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Haskell Weekly News: Issue 163 - Year End Issue
by Daniel Santa Cruz 31 Dec '10

31 Dec '10

Welcome to issue 163 of the HWN, a newsletter covering developments in the [1]Haskell community. This release of the newsletter contains some summary data for the year 2010. Thanks to everyone involved for making this such a wonderful community! Big cheers to Miran Lipovaa, who got multiple top Reddit stories this year for his work on Learn You a Haskell! Also kudos to Don Stewart, Norman Ramsey, camccann, sepp2k, and KennyTM for taking the time to answer so many questions in StackOverflow. The folks at #haskell never cease to amaze with their friendliness and their helpfulness as well. What did Reddit and StackOverflow think was hot this year? Top Reddit Stories this Year * Galois releases the Haskell Lightweight Virtual Machine (HaLVM): From (galois.com) scored 103 with 26 comments. Read on [2]reddit or the [3]original post. * Try Haskell!: From (self.haskell), scored 105 with 29 comments. Read on [4]reddit or the [5]original post. * GHC 7.0.1 released!: From (haskell.org) scored 100 with 31 comments. Read on [6]reddit or the [7]original post. * Learn You a Haskell: Zippers: From (learnyouahaskell.com) scored 93 with 44 comments. Read on [8]reddit or the [9]original post. * The new LLVM backend to GHC is ready to merge in!: From (haskell.org) scored 89 with 27 comments. Read on [10]reddit or the [11]original post. * Haskell vs. Erlang for bittorent clients: laziness, dynamic typing ..: From (jlouisramblings.blogspot.com) scored 88 with 8 comments. Read on [12]reddit or the [13]original post. * There are more than 4000 people in the Haskell Reddit. Tell us what you're using Haskell for! Work and/or play? What would most help you get the job done?: From (self.haskell), scored 84 with 171 comments. Read on [14]reddit or the [15]original post. * Smoking fast Haskell code using GHC's new LLVM codegen: From (donsbot.wordpress.com) scored 83 with 2 comments. Read on [16]reddit or the [17]original post. * Learn You a Haskell for Great Good! The Book!: From (amazon.com) scored 79 with 29 comments. Read on [18]reddit or the [19]original post. * LYAH: Intro to Monads: From (learnyouahaskell.com) scored 78 with 49 comments. Read on [20]reddit or the [21]original post. Top StackOverflow Answers this Year * [22]Large-scale design in Haskell? | votes: 1 I talk a bit about this in Engineering Large Projects in Haskell and in the Design and Implementation of XMonad. Engineering in the large is about managing complexity. The primary code structuring mechanisms in Haskell for managing complexity are : The type system Use the type system to enforce abstractions, simplifying interactions. Enforce key ... * [23]Curious about the HashTable problem | votes: 1 The problem was that the garbage collector is required to traverse mutable arrays of pointers ("boxed arrays") looking for pointers to data that might be ready to deallocate. Boxed, mutable arrays are the main mechanism for implementing a hashtable, so that particular structure showed up the GC traversal issue. This is common to many languages. The symptom ... * [24]Why are side-effects modeled as monads in Haskell? | votes: 1 Suppose a function has side effects. If we take all the effects it produce as the input and output parameters, then the function is pure to the outside world. So for an impure function f' :: Int -> Int we add the RealWorld to the consideration f :: Int -> RealWorld -> (Int, RealWorld) -- input some states of the whole world, -- modify the ... * [25]Haskell - I am too old for this Švotes: 1 (f . g) x = f (g x) This is true. You concluded from that that (f . g) x y = f (g x y) must also be true, but that is not the case. In fact, the following is true: (f . g) x y = f (g x) y which is not the same. Why is this true? Well (f . g) x y is the same as ((f . g) x) y and since we know that (f . g) x = f (g x) we can reduce that to (f (g x)) ... * [26]Haskell: How is <*> pronounced? | votes: 1 Sorry, I don't really know my math, so I'm curious how to pronounce the functions in the Applicative typeclass Knowing your math, or not, is largely irrelevant here, I think. As you're probably aware, Haskell borrows a few bits of terminology from various fields of abstract math, most notably Category Theory, from whence we get functors and monads. The ... * [27]Haskell Weird Kinds | votes: 1 These are GHC-specific extensions of the Haskell kind system. The Haskell 98 report specifies only a simple kind system: ... type expressions are classified into different kinds, which take one of two