lua闭包函数

array={"Google","Runoob"}
function elementIterator (collection)
    local index=0
    local count=#collection
    --闭包函数
    return  function()
        index=index+1
        if index<=count
        then
            return collection[index]
        end
    end
end

for element in elementIterator (array)
do 
    print(element)
end