statemachine.lua

--[[
    statemachine.lua
    Copyright (c) 2013 Erin Lin
    erinylin.blogspot.com
    Licensed under the MIT license.

    Usage:
    local sm = require("statemachine")

    local process = sm.new(function(self, time)
        self:sleep(100)
        print("hello") 
        self:sleep(100)
        print("hehe...")
        self:sleep(100)
        print("end")
    end)

    process:run()

    local process1 = sm.new(function(self, time)
        local txt = display.newText( "Press Me", display.contentCenterX, display.contentCenterY, native.systemFont, 32)
        txt:addEventListener("touch", function(evt)
            self:continue()
        end)
        self:waiting()
        txt.text = "Hello!"
        self:sleep(200)
        txt.text = "Bye Bye!"
    end)
     
    process1:run()
]]--
local StateMachine = {}
local StateMachine_mt = { __index = StateMachine }

local coroutine = {
    yield = coroutine.yield,
    resume = coroutine.resume,
    create = coroutine.create,
    status = coroutine.status
}

function StateMachine:sleep(msec)
    self._wakeup = system.getTimer() + msec
    while self._wakeup > 0 do
        coroutine.yield()
    end
end

function StateMachine:enterFrame(event)
    if self._wakeup > 0 then
        if event.time > self._wakeup then
            self._wakeup = 0
        end
    else
        local state = coroutine.status(self._co)
        if state == "suspended" then
            coroutine.resume(self._co, self)
        elseif state == "dead" then
            if self._isLoop then
                self._co = coroutine.create( self._callback )
            else
                Runtime:removeEventListener("enterFrame", self)
                self._co = nil
            end
        end
    end
end

function StateMachine:pause()
    self._stopTime = system.getTimer()
    Runtime:removeEventListener("enterFrame", self)
end

function StateMachine:resume()
    if self._co then
        if self._wakeup > 0 then
            self._wakeup = self._wakeup + system.getTimer() - self._stopTime
        end
        Runtime:addEventListener("enterFrame", self)
    else
        self:run()
    end
end
-- you can loop this.
function StateMachine:run(isLoop)
    self._isLoop = isLoop
    if not self._co then
        self._wakeup = 0
        self._stopTime = 0
        Runtime:addEventListener("enterFrame", self )
        self._co = coroutine.create( self._callback )
    end
end

function StateMachine:isRunning()
    return self._co ~= nil
end

function StateMachine:destroy()
    Runtime:removeEventListener("enterFrame", self )
    self._callback, self._co, self = nil, nil, nil
end

function StateMachine:cancel()
    Runtime:removeEventListener("enterFrame", self )
    self._co = nil
end

function StateMachine:waiting()
    self._isPass = false
    while not self._isPass do
        coroutine.yield()
    end
end

function StateMachine:continue()
    self._isPass = true
end 

local function new(callback)
    local ds = {}
    setmetatable(ds, StateMachine_mt)
    ds._callback = callback
    ds._wakeup = 0
   return ds
end

return {new=new}