Ruby Struct

A Struct is like a mini-class.

Circle = Struct.new(:radius) do
  PI = 3.14
  
  def area
    radius * radius * PI
  end


  def circumference
    2 * PI * radius
  end
end

circle = Circle.new(3)
circle.area            #=> 28.26
circle.circumference   #=> 18.84
circle.radius          #=> 3

Another example of a Struct:

ApiResponse = Struct.new(:status_code) do
  def success?
    status_code == 200 ? true : false
  end
end
response = ApiResponse.new(200)
response.status_code # => 200 
response.success?    # => true