- Haskell-Cafe - Haskell.org

gtk2hs
by Christian Buschmann 15 Jun '03

15 Jun '03

Hi! I tried to implement a simple counter with gtk2hs. To increase my counter I defined following event: onClicked btn $ do si <- textBufferGetStartIter tb ei <- textBufferGetEndIter tb val <- textBufferGetText tb si ei False textBufferSetText tb $ show $ (+1) $ read val But now I don't want always read the textfield to get my counter-value, I would like to save the state of my increased value and would like to pass it to the next call of the function. How can I do this? thanks Christian This is the complete code: import Gtk quitDialog :: IO Bool quitDialog = ..... main :: IO () main = do initGUI --main window win <- windowNew onDelete win (\_->(quitDialog>>= (return . not ))) onDestroy win mainQuit vb <- vBoxNew True 5 hb <- hBoxNew True 5 btn <- buttonNewFromStock stockExecute btn2 <- buttonNewFromStock stockQuit tv <- textViewNew tb <- textBufferNew Nothing textBufferSetText tb "0" textViewSetEditable tv False textViewSetCursorVisible tv False textViewSetBuffer tv tb boxPackStartDefaults vb tv boxPackStartDefaults vb hb boxPackStartDefaults hb btn boxPackStartDefaults hb btn2 hgf <- onClicked btn $ do si <- textBufferGetStartIter tb ei <- textBufferGetEndIter tb val <- textBufferGetText tb si ei False textBufferSetText tb $ show $ (+1) $ read val disconnect hgf onClicked btn2 $ do quit <- quitDialog if quit then widgetDestroy win else return () containerAdd win vb widgetShowAll win mainGUI

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未承諾広告＊５億９千万円収入証拠から３億円へ一歩　　　
by ５億９千万円証拠有ビジネス 15 Jun '03

15 Jun '03

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no subject
by Team domeus 15 Jun '03

15 Jun '03

Hello haskell-cafe(a)haskell.org, You successfully unsubscribed from the group intelligentlearning(a)domeus.co.uk. You will not receive any more messages from this group. Best regards, Your Domeus Team

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Welcome to the group Intelligent Learning
by Team domeus 15 Jun '03

15 Jun '03

Hello haskell-cafe(a)haskell.org, You have been added to the group Intelligent Learning (intelligentlearning(a)domeus.co.uk) The group owner sends the following welcome message: ---------------------------- Welcome to Intelligent Learning! Our systems and programs can help you to successfully optimize your professional potential in a changing world. To be able to progress efficiently in any area today, we promote new smart working and learning systems through new techniques, tools and methodologies (TTMs) in key Smart Learning Areas: Knowledge Management, Change Management, Quantitative Learning, Qualitative Learning, Skill Management and Business Intelligence. For more information visit our web www.amjsmartlearning.com info(a)amjsmartlearning.com ---------------------------- If you do not wish to receive mails from this group, please return this eMail by clicking on reply. Alternatively, you can send an eMail to intelligentlearning-unsubscribe(a)domeus.co.uk. To unsubscribe via the web please use the following link: http://uk.domeus.com/public/unsubscribe.jsp?tsp=1055676075383&gid=337463&ui… Either way you will be directly deleted from the distribution list. If you have any questions or concerns, please contact the moderators of this Domeus group at intelligentlearning-moderators(a)domeus.co.uk. If your eMail address has been added to this list without your consent and you do not wish to receive any eMails from Domeus, please forward this message to: set_account_inactive(a)domeus.co.uk. Please note that this will disable your eMail address throughout the Domeus system. If you have any questions or problems concerning domeus please contact admin(a)domeus.co.uk. Best regards, Your Domeus Team

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Haskell.org out of date
by Hampus Ram 15 Jun '03

15 Jun '03

Who takes care of haskell.org? If it is the "community" we're obviously not doing it right, lots of broken links and some that is there but does not work (e.g. the wish-list). Only the "libraries and tools" page contains 16 broken links (according to linkchecker.sf.net) and some of the tools should in my opinion be marked clearly with "antique" so you do not get upset when they require ghc 2 to compile without problem... /Hampus - (I can't decide where it's best to post this...) -- Homepage: http://www.dtek.chalmers.se/~d00ram E-mail: d00ram(a)dtek.chalmers.se "Det är aldrig försent att ge upp"

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REPLY REQUIRED: Confirm subscription to group Intelligent Learning
by Team domeus 14 Jun '03

14 Jun '03

Hello haskell-cafe(a)haskell.org, thanks for your interest in the group Intelligent Learning (intelligentlearning(a)domeus.co.uk) If you would like to accept this invitation, please return this eMail by clicking on reply or subscribe via the Web. http://uk.domeus.com/public/subscribe.jsp?tsp=1055553244893&gid=337463&uid=… If you are not interested in joining, please ignore this eMail and you will receive no further eMails from us. The group owner sends the following welcome message: ----------------------------- Welcome to Intelligent Learning! Our systems and programs can help you to successfully optimize your professional potential in a changing world. To be able to progress efficiently in any area today, we promote new smart working and learning systems through new techniques, tools and methodologies (TTMs) in key Smart Learning Areas: Knowledge Management, Change Management, Quantitative Learning, Qualitative Learning, Skill Management and Business Intelligence. For more information visit our web www.amjsmartlearning.com info(a)amjsmartlearning.com ----------------------------- If you would like to use the full range of features, just log in at http://uk.domeus.com using the following log-in information: username: haskell-cafe(a)haskell.org password: fetifak8 If your eMail address has been added to this list without your consent and you do not wish to receive eMails from Domeus, please forward this message to: set_account_inactive(a)domeus.co.uk. Please note that this will disable your eMail address throughout the Domeus system. Best regards, Your Domeus Team

