Need a bit help on "module_function" method

rubyonrails-talk
1

The documentation is very straight forward and the mentioned example also cleared all the lines except the one mentioned inside **.

Creates module functions for the named methods. These functions may be called with the module as a receiver, and also become available as instance methods to classes that mix in the module. Module functions are copies of the original, and so may be changed independently. The instance-method versions are made private. *If used with no arguments, subsequently defined methods become module functions.*

module Mod   def one     "This is one"   end   module_function :one end class Cls   include Mod   def call_one     one   end end Mod.one #=> "This is one" c = Cls.new c.call_one #=> "This is one" module Mod   def one     "This is the new one"   end end Mod.one #=> "This is one" c.call_one #=> "This is the new one"

Please help me to understand what does mean by "If used with no arguments, subsequently defined methods become module functions."?

2

Please help me to understand what does mean by "If used with no arguments, subsequently defined methods become module functions."?

Okay got it now:-

module Party   module_function   def foo     "I am foo"   end   def bar     "I am bar"   end end

Party.foo # => "I am foo" Party.bar # => "I am bar"

3

That means you can use it as a means of saying "All the methods defined below are module functions":

Module M

  def foo   end

  module_function

  def bar   end

  def baz   end

end

and so you can then call M.bar and M.baz, but not M.foo.

This is identical to:

Module M   def foo;end   def bar;end   def baz;end   module_function :bar, :baz end

It is *also* identical to:

Module M   def foo;end   def self.bar; end   def self.baz; end end