- Haskell-Cafe - Haskell.org

maybe IO doesn't suck, but my code does...
by Frédéric Gobry 05 Dec '04

05 Dec '04

Hello, I'm a haskell beginner, and I'm struggling with the following problem: I've started writing a simple apache log file analyzer, but I cannot get rid of important memory usage problems (in fact, at each attempt, I fear I won't be able to unlock my box as my linux 2.6.9 kernel is on its knees, which reminds me on my early days writing C on MMU-less processors... not because of the language of course :-)) Enclosed is a sample code, which aborts on a large (> 100000 lines) file. I tried different variations (readFile $ lines, openFile, openFile + IORef,...) but with no success... So, if the enclosed version is not too far, please give me a hint. Alternatively, if I took the wrong direction, please refocus my search .-) Thanks in advance, Frédéric -- Frédéric Gobry Infoscience DIT-KIS / EPFL Tel: +41216932288 http://people.epfl.ch/frederic.gobry

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more haskell in the news (for nerds)
by isaac jones 04 Dec '04

04 Dec '04

(please followup-to haskell-cafe) This slashdot story mentions Haskell being used to solve puzzles: http://developers.slashdot.org/developers/04/12/04/0116231.shtml?tid=159&ti… I did a quick search on slashdot to discover that Haskell has been in the topic of a slashdot story 4 times in the last 10 months (since march 2003). 5 times if you count a review of "Purely Functional Data Structures". In the year before that, it was mentioned only once in passing. In 2001, it was the topic once, and mentioned once in passing. In 2000 there were several stories on functional programming that mentioned Haskell. Any way you look at it, Haskell has gotten a lot more attention on Slashdot lately than it has since the beginning of the archives. Here's a link to the stories: http://slashdot.org/search.pl?tid=&query=haskell&author=&sort=1&op=stories peace, isaac

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Quzzle
by Thomas Davie 04 Dec '04

04 Dec '04

Hi, Having read an interesting, but simplistic article on the development of Quzzle in Haskell on slashdot (http://developers.slashdot.org/article.pl?sid=04/12/04/ 0116231&threshold=1&tid=159&tid=156). I was wondering if anyone knew of any more in depth reviews of what Jim Lewis did to create the puzzle. Is there a paper available on it? Thanks Tom Davie -- Computer Science is as much about computers as astronomy is about telescopes -- Edsgar Dijkstra

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Re: [Haskell-cafe] Non-technical Haskell question
by Keean Schupke 04 Dec '04

04 Dec '04

Some of the features they are adding to c# are pretty cool. Nothing you can't do in Haskell, but it does have the advantage of familiar syntax. On the other hand they say it is easier to teach functional programming to people who have never programmed before. I was of course thinking of how to persuade someone to adopt Haskell as yet another programming language. Marc Charpentier wrote: > On 3 déc. 2004, at 17:18, Keean Schupke wrote: > > Its not yet another programming language - it's the future and you > don't want to be left behind... > > Keean. > > > But Erik Meijer wrote (http://blogs.gotdotnet.com/emeijer/) > > " Pure functional programmers, your days are numbered. The grim reaper > is knocking at your door." > > :-/ > > > > > Marc Charpentier

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Classes in type declarations in Hugs
by John Goerzen 04 Dec '04

04 Dec '04

Hello, I have this line: type CPResult a = MonadError CPError m => m a GHC (with various command-line options I'm already using) compiles this fine. hugs, with -98 +o, complains: Syntax error in input (unexpected `=>') How do I make this work both places?

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Top-level state debate on the wiki
by George Russell 03 Dec '04

03 Dec '04

Ben Rudiak wrote (snipped): > I put up a wiki page summarizing the main proposals for top-level > mutable state. The type-dictionary approach isn't there yet, but there's > a space for it; I'll probably fill it in within the next 24 hours unless > someone else feels like doing it first. > > Please add more detail, objections, examples. Especially examples! > > Here's the page: > > http://haskell.org/hawiki/GlobalMutableState I have added a summary of the type-dictionary approach. I recommend other people look at this page and, if there is something they disagree with, amend it so that their own view is reflected. IMO the WiKi approach is an excellent way of obtaining consensus and providing an overview of the topic.

