A few more observations not necessarily supporting either side: - Why only map, flatMap, and filter? drop, prefix, and sorted can also benefit from keyPaths. - Adding these overloads only to Sequence will have a very interesting side effect on code like: xs.lazy.map(\.name), because lazy. Therefore all these overloads will have to be duplicated everywhere. - Naive implementation (the one that simply calls the closure taking overload) was 4 times slower when I quickly tested it. On the positive side though, this same naive implementation does not have to be a part of standard library and can easily be provided by a third-party package...
Max > On Jul 5, 2017, at 10:08 AM, Benjamin Herzog via swift-evolution > <[email protected]> wrote: > > Hey guys, > > I would like to pitch a small convenient change to the Swift stdlib. With > KeyPaths added in SE-0161 I would like to add some convenience calls to map, > flatMap and filter in Sequences. To extract properties of an array of objects > we currently use trailing closure syntax together with the shorthand $0 for > the first closure argument. This is still kind of verbose and also hard to > read in some situations. > I think it is much better to understand what is going on when using the type > safe KeyPaths for that. I already implemented a working solution and would > like to pitch the idea here to get some feedback before opening the swift > evolution proposal. > I propose using > > persons.flatMap(keyPath: \.name) > > over > > persons.flatMap { $0.name } > > Link to pull request: https://github.com/apple/swift/pull/10760 > <https://github.com/apple/swift/pull/10760> > > Link to proposal draft: > https://github.com/BenchR267/swift-evolution/blob/keypath-based-map/proposals/0181-keypath-based-map-flatmap-filter.md > > <https://github.com/BenchR267/swift-evolution/blob/keypath-based-map/proposals/0181-keypath-based-map-flatmap-filter.md> > > Thanks in advance for your feedback! > ______________________ > > Benjamin Herzog > > _______________________________________________ > swift-evolution mailing list > [email protected] > https://lists.swift.org/mailman/listinfo/swift-evolution
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