<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Mar 30, 2017, at 2:03 PM, Karl Wagner 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-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px;">So, running with the parallel, why not add a conditional conformance: "<font face="Courier" class="">Slice: Unicode where Base: Unicode</font>”?</div><br class="Apple-interchange-newline"></div></blockquote></div><br class=""><div class="">Primarily because this would rule out giving substrings the “small string optimization" where we pack the characters into the struct directly when they’ll fit.</div><div class=""><br class=""></div><div class="">(or rather, given substrings will be 2-3 words, the not-even-that-small string optimization)</div><div class=""><br class=""></div><div class=""><br class=""></div></body></html>