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Testing was Re: main modules in GHC, deriving differences between GHC and Hugs
by Matthew Donadio 14 Jun '03

14 Jun '03

(redirected to haskell-cafe) Hal Daume III wrote: > Yes, but there's a problem with this solution. Namely, if Foo.hs takes a > long time to compile, then you can't leverage having already created Foo.o > and Foo.hi when making the Main. Yeah, it's not perfect, but I think we just have different methodologies for testing. Typically, I do most of my development with ghci or hugs. Each module will have a single variable that represents the tests tests :: [Bool] tests = [ test1, test2, test3 ... ] and then I define a variable called test :: Bool test = and tests so I can just load a module and either evaluate tests or test to check things out. This generalizes to importing and testing several modules at once (as long as I take care of name conflists). This only works for simple modules, though. For more complicated ones, I have a "pretty" tester. For example, my Haskell FFT library is collection of mutually recursive modules. I have a specialzed test function for this that tests a range of lengths. It looks someone like main = testfft n1 n2 testfft n1 n2 = sequence $ map test1fft [n1..n2] test1fft n = do putStr $ show n ++ ":\t" putStr $ if ok then "OK\n" else "ERROR\n" where ok = and [ test1 n, test2 n, test3 n ] This way I can compile the code, and run the executable as ffttest 2 2048 | grep ERROR and I am confident that I get full coverage of the algorithm. I am always to hear about other methods of automated testing. -- Matthew Donadio (m.p.donadio(a)ieee.org)

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powerset
by Graham Klyne 13 Jun '03

13 Jun '03

A brief search of the libraries didn't reveal (top me) a ready-to-roll powerset function. I thought this may be a useful exercise to see how well I'm picking up on functional programming idioms, so I offer the following for comment: [[ -- |Powerset of a list, in ascending order of size. -- Assumes the supplied list has no duplicate elements. powerSet :: [a] -> [[a]] powerSet as = foldl (++) [] [ combinations n as | n <- intRange 1 (length as) ] -- |Combinations of n elements from a list, each being returned in the -- order that they appear in the list. combinations :: Int -> [a] -> [[a]] combinations _ [] = [] -- Don't include empty combinations combinations n as@(ah:at) | n <= 0 = [[]] | n > length as = [] | n == length as = [as] | otherwise = (map (ah:) $ combinations (n-1) at) ++ (combinations n at) -- |Return list of integers from lo to hi. intRange :: Int -> Int -> [Int] intRange lo hi = take (hi-lo+1) (iterate (+1) 1) -- Tests testcomb0 = combinations 0 "abcd" -- [] testcomb1 = combinations 1 "abcd" -- ["a","b","c","d"] testcomb2 = combinations 2 "abcd" -- ["ab","ac","ad","bc","bd","cd"] testcomb3 = combinations 3 "abcd" -- ["abc","abd","acd","bcd"] testcomb4 = combinations 4 "abcd" -- ["abcd"] testcomb5 = combinations 5 "abcd" -- [] testpower = powerSet "abc" -- ["a","b","c","ab","ac","bc","abc"] ]] I think the recursive use of 'combinations' may be inefficient, and could maybe be improved by "memoizing"? #g ------------------- Graham Klyne <GK(a)NineByNine.org> PGP: 0FAA 69FF C083 000B A2E9 A131 01B9 1C7A DBCA CB5E

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Green Card and Exceptions
by Matthew Donadio 13 Jun '03

13 Jun '03

Hi all, I have a couple of questions about Green Card and exceptions. I am interfaceing to the GSL to get access to a few functions, and eventually interface all of the special functions to Haskell. And unlike my DSP library, and am trying to get it right the first time. :) Below is a Green Card interface to one of the functions. %fun airy_Ai_e :: Double -> (Double, Double) %call (double x) %code int rc; % double val; % double err; % gsl_sf_result result; % rc = gsl_sf_airy_Ai_e(x, GSL_PREC_DOUBLE, &result); % val = result.val; % err = result.err; %result (double val, double err) This definition works, but it ignores the return code from the library function. The various return codes are from an enum defined in a header file. I would like to throw a Haskell exception (one of the ArithExceptions defined in Control.Exception) depending on the value of "rc". Do I need to create a new DIS for the return values (which are an enum defined in a header), change the function to return a triplet (var,err,rc), and then throw the exception in Haskell land? Is there a way I can do this directly from the GC interface? If I have to create a DIS, can this be shared across several modules that all need the same functionality? Thanks. -- Matthew Donadio (m.p.donadio(a)ieee.org)

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chance to help out on the wiki
by Isaac Jones 13 Jun '03

13 Jun '03

Greetings. We added a page "Fundamental Concepts" to the wiki so that we might have a very specific reference to pass along to people with questions, and to add links to definitions throughout the wiki. http://www.haskell.org/hawiki/FundamentalConcepts A lot of concepts need to be filled in, and if you haven't participated in the Wiki yet, now is a good time :) If you've never used a wiki, you can read about it here: http://www.haskell.org/hawiki/HelpForBeginners You might model your explanations after a page I wrote for PatternMatching which has: - a reference to a tutorial - a reference to the haskell report - an explanation - some examples Feel free to extend and / or correct anything already there. The front page of the wiki is here: http://www.haskell.org/hawiki/FrontPage peace, isaac

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