<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><blockquote type="cite" class=""><div class="">On Mar 17, 2017, at 10:04 AM, Michael LeHew via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:</div><div class=""><meta http-equiv="Content-Type" content="text/html charset=us-ascii" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div dir="auto" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div class=""><h2 id="toc_1" style="-webkit-print-color-adjust: exact; margin: 20px 0px 10px; padding: 0px; -webkit-font-smoothing: antialiased; cursor: text; position: relative; font-size: 24px; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: rgb(204, 204, 204); font-family: Helvetica, arial, sans-serif; background-color: rgb(255, 255, 255);" class="">Introduction</h2><p style="-webkit-print-color-adjust: exact; margin: 15px 0px; font-family: Helvetica, arial, sans-serif; font-size: 14px; background-color: rgb(255, 255, 255);" class="">We propose a family of concrete <em style="-webkit-print-color-adjust: exact;" class="">Key Path</em> types that represent uninvoked references to properties that can be composed to form paths through many values and directly get/set their underlying values.</p></div></div></div></div></blockquote>I don't know how to express the level of "Yes" I feel in response to this proposal without using language that's inappropriate on a public mailing list.</div><div><br class=""></div><div>A few questions:</div><div><br class=""></div><div><ul class="MailOutline"><li class="">How do key paths interact with Optionals? Can you form a key path to `Person.bestFriend.name`, and is that the syntax, or is it `Person.bestFriend?.name`?<br class=""><br class=""></li><li class="">Foundation key paths have a sometimes-useful property where, if they traverse a collection, the result becomes a collection of the ending type. Is a similar feature planned for smart key paths—perhaps something like `Person.friends[].name`?<br class=""><br class=""></li><li class="">Given that Swift has a syntax called #keyPath which is unrelated to these "key paths", have you considered using a different name to avoid confusion? Maybe "property paths" or "accessor paths"?</li></ul><blockquote type="cite" class=""><div class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div dir="auto" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div class=""></div></div></div></div></blockquote></div><br class=""><div class="">
<span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; "><div class=""><div style="font-size: 12px; " class="">-- </div><div style="font-size: 12px; " class="">Brent Royal-Gordon</div><div style="font-size: 12px; " class="">Architechies</div></div></span>
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