<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body 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 color="#000000"><span style="background-color: rgba(255, 255, 255, 0);"><a id="v:sortOn" class="def" 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;">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 color="#000000"><span style="background-color: rgba(255, 255, 255, 0);"><a id="v:sortBy" class="def" 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;">Ordering</a>) -> [a] -> [a]</span></font></div><div style="direction: inherit;"><font color="#000000"><span style="background-color: rgba(255, 255, 255, 0);"><br></span></font></div><div style="direction: inherit;"><font color="#000000"><span style="background-color: rgba(255, 255, 255, 0);">in Haskell.</span></font></div></body></html>