<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="">Yes, one stops being used - i.e. ends it useful cycle… while the other contains all the cars.<div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On 2016-02-14, at 23:39:31, Dave Abrahams 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=""><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">on Sun Feb 14 2016, David Hart <</span><a href="mailto:swift-evolution@swift.org" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">swift-evolution@swift.org</a><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">> wrote:</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><blockquote type="cite" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">I don’t really agree with Dave’s comments about removing ‘with',<span class="Apple-converted-space"> </span><br class=""></blockquote><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">When one road merges with another, both are changed.</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><blockquote type="cite" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">but here’s one of mine – making the non-mutating difference an<br class="">override of intersection because it sounds clearer to me and is<br class="">consistent with the mutable versions being overrides:<br class=""></blockquote><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">I don't see any overrides around here. Care to clarify?</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><blockquote type="cite" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">Non-mutable<br class=""><br class="">let union = a.merged(with: b)<br class="">let intersection = a.members(in: b)<br class="">let difference = a.members(notIn: b)<br class="">let symmetricDifference = a.merged(with: b, removingMembersInCommon: true)<br class=""><br class="">Mutable (In-Place)<br class=""><br class="">a.merge(with: b) // union in-place<br class="">a.removeMembers(notIn: b) // intersect in-place<br class="">a.removeMembers(in: b)<span class="Apple-tab-span" style="white-space: pre;"> </span>// difference in-place<br class="">a.merge(with: b, removingMembersInCommon: true) // symmetric difference in-place<br class=""><br class=""><blockquote type="cite" class="">On 14 Feb 2016, at 17:10, Dave Abrahams via swift-evolution<br class=""><<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:<br class=""><br class=""><br class="">on Sat Feb 13 2016, Ricardo Parada <<a href="http://rparada-at-mac.com" class="">rparada-AT-mac.com</a>> wrote:<br class=""><br class=""><blockquote type="cite" class="">Hi Dave,<br class=""><br class="">I would be okay with staying away from the mathematical terms similar<br class="">to what you are suggesting except that the union can still be made<br class="">more concise if you use merged / merge for the base name and shorten<br class="">the labels to a bare minimum without loosing clarity. In addition,<br class="">the merge can have a second parameter with a default to false in order<br class="">to implement the symmetric difference (a.k.a. exclusive or). Recall<br class="">that symmetric difference is the union of two sets and then removing<br class="">the intersection (or members in common). I think it looks perfect<br class="">(concise and clear). What does everybody else think?<br class=""><br class="">Non-mutable<br class=""><br class="">let union =<span class="Apple-converted-space"> </span><span class="Apple-tab-span" style="white-space: pre;"> </span><span class="Apple-tab-span" style="white-space: pre;"> </span><span class="Apple-tab-span" style="white-space: pre;"> </span>a.merged(with: b)<br class="">let intersection =<span class="Apple-converted-space"> </span><span class="Apple-tab-span" style="white-space: pre;"> </span><span class="Apple-tab-span" style="white-space: pre;"> </span>a.members(in: b)<br class="">let difference =<span class="Apple-converted-space"> </span><span class="Apple-tab-span" style="white-space: pre;"> </span><span class="Apple-tab-span" style="white-space: pre;"> </span>a.removingMembers(in: b)<br class="">let symmetricDifference =<span class="Apple-converted-space"> </span><span class="Apple-tab-span" style="white-space: pre;"> </span>a.merged(with: b, removingMembersInCommon: true)<br class=""><br class="">Mutable (In-Place)<br class=""><br class="">a.merge(with: b)<span class="Apple-tab-span" style="white-space: pre;"> </span><span class="Apple-tab-span" style="white-space: pre;"> </span>// union in-place<br class="">a.removeMembers(notIn: b)<span class="Apple-tab-span" style="white-space: pre;"> </span>// intersect in-place<br class="">a.removeMembers(in: b)<span class="Apple-tab-span" style="white-space: pre;"> </span><span class="Apple-tab-span" style="white-space: pre;"> </span>// difference in-place<br class="">a.merge(with: b, removeMembersInCommon: true)<span class="Apple-tab-span" style="white-space: pre;"> </span>// symmetric difference in-place<br class=""></blockquote><br class="">I love your changes to my suggestion, Ricardo! The minor alterations I<br class="">would make are:<br class=""><br class="">1. In both cases the Bool parameter ought to be called<br class=""> “removingMembersInCommon”<br class=""><br class="">2. I would remove “with” from the in-place merge operation. We're<br class=""> really asking the receiver to merge b into itself. “With” gives it<br class=""> the sense that it might almost be mutating b.