seraphr

val dockerPublish = taskKey[Unit]("ダミーのタスク。本来sbt-native-packagerのやつ")
lazy val commonSettings = Def.settings(
  dockerPublish := {
    import java.time.LocalTime

    println(s"${LocalTime.now()} ${name.value} のpublish開始")
    // 並列で実行されるのがわかりやすいように、途中sleepする
    Thread.sleep(3000)
    println(s"${LocalTime.now()} ${name.value} のpublish終了")
  }

seraphr

> scala -Xlog-implicits
Welcome to Scala 2.12.6 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_172).
Type in expressions for evaluation. Or try :help.

scala> object A {
     |   import scala.language.implicitConversions
     |   implicit val int: Int = 1
     |   def a[A]: A = ???
     |   implicit def asString[A](implicit i: Int): Long => A = _ => a[A]
     |

seraphr

scala> class Hoge {
     |   def m1: this.type = this // OK
     |   def m2: this.type = new Hoge // NG
     | }
<console>:9: error: type mismatch;
 found   : Hoge
 required: Hoge.this.type
         def m2: this.type = new Hoge // NG

seraphr

2017/06/08 06:49
ブックマーク数100以上
連載中
文字数10万文字以上

all novel count = 30060
unique novel count = 12320
filtered novel count = 2759

順位	URL	文字数	ポイント評価	ブックマーク数	(ポイント評価 / ブックマーク数)	title	keyword

seraphr

import scala.language.experimental.macros
import scala.reflect.macros.whitebox.Context

/**
 */
object MethodsMacro {
  def apply[T]: Seq[String] = macro genMethods[T]

  def genMethods[T: c.WeakTypeTag](c: Context): c.Tree = {

seraphr

import upickle.{Js, Api}

trait UseUpickle {
  val mJsonApi: upickle.Api

  def write[T: mJsonApi.Writer](a: T): String = mJsonApi.write(a)
  def writeHoge(aHoge: Hoge): String = {
    import mJsonApi._
    mJsonApi.write(aHoge)

seraphr

case class State[S, +A](run: S => (A, S)) {
  def map[B](f: A => B): State[S, B] = State { s0 =>
    val (a, s1) = run(s0)
    (f(a), s1)
  }

  def map2[B, C](that: State[S, B])(f: (A, B) => C): State[S, C] = State { s0 =>
    val (a, s1) = this.run(s0)
    val (b, s2) = that.run(s1)
    (f(a, b), s2)

seraphr

trait RNG {
  def nextInt: (Int, RNG)
}

object RNG {
  case class Simple(seed: Long) extends RNG {
    def nextInt: (Int, RNG) = {
      val newSeed = (seed * 0x5DEECE66DL + 0xBL) & 0xFFFFFFFFFFFFL // `&` is bitwise AND. We use the current seed to generate a new seed.
      val nextRNG = Simple(newSeed) // The next state, which is an `RNG` instance created from the new seed.
      val n = (newSeed >>> 16).toInt // `>>>` is right binary shift with zero fill. The value `n` is our new pseudo-random integer.

seraphr

def unfold[A, S](s: S)(f: S => Option[(A, S)]): Stream[A] = f(s) match {
  case Some((a, s1)) => a #:: unfold(s1)(f)
  case _ => Stream.empty[A]
}

def fibs: Stream[Int] = 0 #:: 1 #:: unfold((0, 1)) {
  case (n0, n1) =>
    val n2 = n0 + n1
    Option((n2, (n1, n2)))
}

seraphr

def foldRight[A, B](s: Stream[A])(z: => B)(f: (A, => B) => B): B = s match {
  case x #:: xs => f(x, foldRight(xs)(z)(f))
  case _ => z
}

def headOptionViaFoldRight[A](s: Stream[A]): Option[A] = foldRight(s)(None: Option[A]) {
  (e, acc) => Some(e)
}

def map[A, B](s: Stream[A])(f: A => B): Stream[B] = foldRight(s)(Stream.empty[B]) {