<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 Dec 21, 2015, at 11:50 AM, Jordan Rose <<a href="mailto:jordan_rose@apple.com" class="">jordan_rose@apple.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="" style="font-family: ProximaNovaA-Regular; font-size: 13px; 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;">If you replace a method on someone else's class, you don't actually know what semantics they're relying on. Of course Apple code will have bugs in it. Trying to patch over these bugs in your own code is (1) obviously not an answer Apple would support, but also (2) fraught with peril, and (3) likely to break in the next OS release.</div><div class="" style="font-family: ProximaNovaA-Regular; font-size: 13px; 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: ProximaNovaA-Regular; font-size: 13px; 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;">TLDR: It's already unsafe to do this with the existing set of Swift features. Yes, this makes things "worse", but it's not something we're interested in supporting anyway.</div></div></blockquote></div><br class=""><div class="">Presumably a goal for Swift is that application developers will use it to build user-facing apps for Apple’s platforms. And presumably a goal for Apple is that developers help promote Apple’s platforms by shipping apps that take advantage of the new OS features when they ship. I fear that you and others dramatically underestimate the difficultly of doing that. I acknowledge your three points. But understand that we are professionals trying to serve our mutual customers. Temporary hacks in the service of shipping is the nature of the business.</div><div class=""><br class=""></div><div class="">I don’t know how to make the case more strongly than I already have. This thread makes me worry that the team does not understand what it’s like for third party developers trying to serve our mutual customers.</div><div class=""><br class=""></div><div class=""><div class="">Sincerely,</div><div class=""><br class=""></div><div class="">Curt</div><div class="">-----------------------------------------------------------------------------</div><div class="">Curt Clifton, PhD</div><div class="">Software Engineer</div><div class="">The Omni Group</div><div class=""><a href="http://www.curtclifton.net" class="">www.curtclifton.net</a></div></div><div class=""><br class=""></div></body></html>