Modules in Ruby

By IncludeHelp Last updated : December 03, 2024

Modules

In Ruby, modules are similar to classes but not exactly considered as classes. You cannot instantiate a module, which simply means that you cannot create objects of modules and provide memory to them. Modules are a collection of methods, classes, and constants. Any variable declared inside a module is treated as a constant and its value can never be changed in the future. With the help of modules, you can share the methods between two classes. You only need to include them in the classes and the methods of modules become accessible to the class.

Modules provide great help when you want to make use of the same method in different classes but also wants to escape from redefining them again and again.

Syntax to Create a Module

Now, let us understand the syntax of the module first which is given below:

module Module_name
  #code
end

You are supposed to use "module" keyword to define a module.

Example of a Module

Now, to have a better understanding of the concept, let us go through some of its examples which are specified below:

=begin
Ruby program to demonstrate implementation of module.
=end

module Student  
  Const = 100 
  
  def Student.names 
    puts "Your name is not available!"
  end
    
  def Student.address 
    puts "Your address is not available!"
  end
    
  def Student.education 
    puts "Education is not available!"
  end
  
end

puts Student::Const
 
Student.names
Student.address
Student.education

Output

100
Your name is not available!
Your address is not available!
Education is not available!

You can observe in the above code that we are creating a module named "Student". We have defined multiple methods. To make use of module constant, you will have to use :: operator amid module name and constant.

Using a Module Inside a Class

Now, let us see how we can use a module inside a class or you can say that how to achieve one of the main objectives of the module with the help of an example provided below:

=begin
Ruby program to demonstrate implementation of module.
=end

module Student  
  Const = 100 
  
  def names 
    puts "Your name is not available!"
  end
    
  def address 
    puts "Your address is not available!"
  end
    
  def education 
    puts "Education is not available!"
  end
  
end

class School
  include Student
  def gets
    puts"Welcome to the school!"
  end
end
 obj = School.new
 obj.education
 obj.address
 obj.names
 obj.gets

Output

Education is not available!
Your address is not available!
Your name is not available!
Welcome to the school!

In the above code, you can observe that we are creating a module named as Student. Then we are creating a class named as School. We are including the Student module in the School class with the help of "include" keyword. We have instantiated the School class and then have invoked the methods of objects as well as the methods of a class with the help of that object.

Ruby Multithreading

Ruby Mixins

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