> On Jun 27, 2017, at 2:49 PM, David Hart via swift-evolution > <[email protected]> wrote: > > >> On 27 Jun 2017, at 20:23, Dave DeLong via swift-evolution >> <[email protected] <mailto:[email protected]>> 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 >>> <[email protected] <mailto:[email protected]>> 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 >>> [email protected] <mailto:[email protected]> >>> >>> 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 >>>> <https://gist.github.com/erica/423e4b1c63b95c4c90338cdff4939a9b> >>>> >>>> Thank you for your thoughtful feedback, -- E >>>> >>>> _______________________________________________ >>>> swift-evolution mailing list >>>> [email protected] <mailto:[email protected]> >>>> https://lists.swift.org/mailman/listinfo/swift-evolution >>>> <https://lists.swift.org/mailman/listinfo/swift-evolution> >>> >>> _______________________________________________ >>> swift-evolution mailing list >>> [email protected] <mailto:[email protected]> >>> https://lists.swift.org/mailman/listinfo/swift-evolution >>> <https://lists.swift.org/mailman/listinfo/swift-evolution> >> >> _______________________________________________ >> swift-evolution mailing list >> [email protected] <mailto:[email protected]> >> https://lists.swift.org/mailman/listinfo/swift-evolution > > _______________________________________________ > swift-evolution mailing list > [email protected] > https://lists.swift.org/mailman/listinfo/swift-evolution
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