possible forms: The symbol * represents the kind of all nullary type constructors. If k1 and k2 are kinds, then k1->k2 is the kind of types ... * [28]Is Haskell really a purely functional language considering unsafePerformIO? | votes: 1 The Languages We Call Haskell unsafePerformIO is part of the Foreign Function Interface specification, not core Haskell 98 specification. It can be used to do local side effects that don't escape some scope, in order to expose a purely functional interface. That is, we use it to hide effects when the type checker can't do it for us (unlike the ST monad, ... * [29]What language to learn after Haskell? | votes: 1 I would like to broaden my knowledge of programming. (...) I thought I would pose the question here, along with several stipulations about the type of language I am looking for. Some are subjective, some are intended to ease the transition from Haskell. Strong type system. (...) It also makes informally reasoning about the correctness of my program ... * [30]Why is writing a compiler in a functional language easier? | votes: 1 Often times a compiler works a lot with trees. The source code is parsed into a syntax tree. That tree might then be transformed into another tree with type annotations to perform type checking. Now you might convert that tree into a tree only containing core language elements (converting syntactic sugar-like notations into an unsugared form). Now you might ... * [31]GHC's RTS options for garbage collection | votes: 1 Generally speaking, garbage collection is a space/time tradeoff. Give the GC more space, and it will take less time. There are (many) other factors in play, cache in particular, but the space/time tradeoff is the most important one. The tradeoff works like this: the program allocates memory until it reaches some limit (decided by the GC's automatic tuning ... About the Haskell Weekly News At this point in time, the HWN has been a bit sporadic. I'm hoping that 2011 will see a much more regular schedule for this channel. I'd like to thank everyone who pitched in and sent stories/comments/quotes. If you have any ideas of how to improve this letter, please don't hesitate to contact me at dstcruz(a)gmail.com. The source code that I use to cullate this newsletter will be made available shortly in github. Here is to wishing you a great 2011! Until next time, Daniel Santa Cruz References 1. http://haskell.org/ 2. http://www.reddit.com/r/haskell/comments/ee4ve/galois_releases_the_haskell_… 3. http://www.galois.com/blog/2010/11/30/galois-releases-the-haskell-lightweig… 4. http://www.reddit.com/r/haskell/comments/b58rk/try_haskell/ 5. file://localhost/r/haskell/comments/b58rk/try_haskell/ 6. http://www.reddit.com/r/haskell/comments/e6o0y/ghc_701_released/ 7. http://haskell.org/ghc/download_ghc_7_0_1.html 8. http://www.reddit.com/r/haskell/comments/e0qqz/learn_you_a_haskell_zippers/ 9. http://learnyouahaskell.com/zippers 10. http://www.reddit.com/r/haskell/comments/b3tby/the_new_llvm_backend_to_ghc_… 11. http://www.haskell.org/pipermail/cvs-ghc/2010-February/052606.html 12. http://www.reddit.com/r/haskell/comments/bwrhz/haskell_vs_erlang_for_bittor… 13. http://jlouisramblings.blogspot.com/2010/04/haskell-vs-erlang-for-bittorent… 14. http://www.reddit.com/r/haskell/comments/bhygx/there_are_more_than_4000_peo… 15. file://localhost/r/haskell/comments/bhygx/there_are_more_than_4000_people_in_the_haskell/ 16. http://www.reddit.com/r/haskell/comments/b4tel/smoking_fast_haskell_code_us… 17. http://donsbot.wordpress.com/2010/02/21/smoking-fast-haskell-code-using-ghc… 18. http://www.reddit.com/r/haskell/comments/dook4/learn_you_a_haskell_for_grea… 19. http://www.amazon.com/Learn-You-Haskell-Great-Good/dp/1593272839/ 20. http://www.reddit.com/r/haskell/comments/d51ao/lyah_intro_to_monads/ 21. http://learnyouahaskell.com/monads 22. http://stackoverflow.com/questions/3077866/large-scale-design-in-haskell/30… 23. http://stackoverflow.com/questions/3058529/curious-about-the-hashtable-prob… 24. http://stackoverflow.com/questions/2488646/why-are-side-effects-modeled-as-… 25. http://stackoverflow.com/questions/3884121/haskell-i-am-too-old-for-this/38… 26. http://stackoverflow.com/questions/3242361/haskell-how-is-pronounced/324285… 27. http://stackoverflow.com/questions/3034264/haskell-weird-kinds/3034295#3034… 28. http://stackoverflow.com/questions/3124591/is-haskell-really-a-purely-funct… 29. http://stackoverflow.com/questions/3770774/what-language-to-learn-after-has… 30. http://stackoverflow.com/questions/2906064/why-is-writing-a-compiler-in-a-f… 31. http://stackoverflow.com/questions/3171922/ghcs-rts-options-for-garbage-col…

