- Haskell-Cafe - Haskell.org

Fwd: pair hacking on the Platform this weekend?
by Mark Lentczner 03 Jul '14

03 Jul '14

Okay - My mind is rattling around like a cage against this codebase... I'm rattling around too many design decisions and feeling blue 'cause I'm writing shell scripts! I'm looking for another hacker in the SF Bay area this weekend to work with me on the Mac installation in particular, and the Platform build in general. A few hours any day would be much appreciated. Any takers? - Mark

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Declarative database migrations
by Timur Amirov 03 Jul '14

03 Jul '14

Hello! Looking for tools to use discovered that I miss something like Rails database migrations in haskell. Is there a package for it (describe the whole schema and/or particular migrations)? -- Timur Amirov Berlin, Germany

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Re: [Haskell-cafe] Specifying cabal sandbox flag for local package
by Vlatko Basic 03 Jul '14

03 Jul '14

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Re: [Haskell-cafe] Specifying cabal sandbox flag for local package
by Vlatko Basic 03 Jul '14

03 Jul '14

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Final Call for Papers: OCL 2014 Submissions Due in One Week
by Achim D. Brucker 03 Jul '14

03 Jul '14

(Apologies for duplicates) CALL FOR PAPERS 14th International Workshop on OCL and Textual Modeling Applications and Case Studies (OCL 2014) Co-located with ACM/IEEE 17th International Conference on Model Driven Engineering Languages and Systems (MODELS 2014) September 28-30 (tbc), 2014, VALENCIA, SPAIN http://www.software.imdea.org/OCL2014/ Modeling started out with UML and its precursors as a graphical notation. Such visual representations enable direct intuitive capturing of reality, but some of their features are difficult to formalize and lack the level of precision required to create complete and unambiguous specifications. Limitations of the graphical notations encouraged the development of text-based modeling languages that either integrate with or replace graphical notations for modeling. Typical examples of such languages are OCL, textual MOF, Epsilon, and Alloy. Textual modeling languages have their roots in formal language paradigms like logic, programming and databases. The goal of this workshop is create a forum where researchers and practitioners interested in building models using OCL or other kinds of textual languages can directly interact, report advances, share results, identify tools for language development, and discuss appropriate standards. In particular, the workshop will encourage discussions for achieving synergy from different modeling language concepts and modeling language use. The close interaction will enable researchers and practitioners to identify common interests and options for potential cooperation. Topics of interest include (but are not limited to) =================================================== - Mappings between textual modeling languages and other languages/formalisms - Algorithms, evaluation strategies and optimizations in the context of textual modeling languages for -- validation, verification, and testing, -- model transformation and code generation, -- metamodeling and DSLs, and -- query and constraint specifications - Alternative graphical/textual notations for textual modeling languages - Evolution, transformation and simplification of textual modeling expressions - Libraries, templates and patterns for textual modeling languages - Complexity results for textual modeling languages - Quality models and benchmarks for comparing and evaluating textual modeling tools and algorithms - Successful applications of textual modeling languages - Case studies on industrial applications of textual modeling languages - Experience reports -- usage of textual modeling languages and tools in complex domains, -- usability of textual modeling languages and tools for end-users - Empirical studies about the benefits and drawbacks of textual modeling languages - Innovative textual modeling