<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class=""><div style="margin: 0px; line-height: normal;" class=""><div style="margin: 0px; line-height: normal; min-height: 14px;" class=""><blockquote type="cite" class="">* What is your evaluation of the proposal?</blockquote><div style="margin: 0px; line-height: normal; min-height: 14px;" class="">+1 in general</div><blockquote type="cite" class="">* Is the problem being addressed significant enough to warrant a change to Swift?</blockquote><div style="margin: 0px; line-height: normal; min-height: 14px;" class="">Yes.</div><blockquote type="cite" class="">* Does this proposal fit well with the feel and direction of Swift?</blockquote><div style="margin: 0px; line-height: normal; min-height: 14px;" class="">Yes, with some nitpicks detailed below.</div><blockquote type="cite" class="">* If you have used other languages or libraries with a similar feature, how do you feel that this proposal compares to those?</blockquote><div style="margin: 0px; line-height: normal; min-height: 14px;" class="">-</div><blockquote type="cite" class="">* How much effort did you put into your review? A glance, a quick reading, or an in-depth study?</blockquote></div><div style="margin: 0px; line-height: normal; min-height: 14px;" class="">An afternoon of detailed study.</div><div class=""><br class=""></div><div class=""><br class=""></div></div><div style="margin: 0px; line-height: normal;" class="">As the author of a Swift package for arbitrary integers (<a href="https://github.com/lorentey/BigInt" class="">https://github.com/lorentey/BigInt</a>), I’m delighted by this proposal.</div><div style="margin: 0px; line-height: normal; min-height: 14px;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">I’m especially stoked about `FixedWidthInteger.doubleWidthMultiply`, which will likely lead to a measurable speedup. Why is there no `doubleWidthQuotientAndRemainder` or `doubleWidthDivide`, though?</div><div style="margin: 0px; line-height: normal;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">What is the intended behavior for `nthWord` for negative numbers? Can we prevent having to answer this question by e.g. moving this method down to UnsignedInteger? Big integer libs often use a signed magnitude representation; having to e.g. convert it to two’s complement on the fly to satisfy the API would be weird. (Also, the name `nthWord` seems unswifty to me.)</div><div style="margin: 0px; line-height: normal; min-height: 14px;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">Like others on this list, I also find signBitIndex confusing. The name does not make much sense for unsigned integers, or signed integers that do not use an embedded sign bit. Is it supposed to return the width (in bits) of the binary representation of the integer’s absolute value? (Why -1 for zero, then? What’s the signBitIndex for 1?) </div><div style="margin: 0px; line-height: normal; min-height: 14px;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">I can’t find any mention of the unary bitwise not (~) operation. It should be in FixedWidthInteger, right?</div><div style="margin: 0px; line-height: normal; min-height: 14px;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">Binary bitwise operations (or/and/xor) are in FixedWidthInteger, but I believe they can be implemented on big integers in a way that is perfectly consistent with fixed width integers. Admittedly, I don’t know of any generic algorithms that want these.</div><div style="margin: 0px; line-height: normal; min-height: 14px;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">To support big integers better, I think IntegerLiteralConvertible should also be updated at some point to work in terms of machine words. (Having to implement StringLiteralConvertible to provide source-level support for huge numbers works, but it isn’t great.)</div><div style="margin: 0px; line-height: normal; min-height: 14px;" class=""><br class=""></div><div style="margin: 0px; line-height: normal; min-height: 14px;" class="">I can see myself typing foo.absoluteValue instead of abs(foo) all the time; if its use is to be discouraged, perhaps a less prominent name would be better.</div><div style="margin: 0px; line-height: normal; min-height: 14px;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">There is a typo in the Operators section: “Arithmetic” should read “Integer” in these two lines:</div><div style="margin: 0px; line-height: normal; min-height: 14px;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class=""><span class="Apple-tab-span" style="white-space:pre"> </span>public func % <T: Arithmetic>(lhs: T, rhs: T) -> T</div><div style="margin: 0px; line-height: normal;" class=""><span class="Apple-tab-span" style="white-space:pre"> </span>public func %= <T: Arithmetic>(lhs: inout T, rhs: T)</div><div style="margin: 0px; line-height: normal; min-height: 14px;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">Remark: The gyb is nice when used in moderation, but I find parts of the prototype overuse templating to a point that’s bordering on obfuscation. E.g., I found this code especially hard to read:</div><div style="margin: 0px; line-height: normal; min-height: 14px;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class=""><span class="Apple-tab-span" style="white-space:pre"> </span><a href="https://github.com/apple/swift/blob/master/test/Prototypes/Integers.swift.gyb#L1016-L1033" class="">https://github.com/apple/swift/blob/master/test/Prototypes/Integers.swift.gyb#L1016-L1033</a></div><div style="margin: 0px; line-height: normal;" class=""><br class=""></div><div style="margin: 0px; line-height: normal;" class="">-- </div><div style="margin: 0px; line-height: normal;" class="">Karoly</div><div style="margin: 0px; line-height: normal;" class="">@lorentey</div></div><div class=""><br class=""></div><br class=""><div><blockquote type="cite" class=""><div class="">On 2016-06-23, at 02:52, Chris Lattner via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="">Hello Swift community,<br class=""><br class="">The review of "SE-0104: Protocol-oriented integers" begins now and runs through June 27. The proposal is available here:<br class=""><br class=""><span class="Apple-tab-span" style="white-space:pre"> </span><a href="https://github.com/apple/swift-evolution/blob/master/proposals/0104-improved-integers.md" class="">https://github.com/apple/swift-evolution/blob/master/proposals/0104-improved-integers.md</a><br class=""><br class="">Reviews are an important part of the Swift evolution process. All reviews should be sent to the swift-evolution mailing list at<br class=""><br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>https://lists.swift.org/mailman/listinfo/swift-evolution<br class=""><br class="">or, if you would like to keep your feedback private, directly to the review manager.<br class=""><br class="">What goes into a review?<br class=""><br class="">The goal of the review process is to improve the proposal under review through constructive criticism and contribute to the direction of Swift. When writing your review, here are some questions you might want to answer in your review:<br class=""><br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>* What is your evaluation of the proposal?<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>* Is the problem being addressed significant enough to warrant a change to Swift?<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>* Does this proposal fit well with the feel and direction of Swift?<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>* If you have used other languages or libraries with a similar feature, how do you feel that this proposal compares to those?<br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>* How much effort did you put into your review? A glance, a quick reading, or an in-depth study?<br class=""><br class="">More information about the Swift evolution process is available at<br class=""><br class=""><span class="Apple-tab-span" style="white-space:pre"> </span>https://github.com/apple/swift-evolution/blob/master/process.md<br class=""><br class="">Thank you,<br class=""><br class="">-Chris Lattner<br class="">Review Manager<br class=""><br class=""><br class="">_______________________________________________<br class="">swift-evolution mailing list<br class="">swift-evolution@swift.org<br class="">https://lists.swift.org/mailman/listinfo/swift-evolution<br class=""></div></div></blockquote></div><br class=""></body></html>