Lua 封装类--lua和android

Lua封装类（用面向对象的话说），有三种写法：如下：

方式一

Lib = {}
Lib.name = nil
Lib.foo = function (x,y) return x + y end
Lib.goo = function (x,y) return x - y end

方式二：

Lib = {
    name = nil,
    foo = function (x,y) return x + y end,
    goo = function (x,y) return x - y end,
}

方式三：

Lib = {}
Lib.name = nil
function Lib.foo (x,y)
return x + y
end
function Lib.goo (x,y)
return x - y
end

验证（coronacard in android）：

-----------------------------------------------------------------------------
-- do start and fill screen
print("Start Lua...")
mBackground = display.newRect( 0, 0, 2 * display.contentWidth, 2 * display.contentHeight )
-----------------------------------------------------------------------------

-----------------------------------------------------------------------------
-- define Lib
Lib = {}
Lib.name = nil
Lib.foo = function (x,y) return x + y end
Lib.goo = function (x,y) return x - y end
-----------------------------------------------------------------------------

local libA = Lib
libA.name = "test Lib at 1"
local i,j = 10,20;
print(libA.name.."--"..libA.foo(i, j))
libA.name = "test Lib at 2"
print(libA.name.."--"..libA.goo(i,j))