takkkun

case class JsonRpcBody[P <: Product](jsonrpc: String, method: String, params: P, id: String)

case class SampleParams(_1: String, _2: Int) extends Product2[String, Int]

// JsonRpcBody[SampleParams] にデコードするためには、DecodeJson[JsonRpcBody[SampleParams]] を
// 定義する必要がある。しかし、SampleParams 以外にも増えるのは予想され、その度に DecodeJson[JsonRpcBody[OtherParams]] などを
// 書くと大変めんどう。params の解釈の仕方が違うだけなのに、jsonrpc, method, id の部分も解釈しなきゃだし。
// と言うわけで以下のように書く。

implicit def jsonRpcBodyDecodeJson[P <: Product](implicit paramsDecodeJson: DecodeJson[P]): DecodeJson[JsonRpcBody[P]] =

takkkun

import user
import message

object Main {
  def main(args: Array[String]) {
    import MessageSender._
    
    val natsuki = User("Natsuki Ando")
    val sakura = User("Sakura Domyoji")
    

takkkun

// IDみたいな仕組みがあって

trait Identifier[A] {
  val value: A
}

case class UserId(value: UUID) extends Identifier[UUID]

case class GroupId(value: UUID) extends Identifier[UUID]

takkkun

object Main {
  implicit class Capping[+A](value: A) {
    def cap[B >: A](limit: B)(implicit ordering: Ordering[B]): B = {
      if (ordering.lteq(value, limit)) value else limit
    }
  }

  def main(args: Array[String]) {
    println( 99.cap(100)) // =>  99
    println(101.cap(100)) // => 100

takkkun

class Violation(message: String)

class Funny[V](value: V) {
  def validateWith(validator: Validator[V]): Validity[V] = validator(value)
}

object Funny {
  def apply[V](value: V): Funny[V] = new Funny(value)
}

takkkun

set :unicorn_config_path, -> { current_path.join('config', 'unicorn.rb') }
set :unicorn_pid_path,    -> { current_path.join('tmp', 'pids', 'unicorn.pid') }
set :unicorn_env,         -> { fetch(:rails_env) || fetch(:stage) }

SSHKit.config.command_map[:unicorn_stop]    = 'kill -QUIT'
SSHKit.config.command_map[:unicorn_restart] = 'kill -USR2'

namespace :deploy do

  def unicorn_running?

takkkun

trait Expression {
  def +(right: Expression) = Addition(this, right)
  def *(right: Expression) = Multiplication(this, right)
  def **(right: Expression) = Exponential(this, right)
}

object Expression {
  implicit def intToConst(value: Int) = Const(value)
}

takkkun

var Color = function() {
  if (arguments.length == 1)
    [this.r, this.g, this.b] = Color.parse(arguments[0]);
  else if (arguments.length == 3)
    [this.r, this.g, this.b] = arguments;
  else
    throw 'invalid number of arguments, takes one or three arguments';
};

Color.parse = function(color) {

takkkun

class User < ActiveRecord::Base
  attr_accessor :current_phase
  
  def self.thereafter(phase)
    -> do
      current_phase.nil? or current_phase >= phase
    end
  end
  
  validates :email, presence: true, if: thereafter(1)

takkkun

module Definable
  def self.redefine(object, method_name, &process)
    original_method = object.method(method_name)

    object.define_singleton_method(method_name) do |*args, &block|
      process[*args, &block]
      original_method[*args, &block]
    end
  end