tools - Comparison, evaluation and integration of modeling languages - Correlation between modeling languages and modeling tasks This year, we particularly encourage submissions describing applications and case studies of textual modeling as well as test suites and benchmark collections for evaluating textual modeling tools. Venue ===== The workshop will be organized as a part of MODELS 2014 Conference in Valencia, Spain. It continues the series of OCL workshops held at UML/MODELS conferences: York (2000), Toronto (2001), San Francisco (2003), Lisbon (2004), Montego Bay (2005), Genova (2006), Nashville (2007), Toulouse (2008), Denver (2009), Oslo (2010), Zurich (2011, at the TOOLs conference), 2012 in Innsbruck, and 2013 in Miami. Similar to its predecessors, the workshop addresses both people from academia and industry. The aim is to provide a forum for addressing integration of OCL and other textual modeling languages, as well as tools for textual modeling, and for disseminating good practice and discussing the new requirements for textual modeling. Workshop Format =============== The workshop will include short (about 15 min) presentations, parallel sessions of working groups, and sum-up discussions. Submissions =========== Two types of papers will be considered: * short papers (6 pages) and * full papers (10 pages) in LNCS format. Submissions should be uploaded to EasyChair (https://www.easychair.org/conferences/?conf=ocl2014) The program committee will review the submissions (minimum 2 reviews per paper, usually 3 reviews) and select papers according to their relevance and interest for discussions that will take place at the workshop. Accepted papers will be published online in a pre-conference edition of CEUR (http://www.ceur-ws.org) Authors of selected papers will be invited to submit an extended version of their workshop paper to a special issue of the Electronic Communications of the EASST (http://journal.ub.tu-berlin.de/eceasst) Important Dates =============== Submission of papers: July 11, 2014 Notification: August 8, 2014 Workshop date: one day during September 28-30, 2014 Organizers ========== Achim D. Brucker, SAP AG, Germany Carolina Dania, IMDEA Software Institute, Madrid, Spain Geri Georg, Colorado State University, Fort Collins, Colorado, USA Martin Gogolla, University of Bremen, Germany Programme Committee (partly confirmation pending) =================== Michael Altenhofen, SAP AG, Germany Thomas Baar, University of Applied Sciences Berlin, Germany Mira Balaban, Ben-Gurion University of the Negev, Israel Tricia Balfe, Nomos Software, Ireland Fabian Buettner, Ecole des Mines de Nantes, France Achim D. Brucker, SAP AG, Germany Jordi Cabot, INRIA-Ecole des Mines de Nantes, France Yoonsik Cheon, University of Texas, USA Dan Chiorean, Babes-Bolyai University, Romania Robert Clariso, Universitat Oberta de Catalunya, Spain Tony Clark, Middlesex University, UK Manuel Clavel, IMDEA Software Institute, Madrid, Spain Carolina Dania, IMDEA Software Institute, Madrid, Spain Birgit Demuth, Technische Universitat Dresden, Germany Marina Egea, Atos Research, Madrid, Spain Geri Georg, Colorado State University, Fort Collins, Colorado, USA Martin Gogolla, University of Bremen, Germany Pieter Van Gorp, Eindhoven University of Technology, The Netherlands Heinrich Hussmann, LMU Munchen, Germany Tihamer Levendovszky, Vanderbilt University, USA Shahar Maoz, Tel Aviv University, Israel Istvan Rath, Budapest University of Technology and Economics, Hungary Bernhard Rumpe, RWTH Aachen, Germany Shane Sendall, Snowie Research SA, Switzerland Michael Wahler, ABB Switzerland Ltd Corporate Research, Switzerland Claas Wilke, Technische Universitat Dresden, Germany Edward Willink, Willink Transformations Ltd., UK Burkhart Wolff, Univ Paris-Sud, France Steffen Zschaler, King’s College, London, UK -- Dr. Achim D. Brucker, SAP AG, Vincenz-Priessnitz-Str. 1, D-76131 Karlsruhe Phone: +49 6227 7-52595, http://www.brucker.ch/

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Haskell Weekly News: Issue 298
by Daniel Santa Cruz 03 Jul '14

