template.rb

# Define the skeleton of an algorithm in an operation, deferring some
# steps to subclasses. Template methods lets subclasses redefine certain
# steps of an algorithm without changing the algorithm's structure

class Hero
  attr_reader :damage, :abilities

  def initialize
    @damage = damage_rating
    @abilities = occupation_abilities
  end

  def greet
    greeting = ["Hello"]
    greeting << unique_greeting_line
    greeting
  end

  def unique_greeting_line
    raise "You must define unique_greeting_line"
  end

  def damage_rating
    10
  end

  def occupation_abilities
    []
  end

  def attack
    "Atack dealing #{damage} damage"
  end
end

class Warrior < Hero
  def damage_rating
    15
  end

  def occupation_abilities
    [:strike]
  end

  def unique_greeting_line
    "Warrior is ready to fight!"
  end
end

class Mage < Hero
  def damage_rating
    7
  end

  def occupation_abilities
    [:magic_spell]
  end

  def unique_greeting_line
    "Mage is ready to make powerful spells!"
  end
end