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Haskell Weekly News: Issue 296
by Daniel Santa Cruz 12 Jun '14

12 Jun '14

Welcome to issue 296 of the HWN, an issue covering crowd-sourced bits of information about Haskell from around the web. This issue covers from May 25 to June 7, 2014 Quotes of the Week * mbrock: then you get into a whole thing about the epistemology of abstract algebra, and someone brings up Wittgenstein, somebody brings out a bottle of wine, and it's yet another one of those nights Top Reddit Stories * An alternative Haskell home page Domain: chrisdone.com, Score: 160, Comments: 57 Original: [1] http://goo.gl/Yw2G3a On Reddit: [2] http://goo.gl/m19Ujx * Third generation of the attoparsec parsing library Domain: serpentine.com, Score: 82, Comments: 22 Original: [3] http://goo.gl/kk8i50 On Reddit: [4] http://goo.gl/LZzevb * Music-Suite Domain: music-suite.github.io, Score: 81, Comments: 44 Original: [5] http://goo.gl/u69ybm On Reddit: [6] http://goo.gl/EYKMwI * Erik Meijer: Introduction to Functional Programming Domain: edx.org, Score: 79, Comments: 11 Original: [7] http://goo.gl/YrfbA3 On Reddit: [8] http://goo.gl/oLRm6k * The abject failure of weak typing Domain: techblog.realestate.com.au, Score: 72, Comments: 28 Original: [9] http://goo.gl/h5XDVZ On Reddit: [10] http://goo.gl/nfnLNN * Lazy Dynamic Programming Domain: jelv.is, Score: 64, Comments: 12 Original: [11] http://goo.gl/kdSbkh On Reddit: [12] http://goo.gl/I6XVa8 * First Person 3D Navigation, written in Elm Domain: github.com, Score: 62, Comments: 0 Original: [13] http://goo.gl/qLM3FD On Reddit: [14] http://goo.gl/CRNW6M * Haskell Platform Redesign Domain: self.haskell, Score: 57, Comments: 39 Original: [15] http://goo.gl/A2OqV4 On Reddit: [16] http://goo.gl/A2OqV4 * Benjamin Pierce on clean-slate security architectures Domain: intelligence.org, Score: 54, Comments: 2 Original: [17] http://goo.gl/dCWGlr On Reddit: [18] http://goo.gl/ns7SF6 * Idris 0.9.13 released, featuring a new erasure implementation, Haddock- and Hoogle-inspired tools, and improved IDE support Domain: idris-lang.org, Score: 53, Comments: 6 Original: [19] http://goo.gl/rf9i2U On Reddit: [20] http://goo.gl/tByoYR * Brilliant explanation of Free Monad + Interpreter pattern. Domain: programmers.stackexchange.com, Score: 52, Comments: 16 Original: [21] http://goo.gl/5wVfG1 On Reddit: [22] http://goo.gl/bCb0tD * I got lenses in my Functor Domain: izbicki.me, Score: 52, Comments: 35 Original: [23] http://goo.gl/9xAo4g On Reddit: [24] http://goo.gl/kZBcK8 * The GHC Runtime System [pdf] Domain: scs.stanford.edu, Score: 50, Comments: 15 Original: [25] http://goo.gl/J2iH4W On Reddit: [26] http://goo.gl/B2AiSo * The typeparams library provides a lens-like interface for type level parameters; it allows unboxing unboxed vectors (with benchmarks indicating a 25% performance gain) and supercompilation-like optimizations (with benchmarks showing 40x performance gain in some cases) Domain: github.com, Score: 49, Comments: 14 Original: [27] http://goo.gl/jzIn2E On Reddit: [28] http://goo.gl/fdiRHU * LiquidHaskell: Pointers Gone Wild Domain: goto.ucsd.edu, Score: 48, Comments: 16 Original: [29] http://goo.gl/aKyRnQ On Reddit: [30] http://goo.gl/pexvtf * Sed implementation in Haskell - Episode 6 [youtube] Domain: youtube.com, Score: 45, Comments: 5 Original: [31] http://goo.gl/JQ2ONf On Reddit: [32] http://goo.gl/vLQWVJ * Call Arity [pdf]: A new analysis implemented in GHC Domain: joachim-breitner.de, Score: 44, Comments: 6 Original: [33] http://goo.gl/BdEFfs On Reddit: [34] http://goo.gl/OSv5Rb Top StackOverflow Questions * Understanding Haskell's Bool