03 Jul '14

Welcome to issue 298 of the HWN, an issue covering crowd-sourced bits of information about Haskell from around the web. This issue covers from June 15 to 28, 2014 Quotes of the Week * Kinnison * imagines a radio station playing only things like 'Life tru a Lens', stuff by 'Dire States' or 'Monadonna' Top Reddit Stories * Today I published an introductory book on Haskell Data Analysis Domain: haskelldata.com, Score: 99, Comments: 26 Original: [1] http://goo.gl/R2kRFu On Reddit: [2] http://goo.gl/Ka0oP5 * Backpack: An ML-like module system for Haskell Domain: plv.mpi-sws.org, Score: 76, Comments: 44 Original: [3] http://goo.gl/7Zkxbg On Reddit: [4] http://goo.gl/78H37f * Cgrep, a context-aware grep for source code. Domain: awgn.github.io, Score: 67, Comments: 13 Original: [5] http://goo.gl/q1VdEA On Reddit: [6] http://goo.gl/2NNTrO * Teenage Haskell Domain: twdkz.wordpress.com, Score: 63, Comments: 7 Original: [7] http://goo.gl/cvJ0ap On Reddit: [8] http://goo.gl/aISHlG * GHC 7.10 gains -XBinaryLiterals language syntax extensions Domain: github.com, Score: 63, Comments: 14 Original: [9] http://goo.gl/qfWvAg On Reddit: [10] http://goo.gl/NOVgme * Haskelier - Haskell for the Advanced Layman Domain: haskelier.tumblr.com, Score: 59, Comments: 26 Original: [11] http://goo.gl/pLsRB1 On Reddit: [12] http://goo.gl/5HBSWD * Barely Functional: Writing a Real Program in Haskell Domain: ben.kirw.in, Score: 57, Comments: 36 Original: [13] http://goo.gl/4yWLuL On Reddit: [14] http://goo.gl/B1LX8f * hmatrix 0.16 now BSD3 and with static dimension checking Domain: github.com, Score: 51, Comments: 10 Original: [15] http://goo.gl/C5zKzk On Reddit: [16] http://goo.gl/A94AkD * Formatting: type-safe printf-like library by chrisdone Domain: hackage.haskell.org, Score: 51, Comments: 24 Original: [17] http://goo.gl/DHM0Yn On Reddit: [18] http://goo.gl/zUQN02 * Haskell 2014 accepted papers, with links (pull requests welcome) Domain: github.com, Score: 50, Comments: 5 Original: [19] http://goo.gl/B2f434 On Reddit: [20] http://goo.gl/XSmJGo * Real World Haskell - Outdated Parts? Domain: self.haskell, Score: 50, Comments: 12 Original: [21] http://goo.gl/5YhIOT On Reddit: [22] http://goo.gl/5YhIOT * I'm trying my hardest to learn this language and only get more and more discouraged. Domain: self.haskell, Score: 48, Comments: 111 Original: [23] http://goo.gl/9vuPBe On Reddit: [24] http://goo.gl/9vuPBe * Using f-algebras to produce a statically typed functional programming language Domain: burz.github.io, Score: 47, Comments: 19 Original: [25] http://goo.gl/9YCz4k On Reddit: [26] http://goo.gl/DvWBPS * 'ghc-make' released Domain: neilmitchell.blogspot.de, Score: 47, Comments: 19 Original: [27] http://goo.gl/JlMS1a On Reddit: [28] http://goo.gl/kO2FQP * A simple alternative to De Bruijn indexing, from ICFP 2013 Domain: pchiusano.io, Score: 46, Comments: 24 Original: [29] http://goo.gl/7PBIM2 On Reddit: [30] http://goo.gl/PGmQ6W * Haskoin: A Haskell implementation of the Bitcoin protocol. Domain: github.com, Score: 44, Comments: 0 Original: [31] http://goo.gl/n0eCEI On Reddit: [32] http://goo.gl/bvsE24 * What is the state of "The JavaScript Problem"? What is the currently preferred way to solve in a real world application? Domain: self.haskell, Score: 42, Comments: 55 Original: [33] http://goo.gl/dIww4i On Reddit: [34] http://goo.gl/dIww4i * ANNOUNCE: STM-Containers. A hash map and hash set for STM Domain: hackage.haskell.org, Score: 41, Comments: 13 Original: [35] http://goo.gl/6nuWAc On Reddit: [36] http://goo.gl/rAzIYr Top StackOverflow Questions * Why does flooring infinity does not throw some error? votes: 14, answers: 1 Read on SO: [37] http://goo.gl/f7gUB8 * How long can the name of a type constructor be? votes: 12, answers: 1 Read on SO: [38] http://goo.gl/mGiblp * Difference between $ and () votes: 11, answers: 5 Read on SO: [39] http://goo.gl/lTB24e * Need advice on optimising