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Many broken links
by Henk-Jan van Tuyl 31 Dec '10

31 Dec '10

L.S., I find, quite often, links to haskell.org/xxx pages that have disappeared; isn't it possible to just copy all of these pages, to the original location, before the old server disappears? I used the W3C link checker[0] to check links from the GUI libraries page[1]; the following pages were reported missing: - http://haskell.org/FranTk - http://www.haskell.org/fruit/ - http://haskell.org/ObjectIO - http://haskell.org/graphics/ Other (sets of) pages that are missing: - http://haskell.org/gtk2hs/ - http://haskell.org/hdirect/ - http://www.haskell.org/~simonmar/ - http://www.haskell.org/sitewiki/ - http://www.haskell.org/all_about_monads - http://darcs.haskell.org/hfuse/ - http://darcs.haskell.org/yaht - http://haskell.org/haskore/ - http://www.haskell.org/yampa/ - http://darcs.haskell.org/~lemmih/ and probably many more. I suppose some of the maintainers have left, but the pages might still have some value. Some pages might be copied to the HaskellWiki, if the author gives permission to do so. It would also be good, to know which of these pages are obsolete, so that the links to these pages can be removed. Regards, Henk-Jan van Tuyl [0] http://validator.w3.org/checklink/ [1] http://www.haskell.org/haskellwiki/Applications_and_libraries/GUI_libraries -- http://Van.Tuyl.eu/ http://members.chello.nl/hjgtuyl/tourdemonad.html --

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Come work at Jane Street!
by Yaron Minsky 29 Dec '10

29 Dec '10

Jane Street is looking to hire functional programmers for our offices in New York, London and Hong Kong. We're looking for both interns for this upcoming summer as well as full-time hires. Jane Street has the largest team of OCaml developers in any industrial setting, and probably the world's largest OCaml codebase. We use OCaml for running our entire business, supporting everything from research to systems administration to automated trading systems. If you're interested in using OCaml to solve real-world problems, there's no better place. Compensation is more than competitive, and no prior experience with finance is required. Follow this link to apply: http://janestreet.com/apply And here are some resources you can use to learn more about Jane Street and what we do. - A talk I gave at CMU about how and why we use OCaml http://ocaml.janestreet.com/?q=node/61 - Our technical blog http://ocaml.janestreet.com - Our website http://janestreet.com -- Yaron Minsky

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The Bay Area Haskell Hackathon is coming up: Feb 11-13, 2011
by Bryan O'Sullivan 23 Dec '10

23 Dec '10

Mark Lentczner and I are organizing, and it will be held at Hacker Dojo in Mountain View<http://maps.google.com/maps/place?cid=2122486601784397611&q=hacker+dojo&gl=…> . If you plan to attend, please fill in our sign-up form<https://spreadsheets.google.com/viewform?formkey=dEc5cW1fa3hjQ3JheVF5dHAwdT…> so we know we'll have room. Also, please consider joining the Hackathon's Google group<http://groups.google.com/group/bayhac> . We look forward to seeing you!

