<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=""><blockquote type="cite" class="">protocols starting with an underscore (_ArrayBufferType, _IntegerType, etc) would benefit from the ’sealed’ modifier, because the contract right now only implicitly says: ‘public but please don’t use’.<br class=""></blockquote><div class=""><br class=""></div>I think it's wiser to refactor those protocols to be public and fully usable than to insert another access modifier to a language. Contracts that say "public but please don’t use" are generally a sign of design that is poor or limited by language/compiler.<div class=""><div class="">
<div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 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=""><font color="#929292" class=""><br class="Apple-interchange-newline">Pozdrawiam – Regards,</font></div><div style="color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 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=""><font color="#929292" class="">Adrian Kashivskyy</font></div>
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<br class=""><div><blockquote type="cite" class=""><div class="">Wiadomość napisana przez Felix Gabel <<a href="mailto:felix.gabel@me.com" class="">felix.gabel@me.com</a>> w dniu 04.12.2015, o godz. 01:45:</div><br class="Apple-interchange-newline"><div class=""><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=""><br class="Apple-interchange-newline">On Dec 4, 2015, at 12:25 AM, Dmitri Gribenko <<a href="mailto:gribozavr@gmail.com" class="">gribozavr@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">On Thu, Dec 3, 2015 at 3:09 PM, Douglas Gregor <<a href="mailto:dgregor@apple.com" class="">dgregor@apple.com</a>> wrote:<br class="">><br class="">>> On Dec 3, 2015, at 2:59 PM, Felix Gabel <<a href="mailto:felix.gabel@me.com" class="">felix.gabel@me.com</a>> wrote:<br class="">>><br class="">>> Hey everyone,<br class="">>><br class="">>> I hereby propose adding a ’sealed’ modifier for protocols to enable library developers to declare protocols that can be only conformed to in the scope of the library itself. This is similar to a ’sealed trait’ in Scala with the difference that it does not limit the protocol to be only applicable in the file it is declared in.<br class="">>><br class="">>> Example:<br class="">>><br class="">>> public sealed protocol FooType {<br class="">>> // this protocol can be conformed to only in scope of the library itself<br class="">>> // it can NOT be conformed to by any object declared outside the library<br class="">>> }<br class="">>><br class="">>> What do you think?<br class="">><br class="">><br class="">> Can you elaborate on why a Swift developer would want to distinguish between “public sealed” and “internal”?<br class=""><br class="">There are cases when the library isn't designed to support new conformances for the protocol, but the protocol is public because other public APIs are expressed in terms of it.<br class=""><br class="">We have a case for it in the standard library, 'protocol AnyCollectionType'. Foundation also has a use case -- property list types.<div class=""><br class=""></div><div class="">Dmitri</div></div></div></blockquote><br class=""></div><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="">- protocols starting with an underscore (_ArrayBufferType, _IntegerType, etc) would benefit from the ’sealed’ modifier, because the contract right now only implicitly says: ‘public but please don’t use’.</div><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="">- another use case is grouping a set of types regardless their origin and limit the ability to extend the provided number of types by external forces</div><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=""><br class=""></div><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=""><br class=""></div><img src="https://u2002410.ct.sendgrid.net/wf/open?upn=Q0Y0L54uOhrrHtFzGFlMmzHCkni7p1uaN05dut7Y5S5S0urCwMsa-2FYIFpBa4WM7v3YkKEUHgq1kDDaTb-2Foh6RSS9p-2B7S2zhTnIzBM9nodZpI9L2DT-2FbWmoDK2LW-2FH1-2FMXGKMqpHQK518YIhm1esQnhg88O06xNFr1laz89dgRobiIU3-2FGbPPeS9YyJ5mrteKdLyMj66XAREBOz9zS61ACWYHqy2uTEzZqSdLXnnNVjc-3D" alt="" width="1" height="1" border="0" style="font-family: Helvetica; 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