What's problem of overloading? We only have four methods to do so.<br><br>Dave Abrahams <<a href="mailto:dabrahams@apple.com">dabrahams@apple.com</a>> 於 2016年1月1日星期五 寫道：<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><br><div><blockquote type="cite"><div>On Dec 31, 2015, at 4:14 AM, Tino Heth <<a href="javascript:_e(%7B%7D,'cvml','2th@gmx.de');" target="_blank">2th@gmx.de</a>> wrote:</div><br><div><div style="word-wrap:break-word"><div><br><blockquote type="cite"><div><div style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><font face="Menlo">func byComparing<T, U: Comparable>(getComparisonKey: (T)->U) -> (T, T) -> Bool {</font></div><div style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><font face="Menlo"> return { getComparisonKey($0) < getComparisonKey($1) }</font></div><div style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><font face="Menlo">}</font></div></div></blockquote></div>I've written something similar to bring file URLs into the order of their creation dates.<div>It is a small extension for collection types, and its only downside will disappear as soon as properties are accessible via method calls (afair there is a proposal in the making).</div><div><br></div><div>It was quite a lot fiddling with generics, and I don't have the tiny piece of code on my own computer, but it works in a way that you can do</div><div>let sorted = array.sortUsingAccessor(ElementType.methodThatReturnsComparable)</div><div>Beside the problems with properties, I really liked that approach.</div></div></div></blockquote><div><br></div>This seems to be essentially the same design as Susan’s, and has the same problem: it requires a new overload for every algorithm that takes a comparison predicate.<br></div><br><div>
-Dave
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