class Camera
    function snap() print("taking a photo") end
end

class Phone
    function call() print("calling home") end
end

class Cameraphone extends Camera
    function __construct(public phone) end -- uses composition for the Phone part

    -- Inherits Camera's snap() method.

    -- Phone's call() method can be wrapped.
    function call() self.phone:call() end
end

local p = new Phone()
local cp = new Cameraphone(p)
cp:snap()
cp:call()