Really?? Or we just have #set and #get and no lenses, and it's done for Swift 3?
I never heard of lenses (Google does not help here). Was this serious or were you joking? Unless you can explain why #set and #get without lenses would be bad... or maybe #set and #get *are* lenses, in which case I'm not sure what you were trying to say. Reflexion -> Reflection? -Michael > Am 29.06.2016 um 00:55 schrieb David Hart via swift-evolution > <[email protected]>: > > This looks like lenses. I think we need to wait until after Swift 3 to > discuss it, and come up with a bigger design that ties to reflexion. > >> On 28 Jun 2016, at 22:04, Michael Peternell via swift-evolution >> <[email protected]> wrote: >> >> So you're proposing that `#set(aVariableName)` should translate to >> `{aVariableName=$0}`, right? Where aVariableName can be any valid lvalue >> like `self.users` or `users` or `vc.viewControllers`.. >> >> I think this would be a good extension to Swift. (`users.set` does not work >> BTW, because maybe the `users` object has a `set` property.. maybe I wanted >> to refer to the `set` property which also happens to refer to a closure >> value.) >> >> `#set(aVariableName)` also feels consistent with the >> `#keyPath(aVariableName)` property and falls into a similar category. Maybe >> `#setter(aVariableName)` would be even more clear? Furthermore, I want to >> additionally propose to introduce `#get(aVariableName)` (or >> `#getter(aVariableName)`) too. >> >> -Michael >> >>> Am 28.06.2016 um 20:18 schrieb Austin Feight via swift-evolution >>> <[email protected]>: >>> >>> Proposal: >>> >>> I propose adding setter methods to vars, which could look something like >>> this: `ApiClient().fetchUsers().then(#set(users))` >>> >>> Initially I thought it should work like this: >>> `ApiClient().fetchUsers().then(users.set)` >>> but to accomplish a line of code that flows grammatically, I believe >>> putting "set" where it would naturally fall if the code was being read as a >>> sentence is more Swifty. >>> >>> Rationale: >>> >>> The following code makes me smile: >>> >>> ApiClient().fetchUsers().then(displayUsers) >>> >>> It exemplifies the beauty of Swift. First-class functions make this line of >>> code read very well. Consider some alternatives: >>> >>> 1. ApiClient().fetchUsers().then { displayUsers($0) } >>> 2. ApiClient().fetchUsers().then { users in displayUsers(users) } >>> 3. ApiClient().fetchUsers().then { (users: [User]) in displayUsers(users) } >>> >>> Using the lessons learned from Swift API Design Guidelines (WWDC 2016 >>> Session 403) having an emphasis on clarity, my analysis of the alternatives >>> is: >>> >>> 1. $0 adds no additional information as to the type or explanation of what >>> the argument is, thus adding nothing to the line of code for clarity, and >>> therefore should be omitted >>> 2. adding "users" also adds nothing to the clarity of the code. The >>> function, properly, contains the information necessary to reason about the >>> argument it takes and what it does, and therefore adding "users" is >>> redundant >>> 3. Not only is "users" redundant, but also is the explicit type label. The >>> `displayUsers` method will only accept one type of argument, so we're >>> duplicating information that the compiler (and autocomplete) already gives >>> us >>> >>> With this I conclude that `ApiClient().fetchUsers().then(displayUsers)` is >>> the Swiftiest option. >>> I want to extend this same logic to when I find myself writing code like >>> this: >>> >>> ApiClient().fetchUsers().then { users in >>> self.users = users >>> } >>> >>> or alternatively, because "users" is likely redundant information again, >>> >>> ApiClient().fetchUsers().then { self.users = $0 } >>> >>> Personally I steer clear of `$0` as much as possible, because I very rarely >>> feel that it provides the information necessary for code clarity. But >>> beyond that, this code no longer reads as nicely as the code we had before. >>> >>> Whereas `ApiClient().fetchUsers().then(displayUsers)` flows nicely as a >>> sentence and reads grammatically, `ApiClient().fetchUsers().then { >>> self.users = $0 }` no longer does. >>> >>> I think this feature could have a simple implementation where the compiler >>> replaces `#set(X)` with `{ X = $0 }`, and I believe it would go a long way >>> with respect to code clarity, especially when X is something longer like >>> `self.view.bounds.origin.x` >>> >>> >>> Looking forward to hearing thoughts from the community, >>> Austin Feight >>> _______________________________________________ >>> swift-evolution mailing list >>> [email protected] >>> https://lists.swift.org/mailman/listinfo/swift-evolution >> >> _______________________________________________ >> swift-evolution mailing list >> [email protected] >> https://lists.swift.org/mailman/listinfo/swift-evolution > > _______________________________________________ > swift-evolution mailing list > [email protected] > https://lists.swift.org/mailman/listinfo/swift-evolution _______________________________________________ swift-evolution mailing list [email protected] https://lists.swift.org/mailman/listinfo/swift-evolution
