I'm procrastinating something else, so I wrote the patch to unordered-containers. Feel free to comment on the github link:
https://github.com/tibbe/unordered-containers/pull/67 I'm still against having an Ord version, since my intuition tells me that hash-based data structures are faster than ordered ones. Someone else can write the patch, though! As a tangent, can anyone think of a data structure for which you can write an Ord instance but Hashable/Eq is impossible (or prove otherwise)? How about the converse? Regards, - Clark On Mon, Jul 15, 2013 at 10:40 PM, John Lato <jwl...@gmail.com> wrote: > On Tue, Jul 16, 2013 at 10:31 AM, Ivan Lazar Miljenovic > <ivan.miljeno...@gmail.com> wrote: >> >> On 16 July 2013 11:46, John Lato <jwl...@gmail.com> wrote: >> > In my tests, using unordered-containers was slightly slower than using >> > Ord, >> > although as the number of repeated elements grows unordered-containers >> > appears to have an advantage. I'm sure the relative costs of comparison >> > vs >> > hashing would affect this also. But both are dramatically better than >> > the >> > current nub. >> > >> > Has anyone looked at Bart's patches to see how difficult it would be to >> > apply them (or re-write them)? >> >> If I understand correctly, this function is proposed to be added to >> Data.List which lives in base... but the proposals here are about >> using either Sets from containers or HashSet from >> unordered-containers; I thought base wasn't supposed to depend on any >> other package :/ > > > That was one of the points up for discussion: is it worth including a subset > of Set functionality to enable a much better nub in base? Is it even worth > having Data.List.nub if it has quadratic complexity? > > As an alternative, Bart's proposal was for both including ordNub in > containers and an improved nub (with no dependencies outside base) in > Data.List. Unfortunately the patches are quite old (darcs format), and I > don't know how they'd apply to the current situation. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
