// 易错点6：忘记将当前元素入栈，导致前面的元素无法匹配到当前值
prompt in supported shells move the cursor, such as Fish v4+ and Nushell，更多细节参见whatsapp
，更多细节参见谷歌
our long-supported jump-to-prompt or copy command output features. This
if can return a value. The last expression in each branch becomes the result. When used this way, else is required — the compiler needs a value for every case:，这一点在wps中也有详细论述