I am yet another one that tries to never use ! It feels like bad heritage from C, and it probably should be removed from Swift in the same way for(;;) and ++/-- where removed.
! does not provide any unique functionality, as it is redundant to “== false”. Other than syntax sugar, it does not add any value to the language. I feel a mutating toggle(), invert() or flip() method on Bool provides much more value. The non-mutating counterpart however should probably not be included in the standard library, as it would also be redundant to “== false”. Eneko Alonso > On Jan 12, 2018, at 14:34, Anders Kierulf via swift-evolution > <swift-evolution@swift.org> wrote: > > I also avoid using ! for negation when possible, and `toggle` or `invert` > will be helpful, but in many cases I think the negative case is better > expressed directly. For example, I find that using `nonEmpty` instead of > !isEmpty makes the code easier to read: > > extension String { > var nonEmpty: Bool { return !self.isEmpty } > } > > if !string.isEmpty { … } > > if string.isEmpty.inverted() { … } > > if string.nonEmpty { … } > > For the case of `contains`, maybe define `lacks`? > > if !items.contains(item) { ... } > > if items.contains(item).inverted() { ... } > > if items.lacks(item) { ... } > > Anders Kierulf > >> On Jan 12, 2018, at 12:54 PM, Alejandro Martinez via swift-evolution >> <swift-evolution@swift.org> wrote: >> >> I wouldn't go as far as to ask to fade out ! but in all my code I end >> up doing == false just for readability. That ! knows who to hide >> himself too well :P >> >> On Fri, Jan 12, 2018 at 10:13 AM, Adrian Zubarev via swift-evolution >> <swift-evolution@swift.org> wrote: >>> I’m not sure if this would be considered or not, but I would like if the >>> negation operator `!` would fade out. >>> >>> If this is ever going to a review then I’d suggest that we add a pair of >>> functions, one mutating and the other non-mutating. >>> >>> extension Bool { >>> mutating func invert() { >>> self = !self >>> } >>> >>> func inverted() { >>> return !self >>> } >>> } >>> >>> I’d rather use `inverted` instead of `!` because of the readability this >>> function provides. >>> >>> if !items.contains(item) { ... } >>> >>> if items.contains(item).inverted() { ... } >>> >>> —— >>> >>> I personally have some other extensions like: >>> >>> extension Bool { >>> @discardableResult >>> func whenTrue<T>(execute closure: () throws -> T) rethrows -> T? { >>> if self { return try closure() } >>> return nil >>> } >>> >>> @discardableResult >>> func whenFalse<T>(execute closure: () throws -> T) rethrows -> T? { >>> if !self { return try closure() } >>> return nil >>> } >>> } >>> >>> But this is more a personal preference. >>> >>> —— >>> >>> That said, if the community is fine with the `invert/inverted` pair then I’d >>> say go for it ;) >>> >>> Am 12. Januar 2018 um 09:14:22, Nate Cook via swift-evolution >>> (swift-evolution@swift.org) schrieb: >>> >>> >>> On Jan 12, 2018, at 12:15 AM, Chris Eidhof via swift-evolution >>> <swift-evolution@swift.org> wrote: >>> >>> Hey SE! >>> >>> When we have a bunch of nested structs: >>> >>> struct Sample { >>> var bar: Bar >>> } >>> >>> struct Bar { >>> var show: Bool >>> } >>> >>> var foo = Sample(bar: Bar(show: false)) >>> >>> It can be repetitive to toggle a deeply nested boolean: >>> >>> foo.bar.show = !foo.bar.show // duplication >>> >>> I sometimes add a `toggle` extension on `Bool` >>> >>> extension Bool { >>> mutating func toggle() { >>> self = !self >>> } >>> } >>> >>> This allows you to write the same code without duplication, and makes the >>> intent clearer: >>> >>> foo.bar.show.toggle() >>> >>> >>> I like it! >>> >>> In other languages, I don't think the `toggle` would make as much sense, but >>> the mutable self makes this very useful. >>> >>> After I posted it on Twitter, it turns out I'm not the only one: >>> https://twitter.com/PublicExtension/status/730434956376346624 >>> >>> I would have gone straight to a proposal, but I think we can do some >>> bikeshedding about the name of `toggle`? >>> >>> >>> Another verb that could work is `invert`. >>> >>> The `!` operator that does this is the negation operator, but I think >>> `negate` could sound to some like "make this false" rather than toggling. >>> >>> Nate >>> _______________________________________________ >>> 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 >>> >> >> >> >> -- >> Alejandro Martinez >> http://alejandromp.com >> _______________________________________________ >> 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
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