no A until B=?[求助]

midnight

no A until B = B->A or B->非A?
A until B=?
请指教!

anchoret

以下是引用midnight在2003-8-1 10:50:00的发言：
no A until B = B->A or B->非A?
A until B=?
请指教!

until = if not

so:
A until B = not b -> a    or    not a -> b
no A until B = not b -> not a     or     a->b

midnight

anchoret,谢谢了!但是unless=if not,是不是unless =until?