Yasuyuki Abe yasuabe

関心：アジャイル開発、スクラム、オブジェクト指向、関数型言語、DDD

yasuabe / Chapter14.scala

Created December 15, 2017 19:13

ch14 change

	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 / Chapter16.scala

Last active December 15, 2017 21:59

ch15 mixed concurrencies - ch16 abstraction finally

	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 / RegisterAFP.sc

Created December 19, 2017 06:19

by writer monad

	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 / RegisterAFP2.sc

Created December 19, 2017 06:22

by state monad

	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 / RegisterAFP3.sc

Created December 19, 2017 06:23

by eff monad

	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 / RegisterAFP2_IO.sc

Created December 19, 2017 06:25

by io monad

	// 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 / RegisterAFP2_Free.sc

Created December 19, 2017 06:25

by free monad

	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 / RegisterAFP2_Akka.sc

Created December 19, 2017 06:26

by akka typed

	// 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 / ex01_package.scala

Created December 23, 2017 17:19

(A,A) =f=> (R,R) where f:A=>R

	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 / ex01_Prob.scala

Created December 23, 2017 18:12

Scala version of Prob Monad (from LYAHFGG)

	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)