Hi, thanks for all Your answers (and again I'm amazed how active and good this forum is). I expected OOHaskell to be on the somewhat "extended" side, but I didn't expect it to be so uncommon. This very strong and clear feedback is indeed very valuable. I think I see the complexities of OO-programming in larger programs (unforeseen interactions), but I'm still doubtfull, that functional programming can equally adress all tasks equally efficient. I'm especially interestes in engineering calculation tasks where cellular automata could be used. In that case all u have to do is to give the class the right properties and that "let it grow". Such a localised intelligence approach seems an ideal OO - task. I don't know whether something functional could achieve the same. Sounds like a nice challenge. -- I'll chew on a small example. Cheers Phil -- View this message in context: http://haskell.1045720.n5.nabble.com/H98-OOHaskell-getting-started-with-obje... Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.

On Fri, 14 Jan 2011 12:36:22 -0800 (PST) "Wolfgang Jeltsch-2 [via Haskell]" wrote:

Is this really ideal for OO? I thought that in a cellular automaton, all cells have to change synchronously. In addition, cells have to access the old states of their neighbours to compute their new states. So you would have to heavily synchronize the objects.

In this light, I’d say that the distributed OO approach isn’t very practical. A global control of the whole system might be better.

Note that I’m by no way an expert in cellular automata. I’m just thinking of the game of life. :-)

Best wishes, Wolfgang

Hi Wolfgang, I don't yet have experience with cellular automata either. What u say seems plausible, but then the life game might have been coded that way, because most OO language don't offer concurrent objects and the distributed OO approach (seems to be a very recent concept). Looking at life u probably could save time, if u only would evaluate code on cells, where the neighbors have changed status. So rather than triggering them all centrally and each checks its neighbours, we could use the concept: - let the active ones trigger the neighbours & so pass on activity

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Am Sonntag, den 16.01.2011, 14:48 -0800 schrieb gutti:

Looking at life u probably could save time, if u only would evaluate code on cells, where the neighbors have changed status. So rather than triggering them all centrally and each checks its neighbours, we could use the concept:

- let the active ones trigger the neighbours & so pass on activity

But then you would have to take care to avoid cycles. You could also use on-demand updates with a centralized approach, and a centralized approach would probably make cycle detection easier. Best wishes, Wolfgang

Thanks to all of You, I think I learnt really a lot just on this thread about Haskell and also OO in general. I fear I'm too busy in the near future to come up with a good example and some more questions. Might happen later, because this topic is really interesting. Till then -- Thanks Philipp -- View this message in context: http://haskell.1045720.n5.nabble.com/H98-OOHaskell-getting-started-with-obje... Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.

Hi Philipp, depending on what engineering calculations you are interested in, you might like http://timber-lang.org/ , a direct descendant of O'Haskell, targeted at embedded real-time systems. If you are just stepping out of the OO programming world, it might be helpful to imagine OO as a rather narrow specialization of a concept called type, so that from the FP perspective it is just one of so many alternatives so that it gets lost a little -- which may be a useful translation to use. So the short answer to "where's OO?" in Haskell might just be "data", while the expressive freedom of type classes / families might surprise you. There have been some people playing with cellular automata, Google helps, e.g.: http://mjsottile.wordpress.com/ http://trac.haskell.org/gloss/ Both cases might give you an impression how it's done with Haskell types. If you really are interested in using the OO class concept together with the Haskell type system by a more than practical motivation, an expert in the field who is interested in the subject for a long time is Peter Padawitz (http://fldit-www.cs.uni-dortmund.de/~peter/ http://fldit-www.cs.uni-dortmund.de/%7Epeter/); he has presented a beautiful synthesis based on category theory, swinging types (http://fldit-www.cs.uni-dortmund.de/~peter/Swinging.html http://fldit-www.cs.uni-dortmund.de/%7Epeter/Swinging.html). Of course, he did also use O'Haskell for his programming works in the past. Cheers, Nick On 01/14/2011 12:23 AM, gutti wrote:

Hi,

thanks for all Your answers (and again I'm amazed how active and good this forum is).

I expected OOHaskell to be on the somewhat "extended" side, but I didn't expect it to be so uncommon. This very strong and clear feedback is indeed very valuable.

I think I see the complexities of OO-programming in larger programs (unforeseen interactions), but I'm still doubtfull, that functional programming can equally adress all tasks equally efficient.

I'm especially interestes in engineering calculation tasks where cellular automata could be used. In that case all u have to do is to give the class the right properties and that "let it grow".

Such a localised intelligence approach seems an ideal OO - task. I don't know whether something functional could achieve the same.

Sounds like a nice challenge. -- I'll chew on a small example.

Cheers Phil

Hi! 2011/1/14 gutti I'm especially interestes in engineering calculation tasks where cellular

automata could be used. In that case all u have to do is to give the class the right properties and that "let it grow".

Such a localised intelligence approach seems an ideal OO - task. I don't know whether something functional could achieve the same.

Thanks to your question, I took another look and the old and wonderful OOHaskell paper. It is very well written and describes almost exhaustively the haskell alternatives and their shortcomings: http://homepages.cwi.nl/~ralf/OOHaskell/paper.pdf Honestly, with the information I can have, my view is that the ·"let it grow" issue in the full is only achievable by following the OOHaskell path, but you can use the other ways paying a little price. This past discussion also applies: http://www.haskell.org/pipermail/haskell-cafe/2006-January/013925.html

Sounds like a nice challenge. -- I'll chew on a small example.

Cheers Phil -- View this message in context: http://haskell.1045720.n5.nabble.com/H98-OOHaskell-getting-started-with-obje... Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.

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