()
is an empty tuple, a simple zero-sized type (it uses no memory) with only one value possible, ()
. It’s also known as the unit type. Its use in a return type of Result<(), E>
means “if nothing goes wrong, there’s no further value produced”. The semantics are what’s important—the call was OK.
Result<(), ()>
would also make sense as a return type—either something succeeded, or it failed, with nothing more to report in either case.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…