Deriving an Ord votes: 17, answers: 2 Read on SO: [35] http://goo.gl/7W9WRb * Precise flow control in Haskell votes: 14, answers: 0 Read on SO: [36] http://goo.gl/uoA9i1 * Why aren't there existentially quantified type variables in GHC Haskell votes: 14, answers: 2 Read on SO: [37] http://goo.gl/ZeBJTK * Is the concept of an “interleaved homomorphism” a real thing? votes: 14, answers: 3 Read on SO: [38] http://goo.gl/gpIH6b * Is it possible to get `-=` working with literals? votes: 12, answers: 1 Read on SO: [39] http://goo.gl/R40i7q * How much overhead does sparking incur? votes: 11, answers: 1 Read on SO: [40] http://goo.gl/ixWkKL Until next time, [41]+Daniel Santa Cruz References 1. http://chrisdone.com/posts/haskell-lang 2. http://www.reddit.com/r/haskell/comments/26rilp/an_alternative_haskell_home… 3. http://www.serpentine.com/blog/2014/05/31/attoparsec/ 4. http://www.reddit.com/r/haskell/comments/26xyah/third_generation_of_the_att… 5. http://music-suite.github.io/docs/ref/ 6. http://www.reddit.com/r/haskell/comments/27djwy/musicsuite/ 7. https://www.edx.org/course/delftx/delftx-fp101x-introduction-functional-2126 8. http://www.reddit.com/r/haskell/comments/27bnt7/erik_meijer_introduction_to… 9. http://techblog.realestate.com.au/the-abject-failure-of-weak-typing/ 10. http://www.reddit.com/r/haskell/comments/26pi5b/the_abject_failure_of_weak_… 11. http://jelv.is/blog/Lazy-Dynamic-Programming 12. http://www.reddit.com/r/haskell/comments/26jh2w/lazy_dynamic_programming/ 13. https://github.com/evancz/first-person-elm#first-person-3d-navigation-in-elm 14. http://www.reddit.com/r/haskell/comments/26mjak/first_person_3d_navigation_… 15. http://www.reddit.com/r/haskell/comments/26g9y8/haskell_platform_redesign/ 16. http://www.reddit.com/r/haskell/comments/26g9y8/haskell_platform_redesign/ 17. http://intelligence.org/2014/05/11/benjamin-pierce/ 18. http://www.reddit.com/r/haskell/comments/274k69/benjamin_pierce_on_cleansla… 19. http://www.idris-lang.org/idris-0-9-13-released/ 20. http://www.reddit.com/r/haskell/comments/279wl7/idris_0913_released_featuri… 21. http://programmers.stackexchange.com/questions/242795/what-is-the-free-mona… 22. http://www.reddit.com/r/haskell/comments/2788cw/brilliant_explanation_of_fr… 23. http://izbicki.me/blog/i-got-lenses-in-my-functors 24. http://www.reddit.com/r/haskell/comments/27h0wk/i_got_lenses_in_my_functor/ 25. http://www.scs.stanford.edu/14sp-cs240h/slides/ghc-rts.pdf 26. http://www.reddit.com/r/haskell/comments/26qshw/the_ghc_runtime_system_pdf/ 27. https://github.com/mikeizbicki/typeparams#the-typeparams-library 28. http://www.reddit.com/r/haskell/comments/27avw8/the_typeparams_library_prov… 29. http://goto.ucsd.edu/~rjhala/liquid/haskell/blog/blog/2014/05/28/pointers-g… 30. http://www.reddit.com/r/haskell/comments/26redl/liquidhaskell_pointers_gone… 31. https://www.youtube.com/watch?v=GKRjVITL_oA 32. http://www.reddit.com/r/haskell/comments/26th92/sed_implementation_in_haske… 33. http://www.joachim-breitner.de/publications/CallArity-TFP.pdf 34. http://www.reddit.com/r/haskell/comments/26fdxq/call_arity_pdf_a_new_analys… 35. http://stackoverflow.com/questions/23880626/understanding-haskells-bool-der… 36. http://stackoverflow.com/questions/23869547/precise-flow-control-in-haskell 37. http://stackoverflow.com/questions/23940487/why-arent-there-existentially-q… 38. http://stackoverflow.com/questions/24090758/is-the-concept-of-an-interleave… 39. http://stackoverflow.com/questions/23875471/is-it-possible-to-get-working-w… 40. http://stackoverflow.com/questions/23877737/how-much-overhead-does-sparking… 41. https://plus.google.com/105107667630152149014/about

