December 2008 - Haskell

ANNOUNCE: rangemin-1.0 released
by Louis Wasserman 15 Dec '08

15 Dec '08

http://hackage.haskell.org/cgi-bin/hackage-scripts/package/rangeminefficien… (in effectively linear lazy preprocessing time) processes an array to find minimum elements of subranges of the array in constant time. -- Louis Wasserman wasserman.louis(a)gmail.com

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ANN: typehash version 1.3
by Lennart Augustsson 14 Dec '08

14 Dec '08

The typehash library allows you to produce a unique identifier (a cryptographic hash) for a type. This is useful if you save values of some type to a file (text, binary, whatever format you wish) and then when you read it back in again you want to verify that the type you want to read is the one you actually wrote. The type hash takes into account both the actual name of the type and the structure of the type. The type hash is a compact value that only allows comparing for equality. The library also supports type codes. A type code encodes the complete structure of a type and can be used for finer comparison than just equality, e.g., will the read function be able to read what show produced (in this case renaming types and adding constructors is allowed). The library is on hackage, of course. -- Lennart

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ANNOUNCE: uvector-algorithms 0.1
by Dan Doel 14 Dec '08

14 Dec '08

Hello, I've been sitting on this for a while, waiting for some changes to uvector to go in, but finally decided I should just release it, and fix it up if and when said changes go in. So, I'm announcing the first release of uvector- algorithms. What it is is a library of algorithms (mostly sorting) for the mutable arrays defined in uvector. It has several varieties of sorting, including introsort (quicksort which falls back on heapsort in bad cases), heapsort, a simple top- down merge sort and a radix sort (as well as insertion sort, and optimal sorting for length<=4 arrays, which probably won't get much use outside of the implementation of the other sorts). All modules attempt to export as uniform an interface as possible, so that one can substitute between them freely, say when trying to determine which algorithm is best suited for your particular datasets. Also exposed are the operations that allow you to use the arrays as heaps (which is the basis for implementing heapsort), and partial sorts and selects in heap and intro variety. Lastly, there is a combinator for safely using these mutable array algorithms to sort immutable arrays. All of these algorithms have been painstakingly profiled, and their generated core examined to do as little heap allocation and as much unboxing as possible, and to inline and specialize for maximum performance (unless, of course, I've managed to miss anything). I've been running a relatively simple benchmarking suite that tests various kinds of inputs, and in my experience, the sorts herein tend to beat glibc's sort, and do relatively well compared to GNU's STL sorts over vector<>s (taking 50% or so more time at present, although this library may well be better at heapsorting random arrays, if you want something to brag about :)). For future work, I've been working on an implementation of Python's timsort (which is a very fancy bottom-up merge sort), but it's not ready yet. I'd also like to introduce some combinators for easy Schwartzian transforms, but that again requires modifications to uvector. I may also look at moving some of my benchmark program into the package. Suggestions for other algorithms people would like to see are of course welcome (especially if accompanied by papers/references on how to implement them if they're not well known). The hackage page is here: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/uvector-algorith… Enjoy, and please let me know of any issues. -- Dan

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F# to ship as part of Visual Studio 2010
by Bulat Ziganshin 13 Dec '08

13 Dec '08

Hello , http://blogs.msdn.com/dsyme/archive/2008/12/10/fsharp-to-ship-as-part-of-vi… now we can say definitely that 201x decade will be years of FP replacing OOP in programmers' minds -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com

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Haskell Weekly News: Issue 97 - December 13, 2008
by Brent Yorgey 13 Dec '08

