Re: darcs patch: Add equating p x y = p x == p y

On 10/11/06, Nils Anders Danielsson wrote:

Instead of adding 'comparing', 'equating' etc., I suggest that you add the more general 'on', which is just as easy to use. ('on' has been mentioned on the lists a couple of times before.)

(*) `on` f = \x y -> f x * f y

groupBy ((==) `on` fst) sortBy (compare `on` snd) maximumBy (customCompare `on` f)

Oh, oops. I meant to send this to the list the *first* time... so, um, where is the patch for this?