can not use State.Next() func read lua array

[Fruneng]

       // balabala....

	if l.IsTable(-1) {
		var m = map[string]string{}

		l.PushNil()
		for l.Next(-2) {
			key, _ := l.ToString(-2)
			value, _ := l.ToString(-1)
			l.Pop(1)

			m[key] = value
		}

		l.Pop(2)

		return m
	}

        // balabala....

table is ok, but array will panic.

add some debug log tables.go:215

func arrayIndex(k value) int {
        if n, ok := k.(float64); ok {
           fmt.Println("array_index", k, n)
        } else {
           t := reflect.TypeOf(k)
	   fmt.Println("array_index", t, k)
        }

	if n, ok := k.(float64); ok {
		if i := int(n); float64(i) == n {
			return i
		}
	}
	return -1
}

it is a string type.

array_index <nil> <nil>
array_index string 1
array_index string 1