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Announcement: Bang, a drum DSL for Haskell
by Benjamin J Kovach 11 Jun '14

11 Jun '14

Hi haskell-cafe, I've been working on "Bang" on and off for about a month or two now, and finally thought it was "good enough" to open-source and show to the public! I've been having fun with it, and hopefully some of you will, too. It currently supports basically all of the primitive transformations that I could think of doing on a drum sequence, such as reversing, mirroring, changing duration and tempo. There are a bunch of operators built in that make it easy to write things like polyrhythms, and infinite sequences of notes are possible as well. The source code and basic tutorial are up on Github: https://github.com/5outh/Bang And the package + more detailed documentation is up on Hackage: http://hackage.haskell.org/package/Bang Let me know if you have any questions, comments, and/or suggestions. I'd love to hear them. Thanks! 5outh?

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Re: [Haskell-cafe] Deploy Haskell application
by Corentin Dupont 11 Jun '14

11 Jun '14

Hi, it seems that 'cabal configure' fails if some dependencies are missing. Then cabal copy complains that I should run 'cabal configure' first... On Wed, Jun 11, 2014 at 4:23 PM, Tom Feron <tho.feron(a)gmail.com> wrote: > Hi Corentin, > > I think you're searching for `cabal configure && cabal copy`. It will > still have an exit code of 1 if you don't compile anything but it will copy > the files from data-files (and alike). > > On my machine, it copies share/index.html into > .cabal-sandbox/share/x86_64-openbsd-ghc-7.6.3/dummy-0.1.0.0/share/index.html. > > Tom > > > On 11 June 2014 16:00, Corentin Dupont <corentin.dupont(a)gmail.com> wrote: > >> In the .cabal file you can put a directive "data-files" and they will be >> deployed in ~/.cabal/share... >> I want to trigger only this. >> >> >> On Wed, Jun 11, 2014 at 3:40 PM, Tom Nielsen <tanielsen(a)gmail.com> wrote: >> >>> Not sure what you mean - cabal doesn't do any deployment, or at least I >>> have not found a useful way of making it do so. In our case the deployment >>> is done by running apt-get update && apt-get install on the server. >>> >>> Tom >>> >>> >>> >>> >>> On Wed, Jun 11, 2014 at 3:18 PM, Corentin Dupont < >>> corentin.dupont(a)gmail.com> wrote: >>> >>>> Thanks for your response! >>>> Is there a way to ask Cabal to just deploy the resources and not >>>> compile everything? >>>> >>>> >>>> >>>> On Wed, Jun 11, 2014 at 11:47 AM, Tom Nielsen <tanielsen(a)gmail.com> >>>> wrote: >>>> >>>>> We package up the executables and other files into a Debain .deb >>>>> package using fpm after running cabal. Here is an example Makefile which >>>>> runs cabal, creates the debian package and adds it to our apt server: >>>>> >>>>> https://github.com/openbrainsrc/debcd/blob/master/Makefile >>>>> >>>>> This is run by our CI server after every commit to GitHub. >>>>> >>>>> Tom >>>>> >>>>> >>>>> On Wed, Jun 11, 2014 at 11:33 AM, Vo Minh Thu <noteed(a)gmail.com> >>>>> wrote: >>>>> >>>>>> Hi, >>>>>> >>>>>> These days, an increasingly popular solution to package an application >>>>>> with its dependencies is to use Docker. You can build the Docker image >>>>>> locally and push it to a Docker registry and retrieve it on your >>>>>> remote machine, or you can dump it as a tarball and load it on your >>>>>> remote machine. >>>>>> >>>>>> You have different ways to create the Docker image, one of which would >>>>>> be similar to pushing your Haskell binary to your remote machine. That >>>>>> way is simply to compile your exectuable locally, and copy it to the >>>>>> remote machine with is assets if any (you might even move it to a >>>>>> .cabal directory as if it was installed through `cabal install`). By >>>>>> default your executable will be statically linked, except for libgmp >>>>>> that you have to install on the remote machine. >>>>>> >>>>>> I recommand you look into Docker. You will be able to e-use its >>>>>> knowledge to package increasingly complex applications (that might >>>>>> have more numerous dependencies that you wouldn't have to manage on >>>>>> the host). >>>>>> >>>>>> HTH, >>>>>> Thu >>>>>> >>>>>> 2014-06-11 12:24 GMT+02:00 Corentin Dupont <corentin.dupont(a)gmail.com >>>>>> >: >>>>>> > Hi guys! >>>>>> > Is there a procedure to deploy a Haskell application? >>>>>> > I have an Amazon EC2 micro instance to run my application, but it's >>>>>> way too >>>>>> > small to compile it using cabal (compilation takes half a day >>>>>> rouhgly), so I >>>>>> > compile it on my computer. >>>>>> > Is there a convenient way to bundle the executable with the >>>>>> resources and >>>>>> > ship it to the server? >>>>>> > >>>>>> > Thanks! >>>>>> > Corentin >>>>>> > >>>>>> > _______________________________________________ >>>>>> > Haskell-Cafe mailing list >>>>>> > Haskell-Cafe(a)haskell.org >>>>>> > http://www.haskell.org/mailman/listinfo/haskell-cafe >>>>>> > >>>>>> _______________________________________________ >>>>>> Haskell-Cafe mailing list >>>>>> Haskell-Cafe(a)haskell.org >>>>>> http://www.haskell.org/mailman/listinfo/haskell-cafe >>>>>> >>>>> >>>>> >>>> >>> >> >> _______________________________________________ >> Haskell-Cafe mailing list >> Haskell-Cafe(a)haskell.org >> http://www.haskell.org/mailman/listinfo/haskell-cafe >> >> >

