Module Functions

gistfile1.rb

module ExampleModuleFunctions

  def self.use_class_method
    "module singleton class method"
  end

  def use_normal_method
    "normally included method"
  end

module_function

  def use_module_function
    "this is a module function"
  end

end

ExampleModuleFunctions.use_class_method
# => "module singleton class method"

ExampleModuleFunctions.use_module_function
# => "this is a module function"

obj = Object.new
obj.extend ExampleModuleFunctions
obj.use_normal_method
# => "normally included method"

obj.use_class_method
# => NoMethodError: undefined method `use_class_method'

obj.use_module_function
# => NoMethodError: private method `use_module_function' called

class Foo
  include ExampleModuleFunctions

  def delegate_to_module_function
    use_module_function
  end
end

foo = Foo.new
foo.use_normal_method
# => "normally included method"

foo.delegate_to_module_function
# => "this is a module function"

foo.use_module_function
# => NoMethodError: private method `use_module_function' called

foo.use_class_method
# => NoMethodError: undefined method `use_class_method'