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Please help me to reconstruct the Yarrow website! Re: New haskell.org server
by Frank Rosemeier 19 Dec '10

19 Dec '10

Dear Haskellers, today I have noticed that the link http://www.haskell.org/yarrow is broken! Who is responsible or can help me to reconstruct the Yarrow home page? To my mind this it is not a fair treatment of the Yarrow wersite: I asked in September for prolongation of this website, than I have been informed thirty days ago that it has to be moved, so that I asked for support with the migration process about a week ago and today the homepage is not accessible. I would like to have more time and more support! Is it possible to setup the old home page for some weeks (or better months) again? Kind regards Frank Rosemeier Anfang der weitergeleiteten E-Mail: > Von: Frank Rosemeier <frank(a)rosemeier.info> > Datum: 2. Dezember 2010 10:08:08 GMT+01:00 > An: Ian Lynagh <igloo(a)earth.li> > Kopie: "Frank ((FH Hamm)) Rosemeier" <frank.rosemeier(a)fh-hamm.srh.de> > Betreff: Re: Yarrow website! Re: [Haskell] New haskell.org server > > > Hello Ian, > > I am sorry that the Yarrow homepage has to be moved. > How long will the old website be accessible? > > I would prefer to have the redirection for some years (not only for > some months) > because presumably it will take some months to create the new home > for Yarrow. > > Are there any tools or tutors to help me with this migration? > > > Kind regards > > Frank > > > > Am 20.11.2010 um 16:29 schrieb Ian Lynagh: > >> >> Hi Frank, >> >> Sorry for the slow reply; it's taken longer than I expected to get >> everything worked out. >> >> On Thu, Sep 09, 2010 at 07:21:48PM +0200, Frank Rosemeier wrote: >>> >>> the Yarrow website has been hosted by haskell.org for some years now >>> (http://www.haskell.org/yarrow/ ). >>> Thank you very much for this service! >>> >>> I would be very happy, if you could transfer these pages to the new >>> server. >> >> The haskell.org committee have decided that the community server >> would >> be a better fit for the yarrow site. We will be happy to add a >> redirect >> from http://www.haskell.org/yarrow/ to the community site for a few >> months, so links don't instantly break. >> >> To get an account on the community server, you need to fill in: >> http://community.haskell.org/admin/account_request.html >> and then to get a project for yarrow: >> http://community.haskell.org/admin/project_request.html >> Information on how to use a community project is here: >> http://community.haskell.org/admin/using_project.html >> >> Please let me know if you have any problems. >> >> >> Thanks >> Ian >> >

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macports, cabal, cabal-install difficulty
by Matthew Fairtlough 18 Dec '10

