Lua的类有点像javascript,但是更简明灵活，table即对象，对象就是类。Metatables比起ruby里的MetaClass更加好用，缺点是实例化和继承的代码有点多，

不像ruby里的“<”和“<<”,继承链就是查找方法时的方法链。

Account={
  test1=function(a) print("Account test1") end
}

Account.test2=function(a) print("Account test2") end

function Account.test3(a) print("Account test3") end


function Account:new (o) --类的实例化

  o = o or {}

  setmetatable(o, self)

  self.__index = self

  return o

end

function Account.print0(o,a)
  print(a)
end

function Account:print1(a)
  print(a)
end


--方法定义测试
Account.test1()
Account.test2()
Account.test3()

--类测试
acc=Account:new()
acc.test1()
acc.print0(acc,"dot print0")
acc:print0("not dot print0")
acc.print1(acc,"dot print1")
acc:print1("not dot print1")

acc.specialMethod=function(specialMethodTest)
  print(specialMethodTest)
end

acc.specialMethod("smt test")

--继承测试
SpecialAccount = Account:new()
s = SpecialAccount:new{limit=1000.00}

--多重继承测试
Named = {}

function Named:getname ()

  return self.name

end

function Named:setname (n)

  self.name = n

end

local function search (k, plist)

  for i=1, table.getn(plist) do

    local v = plist[i][k]

    if v then return v end

  end

end

function createClass (...)

  local c = {}   -- new class

  setmetatable(c, {__index = function (t, k)

  return search(k, arg)

end})

c.__index = c

function c:new (o)

  o = o or {}

  setmetatable(o, c)

  return o

end

  return c

end
NamedAccount = createClass(Account, Named)

account = NamedAccount:new{name = "Paul"}

print(account:getname())