Comparison between state_machine and micromachine.

fsm.rb

require "state_machine"
require "micromachine"
require "benchmark"

module SM
  class Vehicle
    state_machine :alarm_state, :initial => :active, :namespace => "alarm" do
      event :enable do
        transition all => :active
      end

      event :disable do
        transition all => :off
      end

      state :active, :value => 1
      state :off, :value => 0
    end
  end
end

module MM
  class Vehicle
    attr :alarm_state

    def initialize
      @alarm_state = 1
    end

    def alarm
      @alarm ||= begin
        MicroMachine.new(:active).tap do |fsm|

          # Transitions.
          fsm.when(:enable,   :off => :active)
          fsm.when(:disable,  :active => :off)

          # Callbacks.
          fsm.on(:active) { @alarm_state = 1 }
          fsm.on(:off)    { @alarm_state = 0 }
        end
      end
    end

    def alarm_state_name
      alarm.state
    end

    def can_disable_alarm?
      alarm.trigger?(:disable)
    end

    def disable_alarm
      alarm.trigger(:disable)
    end
  end
end

scope do
  test "state_machine" do
    vehicle = SM::Vehicle.new
    assert_equal 1, vehicle.alarm_state
    assert_equal :active, vehicle.alarm_state_name
    assert_equal true, vehicle.can_disable_alarm?
  end

  test "micromachine" do
    vehicle = MM::Vehicle.new
    assert_equal 1, vehicle.alarm_state
    assert_equal :active, vehicle.alarm_state_name
    assert_equal true, vehicle.can_disable_alarm?
  end
end

puts

Benchmark.bm(14) do |bm|
  bm.report("state_machine:") do
    10000.times do
      vehicle = SM::Vehicle.new
      vehicle.alarm_state
      vehicle.alarm_state_name
      vehicle.can_disable_alarm?
      vehicle.disable_alarm
    end
  end

  bm.report("micromachine:") do
    10000.times do
      vehicle = MM::Vehicle.new
      vehicle.alarm_state
      vehicle.alarm_state_name
      vehicle.can_disable_alarm?
      vehicle.disable_alarm
    end
  end
end

# :!cutest fsm.rb
# ......
#                      user     system      total        real
# state_machine:   2.820000   0.000000   2.820000 (  2.824512)
# micromachine:    0.260000   0.000000   0.260000 (  0.269632)