KamilLelonek

[1] (pry) main: 0> default_array = [];
[2] (pry) main: 0> my_hash = Hash.new default_array;
[3] (pry) main: 0> my_hash[:hobbies] << 'dancing';
[4] (pry) main: 0> my_hash[:skills]  << 'php';
[5] (pry) main: 0> my_hash[:hobbies] == my_hash[:skills]
=> true
[6] (pry) main: 0> my_hash[:hobbies] == default_array
=> true
[7] (pry) main: 0> default_array
=> ["dancing", "php"]

KamilLelonek

[1] (pry) main: 0> my_hash = Hash.new { |hash, key| hash[key] = [] }
=> {}
[2] (pry) main: 0> my_hash[:hobbies] << 'swimming';
[3] (pry) main: 0> my_hash[:skills]  << 'java';
[4] (pry) main: 0> my_hash[:hobbies]
=> ["swimming"]
[5] (pry) main: 0> my_hash[:hobbies].object_id
=> 70144893987080
[6] (pry) main: 0> my_hash[:skills]
=> ["java"]

KamilLelonek

import scala.language.reflectiveCalls
import scala.language.postfixOps
import scala.reflect.Manifest
import scala.reflect.ClassTag

def |[T: ClassTag](x: T*) = new { def | = x.toArray }

val a = |(1, 2, 3)|
val b = |("a", "b", "c")|
val c = |(true, false)|

KamilLelonek

class DoSomeAction
  def initialize(dependency_injection_arguments)
    # ...
  end
  
  def call(optional_arguments)
    # ...
  end
  
  private

KamilLelonek

scala> import scala.collection.JavaConverters._
import scala.collection.JavaConverters._

scala> scalaList.asJava
res11: java.util.List[Int] = [1, 2, 3]

KamilLelonek

scala> import scala.collection.JavaConversions._
import scala.collection.JavaConversions._

scala> val javaList: java.util.List[Int] = scalaList
javaList: java.util.List[Int] = [1, 2, 3]

KamilLelonek

  def startpakkerCountForTelenor = startpakkerCount(Brands.Telenor)
  def startpakkerCountForCBB     = startpakkerCount(Brands.CBB)
  def startpakkerCountForOne     = startpakkerCount(Brands.One)
  def startpakkerCountForColour  = startpakkerCount(Brands.Colour)

  private def startpakkerCount(brand: Brand) = startpakkerForBrand(brand) match {
    case None       => None
    case Some(list) => Some(list.size)
  }

KamilLelonek

class ClientsController < ActionController::API
  def update_registration_number
    update_registration_number_service.(registration_number)
    render_success
  rescue UpdateRegistrationNumber::RegistrationNumberAlreadyExist
    render_error
  end
  # ...
end

KamilLelonek

class CarDealer
  def sell_car(client_id, car_id)
    # queries
    client = find_client(client_id)
    car    = find_car(car_id)
    
    # services
    oder_car_for_client(car, client)
    prepare_an_invoice(car, client)
    deliver_car(car, client)

KamilLelonek

require 'benchmark/ips'

def rescue_exception(divider)
  1 / divider
rescue ZeroDivisionError
end

def without_rescue(divider)
  1 / divider
end