<br class=""><br class=""><blockquote type="cite" class="">Ricardo Parada<br class=""><br class=""><blockquote type="cite" class="">On Feb 13, 2016, at 1:16 PM, Dave Abrahams via swift-evolution<br class=""><<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:<br class=""><br class=""><br class="">on Fri Feb 12 2016, Ricardo Parada <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a><br class=""><<a href="mailto:swift-evolution@swift.org" class="">mailto:swift-evolution@swift.org</a>>> wrote:<br class=""><br class=""><blockquote type="cite" class="">Hi all,<br class=""><br class="">I can’t make up my mind. Let me propose two different alternatives<br class="">that I’m not sure if they have been considered:<br class=""><br class="">ALTERNATIVE 1<br class=""><br class="">Non-mutable (noun-based)<br class=""><br class="">- func union(other: Self) -> Self<br class="">+ func union(other: Self) -> Self<span class="Apple-tab-span" style="white-space: pre;"> </span><span class="Apple-tab-span" style="white-space: pre;"> </span>Assumes union is a noun, i.e. not a verb<br class=""><br class="">- func intersect(other: Self) -> Self<br class="">+ func intersection(other: Self) -> Self<br class=""><br class="">- func subtract(other: Self) -> Self<br class="">+ func subtraction(other: Self) -> Self<br class=""><br class="">- func exclusiveOr(other: Self) -> Self<br class="">+ func symmetricSubtraction(other: Self) -> Self<br class=""><br class="">Mutable (verb-based)<br class=""><br class="">- mutating func unionInPlace(other: Self)<br class="">+ mutating func unite(other: Self)<br class=""><br class="">- mutating func intersectInPlace(other: Self)<br class="">+ mutating func intersect(other: Self)<br class=""><br class="">- mutating func subtractInPlace(other: Self)<br class="">+ mutating func subtract(other: Self)<br class=""><br class="">- mutating func exclusiveOrInPlace(other: Self)<br class="">+ mutating func symmetricSubtract(other: Self)<br class=""><br class="">Comments:<span class="Apple-converted-space"> </span><br class=""><br class="">With this alternative we keep the union name which I assume is<br class="">popular. However, one has to accept unite as a verb (for the mutable<br class="">version) as I wanted all the mutable methods use verbs for<br class="">consistency. I think unite is acceptable because it can be found in<br class="">the dictionary and it is a verb.<br class=""><br class="">Notice that all the non-mutable methods use nouns: union,<br class="">intersection, subtraction and symmetricSubtraction.<br class=""><br class="">I understand some may oppose to symmetricSubtraction saying that<br class="">symmetricSubraction is not as common as "exclusive or". However,<br class="">using symmetricSubtraction is consistent with subtraction and it hints<br class="">to a variation of the “subtraction" operation. We will get used to it<br class="">quickly / easily.<br class=""><br class="">The mutable methods all use verbs: unite, intersect, subtract and symmetricSubtract.<br class=""><br class="">ALTERNATIVE 2<br class=""><br class="">Non-mutable<br class=""><br class="">- func union(other: Self) -> Self<br class="">+ func adding(other: Self) -> Self<br class=""><br class="">- func intersect(other: Self) -> Self<br class="">+ func intersecting(other: Self) -> Self<br class=""><br class="">- func exclusiveOr(other: Self) -> Self<br class="">+ func exclusiveOring(other: Self) -> Self<br class=""><br class="">- func subtract(other: Self) -> Self<br class="">+ func removing(other: Self) -> Self<br class=""><br class="">Mutable<br class=""><br class="">- mutating func unionInPlace(other: Self)<br class="">+ mutating func add(other: Self)<br class=""><br class="">- mutating func intersectInPlace(other: Self)<br class="">+ mutating func intersect(other: Self)<br class=""><br class="">- mutating func exclusiveOrInPlace(other: Self)<br class="">+ mutating func exclusiveOr(other: Self)<br class=""><br class="">- mutating func subtractInPlace(other: Self)<br class="">+ mutating func remove(other: Self)<br class=""><br class="">Comments: This alternative gives up on union in favor or add. Many<br class="">may not like this, that is why I have it as the second alternative.<br class="">It brings back exclusiveOr and treats it as a verb. Some may argue<br class="">that exclusiveOr is a noun for the "exclusive or" operation.<br class=""></blockquote><br class="">If we are going to force Set fit the naming guidelines, I would prefer<br class="">to stay away from the mathematical terms altogether.<br class=""><br class="">func insertingContentsOf(other: Self) -> Self // union<br class="">mutating func insertContentsOf(other)<br class=""><br class="">func members(in other: Self) -> Self // intersection<br class="">mutating func removeMembers(notIn: other)<br class=""><br class="">func removingMembersAndAddingNonMembers(in other: Self) -> Self // symmetric difference<br class="">mutating func removeMembersAndAddingNonMembers(in other: Self)<br class=""><br class="">func removingMembers(in other: Self) -> Self // subtract<br class="">mutating func removeMembers(in other: Self)<br class=""><br class="">If it would help with clarity, we could replace "in" with "foundIn"<br class="">above.<br class=""><br class="">--<span class="Apple-converted-space"> </span><br class="">-Dave<br class=""><br class="">_______________________________________________<br class="">swift-evolution mailing list<br class=""><a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a><br class=""><mailto:swift-evolution@swift.org><br class="">https://lists.swift.org/mailman/listinfo/swift-evolution<br class=""><https://lists.swift.org/mailman/listinfo/swift-evolution><br class=""></blockquote></blockquote><br class="">--<span class="Apple-converted-space"> </span><br class="">-Dave<br class="">_______________________________________________<br class="">swift-evolution mailing list<br class=""><a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a><br class="">https://lists.swift.org/mailman/listinfo/swift-evolution<br class=""></blockquote><br class="">_______________________________________________<br class="">swift-evolution mailing list<br class=""><a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a><br class="">https://lists.swift.org/mailman/listinfo/swift-evolution<br class=""></blockquote><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">--<span class="Apple-converted-space"> </span></span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">-Dave</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; 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