Simple Finite State Machines in GO

In computation theory, the Finite State Machine (FSM) are those machines that can have finite number of states at a given time. These machines are used in our daily life such as; vending machines, elevators, traffic lights etc. Not only in hardware these machines are used in software also...

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Learn more about finite state machines here

Inspired from @davidkpiano X-State library. (minimal finite state machine library in javascript) @xstate/fsm

Figure from xstate.js.org/viz/

Basic State Machine

machine := statemachine.Machine{
    ID:      "machine-1",
    Initial: "on",
    States: statemachine.StateMap{
        "on": statemachine.MachineState{
            On: statemachine.TransitionMap{
                "TOGGLE": statemachine.MachineTransition{
                    To: "off",
                },
            },
        },
        "off": statemachine.MachineState{
            On: statemachine.TransitionMap{
                "TOGGLE": statemachine.MachineTransition{
                    To: "on",
                },
            },
        },
    },
}
output := machine.Transition("TOGGLE")
// output will contain state of the machine
// after sending TOGGLE event

Parallel Machine

You can also build a parallel state machine, that bundles up multiple state machines together.

parallel := statemachine.ParallelMachine{
    Machines: statemachine.Machines{
        "machine-1": &machineOne,
        "machine-2": &machineTwo,
    },
    Subscribers: statemachine.ParallelSubscribers{
        // some state subscribers
    },
}

// Send machine-1 TOGGLE state  
next, err := parallel.Transition("machine-1.TOGGLE")

Checklist

• Implement basic finite state machine with transition
• Add condition cond function calling to get the output.
• Add multiple actions and call the function on state change.
• Add state change listeners.
• Support for parallel state machines.
• Implement Parallel State machines state listeners.