13 Dec '08

--------------------------------------------------------------------------- Haskell Weekly News http://sequence.complete.org/hwn/20081213 Issue 97 - December 13, 2008 --------------------------------------------------------------------------- Welcome to issue 97 of HWN, a newsletter covering developments in the [1]Haskell community. Lots of neat blog posts and funny quotes this week. Don't forget to keep adding [2]haiku to the wiki, and don't miss Alex McLean (yaxu)'s [3]streaming livecoding performance tonight! Announcements Spam on HaskellWiki. Ashley Yakeley [4]asked what people would like to do about the increasing amounts of spam on the Haskell wiki, and offered some suggestions. The Timber compiler 1.0.2. Johan Nordlander [5]announced the first public release of the [6]Timber compiler. Timber is a modern language for building event-driven systems, based around the notion of reactive objects. It is also a purely functional language derived from Haskell, although with a strict evaluation semantics. To try it out, just grab the [7]timberc package on Hackage. Retrospective on 2008?. Don Stewart [8]proposed the idea of a 2008 retrospective. How would you choose the 10 best new libraries, applications, blog posts, etc. of 2008? a haskell_proposals subreddit. Jason Dusek [9]announced a [10]subreddit for Haskell library proposals. The idea is that Web 2.0 will help us to allocate our collective talents more efficiently when it comes to extensions (and perhaps clue us in when our pet project is something people really want). permutation-0.2. Patrick Perry [11]announced a [12]new version of the permutation library, which includes data types for storing permutations. It implements pure and impure types, the latter which can be modified in-place. The main utility of the library is converting between the linear representation of a permutation to a sequence of swaps. This allows, for instance, applying a permutation or its inverse to an array with O(1) memory use. Data.List.Split. Brent Yorgey [13]announced the creation of a wiki page for [14]Data.List.Split, a hypothetical module containing implementations of every conceivable way of splitting lists known to man, so we no longer have to (1) argue about the 'one true' interface for a 'split' function, or (2) be embarrassed when people ask why there isn't a split function in the standard libraries. Please add code or comments! At some point it will be uploaded as a new module to Hackage. Announcing Haskell protocol-buffers version 1.2.2. Chris Kuklewicz [15]announced new versions of [16]protocol-buffers, [17]protocol-buffers-descriptor, and [18]hprotoc. Discussion A curious monad. Andrew Coppin [19]exhibited an interesting Storage monad, which (it turns out) is similar to ST. An enlightening discussion if you want to understand how ST works and the motivation behind it. Origins of '$'. George Pollard [20]asked about the origins of the $ operator (low-precedence function application) in the standard libraries, leading to some interesting history and general discussion about notation. Blog noise [21]Haskell news from the [22]blogosphere. * Jamie Brandon: [23]Zombified GMap. Jamie is determined to get his SoC generalized map library released! * Philip Wadler: [24]Informatics 1 - Fancy Dress and Competition. * >>> Eduard - Gabriel Munteanu: [25]Learning Haskell, part 2. * Martin Sulzmann: [26]Equality, containment and intersection among regular expressions via symbolic manipulation. * Neil Mitchell: [27]mapM, mapM_ and monadic statements. * Alson Kemp: [28]A HAML parser for Haskell. * Chris Done: [29]More Haskell blogging. * Twan van Laarhoven: [30]Knight in n, part 4: tensors. Part four of Twan's enlightening series on computing knight moves. * Alex McLean: [31]Saturday night stream. All the cool kids will be watching