- Haskell-Cafe - Haskell.org

Distributing Haskell on a cluster
by felipe zapata 16 Mar '15

16 Mar '15

Hi all, I have posted the following question on stackoverflow, but so far I have not received an answer. http://stackoverflow.com/questions/29039815/distributing-haskell-on-a-clust… I have a piece of code that process files, processFiles :: [FilePath] -> (FilePath -> IO ()) -> IO () This function spawns an async process that execute an IO action. This IO action must be submitted to a cluster through a job scheduling system (e.g Slurm). Because I must use the job scheduling system, it's not possible to use cloudHaskell to distribute the closure. Instead the program writes a new *Main.hs* containing the desired computations, that is copy to the cluster node together with all the modules that main depends on and then it is executed remotely with "runhaskell Main.hs [opts]". Then the async process should ask periodically to the job scheduling system (using *threadDelay*) if the job is done. Is there a way to avoid creating a new Main? Can I serialize the IO action and execute it somehow in the node? Best, Felipe

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is build breakage data about the main Haskell platform projects available?
by Johan Larson 16 Mar '15

16 Mar '15

Dan Luu recently dug up some build performance data about various open source projects, and found that many such projects have broken builds more than half the time. http://danluu.com/broken-builds/ Unfortunately Luu's data set doesn't include Haskell. Does anyone have the facts on this? (A brief search didn't turn up anything.) -- Johan Larson -- Toronto, Canada

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package ParsecToken
by Kattamuri Ekanadham 15 Mar '15

15 Mar '15

I am new to the community and learning Parsec, reading the tutorial "Parsec, a fast combinator Parse" by Daan Leijen. In the tutorial, the examples import the package called "ParsecToken" and I could not find this package any where (I found many variants like Text.Parsec.Token, Text.ParseCombinators.Parsec.Token etc.) So I was unable to execute those examples given there. Q1. How do I find the package name for "ParsecToken" so that I can do cabal import? Thanks.

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Wrong .hsc file paths on Windows
by Marcin Mrotek 15 Mar '15

15 Mar '15

Hello, I was trying to port some of my code to Windows. I've installed GHC with MinGHC (https://github.com/fpco/minghc) Unfortunately some packages, namely zlib and network, won't install, with the same error: getModificationTime cannot locate a file like CodecCompressionZlibStream.hsc or NetworkSocketTypes.hsc. With zlib, I figured out I just need to change mentions of "Codec/Compression/(...)" adding two slashes instead of one. Now with network I'm stuck, I can't find where the path was set at all. Is there some step I should have done prior to installation that would get the paths right? Best regards, Marcin Mrotek

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π-day
by Henk-Jan van Tuyl 14 Mar '15

14 Mar '15

Happy super pi day everybody! Henk-Jan van Tuyl -- Folding@home What if you could share your unused computer power to help find a cure? In just 5 minutes you can join the world's biggest networked computer and get us closer sooner. Watch the video. http://folding.stanford.edu/ http://Van.Tuyl.eu/ http://members.chello.nl/hjgtuyl/tourdemonad.html Haskell programming --

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Re: [Haskell-cafe] install 7.8.4 64 bits on arch linux
by Lars Hupel 14 Mar '15

14 Mar '15

> sudo pacman -S ghc > And I get the same errormessage. > Even sudo pacman -R ghc gives the same error. Odd. Before installing 'ghc', please try this: $ sudo pacman -Rucs ghc haddock haskell-ghc-paths '-Rucs' will recursively remove all existing dependencies. Please double-check the list of packages pacman prints, because they will all be removed. Cheers Lars PS: Please CC the list when you reply to messages. There might be more competent people than me lurking there :-)

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install 7.8.4 64 bits on arch linux
by Kees Bleijenberg 14 Mar '15

14 Mar '15

I want to upgrade from 7.8.3 32 bits to 7.8.4 64 bits on Arch Linux. So I removed ghc, cabal etc and followed the instruction at: http://sapiengames.com/2014/04/05/install-haskell-platform-arch-linux/ Added the lines [haskell-core] Server = http://xsounds.org/~haskell/core/$arch to pacman.conf added the pacman-key as described updated pacman and finally the fun parts should start.. $ sudo pacman -S ghc cabal-install happy alex looking for inter-conflicts... error: failed to prepare transaction (could not satisfy dependencies) :: haddock: requires ghc=7.8.3-2 :: haskell-ghc-paths: requires ghc=7.8.3-1 What is wrong and what can I do? Kees

