What is the difference between modules and classes in Ruby?

What is the difference between modules and classes in Ruby?

In Ruby, classes are blueprints for creating objects, while modules are collections of methods and constants that can be mixed into classes.

Can you give me an example of how to use a module in Ruby?

Sure! You can define a module like this:

module Greeting
  def say_hello
    puts 'Hello!'
  end
end

Then, include it in a class:

class Person
  include Greeting
end

Now, instances of Person can use the say_hello method.

Are modules in Ruby similar to interfaces in other languages?

Not exactly. Modules can provide implementations, while interfaces typically only define method signatures. Ruby modules can be mixed into classes to share behavior.

When should I use a module instead of a class?

Use a module when you want to share reusable code across multiple classes without creating a hierarchy. Classes are for creating objects.