Question

 class Bike
   attr_reader :gears

   def initialize(g = 5)
     @gears = g
   end
 end

class AnotherBike < Bike
  attr_reader :seats

  def initialize(g, s = 2)
    super(g)
    @seats = s
  end
end

Is it possible to create a AnotherBike instance ‘AnotherBike.new’
that will take default value for ‘gears’ from super when argument is not given?

so for e.g

my_bike = AnotherBike.new  
...
my_bike.gears #=> 5
my_bike.seats #=> 2

my_bike = AnotherBike.new(10)  
...
my_bike.gears #=> 10
my_bike.seats #=> 2

my_bike = AnotherBike.new(1,1)  
...
my_bike.gears #=> 1
my_bike.seats #=> 1

I am using Ruby 1.9.3.

Answer 1

You can change an order of args to make it little more elegant

class AnotherBike < Bike
  attr_reader :seats

  def initialize(s = 2, g = nil)
    g ? super(g) : super()
    @seats = s
  end
end

AnotherBike.new()
AnotherBike.new(4)
AnotherBike.new(4, 6)

to support your examples @Matzi answer will be ok