Haskell data processing votes: 11, answers: 3 Read on SO: [40] http://goo.gl/NnEqgn * Reconciling lens usage with database access votes: 11, answers: 1 Read on SO: [41] http://goo.gl/Zczjjf * Why constraints on data are a bad thing? votes: 11, answers: 3 Read on SO: [42] http://goo.gl/l0WXtP * Can I use template haskell to define missing functions? votes: 10, answers: 2 Read on SO: [43] http://goo.gl/AFFS2T * Is there a reason we can't populate types with DataKinds? votes: 10, answers: 2 Read on SO: [44] http://goo.gl/1gpZej * Why is a built-in function applied to too few arguments considered to be in weak head normal form? votes: 10, answers: 2 Read on SO: [45] http://goo.gl/6iFG8a Until next time, [46]+Daniel Santa Cruz References 1. http://haskelldata.com/ 2. http://www.reddit.com/r/haskell/comments/296l80/today_i_published_an_introd… 3. http://plv.mpi-sws.org/backpack/ 4. http://www.reddit.com/r/haskell/comments/28v6c9/backpack_an_mllike_module_s… 5. http://awgn.github.io/cgrep/ 6. http://www.reddit.com/r/haskell/comments/28moo0/cgrep_a_contextaware_grep_f… 7. http://twdkz.wordpress.com/2014/06/26/teenage-haskell/ 8. http://www.reddit.com/r/haskell/comments/29abyz/teenage_haskell/ 9. https://github.com/ghc/ghc/commit/1c0b5fdc9f2b6ea8166cc565383d4cd20432343c 10. http://www.reddit.com/r/haskell/comments/29b2jj/ghc_710_gains_xbinarylitera… 11. http://haskelier.tumblr.com/ 12. http://www.reddit.com/r/haskell/comments/28d7ma/haskelier_haskell_for_the_a… 13. http://ben.kirw.in/2014/06/24/barely-functional-1-rlp/ 14. http://www.reddit.com/r/haskell/comments/28zwoc/barely_functional_writing_a… 15. https://github.com/albertoruiz/hmatrix 16. http://www.reddit.com/r/haskell/comments/28peug/hmatrix_016_now_bsd3_and_wi… 17. http://hackage.haskell.org/package/formatting 18. http://www.reddit.com/r/haskell/comments/291wel/formatting_typesafe_printfl… 19. https://github.com/yallop/haskell2014-papers 20. http://www.reddit.com/r/haskell/comments/28yu1f/haskell_2014_accepted_paper… 21. http://www.reddit.com/r/haskell/comments/2938yb/real_world_haskell_outdated… 22. http://www.reddit.com/r/haskell/comments/2938yb/real_world_haskell_outdated… 23. http://www.reddit.com/r/haskell/comments/288egd/im_trying_my_hardest_to_lea… 24. http://www.reddit.com/r/haskell/comments/288egd/im_trying_my_hardest_to_lea… 25. http://burz.github.io/2014/06/15/feval.html 26. http://www.reddit.com/r/haskell/comments/28rbwr/using_falgebras_to_produce_… 27. http://neilmitchell.blogspot.de/2014/06/announcing-ghc-make.html 28. http://www.reddit.com/r/haskell/comments/28tttf/ghcmake_released/ 29. http://pchiusano.io/2014-06-20/simple-debruijn-alternative.html 30. http://www.reddit.com/r/haskell/comments/28vfd0/a_simple_alternative_to_de_… 31. https://github.com/haskoin/haskoin 32. http://www.reddit.com/r/haskell/comments/28y454/haskoin_a_haskell_implement… 33. http://www.reddit.com/r/haskell/comments/28o7my/what_is_the_state_of_the_ja… 34. http://www.reddit.com/r/haskell/comments/28o7my/what_is_the_state_of_the_ja… 35. http://hackage.haskell.org/package/stm-containers 36. http://www.reddit.com/r/haskell/comments/295lbr/announce_stmcontainers_a_ha… 37. http://stackoverflow.com/questions/24338673/why-does-flooring-infinity-does… 38. http://stackoverflow.com/questions/24335869/how-long-can-the-name-of-a-type… 39. http://stackoverflow.com/questions/24271129/difference-between-and 40. http://stackoverflow.com/questions/24278006/need-advice-on-optimising-haske… 41. http://stackoverflow.com/questions/24462070/reconciling-lens-usage-with-dat… 42. http://stackoverflow.com/questions/24465586/why-constraints-on-data-are-a-b… 43. http://stackoverflow.com/questions/24233346/can-i-use-template-haskell-to-d… 44. http://stackoverflow.com/questions/24439618/is-there-a-reason-we-cant-popul… 45. http://stackoverflow.com/questions/24447324/why-is-a-built-in-function-appl… 46. https://plus.google.com/105107667630152149014/about

