# 示例：安全处理嵌套LeftSequence
def process_left_sequence(seq, max_depth=1000):
    if not seq or max_depth <= 0:
        return None
    head, *tail = seq
    return {
        'value': head,
        'next': process_left_sequence(tail, max_depth - 1)
    }

# 使用迭代代替递归
def flatten_left_sequence(seq):
    result = []
    while seq:
        head, *seq = seq
        result.append(head)
    return result

// TypeScript示例：定义类型安全的LeftSequence
type LeftSequence<T> = [T, LeftSequence<T>] | [];

function processSequence<T>(seq: LeftSequence<T>): T[] {
    if (seq.length === 0) return [];
    const [head, ...tail] = seq;
    return [head, ...processSequence(tail)];
}

-- Haskell示例：惰性LeftSequence
data LeftSeq a = Empty | Cons a (LeftSeq a)

takeLeftSeq :: Int -> LeftSeq a -> LeftSeq a
takeLeftSeq 0 _ = Empty
takeLeftSeq _ Empty = Empty
takeLeftSeq n (Cons x xs) = Cons x (takeLeftSeq (n-1) xs)