<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="">It's an interesting idea, but I have to agree from a not-promoting-singletons standpoint. One can just add a static let to a class to return an instance and make the init private to get similar behavior. <div class=""><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Dec 11, 2015, at 5:55 PM, Jordan Rose 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="" 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;">-1. Enforced singletons lead to code that can't be unit-tested. Local types are occasionally convenient and they can't be unit-tested either, but spending one extra line to name the thing isn't going to hurt. You also can't pick an initializer here (at least not in this version).</div><div class="" 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;"><br class=""></div><div class="" 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;">IMHO, this just adds "another kind of thing" just to make code shorter, and "shorter" is not the right goal for Swift.</div><div class="" 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;"><br class=""></div><div class="" 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;">Best,</div><div class="" 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;">Jordan</div><div class="" 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;"><br class=""></div><br class="" 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;"><div 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" class=""><div class="">On Dec 11, 2015, at 14:07, Marc Knaup 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 dir="ltr" class="">Hey guys,<div class=""><br class=""></div><div class="">I am working on a proposal which touches (and could even partially depend on) another interesting concept which I think would be a great addition for Swift.</div><div class=""><br class=""></div><div class="">Object declarations could be a way to declare a class or struct with exactly one instance. They are perfect for singletons, anonymous subclasses and to anonymously implement a protocol.</div><div class=""><br class=""></div><div class="">Here some examples how it could look like:</div><div class=""><br class=""></div><div class=""><font face="monospace, monospace" class="">// singleton</font></div><div class=""><font face="monospace, monospace" class="">object GlobalResource {</font></div><div class=""><font face="monospace, monospace" class=""> func doSomething() { … }</font></div><div class=""><font face="monospace, monospace" class="">}</font></div><div class=""><font face="monospace, monospace" class=""><br class=""></font></div><div class=""><font face="monospace, monospace" class="">let resource = GlobalResource</font></div><div class=""><font face="monospace, monospace" class=""><br class=""></font></div><div class=""><font face="monospace, monospace" class="">// could all be the same</font></div><div class=""><font face="monospace, monospace" class="">resource.doSomething()</font></div><div class=""><font face="monospace, monospace" class="">GlobalResource.doSomething()</font></div><div class=""><font face="monospace, monospace" class="">GlobalResource.Type.doSomething()</font></div><div class=""><br class=""></div><div class=""><font face="monospace, monospace" class=""><br class=""></font></div><div class=""><font face="monospace, monospace" class="">// anonymous subclass</font></div><div class=""><font face="monospace, monospace" class="">class ViewController: UIViewController {</font></div><div class=""><font face="monospace, monospace" class=""><br class=""></font></div><div class=""><font face="monospace, monospace" class=""> override func loadView() {</font></div><div class=""><font face="monospace, monospace" class=""> view = object: UIView {</font></div><div class=""><font face="monospace, monospace" class=""> // configure view</font></div><div class=""><font face="monospace, monospace" class=""> }</font></div><div class=""><font face="monospace, monospace" class=""> }</font></div><div class=""><font face="monospace, monospace" class="">}</font></div><div class=""><font face="monospace, monospace" class=""><br class=""></font></div><div class=""><font face="monospace, monospace" class=""><br class=""></font></div><div class=""><font face="monospace, monospace" class="">// anonymous protocol implementation</font></div><div class=""><font face="monospace, monospace" class="">protocol TapHandler {</font></div><div class=""><font face="monospace, monospace" class=""> func handleTap()</font></div><div class=""><font face="monospace, monospace" class="">}</font></div><div class=""><font face="monospace, monospace" class=""><br class=""></font></div><div class=""><font face="monospace, monospace" class="">view.tapHandler = object: TapHandler {</font></div><div class=""><font face="monospace, monospace" class=""> func handleTap() {</font></div><div class=""><font face="monospace, monospace" class=""> // …</font></div><div class=""><font face="monospace, monospace" class=""> }</font></div><div class=""><font face="monospace, monospace" class="">}</font></div><div class=""><font face="monospace, monospace" class=""><br class=""></font></div><div class=""><br class=""></div><div class="">Kotlin is an example for a a modern language which uses this concept:</div><div class=""><a href="https://kotlinlang.org/docs/reference/object-declarations.html" class="">https://kotlinlang.org/docs/reference/object-declarations.html</a><br class=""></div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">What do you think about such an addition?</div></div><img src="https://u2002410.ct.sendgrid.net/wf/open?upn=ZEz4qHYnXhPr3bBPu-2FxP4tN3HfWKL-2FtJpqkQ0gkOVSAWVUCgq6j2gIMHLwUtsMvkh6zS-2F42OEDmC-2FuP8IhnJLSUcx5onHlpzOIn-2Frg3W6-2FKCm-2BXK-2FwGfUgVX09VHJVmk0TZUSq1TJuaeeSv-2FaBPGDu-2B53-2Bqq59Y9-2B5QQfYQCKUU-2Ft-2FjzKmkw6Hagd6EvybiQEVi8zW1ZX8PM26dnKJqSktSHIVAl3j0WqiS-2BX-2BGJKow-3D" alt="" width="1" height="1" border="0" class="" style="height: 1px !important; width: 1px !important; border-width: 0px !important; margin: 0px !important; padding: 0px !important;"><span class="Apple-converted-space"> </span>_______________________________________________<br class="">swift-evolution mailing list<br class=""><a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a><br class=""><a href="https://lists.swift.org/mailman/listinfo/swift-evolution" class="">https://lists.swift.org/mailman/listinfo/swift-evolution</a><br class=""></div></blockquote></div><br class="" 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;"><img src="https://u2002410.ct.sendgrid.net/wf/open?upn=AxVqvhl7qaAz-2FE20TrrgNT-2F44XdgxmRgRA416dJII-2BTV-2F9S0v-2Bl4oTQaA55lb5DEqrifFVHmPDM15ObrVHEeEeePkU-2FfZUAruD-2FlL77P7t446s4SUNesD12T4LA7oFJoT9MZLh-2Br-2FQTbWUl15i64lSEI3QUJYQ77Bh2UF4BzyO-2FZTTHWq7FMxafcAo248hq4an29N3WCZ04H5-2F4Z7tDr5ap-2BOTg1vdyRYnAa8IHchFY-3D" alt="" width="1" height="1" border="0" style="font-family: Helvetica; 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