Alex's streaming livecoding performance TONIGHT, using (among other things) a tool implemented in Haskell. * David Sankel: [32]Synchronous Events. * Lennart Augustsson: [33]The OCaml code again. * Lennart Augustsson: [34]Abstracting on, suggested solutions. * Lennart Augustsson: [35]The abstraction continues. * Conal Elliott: [36]Functional interactive behavior. * Conal Elliott: [37]Trimming inputs in functional reactive programming. * Mikael Vejdemo Johansson (Syzygy-): [38]J, or how I learned to stop worrying and love the matrix. * Conal Elliott: [39]Why classic FRP does not fit interactive behavior. * Clifford Beshers: [40]Functional Programming Marketing. * Lennart Augustsson: [41]A somewhat failed adventure in Haskell abstraction. * >>> Joey Hess: [42]haskell and xmonad. * Andy Gill: [43]The Timber compiler 1.0.2. * Manuel M T Chakravarty: [44]Not a particularly good article, but.... * >>> Chris Double: [45]Random and Binary IO using Iteratees. * >>> Chris Double: [46]Not a Tutorial on HAppS. * "FP Lunch": [47]The new GHC API. * Luke Palmer: [48]Compact data types. * Neil Mitchell: [49]F# from a Haskell perspective. * Real-World Haskell: [50]RWH Now In Store. * >>> Sebastian Fischer: [51]Constraint Functional-Logic Programming. * >>> fhtr: [52]Hexagons with Haskell. * >>> Eduard - Gabriel Munteanu: [53]Learning Haskell. * Bryan O'Sullivan: [54]Functional programmers on Twitter. * Martin Sulzmann: [55]Parallel Join Patterns with Guards and Propagation. * Martin Sulzmann: [56]Multi-set rewrite rules with guards and a parallel execution scheme. * Martin Sulzmann: [57]STM with control: Communication for retrying transactions. * Martin Sulzmann: [58]Concurrent Goal-Based Execution of Constraint Handling Rules. * >>> talkingCode: [59]Haskell, GTK and Multi-Threading. * >>> Gianfranco Alongi: [60]QuickCheck(ing) the code I C - source. Quotes of the Week * quicksilver: Baughn: glFlush? the 80s called, they want your programs back? * gwern: the best way to optimize a program is to make it lazier or stricter. * ksf: Perl is obfuscated by design, haskell is designed by obfuscation. * conal: omg -- i can print right from emacs again. praise be to Linux! * mmorrow: [I] didn't realize what it really said until after i @remembered it * blackh: Haskell is great because of all the wonderful things you can't do with it. * JustinBogner: gitit's 46 dependencies convinced me to install cabal-install, and now I couldn't be happier! * Anonymous: I'd love to explain to you how to write hello world in Haskell, but first let me introduce you to basic category theory. * lilac: @type \o-> look at my muscles <lambdabot> forall t nice muscles. t -> nice -> muscles * ook: (:[]) * oink: <^(oo)^> * mmorrow: {-# RULES "HAI; CAN HAS STDIO?" id = unsafePerformIO (system "killall -9 breathingMachine && xeyes &" >> return id) #-} * gwern: We will be welcomed as liberators! I estimate that we will need 50000 haskellers at most and will be able to wind up the occupation quickly About the Haskell Weekly News New editions are posted to [61]the Haskell mailing list as well as to [62]the Haskell Sequence and [63]Planet Haskell. [64]RSS is also available, and headlines appear on [65]haskell.org. To help create new editions of this newsletter, please see the information on [66]how to contribute. Send stories to byorgey at cis dot upenn dot edu. The darcs repository is available at darcs get [67]http://code.haskell.org/~byorgey/code/hwn/ . References 1. http://haskell.org/ 2. http://haskell.org/haskellwiki/Haikus 3. http://yaxu.org/saturday-night-stream/ 4. http://article.gmane.org/gmane.comp.lang.haskell.general/16678 5. http://article.gmane.org/gmane.comp.lang.haskell.general/16672 6. http://timber-lang.org/ 7. