<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 agree that a lot of developers might not end up using partial application if we went with Bartlomiej Cichosz's. However, it seems to me that the cost difference between his suggestion and the main one is very small, and partial application is definitely a lot more powerful. I find it pretty relevant considering that the special syntax for curried functions is going away. One parameter per underscore covers most use cases and you can fall back to closures if you need to.<div class=""><br class=""></div><div class="">I think that the current proposal is better than the statu quo, but I like that other solution best.<br class=""><div class=""><div class=""><div class=""><div class=""><div class=""><div class="">
<br class="Apple-interchange-newline"><span style="color: rgb(0, 0, 0); font-family: 'Lucida Grande'; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; display: inline !important; float: none;" class="">Félix</span>
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<br class=""><div><blockquote type="cite" class=""><div class="">Le 11 janv. 2016 à 14:13:43, Douglas Gregor via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> a écrit :</div><br class="Apple-interchange-newline"><div class=""><div style="font-family: LucidaGrande; 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" class=""><div class=""><br class="Apple-interchange-newline">On Jan 11, 2016, at 11:12 AM, T.J. Usiyan <<a href="mailto:griotspeak@gmail.com" class="">griotspeak@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class=""><div class="">I thought that the backpacks were workable but this does look nicer. </div></div></div></blockquote><div class=""><br class=""></div><div class="">Backticks were workable and general but ugly.</div><br class=""><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><div class=""><br class=""></div><div class="">Is there any way to specify which module/framework you are pulling the selector from? Is that information even part of the selector? Am I overestimated the usefulness of that possibility?<br class=""></div></div></div></blockquote><div class=""><br class=""></div><div class="">This is about naming functions. You can use “modulename.fnname(arglabel1:arglabel2:)” to name a specific function from a module.</div><div class=""><br class=""></div><span class="Apple-tab-span" style="white-space: pre;"> </span>- Doug</div><div style="font-family: LucidaGrande; 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 class=""><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><div class=""><br class=""></div><div class="">TJ</div><div class=""><br class=""></div></div><div class="gmail_extra"><br class=""><div class="gmail_quote">On Mon, Jan 11, 2016 at 2:03 PM, Douglas Gregor via swift-evolution<span class="Apple-converted-space"> </span><span dir="ltr" class=""><<a href="mailto:swift-evolution@swift.org" target="_blank" class="">swift-evolution@swift.org</a>></span><span class="Apple-converted-space"> </span>wrote:<br class=""><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-color: rgb(204, 204, 204); border-left-style: solid; padding-left: 1ex;"><div class="" style="word-wrap: break-word;">Hi all,<div class=""><br class=""></div><div class="">I’ve updated and simplified my “Generalized Naming for Any Function” proposal to only deal with naming functions with argument labels, and dropping the back-ticks. Comments welcome! Proposal is here</div><div class=""><br class=""></div><div class=""><span class="" style="white-space: pre-wrap;"> </span><a href="https://github.com/DougGregor/swift-evolution/blob/generalized-naming/proposals/0000-generalized-naming.md" target="_blank" class="">https://github.com/DougGregor/swift-evolution/blob/generalized-naming/proposals/0000-generalized-naming.md</a></div><div class=""><br class=""></div><div class="">and inline:</div><div class=""><br class=""></div><div class=""><h1 class="" style="font-size: 2.25em; margin-right: 0px; margin-bottom: 16px; margin-left: 0px; line-height: 1.2; padding-bottom: 0.3em; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: rgb(238, 238, 238); color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; background-color: rgb(255, 255, 255); margin-top: 0px !important;">Naming Functions with Argument Labels</h1><ul class="" style="padding: 0px 0px 0px 2em; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);"><li class="">Proposal: <a href="https://github.com/apple/swift-evolution/blob/master/proposals/0000-generalized-naming.md" target="_blank" class="" style="background-color: transparent; color: rgb(64, 120, 192); text-decoration: none;">SE-NNNN</a></li><li class="">Author(s): <a href="https://github.com/DougGregor" target="_blank" class="" style="background-color: transparent; color: rgb(64, 120, 192); text-decoration: none;">Doug Gregor</a></li><li class="">Status: <strong class="">Awaiting Review</strong></li><li class="">Review manager: TBD</li></ul><h2 class="" style="margin-top: 1em; margin-bottom: 16px; line-height: 1.225; font-size: 1.75em; padding-bottom: 0.3em; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: rgb(238, 238, 238); color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; background-color: rgb(255, 255, 255);"><a href="https://github.com/DougGregor/swift-evolution/tree/generalized-naming#introduction" target="_blank" class="" style="background-color: transparent; color: rgb(64, 120, 192); text-decoration: