December 2010 - Haskell

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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Post positive reviews
by Eugene Zola 14 Dec '10

14 Dec '10

Google’s Huge Change and How it affects you. • Anyone can now post bad reviews and kill your rank. • We post good reviews and improve your rank. • We post good reviews to keep others from killing your rank. Google: Judge, Jury and Online Shopping Executioner Google rank is based on reviews of your business? Google Statement: "...in the last few days we developed an algorithmic solution which detects the merchant from the Times article along with hundreds of other merchants that, in our opinion, provide an extremely poor user experience. The algorithm we incorporated into our search rankings represents an initial solution to this issue, and Google users are now getting a better experience as a result." This means that anyone can write bad reviews about your business and lower your ranking. We knew that getting good reviews and not getting bad reviews was always important. Now it is a must to have good reviews for your business to keep the rank safe or to improve rank with Google. We post positive reviews for your company. We have the experience and ability to post hundreds of positive reviews that are all unique content and posted on unique IP addresses. www.postingpositivereviews.com

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missing http://www.haskell.org/~pairwise/intro/intro.html
by Ben Clifford 14 Dec '10

14 Dec '10

it was just pointed out to me that http://www.haskell.org/~pairwise/intro/intro.html is missing, which is linked from the tutorial page. I don't own that page but I'm forwarding the observation here in case someone else thinks they do... Ben -- http://www.hawaga.org.uk/ben/

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Functor => Applicative => Monad
by John Smith 14 Dec '10

14 Dec '10

I would like to formally propose that Monad become a subclass of Applicative, with a call for consensus by 1 February. The change is described on the wiki at http://haskell.org/haskellwiki/Functor-Applicative-Monad_Proposal, and ticketed at http://hackage.haskell.org/trac/ghc/ticket/4834. As this would require a change to the prelude, it will presumably be necessary for GHC and the Haskell report to change in tandem. The Haskell' committee expects proposals to have been implemented before changing the standard, so I will propose this to Haskell' after it is accepted for GHC. Hopefully this will be sufficient to avoid a race condition.

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reference to DoCon
by Serge D. Mechveliani 13 Dec '10

13 Dec '10

Dear administration of www.haskell.org, (I am sorry for not finding a more appropriate list for this letter) In old days, my program system DoCon (computer algebra written in Haskell) had its copy on www.haskell.org/docon/ -- if I remember correct. Now, I need to set a certain reference, but do not find any DoCon copy on the Haskell site. Then, I searched just for any reference to DoCon at www.haskell.org. It mentions DoCon in the application section of "Computer Algebra", but the reference does not work: "page not found". On the other hand, each year someone of the Haskell site asks me to confirm the references to my Haskell applications, and I respond, and this always looked all right. Now, if you decide to remove the DoCon directory from haskell.org, then, can you, please, inform me explicitly? Also I ask you at least to provide in an appropriate place the reference http://botik.ru/pub/local/Mechveliani/docon/ to the home of DoCon; so far, this place is the most supported. Please, copy the respond to mechvel(a)botik.ru With kind regards, ----------------- Serge Mechveliani mechvel(a)botik.ru

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Re: [Haskell] Please help me to reconstruct the Yarrow website! Re: New haskell.org server
by Frank Rosemeier 12 Dec '10

12 Dec '10

Hello Malcolm, As I mentioned in my mail thirty days are not enough for me to realize such a change. It has not been mentioned how long the old website will be available. Please help me to obtain a fair treatment for the Yarrow website! Is there any chance to obtain an account for the old internet address for a sufficient time? Kind regards Frank Rosemeier Am 10.12.2010 um 17:46 schrieb Malcolm Wallace: > Hello Frank. > > In the email quoted below, Ian gave you links to instructions on > how to apply for an account and project on community.haskell.org. > To my knowledge, you have not yet applied for such an account. > That will be the first step to getting your website running again. > > Regards, > Malcolm > >> 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@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 >>>> >>> >> >> _______________________________________________ >> Haskell mailing list >> Haskell(a)haskell.org >> http://www.haskell.org/mailman/listinfo/haskell >

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ANN: blaze-builder-0.2.1.0 and blaze-builder-enumerator-0.2.0.0
by Simon Meier 12 Dec '10

