ruby-patterns

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class BoardBuilder
  def initialize(width, height)
    @board = Board.new
    @board.width = width
    @board.height = height
    @board.tiles = []
    @board.monsters = []
  end

  def add_tiles(n)
    n.times{ @board.tiles  Board Object
board = builder.board
puts board.width
# => 2
builder.add_tiles(3)
builder.add_monsters(2)
puts board.tiles.size
# => 3
puts board.monsters.size
# => 2

class Turn
  def initialize
    @commands = []
  end

  def run_command(command)
    command.execute
    @commands  110
turn.run_command(get_money)
puts hero.money
# => 10
turn.undo_command
puts hero.money
# => 0

class CompositeQuest
  def initialize
    @tasks = []
  end

  def  300

quest2 = Quest.new
quest2  600

class ItemDecorator
  def initialize(item)
    @item = item
  end
  # this needs to be delegated with other efective way
  def use
    @item.use
  end
end

class MagicItemDecorator  30
puts magic_item.description
# => Item Magic

masterpiece_item = MasterpieceItemDecorator.new(item)
puts masterpiece_item.price
# => 20
puts masterpiece_item.description
# => Item Masterpiece

# all next lines puts "do something"
item.use
magic_item.use
masterpiece_item.use

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class Party
  attr_reader :members
  def initialize(factory)
    @members = []
    @factory = factory
  end

  def add_warriors(n)
    n.times{ @members  5
puts party.members.count{ |member| member.class == "Mage" }
# => 2

…

class Parent
  attr_reader :first_name

  def initialize(first_name, gender)
    @first_name = first_name
    @gender = gender
  end
end

class Child  Robert
#    Susan
#    Lucas
#    James
#    Rose

module Observable
  attr_reader :observers

  def initialize(attrs = {})
    @observers = []
  end

  def add_observer(observer)
    @observers  6
puts hero.cursed?
# => true

…

class HeroFactory
  @@instance = nil

  def self.instance
    @@instance ||= HeroFactory.send(:new)
  end

  def create_warrior
    Warrior.new
  end

  def create_mage
    Mage.new
  end

  private_class_method :new
end

# Usage
factory = HeroFactory.instance
another_factory = HeroFactory.instance
puts factory == another_factory
# => true
HeroFactory.new
# => Raise Exception

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