<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="">I could see myself supporting this naming strategy. It is semantically transparent while following the guidelines (even though I am still very sceptical about the practicability of the “be grammatical rule”). Functions like union, intersect etc. can be implemented as global generics that operate on suitable protocols. <div class=""><br class=""></div><div class="">Best, </div><div class=""><br class=""></div><div class=""> Taras <div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On 14 Feb 2016, at 06:09, Ricardo Parada 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=""><meta http-equiv="Content-Type" content="text/html charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hi Dave,<div class=""><br class=""></div><div class="">I would be okay with staying away from the mathematical terms similar to what you are suggesting except that the union can still be made more concise if you use merged / merge for the base name and shorten the labels to a bare minimum without loosing clarity. In addition, the merge can have a second parameter with a default to false in order to implement the symmetric difference (a.k.a. exclusive or). Recall that symmetric difference is the union of two sets and then removing the intersection (or members in common). I think it looks perfect (concise and clear). What does everybody else think?</div><div class=""><br class=""></div><div class=""><b class="">Non-mutable</b></div><div class=""><br class=""></div><div class=""><font face="Consolas" class="">let union = <span class="Apple-tab-span" style="white-space:pre"> </span>a.merged(with: b)</font></div><div class=""><div class=""><font face="Consolas" class="">let intersection = <span class="Apple-tab-span" style="white-space:pre"> </span>a.members(in: b)</font></div><div class=""><font face="Consolas" class="">let difference = <span class="Apple-tab-span" style="white-space:pre"> </span>a.removingMembers(in: b)</font></div><div class=""><font face="Consolas" class="">let symmetricDifference = <span class="Apple-tab-span" style="white-space:pre"> </span>a.merged(with: b, removingMembersInCommon: true)</font></div><div class=""><br class=""></div><div class=""><div class=""><b class="">Mutable (In-Place)</b></div><div class=""><br class=""></div><div class=""><font face="Consolas" class="">a.merge(with: b)<span class="Apple-tab-span" style="white-space:pre"> </span>// union in-place</font></div><div class=""><div class=""><font face="Consolas" class="">a.removeMembers(notIn: b)<span class="Apple-tab-span" style="white-space:pre"> </span>// intersect in-place</font></div><div class=""><font face="Consolas" class="">a.removeMembers(in: b)<span class="Apple-tab-span" style="white-space:pre"> </span>// difference in-place</font></div><div class=""><font face="Consolas" class="">a.merge(with: b, removeMembersInCommon: true)<span class="Apple-tab-span" style="white-space:pre"> </span>// symmetric difference in-place</font></div></div></div><div class=""><br class=""></div><div class=""><div class="">Ricardo Parada</div><div class=""><font face="Consolas" size="2" class=""><span style="background-color: rgb(255, 236, 236);" class=""><br class=""></span></font></div><div class=""><font face="Consolas" size="2" class=""><span style="background-color: rgb(255, 236, 236);" class=""><br class=""></span></font></div><div class=""><blockquote type="cite" class=""><div class="">On Feb 13, 2016, at 1:16 PM, 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: 14px; 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: 14px; 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 Fri Feb 12 2016, Ricardo Parada <</span><a href="mailto:swift-evolution@swift.org" style="font-family: Helvetica; font-size: 14px; 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: 14px; 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: 14px; 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: 14px; 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: 14px; 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="">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 style="font-family: Helvetica; font-size: 14px; 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: 14px; 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="">If we are going to force Set fit the naming guidelines, I would prefer</span><br style="font-family: Helvetica; font-size: 14px; 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: 14px; 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="">to stay away from the mathematical terms altogether.</span><br style="font-family: Helvetica; font-size: 14px; 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: 14px; 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: 14px; 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=""> func insertingContentsOf(other: Self) -> Self // union</span><br style="font-family: Helvetica; font-size: 14px; 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: 14px; 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=""> mutating func insertContentsOf(other)</span><br style="font-family: Helvetica; font-size: 14px; 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: 14px; 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: 14px; 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=""> func members(in other: Self) -> Self // intersection</span><br style="font-family: Helvetica; font-size: 14px; 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: 14px; 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=""> mutating func removeMembers(notIn: other)</span><br style="font-family: Helvetica; font-size: 14px; 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: 14px; 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: 14px; 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=""> func removingMembersAndAddingNonMembers(in other: Self) -> Self // symmetric difference</span><br style="font-family: Helvetica; font-size: 14px; 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: 14px; 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=""> mutating func removeMembersAndAddingNonMembers(in other: Self)</span><br style="font-family: Helvetica; font-size: 14px; 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: 14px; 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: 14px; 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=""> func removingMembers(in other: Self) -> Self // subtract</span><br style="font-family: Helvetica; font-size: 14px; 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: 14px; 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=""> mutating func removeMembers(in other: Self)</span><br style="font-family: Helvetica; font-size: 14px; 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: 14px; 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: 14px; 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="">If it would help with clarity, we could replace "in" with "foundIn"</span><br style="font-family: Helvetica; font-size: 14px; 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: 14px; 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="">above.</span><br style="font-family: Helvetica; font-size: 14px; 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: 14px; 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: 14px; 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: 14px; 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: 14px; 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: 14px; 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: 14px; font-style: normal; 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