12 Dec '10

Dear Haskellers, I'm pleased to announce the release of blaze-builder-0.2.1.0 and blaze-builder-enumerator-0.2.0.0. The blaze-builder package provides a builder type that allows for the serialization of Haskell values in a form that can be output efficiently over the network, to a file, or just into a lazy bytestring. The blaze-builder-enumerator package allows for the incremental execution of builders and passing-on the produced bytestrings to another iteratee. Note that both packages are work-in-progress. Currently, their development is driven by the objective to use the builder monoid as the core representation of byte sequences in the output path of the snap framework HTTP server. Once the packages become more stable, I will work towards separating their functionality more precisely and integrating them smoothly with existing packages like, for example, bytestring, binary, and enumerator. Note also that currently compiling blaze-builder with the LLVM backend results in a library that segfaults! I hope to find a more minimal test case than the current testsuite of blaze-builder to make an appropriate bug entry for GHC. blaze-builder changes since 0.2.0.0 * new functionality - Blaze.ByteString.Builder.HTTP: provides a builder transformer for doing in-buffer chunked HTTP encoding of an arbitrary other builder. - Blaze.ByteString.Builder.Char8: provides functions to serialize the lower 8-bits of characters similiar to what 'Data.ByteString.Char8' provides for bytestrings. * bugfixes: - use ' instead of ' for HTML escaping - compiles with GHC 7.0.1 (http://hackage.haskell.org/trac/ghc/ticket/4498 was a problem) * internal restructuring: - `BuildStep's support returning a result in `Done`, which enables to implement a `Put` monad using CPS. Hence, we can now build a full replacement of the encoding part of the 'binary' package based on blaze-builder. - The `Write` abstraction has been restructured to allow for a more efficient Monoid instance and better insulation of user code from abstraction changes. best regards, Simon Meier

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[ANNOUNCE] haskell-mpi-1.0.0
by Dmitry Astapov 09 Dec '10

09 Dec '10

Dear Haskellers, We are pleased to announce the release of haskell-mpi-1.0.0, a suite of Haskell bindings to the C MPI library and convenience APIs on top of it. About MPI --------- MPI, the Message Passing Interface, is a popular communications protocol for distributed parallel computing (http://www.mpi-forum.org/) MPI applications consist of independent computing processes which share information by message passing. It supports both point-to-point and collective communication operators, and manages much of the mundane aspects of message delivery. There are several high-quality implementations of MPI available, all of which conform to the standard API specification (the latest version of which is 2.2). The MPI specification defines interfaces for C, C++ and Fortran, and bindings are available for many other programming languages. About Haskell-MPI ----------------- As the name suggests, Haskell-MPI provides a Haskell interface to MPI, and thus facilitates distributed parallel programming in Haskell. It is implemented on top of the C API via Haskell's foreign function interface. Haskell-MPI provides three different ways to access MPI's functionality: * A direct binding to the C interface (see Control.Parallel.MPI.Internal). * A convenient interface for sending arbitrary serializable Haskell data values as messages (see Control.Parallel.MPI.Simple). * A high-performance interface for working with (possibly mutable) arrays of storable Haskell data types (see Control.Parallel.MPI.Fast). We do not currently provide exhaustive coverage of all the functions and types defined by MPI 2.2, although we do provide bindings to the most commonly used parts. In future we plan to extend coverage based on the needs of projects which use the library. The package is available from http://hackage.haskell.org/package/haskell-mpi. Examples and comprehensive testsuite are included in the source distribution. Code was tested on 32- and 64-bit platforms, with MPICH2 and OpenMPI. The Fast API shows performance comparable to C, and the Simple API is generally 2-7 time slower due to (de)serialization overhead and necessity to issue additional MPI requests behind the curtains in some cases. Bernie Pope started this project as a rewrite of hMPI which was written by Michael Weber and Hal Daume III. He was later joined by Dmitry Astapov, working on the library as part of Well-Typed LLP's Parallel Haskell Project. Development is happening on GitHub, in git://github.com/bjpop/haskell-mpi. Please join in! Sincerely yours, Dmitry Astapov, Bernie Pope -- Dmitry Astapov Well-Typed LLP, http://www.well-typed.com/

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haskell.org migration complete
by Ian Lynagh 09 Dec '10

09 Dec '10

Hi all, The haskell.org server migration is now complete. Please let us know if you have any problems. Thanks Ian

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