Pallet Town: Ruby Modules, Mixins & Flying Pikachu?

If you’ve been working with Ruby for more than five minutes, you’ve probably heard about modules. They’re a great way to share behavior across multiple classes without getting tangled in inheritance chains that resemble an over-leveled Zubat spamming Confuse Ray.

But let’s make it real. Instead of talking about include and extend in the abstract, we’re going to build something solid—Pokémon abilities using modules. Let’s make sure that pesky Pikachu keeps his paws on the ground!

The Problem: Not Every Pokémon Can Fly

Let’s say we’re designing a simple Ruby class for our Pokémon. We might start with something like this:

class Pokemon
  attr_reader :name, :type

  def initialize(name, type)
    @name = name
    @type = type
  end

  def attack
    puts "#{@name} uses a basic attack!"
  end
end

pikachu = Pokemon.new("Pikachu", "Electric")
pikachu.attack # Pikachu uses a basic attack!

Cool, but here’s the issue: some Pokémon can fly, some can swim, and some can dig underground. These aren’t things that should be in every Pokémon’s base class because that would make zero sense—imagine a Snorlax trying to fly.

Modules, I Choose You!

Instead of bloating our Pokemon class with abilities that don’t apply to every Pokémon, we break them out into modules:

module Flyable
  def fly
    puts "#{@name} soars through the sky!"
  end
end

module Swimmable
  def swim
    puts "#{@name} dives into the water!"
  end
end

Now, let’s apply these abilities where they make sense.

class FlyingPokemon < Pokemon
  include Flyable
end

class WaterPokemon < Pokemon
  include Swimmable
end

Now to try it out!

pidgeot = FlyingPokemon.new("Pidgeot", "Flying")
pidgeot.fly # Pidgeot soars through the sky!

gyarados = WaterPokemon.new("Gyarados", "Water/Flying")
gyarados.swim # Gyarados dives into the water!

Why This is Better Than Inheritance Alone

class Gyarados < Pokemon
  include Flyable
  include Swimmable
end

gyarados = Gyarados.new("Gyarados", "Water/Flying")
gyarados.fly  # Gyarados soars through the sky!
gyarados.swim # Gyarados dives into the water!