none; display: inline-block; padding-right: 2px; line-height: 1;"><span class="" style="font-weight: normal; font-size: 16px; line-height: 1; font-family: octicons; display: inline-block; vertical-align: middle;"></span></a>Introduction</h2><p class="" style="margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);">Swift includes support for first-class functions, such that any function (or method) can be placed into a value of function type. However, when specifying the name of a function, one can only provide the base name, (e.g., <code class="" style="font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;">insertSubview</code>) without the argument labels. For overloaded functions, this means that one must disambiguate based on type information, which is awkward and verbose. This proposal allwos one </p><p class="" style="margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);">it is not possible to specifically name every function that is part of a Swift program---one cannot provide the argument labels when naming a function, nor are property and subscript getters and setters referenceable. This proposal introduces a general syntax that allows one to name anything that is a function within Swift in an extensible manner.</p><p class="" style="margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);">Swift-evolution thread: The first draft of this proposal was discussed <a href="https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20151221/004555.html" target="_blank" class="" style="background-color: transparent; color: rgb(64, 120, 192); text-decoration: none;">here</a>. It included support for naming getters/setters (separately brought up by Michael Henson <a href="https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20151207/002168.html" target="_blank" class="" style="background-color: transparent; color: rgb(64, 120, 192); text-decoration: none;">here</a>, continued <a href="https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20151214/002203.html" target="_blank" class="" style="background-color: transparent; color: rgb(64, 120, 192); text-decoration: none;">here</a>). Joe Groff <a href="https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20151221/004579.html" target="_blank" class="" style="background-color: transparent; color: rgb(64, 120, 192); text-decoration: none;">convinced</a> me that lenses are a better approach for working with getters/setters, so I've dropped them from this version of the proposal.</p><h2 class="" style="margin-top: 1em; margin-bottom: 16px; line-height: 1.225; font-size: 1.75em; padding-bottom: 0.3em; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: rgb(238, 238, 238); color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; background-color: rgb(255, 255, 255);"><a href="https://github.com/DougGregor/swift-evolution/tree/generalized-naming#motivation" target="_blank" class="" style="background-color: transparent; color: rgb(64, 120, 192); text-decoration: none; display: inline-block; padding-right: 2px; line-height: 1;"><span class="" style="font-weight: normal; font-size: 16px; line-height: 1; font-family: octicons; display: inline-block; vertical-align: middle;"></span></a>Motivation</h2><p class="" style="margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);">It's fairly common in Swift for multiple functions or methods to have the same "base name", but be distinguished by parameter labels. For example, <code class="" style="font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;">UIView</code> has three methods with the same base name <code class="" style="font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;">insertSubview</code>:</p><div class="" style="margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);"><pre class="" style="overflow: auto; font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; margin-top: 0px; margin-bottom: 0px; line-height: 1.45; padding: 16px; background-color: rgb(247, 247, 247); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; word-wrap: normal; word-break: normal;"><span class="" style="color: rgb(167, 29, 93);">extension</span> UIView {
<span class="" style="color: rgb(167, 29, 93);">func</span> <span class="" style="color: rgb(121, 93, 163);">insertSubview</span>(view: UIView, at <span class="">index</span>: <span class="" style="color: rgb(0, 134, 179);">Int</span>)
<span class="" style="color: rgb(167, 29, 93);">func</span> <span class="" style="color: rgb(121, 93, 163);">insertSubview</span>(view: UIView, aboveSubview <span class="">siblingSubview</span>: UIView)
<span class="" style="color: rgb(167, 29, 93);">func</span> <span class="" style="color: rgb(121, 93, 163);">insertSubview</span>(view: UIView, belowSubview <span class="">siblingSubview</span>: UIView)
}</pre></div><p class="" style="margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);">When calling these methods, the argument labels distinguish the different methods, e.g.,</p><div class="" style="margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);"><pre class="" style="overflow: auto; font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; margin-top: 0px; margin-bottom: 0px; line-height: 1.45; padding: 16px; background-color: rgb(247, 247, 247); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; word-wrap: normal; word-break: normal;">someView<span class="" style="color: rgb(167, 29, 93);">.</span>insertSubview(view, at: <span class="" style="color: rgb(0, 134, 179);">3</span>)
