struct_example.rb

#Struct.new returns a class object that has attributes that you pass in
Car = Struct.new(:wheels, :rpm) #Car is a Class object that has attributes *wheels* & *rpm* now

porsche = Car.new(4,1600)

#Since Struct.new is basically an expression returning a Class object - even the following would work

class Car < Struct.new(:wheels,:rpm)
end

#Finally Struct.new method also takes a block letting you define instance methods for the returned Class object

Car = Struct.new(:wheeels, :rpm) do
  def to_s
    puts "#{self} has #{wheels} wheels with an rpm of #{rpm}"
  end
end