state_machine

https://github.com/pluginaweek/state_machine

Ruby

Adds support for creating state machines for attributes on any Ruby class

StateMachine::Transition#rollback

Rolls back changes made to the object's state via this transition.  This
will revert the state back to the +from+ value.

== Example

  class Vehicle
    state_machine :initial => :parked do
      event :ignite do
        transition :parked => :idling
      end
    end
  end
  
  vehicle = Vehicle.new     # => #<Vehicle:0xb7b7f568 @state="parked">
  transition = StateMachine::Transition.new(vehicle, Vehicle.state_machine, :ignite, :parked, :idling)
  
  # Persist the new state
  vehicle.state             # => "parked"
  transition.persist
  vehicle.state             # => "idling"
  
  # Roll back to the original state
  transition.rollback
  vehicle.state             # => "parked"

Source | Google | Stack overflow

Edit

git clone [email protected]:pluginaweek/state_machine.git
cd state_machine
open lib/state_machine/transition.rb

Contribute

# Make a new branch
git checkout -b -your-name--update-docs-StateMachine--Transition-rollback-for-pr

# Commit to git
git add lib/state_machine/transition.rbgit commit -m "better docs for StateMachine::Transition#rollback"

# Open pull request
gem install hub # on a mac you can `brew install hub`
hub fork
git push <your name> -your-name--update-docs-StateMachine--Transition-rollback-for-pr
hub pull-request

# Celebrate!