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ANNOUNCE: Euterpea 1.0.0
by Daniel Winograd-Cort 13 Mar '15

13 Mar '15

We are happy to announce the official release of Euterpea! Euterpea is a library for computer music research, education, and development, providing both note-level and signal-level abstractions. It is a descendant of Haskore and HasSound and is intended for both educational purposes as well as serious computer music applications. Euterpea is suitable for high-level music representation, algorithmic composition, and analysis; mid-level concepts such as MIDI; and low-level audio processing, sound synthesis, and instrument design. It also includes an extensible system for building musical user interfaces using UISF, a new AFRP UI library. Euterpea's performance is sufficient for most real-time midi applications and some basic real-time audio synthesis. Try it out with cabal install Euterpea You can find more at... euterpea.com - a site for a quick start, tutorials, and working examples haskell.cs.yale.edu/euterpea - more detailed info and help, including an in-progress textbook (Haskell School of Music) hackage.haskell.org/package/Euterpea - the hackage page with some docs

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Additional functionality using cabal configure flags
by Sumit Sahrawat, Maths & Computing, IIT (BHU) 13 Mar '15

13 Mar '15

Hi everybody, I am looking for the correct way to provide additional functionality using cabal configure flags. Even though the developer faq [1] says that it is not recommended, I don't see any downsides for an executable package. Is it 'not recommended' even for executable packages? If not, then how can I do it? [1]: https://wiki.haskell.org/Cabal/Developer-FAQ -- Regards Sumit Sahrawat

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Haskell Weekly News: Issue 320
by Semen Trygubenko / Семен Тригубен ко 13 Mar '15

13 Mar '15

New Releases The sbv package SBV can now generate proof goals that are discharged by ABC, using state-of-the-art SAT based techniques, has better support for IEEE-floats, and a reworked implementation of the connection to the Boolector solver. http://hackage.haskell.org/package/sbv-4.1 Talks Stop Treading Water: Learning to Learn A talk about the alternative to Feynman's algorithm (that can be taught), the total cost of using wrong solutions (integrated over your entire career), the dual of "How to be a Genius" (and how to become a Genius Consultant), and how to beat the exponential decay of human memory (using Spaced Repetition and Going Deeper When You Come Back strategies)! https://yow.eventer.com/yow-2014-1222/stop-treading-water-learning-to-learn… Discussion Solutions in search of problems and problems in search of solutions A comment by Edward Kmett. http://www.reddit.com/r/haskell/comments/2yfris/stop_treading_water_learnin… Once you've seen the beautiful, you don't want to go back to the ugly Discussion of which Haskell ways can benefit what other languages and how to stay employed and satisfied. http://www.reddit.com/r/haskell/comments/2y47rf/once_youve_seen_the_beautif… Learning Haskell — A Racket programmer's documentation of her foray into the land of Haskell (inspired by Learning Racket) Days 0 through 2 are documented so far. http://lexi-lambda.github.io/learning-haskell/ What imperative languages do Haskellers like? Haskell is at the top of the list, followed by C++. http://www.reddit.com/r/haskell/comments/2yqnst/what_imperative_languages_d… Quotes of the Week "Practically every modern human has at least half an hour of spare time a day. If you want to fill that with textbooks or Better Call Saul is up to you." (kqr) "Fritz Henglein's work on discrimination gives you linear time versions of almost everything." (edwardkmett) http://www.reddit.com/r/haskell/comments/2yfris/stop_treading_water_learnin… "I think learning C is just as enlightening as learning Haskell. It forces you to get intimate with your machine in ways other languages (including C++) actively discourage or even forbid." (TheManaKnight) "It seems that after trying haskell not only you can not write anything in other languages, but also you can not solve any problem without going to the deep of it and discover something that truly solves the problem in the deeper sense." (agocorona) http://www.reddit.com/r/haskell/comments/2y47rf/once_youve_seen_the_beautif… "How do I use lens confusing?" "You mean 'it's confusing'" "No, I mean Control.Lens.Traversal.confusing" (cocharles) http://hackage.haskell.org/package/lens-4.8/docs/Control-Lens-Traversal.htm…

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