Stateful

• Classes gain the capacity of creating "states"
• States can override instance methods and create new ones
• States are inherited by subclasses
• States are stackable - the state on the top of the stack is the most prioritary
• There are callback functions invoked automatically when a state is entered, exited, pushed, popped ...

Example

local class    = require 'middleclass'
local Stateful = require 'stateful'

local Enemy = class('Enemy')
Enemy:include(Stateful)

function Enemy:initialize(health)
  self.health = health
end

function Enemy:speak()
  return 'My health is' .. tostring(self.health)
end

local Immortal = Enemy:addState('Immortal')

-- overriden function
function Immortal:speak()
  return 'I am UNBREAKABLE!!'
end

-- added function
function Immortal:die()
  return 'I can not die now!'
end

local peter = Enemy:new(10)

peter:speak() -- My health is 10
peter:gotoState('Immortal')
peter:speak() -- I am UNBREAKABLE!!
peter:die() -- I can not die now!
peter:gotoState(nil)
peter:speak() -- My health is 10

Installation

First, make sure that you have downloaded and installed middleclass

Just copy the stateful.lua file wherever you want it (for example on a lib/ folder). Then write this in any Lua file where you want to use it:

local class = require 'middleclass'
local Stateful = require 'stateful'

The package.path variable must be configured so that the folder in which stateful.lua is copied is available, of course.

Specs

This project uses busted for its specs. In order to run them, install busted, and then execute it on the top folder:

busted