<div dir="ltr"><div class="gmail_extra">addendum:  my example was discussed at</div><div class="gmail_extra"><br></div><div class="gmail_extra">    <a href="https://lists.swift.org/pipermail/swift-dev/Week-of-Mon-20151214/000488.html">https://lists.swift.org/pipermail/swift-dev/Week-of-Mon-20151214/000488.html</a></div></div>