stately.define = function (callback) {
var machine = new EventEmitter ()
, privateState = null
, validTransition = function (from, to) {
var allowedTransitions = machine.transitions [from]
if (from === to) return true
else if (typeof allowedTransitions === 'undefined')
machine.emit('error', new Error ("attempting to transition from unknown state: " + from))
else if (typeof allowedTransitions === 'string') return to === allowedTransitions
else return allowedTransitions.indexOf (to) !== -1
}
machine.transition = function (desiredState) {
var stateBefore = privateState
if (validTransition (privateState, desiredState)) {
machine.emit ('beforeTransition', privateState, desiredState)
machine.emit ('beforeTransition:' + privateState + ":" + desiredState)
machine.emit ('beforeExit:' + privateState)
machine.emit ('beforeEnter:' + desiredState)
privateState = desiredState
machine.emit ('afterExit:' + stateBefore)
machine.emit ('afterEnter:' + desiredState)
machine.emit ('afterTransition:' + stateBefore + ":" + desiredState)
machine.emit ('afterTransition', stateBefore, desiredState)
return true
} else {
machine.emit ('illegalTransition', privateState, desiredState)
machine.emit ('illegalTransition:' + privateState + ':' + desiredState)
return false
}
}
'illegalTransition beforeTransition afterTransition'.split(" ").forEach (function (evt) {
machine [evt] = function () {
if (arguments.length === 1) machine.addListener (evt, arguments [0])
else machine.addListener (evt + ":" + arguments [0] + ":" + arguments [1], arguments [2])
}
})
'beforeExit beforeEnter afterExit afterEnter'.split(" ").forEach (function (evt) {
machine [evt] = function (state, fn) { machine.addListener (evt + ":" + state, fn) }
})
machine.start = function () {
privateState = machine.startState
return true
}
machine.__defineSetter__ ("state", function (desiredState) { machine.transition (desiredState) })
machine.__defineGetter__ ("state", function () { return privateState })
callback (machine)
return machine
}