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Deploy Haskell application
by Corentin Dupont 11 Jun '14

11 Jun '14

Hi guys! Is there a procedure to deploy a Haskell application? I have an Amazon EC2 micro instance to run my application, but it's way too small to compile it using cabal (compilation takes half a day rouhgly), so I compile it on my computer. Is there a convenient way to bundle the executable with the resources and ship it to the server? Thanks! Corentin

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non-exhaustive pattern match(es)?
by Semen Trygubenko / Семен Тригубен ко 11 Jun '14

11 Jun '14

Dear Haskell Cafe, In the following program f :: Int -> [(Int,Int)] -> [(Int,Int)] -> [(Int,Int)] f _ cs [] = cs f _ [] _ = [] f i (c:cs) ((i',t):os) | i < i' = [] | i == i' = [] | i > i' = [] -- | otherwise = [] main :: IO () main = do print $ f 0 [] [] without the "otherwise" clause (commented) I get the warning example.hs:2:1: Warning: Pattern match(es) are non-exhaustive In an equation for `f': Patterns not matched: _ (_ : _) ((_, _) : _) Could someone help me uncover which cases that are not… erm… covered by the above patterns? Many thanks, Semen PS This definition, on the other hand, f _ cs [] = cs f _ [] _ = [] f i (c:cs) ((i',t):os) = [] is exhaustive… -- Семен Тригубенко http://trygub.com

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[Rejected Paper] Experience Report: Writing NetBSD Sound Drivers in Haskell
by Kiwamu Okabe 11 Jun '14

11 Jun '14

Hi jhc-hackers, I have written a paper "Experience Report: Writing NetBSD Sound Drivers in Haskell". http://metasepi.org/papers.html It explains Ajhc customized jhc GC, and sometime useful to develop jhc. Thank's, -- Kiwamu Okabe at METASEPI DESIGN

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JOB: AHRC Doctoral Studentship in Computational Musicology
by Richard Lewis 10 Jun '14

