output.txt

state: A
toggled: B
toggled: A
toggled: B
--------------
state: A
cycle: B
cycle: C
cycle: D
cycle: E
cycle: A
cycle: B
cycle: C
cycle: D

toggle_state.rb

# See: smart javascript state toggle
# https://coderwall.com/p/ufl1wa
class State
  attr_reader :state
  def initialize
    @toggle = {'A' => 'B', 'B' => 'A'}
    @state = 'A'
  end

  def toggle
    @state = @toggle[@state]
  end
end

class Cycle
  attr_reader :state

  def initialize
    @cycle = %w(A B C D E)
    @state = 'A'
  end

  def cycle
    @state = (@cycle = @cycle.rotate).first
  end
end

s = State.new
puts "state: #{s.state}"
3.times do
  puts "toggled: #{s.toggle}"
end

puts '--------------'

c = Cycle.new
puts "state: #{c.state}"
8.times do
  puts "cycle: #{c.cycle}"
end