop.forAll
import org.scalacheck.{Arbitrary, Gen, Properties}

object Chapter16 extends Properties("ch16") {
  // ======== TODO ========
  // ======== DONE ========

yasuabe

import cats.data.Writer
import cats.instances.vector._
import cats.syntax.writer._

case class CashRegister(total: Int) {
  def addCash(toAdd: Int) = CashRegister(total + toAdd)
}
type Purchase = CashRegister => CashRegister
def makePurchase(amount: Int): Purchase = (r: CashRegister) => {
  println(s"Purchase in amount: $amount")

yasuabe

import cats.data.State

case class CashRegister(total: Int) {
  def addCash(toAdd: Int) = CashRegister(total + toAdd)
}
type Purchase = CashRegister => CashRegister
def makePurchase(amount: Int): Purchase = (r: CashRegister) => {
  println("Purchase in amount: " + amount)
  r addCash amount
}

yasuabe

import cats.data.{State, Writer}
import org.atnos.eff._
import org.atnos.eff.state._
import org.atnos.eff.writer._
import org.atnos.eff.syntax.all._

case class CashRegister(total: Int) {
  def addCash(toAdd: Int) = CashRegister(total + toAdd)
}
type Purchase = CashRegister => CashRegister

yasuabe

// program 中のregisterの持ち回りを避ける

import cats.data.StateT
import cats.effect.IO

case class CashRegister(total: Int) {
  def addCash(toAdd: Int) = CashRegister(total + toAdd)
}
type Purchase = CashRegister => IO[CashRegister]
def makePurchase(amount: Int): Purchase = (r: CashRegister) => for {

yasuabe

import cats.data.StateT
import cats.effect.IO
import cats.free.Free
import cats.free.Free.liftF
import cats.{Id, ~>}
import cats.instances.vector._
import cats.syntax.foldable._

sealed trait Console[A]
case class   PrintLn(s: String) extends Console[Unit]

yasuabe

// program 中のregisterの持ち回りを避ける

import akka.typed._
import akka.typed.scaladsl.Actor
import akka.typed.scaladsl.Actor.immutable
import cats.data.{ReaderT, WriterT}
import cats.effect.IO
import cats.instances.vector._

trait Command

yasuabe

package object ex01 {
  implicit class T2mapper[A](val t: (A, A)) extends AnyVal {
    def map[R](f: A => R): (R, R) = (f(t._1), f(t._2))
    def foldMap[R, B](f: A => R, g: (R, R) => B): B = g.tupled(t map f)
  }
}

yasuabe

object ProbInstances {
  implicit def probMonad: Monad[Prob] = new Monad[Prob] {
    def flatMap[A, B](pa: Prob[A])(f: A => Prob[B]): Prob[B] = pa flatMap f

    def tailRecM[A, B](a: A)(f: A => Prob[Either[A, B]]): Prob[B] = {
      val buf = List.newBuilder[(B, Rational)]
      @tailrec def go(pes: List[(Prob[Either[A, B]], Rational)]): Unit = pes match {
        case (Prob(e :: es), r0) :: tail => e match {
          case (Right(b), r) => buf += (b -> r * r0) ; go(Prob(es) -> r0 :: tail)
          case (Left(a2), r) => go(f(a2) -> r :: Prob(es) -> r :: tail)