<div style="white-space:pre-wrap">I think a first class sort descriptor style would robustly solve most complex sorting needs. It can deal with multiple sort dimensions, etc. which an attribute wouldn't really solve without language complexity.</div><br><div class="gmail_quote"><div dir="ltr">On Wed, Aug 17, 2016 at 1:12 AM David Rönnqvist <<a href="mailto:swift-evolution@swift.org" target="_blank">swift-evolution@swift.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><div>Haskell also has a `comparing` function</div><div><br></div><div><font face="Menlo"> comparing :: (Ord a) => (b -> a) -> b -> b -> Ordering</font></div><div><br></div><div>which applies a function on both the left hand side and the right hand side to get two values that can be compared/ordered. </div><div>This makes the call site look something like this:</div><div><br></div><div><font face="Menlo"> sortBy (comparing length) names</font></div><div><br></div><div>The same <i>can</i> be done in Swift, resulting in a similar and very English-like calls site:</div><div><br></div><div><font face="Menlo"> names.sort(by: comparing { $0.characters.count })</font></div><div><br></div><div>That said. While this (the `comparing` function) is a fun exercise in higher order functions, a more Swifty syntax for this is probably a separate overload of the sort/ed/ function.</div></div><div style="word-wrap:break-word"><div><br></div><div>- David</div></div><div style="word-wrap:break-word"><br><div><blockquote type="cite"><div>On 17 Aug 2016, at 02:17, Silvan Mosberger via swift-evolution <<a href="mailto:swift-evolution@swift.org" target="_blank">swift-evolution@swift.org</a>> wrote:</div><br><div><div dir="auto"><div></div><blockquote type="cite"><div dir="ltr"><div class="gmail_extra">I'd be in favor. We'd need another name, since the current closure predicate is already standardized to `by:`.</div></div></blockquote><br><div>Haskell uses "on" for sorting with a mapping. There are both</div><div style="direction:inherit"><br></div><div style="direction:inherit"><font><span style="background-color:rgba(255,255,255,0)"><a style="margin:0px;padding:0px;font-weight:bold">sortOn</a> :: <a href="http://hackage.haskell.org/package/base-4.9.0.0/docs/Data-Ord.html#t:Ord" style="margin:0px;padding:0px;text-decoration:none" target="_blank">Ord</a> b => (a -> b) -> [a] -> [a]</span></font></div><div style="direction:inherit"><br></div><div style="direction:inherit">and</div><div style="direction:inherit"><br></div><div style="direction:inherit"><font><span style="background-color:rgba(255,255,255,0)"><a style="margin:0px;padding:0px;font-weight:bold">sortBy</a> :: (a -> a -> <a href="http://hackage.haskell.org/package/base-4.9.0.0/docs/Data-Ord.html#t:Ordering" style="margin:0px;padding:0px;text-decoration:none" target="_blank">Ordering</a>) -> [a] -> [a]</span></font></div><div style="direction:inherit"><font><span style="background-color:rgba(255,255,255,0)"><br></span></font></div><div style="direction:inherit"><font><span style="background-color:rgba(255,255,255,0)">in Haskell.</span></font></div></div>_______________________________________________<br>swift-evolution mailing list<br><a href="mailto:swift-evolution@swift.org" target="_blank">swift-evolution@swift.org</a><br><a href="https://lists.swift.org/mailman/listinfo/swift-evolution" target="_blank">https://lists.swift.org/mailman/listinfo/swift-evolution</a><br></div></blockquote></div><br></div>_______________________________________________<br>
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