someView<span class="" style="color: rgb(167, 29, 93);">.</span>insertSubview(view, aboveSubview: otherView)
someView<span class="" style="color: rgb(167, 29, 93);">.</span>insertSubview(view, belowSubview: otherView)</pre></div><p class="" style="margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);">However, when referencing the function to create a function value, one cannot provide the labels:</p><div class="" style="margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);"><pre class="" style="overflow: auto; font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; margin-top: 0px; margin-bottom: 0px; line-height: 1.45; padding: 16px; background-color: rgb(247, 247, 247); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; word-wrap: normal; word-break: normal;"><span class="" style="color: rgb(167, 29, 93);">let</span> fn <span class="" style="color: rgb(167, 29, 93);">=</span> someView<span class="" style="color: rgb(167, 29, 93);">.</span>insertSubview <span class="" style="color: rgb(150, 152, 150);">// ambiguous: could be any of the three methods</span></pre></div><p class="" style="margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);">In some cases, it is possible to use type annotations to disambiguate:</p><div class="" style="margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);"><pre class="" style="overflow: auto; font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; margin-top: 0px; margin-bottom: 0px; line-height: 1.45; padding: 16px; background-color: rgb(247, 247, 247); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; word-wrap: normal; word-break: normal;"><span class="" style="color: rgb(167, 29, 93);">let</span> fn: (UIView, <span class="" style="color: rgb(0, 134, 179);">Int</span>) <span class="" style="color: rgb(167, 29, 93);">=</span> someView<span class="" style="color: rgb(167, 29, 93);">.</span>insertSubview <span class="" style="color: rgb(150, 152, 150);">// ok: uses insertSubview(_:at:)</span>
<span class="" style="color: rgb(167, 29, 93);">let</span> fn: (UIView, UIView) <span class="" style="color: rgb(167, 29, 93);">=</span> someView<span class="" style="color: rgb(167, 29, 93);">.</span>insertSubview <span class="" style="color: rgb(150, 152, 150);">// error: still ambiguous!</span></pre></div><p class="" style="margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);">To resolve the latter case, one must fall back to creating a closure:</p><div class="" style="margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);"><pre class="" style="overflow: auto; font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; margin-top: 0px; margin-bottom: 0px; line-height: 1.45; padding: 16px; background-color: rgb(247, 247, 247); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; word-wrap: normal; word-break: normal;"><span class="" style="color: rgb(167, 29, 93);">let</span> fn: (UIView, UIView) <span class="" style="color: rgb(167, 29, 93);">=</span> { view, otherView <span class="" style="color: rgb(167, 29, 93);">in</span>
button<span class="" style="color: rgb(167, 29, 93);">.</span>insertSubview(view, aboveSubview: otherView)
}</pre></div><p class="" style="margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);">which is painfully tedious. </p><p class="" style="margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);">One additional bit of motivation: Swift should probably get some way to ask for the Objective-C selector for a given method (rather than writing a string literal). The argument to such an operation would likely be a reference to a method, which would benefit from being able to name any method, including getters and setters.</p><h2 class="" style="margin-top: 1em; margin-bottom: 16px; line-height: 1.225; font-size: 1.75em; padding-bottom: 0.3em; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: rgb(238, 238, 238); color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; background-color: rgb(255, 255, 255);"><a href="https://github.com/DougGregor/swift-evolution/tree/generalized-naming#proposed-solution" target="_blank" class="" style="background-color: transparent; color: rgb(64, 120, 192); text-decoration: none; display: inline-block; padding-right: 2px; line-height: 1;"><span class="" style="font-weight: normal; font-size: 16px; line-height: 1; font-family: octicons; display: inline-block; vertical-align: middle;"></span></a>Proposed solution</h2><p class="" style="margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);">I propose to extend function naming to allow compound Swift names (e.g., <code class="" style="font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;">insertSubview(_:aboveSubview:)</code>) anywhere a name can occur. Specifically,</p><div class="" style="margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);"><pre class="" style="overflow: auto; font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; margin-top: 0px; margin-bottom: 0px; line-height: 1.45; padding: 16px; background-color: rgb(247, 247, 247); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; word-wrap: normal; word-break: normal;"><span class="" style="color: rgb(167, 29, 93);">let</span> fn <span class="" style="color: rgb(167, 29, 93);">=</span> someView<span class="" style="color: rgb(167, 29, 93);">.</span>insertSubview(_:at:)
