Re: [Haskell-cafe] ordNub

15 Jul 2013

      Apologies. I was being lazy. Here's a stable version:

  import qualified Data.HashSet as S

  hashNub :: (Ord a) => [a] -> [a]
  hashNub l = go S.empty l
    where
      go _ []     = []
      go s (x:xs) = if x `S.member` s then go s xs
                                    else x : go (S.insert x s) xs

Which, again, will probably be faster than the one using Ord, and I
can't think of any cases where I'd want the one using Ord instead. I
may just not be creative enough, though.

  - Clark

On Mon, Jul 15, 2013 at 12:46 AM, Brandon Allbery  wrote:
...
On Sun, Jul 14, 2013 at 7:54 AM, Clark Gaebel  wrote:
...
Oops sorry I guess my point wasn't clear.
Why ord based when hashable is faster? Then there's no reason this has to
be in base, it can just be a
Did the point about "stable" fly overhead?
--
brandon s allbery kf8nh                               sine nomine associates
allbery.b@gmail.com                                  ballbery@sinenomine.net
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