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

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