<span class="" style="color: rgb(167, 29, 93);">let</span> fn1 <span class="" style="color: rgb(167, 29, 93);">=</span> someView<span class="" style="color: rgb(167, 29, 93);">.</span>insertSubview(_:aboveSubview:)</pre></div><p class="" style="margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);">The same syntax can also refer to initializers, e.g.,</p><div class="" style="margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);"><pre class="" style="overflow: auto; font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; margin-top: 0px; margin-bottom: 0px; line-height: 1.45; padding: 16px; background-color: rgb(247, 247, 247); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; word-wrap: normal; word-break: normal;"><span class="" style="color: rgb(167, 29, 93);">let</span> buttonFactory <span class="" style="color: rgb(167, 29, 93);">=</span> UIButton<span class="" style="color: rgb(167, 29, 93);">.</span><span class="" style="color: rgb(167, 29, 93);">init</span>(type:)</pre></div><p class="" style="margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);">The "produce the Objective-C selector for the given method" operation will be the subject of a separate proposal. However, here is one possibility that illustrations how it uses the proposed syntax here:</p><div class="" style="margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);"><pre class="" style="overflow: auto; font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; margin-top: 0px; margin-bottom: 0px; line-height: 1.45; padding: 16px; background-color: rgb(247, 247, 247); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; word-wrap: normal; word-break: normal;"><span class="" style="color: rgb(167, 29, 93);">let</span> getter <span class="" style="color: rgb(167, 29, 93);">=</span> Selector(NSDictionary<span class="" style="color: rgb(167, 29, 93);">.</span>insertSubview(_:aboveSubview:)) <span class="" style="color: rgb(150, 152, 150);">// produces insertSubview:aboveSubview:.</span></pre></div><h2 class="" style="margin-top: 1em; margin-bottom: 16px; line-height: 1.225; font-size: 1.75em; padding-bottom: 0.3em; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: rgb(238, 238, 238); color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; background-color: rgb(255, 255, 255);"><a href="https://github.com/DougGregor/swift-evolution/tree/generalized-naming#detailed-design" target="_blank" class="" style="background-color: transparent; color: rgb(64, 120, 192); text-decoration: none; display: inline-block; padding-right: 2px; line-height: 1;"><span class="" style="font-weight: normal; font-size: 16px; line-height: 1; font-family: octicons; display: inline-block; vertical-align: middle;"></span></a>Detailed Design</h2><p class="" style="margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);">Grammatically, the <em class="">primary-expression</em> grammar will change from:</p><pre class="" style="overflow: auto; font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; margin-top: 0px; margin-bottom: 16px; line-height: 1.45; padding: 16px; background-color: rgb(247, 247, 247); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; word-wrap: normal; color: rgb(51, 51, 51);"><code class="" style="font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; padding: 0px; margin: 0px; background-color: transparent; border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; word-break: normal; border: 0px; display: inline; line-height: inherit; word-wrap: normal;">primary-expression -> identifier generic-argument-clause[opt]
</code></pre><p class="" style="margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);">to:</p><pre class="" style="overflow: auto; font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; margin-top: 0px; margin-bottom: 16px; line-height: 1.45; padding: 16px; background-color: rgb(247, 247, 247); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; word-wrap: normal; color: rgb(51, 51, 51);"><code class="" style="font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; padding: 0px; margin: 0px; background-color: transparent; border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; word-break: normal; border: 0px; display: inline; line-height: inherit; word-wrap: normal;">primary-expression -> unqualified-name generic-argument-clause[opt]
unqualified-name -> identifier
| identifier '(' ((identifier | '_') ':')+ ')'
</code></pre><p class="" style="margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);">Within the parentheses, the use of "+" is important, because it disambiguates:</p><div class="" style="margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);"><pre class="" style="overflow: auto; font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; margin-top: 0px; margin-bottom: 0px; line-height: 1.45; padding: 16px; background-color: rgb(247, 247, 247); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; word-wrap: normal; word-break: normal;">f()</pre></div><p class="" style="margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);">as a call to <code class="" style="font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;">f</code> rather than a reference to an <code class="" style="font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;">f</code> with no arguments. Zero-argument function references will still require disambiguation via contextual type information.