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problem building hmake on Mac OS X
by Steven Elkins 03 Dec '04

03 Dec '04

Hello everyone, I'm trying to build hmake on version 10.3.6 of Mac OS, having installed the ghc 6.2.2 dmg I found on haskell.org, but I'm encountering the following problem: Steven-Elkins-Computer:~/haskell/hmake-3.09 sge$ make cd src/hmake; make HC=ghc all config /Users/sge/haskell/hmake-3.09/lib/powerpc-Darwin7/config:9: *** missing separator. Stop. make: *** [targets/powerpc-Darwin7/hmake-ghc] Error 2 Here's lib/powerpc-Darwin7/config: Steven-Elkins-Computer:~/haskell/hmake-3.09 sge$ cat lib/powerpc-Darwin7/config BUILDWITH=ghc BUILDOPTS="" INSTALLVER="3.09 (2004-11-13)" INSTALLINFO="config: powerpc-Darwin7/ by sge(a)Steven-Elkins-Computer.local on Thu Dec 2 04:43:46 EST 2004" BUILDBASEDIR=/Users/sge/haskell/hmake-3.09/targets READLINE="-DUSE_READLINE=1 -lreadline" EXE= GHCSYM=#pragma GCC set_debug_pwd "/Users/sge/haskell/hmake-3.09" 602 TRUE=/usr/bin/true In case Gmail wraps this, line 9 has the oracular '602'. Finally, here's the ./configure output: Steven-Elkins-Computer:~/haskell/hmake-3.09 sge$ ./configure --prefix=/usr/local Configuring for hmake... [ 3.09 (2004-11-13) ] -------- Looking for already-installed Haskell compilers: Looking for hbc... (not found) Note: LMLDIR/HBCDIR variables must be set to enable detection of hbc. Looking for ghc... found 6.2.2 Looking for nhc98... (not found) I am guessing that you want to use ghc to build hmake. Now I'm creating targets/powerpc-Darwin7/hmake3.config for your installation. Done. -------- Configuration report for hmake. (You can re-run configure to change settings before proceeding.) You wish (eventually) to install the following components in these locations: (Installation directories are not created/checked at this stage.) Final install root: /usr/local hmake binaries: /usr/local/lib/hmake/powerpc-Darwin7 Scripts: /usr/local/bin Man pages: /usr/local/man/man1 Now we check/create your build directories: Config directory: targets/powerpc-Darwin7 Build directory root: /Users/sge/haskell/hmake-3.09/targets (exists) Object files build in: /Users/sge/haskell/hmake-3.09/targets/powerpc-Darwin7 (exists) Executables and libs: /Users/sge/haskell/hmake-3.09/lib/powerpc-Darwin7 (created) I have guessed you will build hmake with: ghc Testing for the curses library: -lncurses (detected) Testing for the readline library: -lreadline (detected) Executables need .exe suffix? no (detected) Found /usr/bin/true not /bin/true Adding Makefile config script to /Users/sge/haskell/hmake-3.09/lib/powerpc-Darwin7... Adding build scripts for hmake, hmake-config, and hi to /Users/sge/haskell/hmake-3.09/script... Updating targets/powerpc-Darwin7/hmake3.config... Saving current configuration in targets/powerpc-Darwin7/config.cache Done. Steven-Elkins-Computer:~/haskell/hmake-3.09 sge$ Thanks, Steve

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RE: [Haskell-cafe] Re: Non-technical Haskell question
by Simon Peyton-Jones 02 Dec '04

02 Dec '04

| I also have a very small start on a "haskell for hackers" ("hackers" in | the non-evil sense) sort of document. One this doesn't ignore I/O as | "hard" or "unimportant". I/O in Haskell doesn't suck. It's just that a | lot of people in the community don't have it as a high priority, I | think. As a shameless plug, have you tried "Tackling the awkward squad?". Indeed I/O in Haskell doesn't suck. http://research.microsoft.com/%7Esimonpj/papers/marktoberdorf Simon

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Top-level state debate on the wiki
by Ben Rudiak-Gould 02 Dec '04

02 Dec '04

I put up a wiki page summarizing the main proposals for top-level mutable state. The type-dictionary approach isn't there yet, but there's a space for it; I'll probably fill it in within the next 24 hours unless someone else feels like doing it first. Please add more detail, objections, examples. Especially examples! Here's the page: http://haskell.org/hawiki/GlobalMutableState (It also includes an explanation of why I chose that title, though of course you're welcome to dispute that too.) -- Ben

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memory leak in Random.randoms or makeList?
by S. Alexander Jacobson 01 Dec '04

01 Dec '04

Using ghci, I am getting this error message: *Main> timeOp $ print $ sizeFM bigFM' GHC's heap exhausted: current limit is 268435456 bytes; >From this code: makeList x = map ((\x->x `mod` range).abs) $ Random.randoms (Random.mkStdGen x)::[Int] range=100000 fmRecords' n = listToFM $ take n $ zip (makeList 100) (makeList 200) fmRecords n = listToFM $ take n $ zip [range..] [range..] fmSize=10^6 bigFM = fmRecords fmSize bigFM' = fmRecords' fmSize bigFM works fine so the leak is obviously within makeList. I just don't understand how makeList could produce this error... -Alex- ______________________________________________________________ S. Alexander Jacobson tel:917-770-6565 http://alexjacobson.com

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