rirakkumya

//少人数スタイル
Some(140000) map (_ + 5000) map (_ - 80000)

//多人数スタイル
val rentSupport:Int => Int = _ + 5000
val dormFee:Int => Int = _ - 80000
val salaryCalc = rentSupport andThen dormFee
Some(140000) map salaryCalc

rirakkumya

trait サラダ圏 {
  //対象を定義
  sealed trait Salad
  //マヨサラダ
  case class MaSalad(sa: Salad) extends Salad
  //ツナサラダ
  case class TuSalad(sa: Salad) extends Salad
  //ツナマヨサラダ
  case class TuMaSalad(sa: Salad) extends Salad

rirakkumya

// ネタ元：
// 関手的データモデル入門 2：統一的に制約を書く方法
// http://d.hatena.ne.jp/m-hiyama/20130218/1361145879

//http://www.chimaira.org/img3/funcdata-sample-2.gif
object FunctorialDataModel{
  type Employee = Employee.EmployeeInfo
  type EmployeeNum = Int
  object Employee {
    case class EmployeeInfo(num: Int, office: Office)

rirakkumya

// ネタ元：
// 衝撃的なデータベース理論・関手的データモデル 入門
// http://d.hatena.ne.jp/m-hiyama/20130211/1360577040

//データ保持用
object Strage {
  trait Strage[A] {
    def get: A
  }
}

rirakkumya

/*
 概要：入力されたCSVの契約種別コードに従って計算を行い、結果を出力する
 仕様：
 CSV入力パターン： [名前],[契約種別コード(A or B or C)],[基本料金],[使用量1段階],[使用量2段階]
   ※文字列はクォート無し
   sample: "foo,A,3000,,","bar,B,1000,200,","foobar,C,1000,200,300"
 契約種別コード別料金計算仕様:
   A: 基本料金
   B: 基本料金 + 使用量１段階 * 0.1
   C: 基本料金 + 使用量１段階 * 0.02 + 使用量2段階 * 0.3

rirakkumya

def toDate[A:DateMagnet](x:A) = implicitly[DateMagnet[A]].convert(x)
 
trait DateMagnet[A]{
  type Result
  def convert(x:A):Result
}
 
object DateMagnet {
  implicit def fromInt = new DateMagnet[(Int, Int, Int)] {
    type Result = java.util.Calendar

rirakkumya

Caused by: java.lang.RuntimeException: cannot serialize an immutable.HashSet where all items have the same 32-bit hash code
        at scala.sys.package$.error(package.scala:27)
        at scala.collection.immutable.HashSet$HashSetCollision1.writeObject(HashSet.scala:168)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:601)

rirakkumya

package controllers

import play.api._
import play.api.mvc._

import EA._

object Application extends Controller {
  implicit def either2Bind(s:Either[String,Int]) = new Bind(s)
  implicit def int2Bind(x:Int) = new Bind[String,Int](Right(x))

rirakkumya

def f[a] = (d:List[Either[Throwable,a]]) => 
  d.collect{case Left(x) => x}.headOption.toLeft(d.map{case Right(x) => x})

scala> Some(List(Right("4"),Right("3"))) map f
res11: Option[Product with Either[Throwable,List[java.lang.String]] with Serializable] = Some(Right(List(4, 3)))

scala> Some(List(Right("4"),Left(new RuntimeException),Right("3"))) map f
res12: Option[Product with Either[Throwable,List[java.lang.String]] with Serializable] = Some(Left(java.lang.RuntimeException))

scala> Some(List(Right("4"),Left(new RuntimeException("a")),Right("3"),Left(new RuntimeException("b")))) map f

rirakkumya

scala> val l = Left(3)
l: Left[Int,Nothing] = Left(3)

scala> val r = Right(3)
r: Right[Nothing,Int] = Right(3)

scala> def calc = (x:Either[Int,Int]) => x.right.map(_ + 2).left.map(_ * 2).right.map(_ + 3)
culc: Either[Int,Int] => Product with Either[Int,Int] with Serializable

scala> calc(r)