18 Dec '10

Hello, I'm new to this list and to hackage/cabal/cabal-install and haskell on the mac generally. I don't dare post on cabal-devel because I'm a newbie. I came to this question because I haven't been able to install the unix package properly (some packages I want depend on it) but I've posted separately in haskell-cafe on that. I've port version 1.9.2 and haskell-platform @2009.2.0.2 (devel, haskell) My question: Is cabal currently out-of-the-box compatible with macports? I seem to have problems with cabal-install, in particular the ld warning and the fact that cabal doesn't seem to know what version of cabal-install is installed. bash-3.2# cabal info cabal * Cabal (library) Synopsis: A framework for packaging Haskell software Latest version available: 1.10.0.0 Latest version installed: 1.10.0.0 bash-3.2# cabal install cabal-install-0.8.2 Resolving dependencies... Configuring cabal-install-0.8.2... Preprocessing executables for cabal-install-0.8.2... Building cabal-install-0.8.2... ....<lots of build information deleted>... [40 of 40] Compiling Main ( Main.hs, dist/build/cabal/cabal-tmp/Main.o ) Linking dist/build/cabal/cabal ... ld: warning: -read_only_relocs cannot be used with x86_64 Installing executable(s) in /Users/matthew/.cabal/bin bash-3.2# cabal info cabal-install * cabal-install (program) Synopsis: The command-line interface for Cabal and Hackage. Latest version available: 0.8.2 Latest version installed: [ Unknown ] ....and lots more:... Homepage: http://www.haskell.org/cabal/ Bug reports: http://hackage.haskell.org/trac/hackage/ Description: The \'cabal\' command-line program simplifies the process of managing Haskell software by automating the fetching, configuration, compilation and installation of Haskell libraries and programs. Category: Distribution License: BSD3 Author: Lemmih <lemmih(a)gmail.com> Paolo Martini <paolo(a)nemail.it> Bjorn Bringert <bjorn(a)bringert.net> Isaac Potoczny-Jones <ijones(a)syntaxpolice.org> Duncan Coutts <duncan(a)haskell.org> Maintainer: cabal-devel(a)haskell.org Source repo: http://darcs.haskell.org/cabal-install/ Executables: cabal Flags: old-base, bytestring-in-base Dependencies: unix >=1.0 && <2.5, Win32 ==2.*, bytestring >=0.9, base <2.0 || >=3.0, base >=2.0 && <2.2, old-time >=1 && <1.1, array >=0.1 && <0.4, containers >=0.1 && <0.4, random >=1 && <1.1, pretty >=1 && <1.1, directory >=1 && <1.1, process >=1 && <1.1, base >=3, base <3, time ==1.1.*, zlib >=0.4 && <0.6, HTTP >=4000.0.2 && <4001, network >=1 && <3, filepath >=1.0, Cabal ==1.8.*, base >=2 && <5 Cached: Yes

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Re: [Haskell] letter?
by Simon Peyton-Jones 18 Dec '10

18 Dec '10

Did someone forget to renew www.haskell.org? Who does this? Also plain http://haskell.org/ used to work, but doesn't any more. I'm sure lots of people have noticed this, but it'd be good if someone posted a summary of what's being done about it. Simon

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Haskell Weekly News: Issue 162 - December 15, 2010
by Daniel Santa Cruz 16 Dec '10

