ruby method overwrite (monkey patch pattern)

alias_method.rb

class Country
  def home
    'Japan'
  end
end

# -----

module ExtendContry
  def new_home
    "Fukuoka Japan"
  end
end

class Country
  include ExtendContry
  alias_method :old_home, :home
  alias_method :home, :new_home
end

Country.new.home # => Fukuoka Japan
Country.new.old_home # => Japan
Country.ancestors
# => [Country, ExtendContry, Object, PP::ObjectMixin, Kernel, BasicObject]

delegation.rb

class Country
  def home
    'Japan'
  end
end

# ----

class DelegateCountry < DelegateClass(Country)
  def initialize(country)
    super
  end

  def home
    "Fukuoka #{super}"
  end
end

contry = DelegateCountry.new(Country.new)
contry.home # => Fukuoka Japan

include.rb

class Contry
  def home
    'Japan'
  end
end

# -----

module ExtendContry
  def home
    "Fukuoka #{super}"
  end
end

class Country
  include ExtendContry
end

Country.new.home # => Japan
Country.ancestors
# => [Country, ExtendContry, Object, PP::ObjectMixin, Kernel, BasicObject]

inheritance.rb

class Country
  def home
    'Japan'
  end
end

# -----

class Prefecture < Country
  alias_method :old_home, :home
  def home
    "Fukuoka #{super}"
  end
end

Prefecture.new.home # => Fukuoka Japan
Prefecture.new.old_home # => Japan
Prefecture.ancestors
# => [Prefecture, Country, Object, PP::ObjectMixin, Kernel, BasicObject]

instance_method.rb

class Country
  def home
    'Japan'
  end
end

# ----

class Prefecture
  def home
    method = Country.instance_method(:home)
    "Fukuoka #{method.bind(Country.new).call()}"
  end
end

Prefecture.new.home # Fukuoka Japan

prepend.rb

class Country
  def home
    'Japan'
  end
end

module ExtendCountry
  def home
    "Fukuoka #{super}"
  end
end

class Prefecture < Country
  prepend ExtendCountry
end

Prefecture.new.home # => Fukuoka Japan
Country.new.home # => Japan
refecture.ancestors
# => [ExtendCountry, Prefecture, Country, Object, PP::ObjectMixin, Kernel, BasicObject]