At 09:14 18/11/03 +1300, Tom Pledger wrote:
Graham Klyne writes:
 :
 | Below is some code I have written, which works, but I'm not sure
 | that it's especially efficient or elegant.  Are there any published
 | Haskell libraries that contain something like this?

Hi.

Partially ordered sets are in cahoots with lattices, so you may be
interested in http://www.cse.ogi.edu/~mpj/pubs/lattices.html .

That might be interesting... is full paper available online? (I don't have easy access to a serious technical library.)


And here's some off-the-cuff feedback...

How about using Maybe Ordering, instead of a new data type?
(As in http://www.mail-archive.com/[EMAIL PROTECTED]/msg05635.html)

Duh. That sounds like an excellent idea - I knew there was a reason for posing dumb questions like these!


Instead of hard-wiring Maybe into the element type in dropSubsumed,
how about passing in a partial comparison function?

dropSubsumedBy :: (a -> a -> Maybe Ordering) -> [a] -> [a]

Yes, I agree that would be neater.


(Though I was aware that this code was too specialized in many ways. I have noticed that it's often easier (for me) to code for a specific situation and then generalize the resulting code, than to go immediately for the general case. Haskell seems to be particularly well suited to factoring out the type-specific bits in this way, I think because it's often easy to parameterize any piece of code as a higher order function.)

Thanks for your insights!

#g


------------ Graham Klyne For email: http://www.ninebynine.org/#Contact

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