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/timberc 8. http://article.gmane.org/gmane.comp.lang.haskell.cafe/48778 9. http://article.gmane.org/gmane.comp.lang.haskell.cafe/48721 10. http://www.reddit.com/r/haskell_proposals/ 11. http://article.gmane.org/gmane.comp.lang.haskell.cafe/48663 12. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/permutation 13. http://article.gmane.org/gmane.comp.lang.haskell.cafe/48868 14. http://haskell.org/haskellwiki/Data.List.Split 15. http://article.gmane.org/gmane.comp.lang.haskell.libraries/10406 16. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/protocol-buffers 17. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/protocol-buffers… 18. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hprotoc 19. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/48806 20. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/48622 21. http://planet.haskell.org/ 22. http://haskell.org/haskellwiki/Blog_articles 23. http://jamiiecb.blogspot.com/2008/12/zombified-gmap.html 24. http://wadler.blogspot.com/2008/12/informatics-1-functional-programming.html 25. http://eduard-munteanu.blogspot.com/2008/12/learning-haskell-part-2.html 26. http://sulzmann.blogspot.com/2008/12/equality-containment-and-intersection.… 27. http://neilmitchell.blogspot.com/2008/12/mapm-mapm-and-monadic-statements.h… 28. http://www.alsonkemp.com/programming/a-haml-parser-for-haskell/ 29. http://chrisdone.com/blog/2008/12/11/More-Haskell-blogging 30. http://twan.home.fmf.nl/blog/haskell/Knight4.details 31. http://yaxu.org/saturday-night-stream/ 32. http://netsuperbrain.com/blog/posts/synchronous-events/ 33. http://augustss.blogspot.com/2008/12/ocaml-code-again-im-posting-slight.html 34. http://augustss.blogspot.com/2008/12/abstracting-on-suggested-solutions-i.h… 35. http://augustss.blogspot.com/2008/12/abstraction-continues-i-got-several.ht… 36. http://conal.net/blog/posts/functional-interactive-behavior/ 37. http://conal.net/blog/posts/trimming-inputs-in-functional-reactive-programm… 38. http://blog.mikael.johanssons.org/archive/2008/12/j-or-how-i-learned-to-sto… 39. http://conal.net/blog/posts/why-classic-frp-does-not-fit-interactive-behavi… 40. http://cliffordbeshers.blogspot.com/2007/11/functional-programming-marketin… 41. http://augustss.blogspot.com/2008/12/somewhat-failed-adventure-in-haskell.h… 42. http://kitenet.net/~joey/blog/entry/haskell_and_xmonad/ 43. http://blog.unsafeperformio.com/?p=32 44. http://justtesting.org/post/63809222 45. http://www.bluishcoder.co.nz/2008/12/random-and-binary-io-using-iteratees.h… 46. http://www.bluishcoder.co.nz/2008/12/not-tutorial-on-happs.html 47. http://sneezy.cs.nott.ac.uk/fplunch/weblog/?p=168 48. file://localhost/home/brent/hacking/hwn/20081213.html 49. http://neilmitchell.blogspot.com/2008/12/f-from-haskell-perspective.html 50. http://www.realworldhaskell.org/blog/2008/12/06/rwh-now-in-store/ 51. http://www-ps.informatik.uni-kiel.de/~sebf/projects/cflp.html 52. http://fhtr.blogspot.com/2008/12/hexagons-with-haskell.html 53. http://eduard-munteanu.blogspot.com/2008/12/learning-haskell.html 54. http://www.serpentine.com/blog/2008/12/05/functional-programmers-on-twitter/ 55. http://sulzmann.blogspot.com/2008/12/parallel-join-patterns-with-guards-and… 56. http://sulzmann.blogspot.com/2008/10/multi-set-rewrite-rules-with-guards-an… 57. http://sulzmann.blogspot.com/2008/12/stm-with-control-communication-for.html 58. http://sulzmann.blogspot.com/2008/12/concurrent-goal-based-execution-of.html 59. http://talkingcode.co.uk/2008/12/02/haskell-gtk-and-multi-threading/ 60. http://writert.blogspot.com/2008/12/quickchecking-code-i-c-source.html 61. http://www.haskell.org/mailman/listinfo/haskell 62. http://sequence.complete.org/ 63. http://planet.haskell.org/ 64. http://sequence.complete.org/node/feed 65. http://haskell.org/ 66. http://haskell.org/haskellwiki/HWN 67. http://code.haskell.org/~byorgey/code/hwn/