16 Dec '10

Welcome to issue 162 of the HWN, a newsletter covering developments in the [1]Haskell community in the week of December 05 - 11. Wouter Swierstra [2]sent a call for papers for the ICFP 2011 to be held in Tokyo, Japan between September 19 - 21. The announcement contains all relevant dates of importance Dmitry Astapov [3]announced the realease of haskell-mpi, "a suite of Haskell bindings to the C MPI [Message Passing Interface] and convenience APIs on top of it." David Waern [4]annouced a new version of the venerable Haddock. "This version is compatible with .haddock files produced by the version of Haddock that comes with GHC 7.0.1." Michael Snoyman [5]announced the first release of his library and executable packdeps. "This is a library and executable containing the same functionality as the original packdeps website, namely letting you know when your version bounds exclude the use of the newest version of a library available." Michael also [6]announced the second major release of the mime-mail library. This "is a package providing support for rendering multipart emails." Jasper Van der Jeugt [7]announced the 0.0.2.0 release of the digestive functors library. "The library provides a general API to input consumption, and is an upgrade of formlets." So, what went on this week? Top Reddit Stories * Cartesian Closed Comic: Résumé Domain: ro-che.info, Score: 35, Comments: 1 On Reddit: http://www.reddit.com/r/haskell/comments/ekiao/cartesian_closed_comic_résum… Original: http://ro-che.info/ccc/11.html * GHC blog: An overhaul of stack management, and some performance improvements Domain: hackage.haskell.org, Score: 32, Comments: 2 On Reddit: http://www.reddit.com/r/haskell/comments/emabe/ghc_blog_an_overhaul_of_stac… Original: http://hackage.haskell.org/trac/ghc/blog/stack-chunks * How do You use Emacs for Haskell Development? Domain: self.haskell, Score: 29, Comments: 10 On Reddit: http://www.reddit.com/r/haskell/comments/ehl99/how_do_you_use_emacs_for_has… Original: /r/haskell/comments/ehl99/how_do_you_use_emacs_for_haskell_development/ * Library versus Framework: Yesod's Own World Domain: docs.yesodweb.com, Score: 26, Comments: 22 On Reddit: http://www.reddit.com/r/haskell/comments/ejgen/library_versus_framework_yes… Original: http://docs.yesodweb.com/blog/yesods-own-world/ * Visualizing Haskell types part II, Gin and monotonic : Inside T5 Domain: blog.ezyang.com, Score: 24, Comments: 2 On Reddit: http://www.reddit.com/r/haskell/comments/eiaef/visualizing_haskell_types_pa… Original: http://blog.ezyang.com/2010/12/gin-and-monotonic/ * Package of the day: parallel-io: combinators for sequencing IO actions onto a thread pool Domain: hackage.haskell.org, Score: 21, Comments: 15 On Reddit: http://www.reddit.com/r/haskell/comments/ehsqo/package_of_the_day_paralleli… Original: http://hackage.haskell.org/package/parallel-io-0.2.2 * Package of the day: haskell-mpi: Control.Parallel.MPI for high performance parallel (cluster) computations in Haskell Domain: hackage.haskell.org, Score: 19, Comments: 5 On Reddit: http://www.reddit.com/r/haskell/comments/ej5av/package_of_the_day_haskellmp… Original: http://hackage.haskell.org/package/haskell-mpi-1.0.0 * From Polymorphism To Polytypism Domain: zenzike.com, Score: 19, Comments: On Reddit: http://www.reddit.com/r/haskell/comments/ejleb/from_polymorphism_to_polytyp… Original: http://zenzike.com/posts/2010-12-10-from-polymorphic-to-polytypic/ * Hussling Haskell types into Hasse diagrams : Inside T5 Domain: blog.ezyang.com, Score: 18, Comments: On Reddit: http://www.reddit.com/r/haskell/comments/eh2zw/hussling_haskell_types_into_… Original: http://blog.ezyang.com/2010/12/hussling-haskell-types-into-hasse-diagrams/ * Building a business with Haskell: Case Studies: Cryptol, HaLVM and Copilot Domain: corp.galois.com, Score: 17, Comments: 1 On Reddit: http://www.reddit.com/r/haskell/comments/ejmwq/building_a_business_with_has… Original: http://corp.galois.com/blog/2010/12/10/building-a-business-with-haskell-cas… Top StackOverflow Questions * What is the benefit of purely functional data structure? votes: 15, answers: 4 Read on SO: http://stackoverflow.com/questions/4399837/what-is-the-benefit-of-purely-fu… * Haskell: Equation Expander 1+(1+(1+(1+(…))))=∞ votes: 9, answers: 2 Read on SO: http://stackoverflow.com/questions/4404663/haskell-equation-expander-1111 * Pure Functional Language: Haskell votes: 7, answers: 6 Read on SO: http://stackoverflow.com/questions/4382223/pure-functional-language-haskell * How does a haskell compiler works? votes: 7, answers: 4 Read on SO: http://stackoverflow.com/questions/4385160/how-does-a-haskell-compiler-works * Haskell typeclasses and C++ template classes votes: 7, answers: 6 Read on SO: http://stackoverflow.com/questions/4411279/haskell-typeclasses-and-c-templa… * Are there any special challenges for functional programming in an embedded environment? votes: 7, answers: 1 Read on SO: http://stackoverflow.com/questions/4418617/are-there-any-special-challenges… * Haskell: Where vs. Let votes: 6, answers: 3 Read on SO: http://stackoverflow.com/questions/4362328/haskell-where-vs-let * What are some good example haskell projects? votes: 6, answers: 2 Read on SO: http://stackoverflow.com/questions/4369962/what-are-some-good-example-haske… * Program Structure — Simple Commandline To Do List App — What's the Haskell way? votes: 6, answers: 2 Read on SO: http://stackoverflow.com/questions/4383512/program-structure-simple-command… * Learning to read haskell in english votes: 6, answers: 4 Read on SO: http://stackoverflow.com/questions/4393908/learning-to-read-haskell-in-engl… Quotes of the Week * kmc: it's great how laziness lets you ignore the order of evaluation except all the times when it doesn't * tg_: I can't wait until 100 years from now when 'eating food' will be deprecated from our lexicon in favor of 'oming noms' * kmc: maybe the 9,639,482nd time we argue about C++ we will finally resolve the issue * Berengal: * ddarius liked xmonad better when it was 90 lines... * Berengal liked xmonad better when it was on vinyl About the Haskell Weekly News New editions are posted to [8]the Haskell mailing list as well as to [9]the Haskell Sequence and [10]Planet Haskell. [11]RSS is also available, and headlines appear on [12]haskell.org. To help create new editions of this newsletter, please send stories to dstcruz * at * gmail * dot * com. The code used to produce this version of the newsletter is not yet publicly available, as it is a complete hack designed to get things started again. Until next time, Daniel Santa Cruz References 1. http://haskell.org/ 2. http://article.gmane.org/gmane.comp.lang.haskell.general/18355 3. http://article.gmane.org/gmane.comp.lang.haskell.general/18357 4. http://groups.google.com/group/fa.haskell/browse_thread/thread/b0c838a2249f… 5. http://article.gmane.org/gmane.comp.lang.haskell.cafe/84141 6. http://article.gmane.org/gmane.comp.lang.haskell.cafe/84142 7. http://article.gmane.org/gmane.comp.lang.haskell.cafe/84201 8. http://www.haskell.org/mailman/listinfo/haskell 9. http://sequence.complete.org/ 10. http://planet.haskell.org/ 11. http://sequence.complete.org/node/feed 12. http://haskell.org/

