Can’t we simply overload ?? to support @autoclosure () -> Never now and remove
that overload when Never is the bottom type? Syntactically it would look and do
the same.
--
Adrian Zubarev
Sent with Airmail
Am 27. Juni 2017 um 21:52:01, Matthew Johnson via swift-evolution
(swift-evolution@swift.org) schrieb:
On Jun 27, 2017, at 2:49 PM, David Hart via swift-evolution
<swift-evolution@swift.org> wrote:
On 27 Jun 2017, at 20:23, Dave DeLong via swift-evolution
<swift-evolution@swift.org> wrote:
Also a +1 from me. This is something I always put in to my code.
I agree that having `Never` as a bottom type is interesting, but even if that
were the case, the proposed “!!” operator is still useful, because it
short-circuits having to fatalError() myself. IE:
let last = array.last ?? fatalError(“array must not be empty”)
The above solution with Never is the better solution IMHO:
No new operator
More flexible: what if you want something else than a fatalError? For example,
I might want to define a logAndFatalError() function which stores the error to
a log file before trapping.
+1
vs
let last = array.last !! “Array must not be empty"
I also think having it “fatalError” in shipping code is fine, because it’s
equivalent to what would happen if you incorrect force-unwrap.
Dave
On Jun 27, 2017, at 12:08 PM, Zach Waldowski via swift-evolution
<swift-evolution@swift.org> wrote:
Big +1.
Using `!` is widely seen as a smell. However, the need for it still arises;
they are preconditions, of a sort. It has become prevalent in my teams’
codebases to do “guard else preconditionFailure”.
I like `!!` over something like `?!`; it follows the pattern that almost every
`?` in the language has an equivalent `!`.
The implementation details are ultimately not relevant to me. I’m a fan of
`Never` being a bottom type for more reasons than just this. I also see no
reason why operator funcs couldn’t accept file and line as extra arguments on
the rhs.
Best,
Zachary Waldowski
z...@waldowski.me
On Tue, Jun 27, 2017, at 01:16 PM, Erica Sadun via swift-evolution wrote:
Using an operator to provide feedback on the context of a failed unwrap has
become a commonly implemented approach in the Swift developer Community. What
are your thoughts about adopting this widely-used operator into the standard
library?
guard !lastItem.isEmpty else { return }
let lastItem = array.last !! "Array must be non-empty"
Details here: https://gist.github.com/erica/423e4b1c63b95c4c90338cdff4939a9b
Thank you for your thoughtful feedback, -- E
_______________________________________________
swift-evolution mailing list
swift-evolution@swift.org
https://lists.swift.org/mailman/listinfo/swift-evolution
_______________________________________________
swift-evolution mailing list
swift-evolution@swift.org
https://lists.swift.org/mailman/listinfo/swift-evolution
_______________________________________________
swift-evolution mailing list
swift-evolution@swift.org
https://lists.swift.org/mailman/listinfo/swift-evolution
_______________________________________________
swift-evolution mailing list
swift-evolution@swift.org
https://lists.swift.org/mailman/listinfo/swift-evolution
_______________________________________________
swift-evolution mailing list
swift-evolution@swift.org
https://lists.swift.org/mailman/listinfo/swift-evolution
_______________________________________________
swift-evolution mailing list
swift-evolution@swift.org
https://lists.swift.org/mailman/listinfo/swift-evolution
