ANN: data-ordlist-0.2
I have released data-ordlist 0.2, with a number of changes: 1. The module name is now Data.List.Ordered, instead of Data.OrdList 2. Three bugfixes: (ack!) insertSet and insertBag assumed reverse-ordered lists, nub failed to remove duplicates. Thanks to Topi Karvonen for reporting the first problem. 3. One semantic change: old_nubBy f == new_nubBy (not . f). The new version is better keeping with the spirit of the rest of the library, and makes the old nub bug much more obvious. Now nubBy is the greedy algorithm that returns a sublist such that for all binary predicates: isSortedBy pred (nubBy pred xs) == True 4. Improved documentation, I hope! Please consider taking a look and letting me know what you think. http://hackage.haskell.org/package/data-ordlist Cheers, Leon
Why not wrap lists as Set and Bag abstract datatypes? An added bonus is that you could make them instances of Monoid.
On Sun, Feb 7, 2010 at 6:43 AM, Ross Paterson
Why not wrap lists as Set and Bag abstract datatypes? An added bonus is that you could make them instances of Monoid.
Well, my current thinking is that if you really want an abstract datatype for bags and sets, hackage (and the standard GHC distribution) offer a multitude of options. Previous versions of the code in data-ordlist dates back 9 years or more; I extracted and refurbished data-ordlist from a mess of miscellaneous list functions I use. Personally, I've never really used this code as an abstract datatype; my typical use cases break the set and bag abstractions to some extent. I use a few functions when I happen to know the lists I'm dealing with are ordered, and want a simple and efficient way to manipulate them. The functions I most often use are sortOn, sortOn', nubSort, and to a somewhat lesser extent, the set-like operators. I put this package on hackage as much for my own personal convenience as for others; but I do hope that other people will find it useful. I realize that others might use it in rather different ways than I do, and am open to suggestions and proposals. Cheers, Leon
participants (2)
-
Leon Smith -
Ross Paterson