10 Jun '14

STUDENTSHIP ADVERTISEMENT With apologies for cross posting AHRC Doctoral Studentship in Computational Musicology http://www.transforming-musicology.org/news/2014-06-03_ahrc-doctoral-studen… London, UK (with UK residency requirement unfortunately) Although this is not an explicitly Haskell programming job, the student would be free to work in whatever language they wish. Furthermore, there would be encouragement to consider a functional and/or logic programming approach to research. Award: fees and tax-free stipend at £15,726 p.a. (inc. of London weighting) Application deadline: Tuesday 1 July 2014 Expected start date: October 2014 We invite applications for a Doctoral Studentship, funded by the Arts and Humanities Research Council, in Computational Musicology, located at Queen Mary University of London, under the supervision of Professor Geraint Wiggins. The studentship is part of the "Transforming Musicology" project, including Goldsmiths, University of London, Queen Mary University of London, the University of Oxford and Lancaster University. This project, led by Prof Tim Crawford in the Computing Department of Goldsmiths, University of London, brings together 15 researchers to effect a Digital Transformation of the discipline of musicology. The aim of the open studentship is to research and develop new methods for the representation of, and inference about, music-theoretic and perceptual aspects of music, based on, but not restricted to, past work by Prof. Wiggins and colleagues. This will be deployed using Semantic Web technology. The studentship will be located in a very rich research environment, first within the Transforming Musicology project, but also within the Computational Creativity Lab at QMUL, and the successful candidate will be encouraged to interact with other researchers in both of these contexts. This studentship, funded by an AHRC Doctoral Training Account, is for fees plus a tax-free stipend starting at £15,726 per annum. Further details of the AHRC scheme including terms and conditions can be found here: http://www.ahrc.ac.uk/Funding-Opportunities/Postgraduate-funding/Pages/Curr… Applicants must satisfy the AHRC's UK residence requirements: http://www.ahrc.ac.uk/Funding-Opportunities/Documents/Guide%20to%20Student%… Candidates must have a first class or 2.1 undergraduate degree or equivalent, either with a significant component of music theory, in which case evidence of exceptionally well-developed practical expertise in computing, including programming, will be required, or in computer science or equivalent, in which case evidence of formal training in music theory (e.g. to grade V or equivalent) will be required. Candidates with relevant postgraduate qualifications will be particularly welcome, especially if they are qualified in both music and computer science. Other relevant qualifications and/or areas of expertise include (but are not limited to): artificial intelligence, informatics, formal logic and automated reasoning, musicology, knowledge representation, deductive database theory. The successful applicant may be required to undertake relevant undergraduate and postgraduate interdisciplinary courses as part of the programme of study. Informal enquiries can be made by email to Prof. Geraint Wiggins (geraint.wiggins(a)qmul.ac.uk) Please note that Prof. Wiggins is unable to advise, prior to interview, whether an applicant is likely to be selected. To apply please follow the on-line process (see http://www.qmul.ac.uk/postgraduate/howtoapply/) by selecting "Electronic Engineering" in the "A-Z list of research opportunities" and following the instructions on the right hand side of the web page. Please note that instead of the 'Research Proposal' we request a 'Statement of Research Interests'. Your Statement of Research Interest should answer two questions: (i) Why are you interested in the proposed area? (ii) What is your experience in the proposed area? Your statement should be brief: no more than 500 words or one side of A4 paper. In addition we would also like you to send a sample of your written work, such as your final year dissertation. More details can be found at: http://www.eecs.qmul.ac.uk/phd/how-to-apply Applications must be received by Tuesday 1 July 2014. Interviews are expected to take place during July 2014. -- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Richard Lewis Computing, Goldsmiths' College t: +44 (0)20 7078 5203 @: lewisrichard http://www.transforming-musicology.org/ 905C D796 12CD 4C6E CBFB 69DA EFCE DCDF 71D7 D455 -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

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Problems using ghc 7.8.2 with options -staticlib and -threaded on osx
by Frode Nerbråten 10 Jun '14

10 Jun '14

Hi, I'm having trouble building my Haskell library with GHC 7.8.2 and Cabal 1.20.0.2 on OSX 10.9.3 with both -staticlib and -threaded enabled. The library I'm building exports several functions using FFI to be called from ObjectiveC in an Xcode project. This works fine with just -staticlib enabled, but now I realize I need to call into my Haskell library from multiple OS-threads simultaneously. But when I add -threaded to ghc-options I get an error when linking: error: libtool: can't locate file for: -lpthread error: libtool: file: -lpthread is not an object file (not allowed in a library) The linker command that fails looks like this (... replaces a bunch of -l and -L options): libtool -static -o liba.a dist/build/HsCocoa.o ... -lCffi -lpthread In /usr/lib I have a libpthread.dylib that links to libSystem.dylib, but no libpthread.a. I was under the impression that libpthread was included with the system install. Is this supposed to work or am I misunderstanding something basic? :) Any help would be greatly appreciated! The project source is available on github: https://github.com/froden/digipostarkiv (I asked the same question on stackoverflow: http://stackoverflow.com/q/24096257/777411) Best regards, Frode Nerbråten

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XMonad and xinput.d.
by Magicloud Magiclouds 10 Jun '14

10 Jun '14

Hi, I am using Ubuntu, in which, X input method (ibus, for me) is started by xinput.d scripts. This works fine with KDE, Unity, etc. But when I switch to xmonad, there is no input method window, tray icon. And hotkeys not work, either. Ibus processes are there. Seems like I have to kill the ones started by xinput.d, and restart it myself in xmonad. What did I do wrong? -- 竹密岂妨流水过山高哪阻野云飞 And for G+, please use magiclouds#gmail.com.

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New Functional Programming Job Opportunities
by Functional Jobs 09 Jun '14

09 Jun '14

Here are some functional programming job opportunities that were posted recently: Sr. Software Engineer at Clutch Analytics http://functionaljobs.com/jobs/8720-sr-software-engineer-at-clutch-analytics Cheers, Sean Murphy FunctionalJobs.com

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