How to access a Ruby Module method

I have a Ruby module for constants. It has a list of variables and one metho开发者_如何学Pythond which applies formatting.

I can't seem to access the method in this module. Any idea why?

If you include the module the method becomes an instance method but if you extend the module then it becomes a class method.

module Const
  def format
    puts 'Done!'
  end
end

class Car
  include Const
end

Car.new.format # Done!
Car.format # NoMethodError: undefined method format for Car:Class

class Bus
  extend Const
end

Bus.format # Done!
Bus.new.format # NoMethodError: undefined method format

module Foo
  def self.hello # This is a class method
    puts "self.hello"
  end

  def hello # When you include this module, it becomes an instance method 
    puts "hello"
  end
end

Foo.hello #=> self.hello

class Bar
  include Foo
end

Bar.new.hello #=> hello

Generally, with modules, these things should be happening :

• Autoload path in application.rb, add:

  config.autoload_paths += %W(#{config.root}/lib)
  

• Place module in /lib

• Include module with include NAMEOFMODULE

If the module name has an underscore like "game_engine", you need to use include GameEngine