Object State Transitions using the Mixology C extension

Stateology is an implementation of the State Pattern using the Mixology C extension.  Stateology follows closely the LSL State Pattern implementation and can support a similar syntax.

The following features are supported:

• Dynamic switching between states (mixing and unmixing modules)
• Optional state_entry() and state_exit() hooks for each state (automatically called upon state entry and exit)
• Support for nested states
• States are cleanly inherited by subclasses
• NO MAGIC! Stateology does not use any behind-the-scenes method aliasing nor does it make use of any hooks.

Use as in the following:

class Sample
    include Stateology

    state(:Happy) {
        def state_entry
            puts "entering Happy state"
        end

        def do_something
            puts "Pets a puppy"
        end

        def state_exit
            puts "exiting Happy state"
        end
    }

    state(:Angry) {
        def state_entry
            puts "entering Angry state"
        end

        def do_something
            puts "Kicks a puppy"
        end

        def state_exit
            puts "exiting Angry state"
        end
     }
end
 s = Sample.new

 # switch to Happy state
 s.state :Happy

 # (automatic call to state_entry) => "entering Happy state"

 s.do_something  #=> "Pets a puppy"

 # now switch to Angry state
 s.state :Angry

 # (automatic call to state_exit) => "exiting Happy state"
 # (automatic call to state_entry) => "entering Angry state"

 s.do_something  #=> "Kicks a puppy"

 # now switch back to no state
 s.state nil

 # (automatic call to state_exit) => "exiting Angry state"

Download and Gem

You can download Stateology here: http://github.com/banister/state-ology/tree/master

Or install the Gem: sudo gem install stateology

Tags: mixology, ruby, ruby finite state machine, ruby FSM, ruby states, state pattern, stateology