Moody: An implementation of the State Pattern in ruby
This is an object-oriented way to represent Finite State Machines, where an object can change its behavior at runtime, depending on its internal state.
If you want more information about this pattern, read the explanation by SourceMaking.
For a stupid example of how you would use this, here is a traffic light:
class Stop < Moody::State def color "red" end def next sleep 3 switch_to Go end def enter # turn on camera tu see who crosses on a red light end def leave # turn off camera end end class Go < Moody::State def color "green" end def next sleep 2 switch_to Caution end end class Caution < Moody::State def color "yellow" end def next sleep 1 switch_to Stop end end class TrafficLight extend Moody::Context initial_state Stop delegate_to_state :color, :next end traffic_light - TrafficLight.new loop do puts traffic_light.color traffic_light.next end
As you can see from the example above, Moody also provides callbacks when
entering and leaving a state. If your state classes define instance methods
leave, then they will be called at the appropriate times.
This is a reimplementation of the State Pattern gem by Daniel Cadenas. Check out his implementation at his repository.
gem install moody
- Send a pull request.
- Small, atomic commits, please.
- Make sure to add tests.
- Bonus points if you add features on topic branches.
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