Understanding Ruby Modules: Prepend vs. Include

Introduction:

Module is a collection of constants, methods, classes, and variables in a container.

Modules implement the mixin facility

  module Animal
    def sound
      puts 'animal sound'
    end
  end

    class Dog
      include Animal 
    end

now we can access bark method

    Dog.new.sound # animal sound

you can overwrite the sound method in Dog class

  class Dog
    include Animal 

   def sound
      puts 'bark'
    end
  end

  Dog.new.sound # bark

what if we replace include to prepend

  class Dog
    prepend Animal 

   def sound
      puts 'bark'
    end
  end

  Dog.new.sound #animal sound, why I defined a sound method in a subclass?

although we have overwritten the sound method in Dog class we called it returned the module method because we need to understand the ancestries chains

what are the ancestries chains?
- the path of inheritance leading up to a given class or module

  class Dog
    include Animal 

   def sound
      puts 'bark'
    end
  end

  Dog.ancestors # [Dog Animal Object Kernel BasicObject]

  class Dog
    prepend Animal 

   def sound
      puts 'bark'
    end
  end

  Dog.ancestors # [Animal Dog Object Kernel BasicObject]

using prepend makes Animal Method be executed over The dog method itself and no longer able to overwrite it

Conclusion:

Ruby modules are a powerful feature for organizing and reusing code in Ruby programs.
Understanding how to define, include, and extend modules is essential for effective Ruby programming and code design.

Additional Resources:

Ahmed Abdelaal

Ahmed Abdelaal

Understanding Ruby Modules: Prepend vs. Include