On Thu, Sep 15, 2005 at 02:40:25PM +0200, Christian Maeder wrote:
Serge D. Mechveliani wrote:
How do you think, maybe, Data.Set also needs to provide `lookup' ?
Admittingly, using 'Set.filter (==e) s' to find the matching element may be a bit slower.
When trying to use 'Set.intersection s $ singleton e' I just noticed that intersection is not left-biased (see below)!
I'm not sure if Data.Set should be extended to better support elements with an equivalence relation and a corresponding order. I've such sets too, but never really cared about the additional component.
Do you also want functions 'insertWith', 'unionWith', 'splitLookup' (and what not)?
I'ld rather suggest to use Data.Map instead and use a proper total order for the keys (although that may also be awkward).
Thank you for the help. Set.filter (==e) s looks like similar to find (== e) . Set.toList s, which is slow. Set.intersection s $ singleton e has a chance to be near as fast as `member'. But to have `lookup' looks most natural, to my mind. Generally: I do not know. I would rely on the opinion of developers. If they decide anything about this, then all right. ----------------- Serge Mechveliani mechvel@botik.ru