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DAMP 2009: Call for Participation
by Manuel M T Chakravarty 13 Dec '08

13 Dec '08

C a l l f o r P a r t i c i p a t i o n DAMP 2009: Workshop on Declarative Aspects of Multicore Programming Savannah, Georgia, USA --- January 20, 2009 (co-located with POPL 2009) DAMP 2009 is the fourth in a series of one-day workshops seeking to explore ideas in programming language design that will greatly simplify programming for multicore architectures, and more generally for tightly coupled parallel architectures. DAMP 2009 is co-located with the ACM SIGPLAN - SIGACT Symposium on Principles of Programming Languages (POPL 2009). The advance program is available at http://www.cse.unsw.edu.au/~pls/damp09/programme.html Early registration deadline is 19 December 2008!

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BYTECODE09: Last Call for Papers
by Samir Genaim 10 Dec '08

10 Dec '08

******************************************************** * Last Call for Papers * * * * Fourth Workshop on Bytecode Semantics, * * Verification, Analysis and Transformation * * * * York, UK, 29th March 2009, part of ETAPS 2009 * * * * Venue: The University of York * * * * http://www.clip.dia.fi.upm.es/Conferences/BYTECODE09 * * * ******************************************************** Important Dates =============== Paper Submission December 21, 2008 Notification January 25, 2009 Final Version February 8, 2009 Workshop March 29, 2009 Workshop Description ==================== Bytecode, such as produced by e.g. .Net and Java compilers, has become an important topic of interest, both for industry and academia. The industrial interest stems from the fact that bytecode is typically used for the Internet and mobile devices (smartcards, phones, etc.), where security is a major issue. Moreover, bytecode is device-independent and allows dynamic loading of classes, which provides an extra challenge for the application of formal methods. In addition, the lack of structure of the code and the pervasive presence of the operand stack also provide extra challenges for the analysis of bytecode. This workshop will focus on the latest developments in the semantics, verification, analysis, and transformation of bytecode. Both new theoretical results and tool demonstrations are welcome. Invited Speaker =============== TBA Submission ========== There are two paper categories, Regular and Tool demo papers. Paper should be written using the ENTCS style and submitted through the easy chair page "http://www.easychair.org/conferences/?conf=bytecode09". Please indicate in the submission page the category of your submission. Submissions will be evaluated by the Program Committee for inclusion in the ENTCS proceedings. Regular research papers should be at most 15 pages (including bibliography and excluding well-marked appendices not intended for publication). They must contain original contributions, be written in English and be unpublished and not submitted simultaneously for publication elsewhere. Tool demo papers must describe a completed, robust and well-documented tool -- highlighting the overall functionality of the tool, the interfaces of the tool, interesting examples and applications of the tool, an assessment of the tool's strengths and weaknesses, and a summary of documentation/support available with the tool. The body of the paper must be no longer than 6 pages in length (including bibliography), and it should give an overview of the tool, the methodology associated with its use, a summary of how the tool has been applied and to what effect, and it should indicate what supporting artifacts (user manual, example repository, downloads, etc) are available. This material will be included in the ENTCS proceedings if the paper is accepted. In addition, the paper should include an appendix (limited to six pages) that gives an outline of the proposed demo presentation (this material will NOT appear in the ENTCS proceedings). Program Committee ================= Wolfgang Ahrendt Chalmers University of Technology, SWE Elvira Albert (co-chair) Complutense University of Madrid, ESP June Andronick NICTA, AUS David Aspinall University of Edinburgh, UK Cristina Cifuentes Sun Microsystems, AUS Samir Genaim (co-chair) Technical University of Madrid, ESP Sara Kalvala The University of Warwick, UK Gerwin Klein The University of New South Wales, AUS Francesco Logozzo Microsoft Research, USA David Pichardie INRIA Rennes (IRISA), FRA Tamara Rezk INRIA-Microsoft, FRA Fausto Spoto University of Verona, ITA Eran Yahav IBM T.J. Watson Research Center, USA

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TLDI 2009 Call for Participation
by Amal Ahmed 09 Dec '08

