I haven’t read through the complete proposal in detail, but regarding the ‘scan’ operation I would like to point out that the definition given in the example matches the semantics of what is usually called ‘prescan' or 'exclusive scan', whereas ‘scan’ (aka ‘inclusive scan’ or ‘prefix sum’) would not include the identity element, and each position of the result would include applying the operator to the elements up to and including the element in the same position of the source array, e.g.:
(1..<6).scan(combine: +) // [1, 3, 6, 10, 15, 21] Sources: https://www.cs.cmu.edu/~guyb/papers/Ble93.pdf https://en.wikipedia.org/wiki/Prefix_sum Mark > On Apr 28, 2016, at 11:11 AM, Chris Lattner <[email protected]> wrote: > > Hello Swift community, > > The review of "SE-0045: Add scan, prefix(while:), drop(while:), and iterate > to the stdlib" begins now and runs through May 3. The proposal is available > here: > > > https://github.com/apple/swift-evolution/blob/master/proposals/0045-scan-takewhile-dropwhile.md > > Reviews are an important part of the Swift evolution process. All reviews > should be sent to the swift-evolution mailing list at > > https://lists.swift.org/mailman/listinfo/swift-evolution > > or, if you would like to keep your feedback private, directly to the review > manager. > > What goes into a review? > > The goal of the review process is to improve the proposal under review > through constructive criticism and, eventually, determine the direction of > Swift. When writing your review, here are some questions you might want to > answer in your review: > > * What is your evaluation of the proposal? > * Is the problem being addressed significant enough to warrant a change > to Swift? > * Does this proposal fit well with the feel and direction of Swift? > * If you have you used other languages or libraries with a similar > feature, how do you feel that this proposal compares to those? > * How much effort did you put into your review? A glance, a quick > reading, or an in-depth study? > > More information about the Swift evolution process is available at > > https://github.com/apple/swift-evolution/blob/master/process.md > > Thank you, > > -Chris Lattner > Review Manager > > > _______________________________________________ > swift-evolution-announce mailing list > [email protected] > https://lists.swift.org/mailman/listinfo/swift-evolution-announce
_______________________________________________ swift-evolution mailing list [email protected] https://lists.swift.org/mailman/listinfo/swift-evolution
