Instance variable reference from tail recursive call

tco_ivar.rb

require "tco_method"

class TCOInstance
  extend TCOMethod::Mixin

  attr_reader :tco_cycles

  def initialize
    @tco_cycles = 0
  end

  def tco_instance_var_referrer(n, acc = 1)
    @tco_cycles += 1
    n < 2 ? acc : tco_instance_var_referrer(n - 1, n * acc)
  end
  tco_method :tco_instance_var_referrer
end

x = TCOInstance.new
puts x.tco_instance_var_referrer(10000).to_s.length
puts x.tco_cycles

# => 35660
# => 10000