<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=""><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div class="">If we are going to support something like this, I’d rather see it be something everyone could leverage as there are many use cases for this feature:</div><div class=""><br class=""></div><blockquote class="" style="margin: 0px 0px 0px 40px; border: none; padding: 0px;"><div class=""><font face="Menlo" class="">#if available("package-name", "1.2.*")</font></div><div class=""><font face="Menlo" class="">#endif</font></div></blockquote></div></blockquote><div class=""><br class=""></div>Big +1.<div class=""><br class=""></div><div class="">I've asked specifically to get some kind of <a href="https://lists.swift.org/pipermail/swift-corelibs-dev/Week-of-Mon-20151228/000287.html" class="">conditional compilation on corelibs-foundation</a> being used. corelibs-founcation is currently incompatible with Darwin Foundation, and so it is impractical to make a single codebase build for both.</div><div class=""><br class=""></div><div class="">But building the same application against both Foundations and spotting differences is one of the important ways we're going to spot bugs.</div><div class=""><br class=""></div><div class="">So I think the code quality of Foundation ultimately hinges on getting some feature like this in the language.</div></body></html>