Ruby Module Method Access

Question

I have a ruby module for constants. It has a list of variables and 1 method which applies formatting. I can\'t seem to access the method in this module. Any idea why?

Answer 1

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

Answer 2

Generally, with modules, these things should be happening :

-> Autoload path in application.rb, add line :

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

-> Place module in /lib

-> Include module with 'include NAMEOFMODULE'

(If module has an underscore like game_engine, you need to 'include GameEngine')

Answer 3

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