Ruby - Modules 2020

Modules are a way of grouping together methods, classes, and constants. Modules give us two major benefits:

1. Modules provide a namespace and prevent name clashes.
2. Modules implement the mixin facility.

In this article, we'll learn how to use modules.

#!/usr/bin/ruby
# human.rb

module Human
   attr_accessor :name, :height, :weight
 
   def run
      puts self.name + " runs"
   end
end

Another module:

#!/usr/bin/ruby
# smart.rb

module Smart
   def act_smart
      return "E = mc^2"
   end
end

We we want to write regular Ruby file which needs the modules we created:

#!/usr/bin/ruby
# req.rb
# How to Modules

require_relative "human"
require_relative "smart"

module Animal
   def make_sound
      puts "Urrrr..."
   end
end

class Dog
   include Animal
end

mong = Dog.new
mong.make_sound

class Scientist
   include Human
   #prepend Smart  # prepend supposed to work v.2.1 but it's not.
   include Smart

   def act_smart
      return "Scientist: E=mc**2"
   end
end

ein = Scientist.new
ein.name = "Albert Einstein"

puts ein.name

ein.run

puts ein.name + " says " + ein.act_smart

Output:

$ ./req.rb
Urrrr...
Albert Einstein
Albert Einstein runs
Albert Einstein says Scientist: E=mc**2