</p><h2 class="" style="margin-top: 1em; margin-bottom: 16px; line-height: 1.225; font-size: 1.75em; padding-bottom: 0.3em; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: rgb(238, 238, 238); color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; background-color: rgb(255, 255, 255);"><a href="https://github.com/DougGregor/swift-evolution/tree/generalized-naming#impact-on-existing-code" target="_blank" class="" style="background-color: transparent; color: rgb(64, 120, 192); text-decoration: none; display: inline-block; padding-right: 2px; line-height: 1;"><span class="" style="font-weight: normal; font-size: 16px; line-height: 1; font-family: octicons; display: inline-block; vertical-align: middle;"></span></a>Impact on existing code</h2><p class="" style="margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);">This is a purely additive feature that has no impact on existing code.</p><h2 class="" style="margin-top: 1em; margin-bottom: 16px; line-height: 1.225; font-size: 1.75em; padding-bottom: 0.3em; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: rgb(238, 238, 238); color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; background-color: rgb(255, 255, 255);"><a href="https://github.com/DougGregor/swift-evolution/tree/generalized-naming#alternatives-considered" target="_blank" class="" style="background-color: transparent; color: rgb(64, 120, 192); text-decoration: none; display: inline-block; padding-right: 2px; line-height: 1;"><span class="" style="font-weight: normal; font-size: 16px; line-height: 1; font-family: octicons; display: inline-block; vertical-align: middle;"></span></a>Alternatives considered</h2><ul class="" style="padding: 0px 0px 0px 2em; margin-top: 0px; color: rgb(51, 51, 51); font-family: 'Helvetica Neue', Helvetica, 'Segoe UI', Arial, freesans, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255); margin-bottom: 0px !important;"><li class=""><p class="" style="margin-top: 16px; margin-bottom: 16px;">Joe Groff <a href="https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20151214/003008.html" target="_blank" class="" style="background-color: transparent; color: rgb(64, 120, 192); text-decoration: none;">notes</a> that <em class="">lenses</em> are a better solution than manually retrieving getter/setter functions when the intent is to actually operate on the properties.</p></li><li class=""><p class="" style="margin-top: 16px; margin-bottom: 16px;">Bartlomiej Cichosz <a href="https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20151228/004739.html" target="_blank" class="" style="background-color: transparent; color: rgb(64, 120, 192); text-decoration: none;">suggests</a> a general partial application syntax using <code class="" style="font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;">_</code> as a placeholder, e.g.,</p><div class="" style="margin-bottom: 16px;"><pre class="" style="overflow: auto; font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; margin-top: 0px; margin-bottom: 0px; line-height: 1.45; padding: 16px; background-color: rgb(247, 247, 247); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; word-wrap: normal; word-break: normal;">aGameView<span class="" style="color: rgb(167, 29, 93);">.</span>insertSubview(_, aboveSubview: playingSurfaceView)</pre></div><p class="" style="margin-top: 16px; margin-bottom: 16px;">When all arguments are <code class="" style="font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;">_</code>, this provides the ability to name any method:</p><div class="" style="margin-bottom: 16px;"><pre class="" style="overflow: auto; font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; margin-top: 0px; margin-bottom: 0px; line-height: 1.45; padding: 16px; background-color: rgb(247, 247, 247); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; word-wrap: normal; word-break: normal;">aGameView<span class="" style="color: rgb(167, 29, 93);">.</span>insertSubview(_, aboveSubview: _)</pre></div><p class="" style="margin-top: 16px; margin-bottom: 16px;">I decided not to go with this because I don't believe we need such a general partial application syntax in Swift. Closures using the $ names are nearly as concise, and eliminate any questions about how the <code class="" style="font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; padding: 0.2em 0px; margin: 0px; background-color: rgba(0, 0, 0, 0.0392157); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;">_</code> placeholder maps to an argument of the partially-applied function:</p><div class="" style="margin-bottom: 16px;"><pre class="" style="overflow: auto; font-family: Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 14px; margin-top: 0px; margin-bottom: 0px; line-height: 1.45; padding: 16px; background-color: rgb(247, 247, 247); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; word-wrap: normal; word-break: normal;">{ aGameView<span class="" style="color: rgb(167, 29, 93);">.</span>insertSubview($<span class="" style="color: rgb(0, 134, 179);">0</span>, aboveSubview: playingSurfaceView) }</pre></div></li></ul><div class=""><br class=""></div></div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div><div class=""><span class="" style="white-space: pre-wrap;"> </span>- Doug</div><div class=""><br class=""></div><img src="https://u2002410.ct.sendgrid.net/wf/open?upn=3FGfocPbgxkNkmje7djckg9Iw-2BGYY3X6RxJ1tkUXKCr-2Fld-2FCeVitf1sPvwon4rOYAQLGsABXOcG-2FwlQrKUiUYF-2Frzq1xAvrI7RaGq8fsmswn8j-2BbX-2FvuncNdEOq0wtISI67NN10s474KNC0sqDnGAPuoj1DriE1ubO1avVeJOqdMwvxxS9FN8sbJY9Cvsje0FCa9-2FpHbXL7JXvpggmC-2BNhVZhxjlcWU0CwTGASYXolc-3D" alt="" width="1" height="1" border="0" class="" style="min-height: 1px !important; 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