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GLUT under Windows using ghc 7.8.2?
by Dominick Samperi 03 Jul '14

03 Jul '14

It appears that The Haskell Platform includes libglut32.a and other important libs, so it is self-contained, provided users can work with the version of ghc that is provided: currently 7.6.3 under Windows. In particular, 'cabal install glut' works fine with the default version of ghc. But if I try using ghc-7.8.2 I get: Configuring GLUT-2.5.1.1... cabal: Missing dependencies on a foreign library: * Missing C library: glut32 ... All of the following do not change the result: 1. Adding --extra-lib-dirs=c:\glut-3.7.6-bin to the command line. 2. Using freeglut instead of glut 3. Copying libglut.a from The Haskell Package mingw/lib directory to c:\ghc-3.8.2\mingw\lib (dangerous because I am mixing architectures here). How does cabal decide that the C library glut32 is missing? Where is it looking? Why doesn't it look in the places I specify? Thanks, Dominick

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handling non-string command line arguments
by Johan Larson 02 Jul '14

02 Jul '14

I've been looking at choices for parsing command line arguments, including getOpt. The examples I can find focus on string arguments, whereas I am interested in numbers. In the application at hand, it is particularly important to issue clear error messages when arguments don't parse as numbers or are out of range. I could use getOpt as a first pass with string arguments and then turn the strings into validated numbers in a second pass, but that's a bit awkward. Alternately I could use the options records with Options -> IO Options functions. But both of these solutions treat type mismatches differently from other options errors. Has anyone found a cleaner solution? -- Johan Larson -- Toronto, Canada

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Problem with type in a function
by Leza Morais Lutonda 02 Jul '14

02 Jul '14

Hi, I have the following function plotf :: Ploteable a => ([a] -> IO ()) -> (a -> a) -> [a] -> IO () plotf plot fn xs = plot $ map fn xs that compiles correctly, but when I use it with: plotf win sin [1..100::Double] -- where win :: [Double] -> IO () I'm geting the error: No instance for (Ploteable Double) arising from a use of ‘plotf’ In the expression: plotf win sin [1 .. 100 :: Double] In an equation for ‘it’: it = plotf win sin [1 .. 100 :: Double] What am I missing? Thanks! 50 Aniversario de la Cujae. Inaugurada por Fidel el 2 de diciembre de 1964 http://cujae.edu.cu

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haskell in several upcoming live performances in the UK
by Renick Bell 02 Jul '14

02 Jul '14

Hello everyone. I hope the Haskell Cafe will tolerate this musical interruption. I suppose it's not so often that you can hear two different performers use Haskell in their performances in one concert, but if you live in the UK you have several opportunities to do so in the next few days. Both Alex McLean and I will be playing at Algorave NIME on Thursday night in London at Corsica Studios. The event starts at 21:00. Alex will be playing in the duo Canute with Matthew Yee-King, and I will be playing a solo set. http://www.nime2014.org/public-events/concerts-and-installations/ After that, it's the UK algorave tour, with stops in Brighton (07/04), Sheffield (07/06), Leeds (07/07), Manchester (07/08), and York (07/09): http://algorave.com/ Both Alex and I will perform in Sheffield and Manchester. I will be playing all of the above dates. See Alex fling Haskell in Emacs and me in vim, tmux, and xmonad! If you haven't heard Alex's music recently, he did a great track the other day: https://soundcloud.com/yaxu/at-last There's this set he did in Antwerp in May: https://www.youtube.com/watch?v=fgRDKxkHCSw My sets are likely to resemble this one that I did last Friday in Portugal: https://soundcloud.com/renick/live-at-xcoax-2014-porto-portugal-june-27-2014 Or this one from the Linux Audio Conference in May: https://soundcloud.com/renick/live-at-the-linux-audio-conference-2014-karls… If you come to one of the performances, please come up and say hello. I really want to meet the UK Haskell crew! Hope to see you there, dancing to Haskell or just relaxing and enjoying the music. Best, Renick -- Renick Bell - http://renickbell.net - http://twitter.com/renick - http://the3rd2nd.com

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