<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=""><br class=""><div><blockquote type="cite" class=""><div class="">On Jan 27, 2016, at 10:09 PM, Thorsten Seitz 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=""><meta http-equiv="content-type" content="text/html; charset=utf-8" class=""><div dir="auto" class=""><div class=""></div><div class="">As an alternative to Either for expressing a sum type I'd like to throw real union types like Ceylon uses into the discussion.</div><div class=""><br class=""></div><div class=""><a href="http://ceylon-lang.org/documentation/1.2/tour/types/" class="">http://ceylon-lang.org/documentation/1.2/tour/types/</a></div></div></div></blockquote><div><br class=""></div><div>FWIW, this has been discussed before on swift-evolution. Adding them isn’t out of the question, but it is a lot more complicated than it looks for the type checker.</div><div><br class=""></div><div>-Chris</div></div><br class=""></body></html>