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Terms of Service for Haskell community server
by Frank Rosemeier 16 Dec '10

16 Dec '10

Dear Haskellers, as some of you may have noticed, the Yarrow home page has to be moved because of the migration of the Haskell.org server. It has been recommended to me by Ian Lynagh to transfer the files to the new community server. To do so I need first to request for an account there. This includes producing an ssh certificate. I will try to solve this problem. (May be there will be questions in the future.) The more severe problem is related to the Terms of Service which I have to accept with the account request. It contains lots of legal stuff which I do not understand including regulations for US export controls. Of course I am neither able nor willing to send reports concerning Yarrow to the US government! Are there some experts or tutors who want to help me to understand the Terms of Service especially the export controls? May be these regulations do not apply in my case, because I am living in Germany? (I have expected lots of work to be done with respect to the migration, but I did not imagine to be involved in legal affairs which I do not understand.) Thank you very much for your patience. Kind regards Frank Rosemeier

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I'm a beginner --- struggling with the SimpleJSON example from Real World Haskell
by dhjdhj 14 Dec '10

14 Dec '10

I'm sure this question has been asked many times but I have not been able to find it anywhere. I have written the code below into Lekseh directly from the RWH book. However, I always get the error parse error on input 'getString' and the line number refers to the type declaration for getString. I have no idea what's wrong and would appreciate any suggestions to get past this. Thanks in advance David ---------------------------- module SimpleJSON ( JValue(..), getString, getInt, getDouble, getBool, getObject, getArray, isNull ) where data JValue = JString String | JNumber Double | JBool Bool | JNull | JObject [ (String, JValue) ] | JArray [JValue] deriving (Eq, Ord, Show) getString :: JValue -> Maybe String getString (JString s) = Just s getString _ = Nothing getInt (JNumber n) = Just (truncate n) getInt _ = Nothing getDouble (JNumber n) = Just n getDouble _ = Nothing getBool (JBool b) = Just b getBool _ = Nothing getObject (JObject o) = Just o getObject _ = Nothing getArray (JArray a) = Just a getArray _ = Nothing isNull v = v == JNull -- View this message in context: http://haskell.1045720.n5.nabble.com/I-m-a-beginner-struggling-with-the-Sim… Sent from the Haskell - Haskell mailing list archive at Nabble.com.

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