lua反復器の例

function iter(t)
    local i = 0 
    local n = table.getn(t)
    return function ()
        i = i + 1
        if(i <=n ) then
            return t[i]
        else 
            return nil
        end
    end
end
ar = {1, 2, 3}
ariter = iter(ar)
while true do
    local e = ariter()
    if(e == nil) then
        break
    end
    print(e)
end