09 Dec '08

********************************************************************* CALL FOR PARTICIPATION TLDI 2009 ACM SIGPLAN Workshop on Types in Language Design and Implementation 24 January 2009 Savannah, Georgia, USA To be held in conjunction with POPL 2009 http://ttic.uchicago.edu/~amal/tldi2009/ ********************************************************************* IMPORTANT DATES Hotel reservation deadline: December 18, 2008 Early registration deadline: December 19, 2008 VENUE TLDI'09 and all POPL'09 affiliated events will take place at the Hyatt Regency Savannah. SCOPE The role of types in all aspects of language design, compiler construction, and software development has expanded greatly in recent years. Type systems, type analyses, and formal deduction have led to new concepts in compilation techniques for modern programming languages, verification of safety and security properties of programs, program transformation and optimization, and many other areas. The TLDI Workshop series aims to bring together researchers in all these areas to share novel ideas and stimulate interaction and discussion on the ever expanding use of types. INVITED TALK Ulf Norell, Chalmers University of Technology, Sweden Title: Dependently Typed Programming in Agda PRELIMINARY PROGRAM A preliminary program can be found at the end of this email, or it can be found here: http://ttic.uchicago.edu/~amal/tldi2009/program.html GENERAL CHAIR Andrew Kennedy Microsoft Research, Cambridge PROGRAM CHAIR Amal Ahmed Toyota Technological Institute, Chicago PROGRAM COMMITTEE Amal Ahmed Toyota Technological Institute, Chicago (Chair) Juan Chen Microsoft Research Peter Dybjer Chalmers University of Technology Jeff Foster University of Maryland, College Park Neal Glew Intel Robert Harper Carnegie Mellon University Andrew Myers Cornell University Atsushi Ohori Tohoku University Matthew Parkinson University of Cambridge Didier Remy INRIA Paris-Rocquencourt Andreas Rossberg Max Planck Institute for Software Systems PRELIMINARY PROGRAM * SATURDAY, January 24, 2009 ** Opening remarks: 8:50-9:00 ** Invited talk 9:00-10:00 Ulf Norell, Chalmers University of Technology, Sweden Title: Dependently Typed Programming in Agda ---------------------- ** Session I 10:30-12:00 *** Compiling Functional Types to Relational Specifications for Low Level Imperative Code Nick Benton and Nicolas Tabareau *** Typed Transformations of Typed Abstract Syntax Arthur Baars, S. Doaitse Swierstra and Marcos Viera *** Secure Compilation of a Multi-Tier Web Language Ioannis Baltopoulos and Andrew Gordon ---------------------- ** Session II 1:30-3:00 *** A Generic Type-and-Effect System Daniel Marino and Todd Millstein *** Static Extraction of Sound Hierarchical Runtime Object Graphs Marwan Abi-Antoun and Jonathan Aldrich *** Opis: Reliable Distributed Systems in OCaml Pierre-Evariste Dagand, Dejan Kostic and Viktor Kuncak ---------------------- ** Session III 3:30-5:00 *** Type-theoretic semantics for transactional concurrency Aleksandar Nanevski, Paul Govereau and Greg Morrisett *** Relational Parametricity for References and Recursive Types Lars Birkedal, Kristian Støvring and Jacob Thamsborg *** Design Patterns in Separation Logic Neelakantan R. Krishnaswami, Jonathan Aldrich, Lars Birkedal, Kaspar Svendsen and Alexandre Buisse

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ANNOUNCE: The Timber compiler 1.0.2
by Johan Nordlander 09 Dec '08

09 Dec '08

----------------------------------- ANNOUNCE: The Timber compiler 1.0.2 ----------------------------------- We're pleased to announce the availablility of the first public release of the Timber compiler! Timber is a modern language for building event-driven systems, based around the notion of reactive objects. It is also a purely functional language derived from Haskell, although with a strict evaluation semantics. The Timber compiler currently runs on Linux and MacOS X platforms, but uses gcc as its back-end so it should be easily portable to most POSIX- like environments. For more info, language documentation, source code access and binary installers, see http://timber-lang.org/ Or simply grab the timberc package at http://hackage.haskell.org/. The Timber Team through Johan Nordlander

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[Announce] TTTAS (with excuse for second attempt to post)
by S. Doaitse Swierstra 07 Dec '08

07 Dec '08

We are pleased to announce the availability of the package "TTTAS", which contains the code associated with our paper at the coming TLDI workshop: \@inproceedings{ BSV09, author = {Arthur Baars and S. Doaitse Swierstra and Marcos Viera}, title = {Typed Transformations of Typed Abstract Syntax}, booktitle = {TLDI '09: fourth ACM SIGPLAN Workshop on Types in Language Design and Implementation}, year = {2009}, location = {Savannah, Georgia, USA}, publisher = {ACM}, address = {New York, NY, USA}, } For more information see: http://www.cs.uu.nl/wiki/bin/view/Center/TTTAS Arthur Baars Marcos Viera Doaitse Swierstra

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