Ruby Fundamental - Alias para métodos em Ruby

alias_metodos_01.rb

names = ["Akira", "Fernando", "Jose"]
names.length # => 3
names.size   # => 3

alias_metodos_02.rb

class MyClass1
  def do_something
    "Doing..."
  end

  alias_method :make_something, :do_something
end

m1 = MyClass1.new
m1.do_something   # => "Doing..."
m1.make_something # => "Doing..."

alias_metodos_03.rb

class MyClass2
  def do_something
    "Doing..."
  end

  alias_method :do_something_original, :do_something

  def do_something
    "#{do_something_original} And doing more here..."
  end
end

m2 = MyClass2.new
m2.do_something # => "Doing... And doing more here..."

alias_metodos_04.rb

# You didn't write this code
class ExternalClass
  def some_number
    456 # Just to exemplify
  end
end

# You wrote this code
class ExternalClass
  alias_method :some_number_original, :some_number

  def some_number
    some_number_original + 100
  end
end

external = ExternalClass.new
external.some_number # => 556

alias_metodos_05.rb

# You didn't write this code
class ExternalClass
  def some_number
    456 # Just to exemplify
  end
end

# You wrote this code
module SomeModule
  def self.included(base)
    base.class_eval do
      alias_method :some_number_original, :some_number

      def some_number
        some_number_original + 100
      end
    end
  end
end

e1 = ExternalClass.new
e1.some_number # => 456

ExternalClass.send(:include, SomeModule)
e2 = ExternalClass.new
e2.some_number # => 556