- Haskell - Haskell.org

ANN: data-type-0.0.1, function-combine-0.0.1 and flexiwrap-0.0.1
by Iain Alexander 26 Feb '11

26 Feb '11

Package data-type contains a number of fundamental types and classes useful for type-level programming, such as type-level booleans, natural numbers, and lists. All of them could no doubt be found elsewhere, including the HList package[1,2], but this package aims to make them more accessible. It is a prerequisite for the other two packages. Package function-combine is the outcome of an exercise in type-level programming (e.g. [3, 4]). It illustrates implementations of * A popular generalisation of function composition -- compose zero = (.) -- compose zero f g x = f (g x) -- compose one f g x y = f (g x y) ... etc. * A generalisation of flip -- <rot n f> passes its first argument as the (n + 1)th argument -- to <f>, rotating the intervening arguments along -- e.g. <rot one> = flip It is published primarily for reference purposes, as [yet] an[other] example of the techniques involved. If somebody happens to find it useful in its own right, so much the better. Package flexiwrap is a more substantial use of these techniques, together with phantom types [6], to provide a system of flexible wrappers, intended to facilitate the definition of types which have specified typeclass instances, which is particularly useful with composed types (see e.g. [5]). Automatic instance derivation techniques generally assume that there is only one appropriate candidate, which is frequently not the case for composed types, whereas flexible wrappers allow you to specify the required instance by name. In particular, an illustrative implementation of the Mark Jones / Luc Duponcheel scheme for monad composition[7] is provided. As a taster, type StrictT = FWCTC (FWFlipDefaults :*: FWCompMonadPlusL :*: FWCompDefaults :*: FWCompS :*: TNil ) (FlipT O) Strict defines a (e.g. monad, but in general constructor) transformer StrictT. FWCTC is a flexible wrapper. Its first parameter is an HList-like type-level list of instance specifications. O is the type composition operator, and FlipT flips its arguments. Strict is a user-defined constructor type. FWCompMonadPlusL specifies a particular MonadPlus instance, and FWCompS specifies the Jones/Duponcheel SComp construction [7]. The other two items in the list (apart from the TNil terminator) specify default implementations of other instances. All three packages should be considered experimental. The flexiwrap package in particular is provided as a proof of concept - only enough typeclass instances are provided to illustrate the idea, and many other details are likely to change. They will work with a wide range of versions of GHC, but probably not other compilers. [1] http://www.cwi.nl/~ralf/HList/ [2] http://darcs.haskell.org/HList/ [3] http://www.haskell.org/haskellwiki/GHC/AdvancedOverlap [4] http://okmij.org/ftp/Haskell/types.html [5] http://hackage.haskell.org/package/TypeCompose [6] I don't know any good reference for the current usage of the term phantom types - I may yet write one. [7] http://web.cecs.pdx.edu/~mpj/pubs/RR-1004.pdf

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Onward! 2011: Call for Papers, Essays, Films, and Workshops
by Eelco Visser 24 Feb '11

24 Feb '11

Call for Papers, Essays, Films, and Workshops -=-=-=-=-= Onward! 2011 ACM Conference on New Ideas in Programming and Reflections on Software October 22-27, 2011 Hilton Portland & Executive Tower, Portland, Oregon USA Sponsored by ACM SIGPLAN http://onward-conference.org/2011/ http://onward-conference.org/2011/poster.html -=-=-=-=-=-=-=-=-=-= Onward! is more radical, more visionary, and more open than other conferences to not (yet) so well-proven but well-argued ideas. We welcome different ways of thinking about, approaching, and reporting on programming language and software engineering research. Onward! fosters the multidisciplinarity of software development. We are interested in anything to do with programming and software. Processes, methods, languages, art, philosophy, biology, economics, communities, politics, ethics, and of course applications. Anything! Sounds good? Do you want to report on and present your new ideas to the community and get feedback? Do you have a video to show or a story to tell, an essay perhaps? Do you want to bring reflections and new insights to the community? Or do you simply want to know more about innovations, visions, and the future of programming languages and software engineering? Then... Join Onward!, the unique, creative, and collaborative environment to discuss and investigate challenging problems related to software, its creation, and nurturing. -=-=-=-=-=-=-=-=-=-= Call for Research Papers: * http://onward-conference.org/2011/papers-call.html * Research papers submission: April 8, 2011 * Research papers notification: June 13, 2011 * Camera-ready copy of research papers due: July 25, 2011 Call for Essays: * http://onward-conference.org/2011/essays-call.html * Essays submission: April 18, 2011 * Essays notification: June 13, 2011 * Camera-ready copy of essays due: July 15, 2011 Call for Films: * http://onward-conference.org/2011/films-call.html * Films submission: May 10, 2011 * Films notification: July 1, 2011 * Final Films due: August 1, 2011 Call for Workshops: * http://onward-conference.org/2011/workshops-call.html * Workshop proposal submission: April 8, 2011 * Workshop proposal notification: May 8, 2011 * Camera-ready copy of workshop abstracts due: June 8, 2011 -=-=-=-=-=-=-=-=-=-= Organization * General Chair: Robert Hirschfeld, Hasso-Plattner-Institut Potsdam, Germany * Steering Committee Chair and General Co-Chair: Richard P. Gabriel, IBM Research, USA * Program Chair: Eelco Visser, Delft University of Technology, The Netherlands * Workshops Chair: Pascal Costanza, Vrije Universiteit Brussel, Belgium * Essays Chair: David West, New Mexico Highlands University, USA * Films Chair: Bernd Bruegge, Technische Universitaet Muenchen, Germany * Web Chair: Tobias Pape, Hasso-Plattner-Institute Potsdam, Germany * Design: Constanze Langer, Institute of Industrial Design, Hochschule Magdeburg-Stendal, Germany -=-=-=-=-=-=-=-=-=-=

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Haskell Weekly News: Issue 170
by Daniel Santa Cruz 24 Feb '11

24 Feb '11

Welcome to issue 170 of the HWN, a newsletter covering developments in the [1]Haskell community. This release covers the week of February 13 - 19, 2011. Announcements Simon Michael [2]informed us of reviving of FunGEn as a community project. "FunGEn (Functional Game Engine) is a platform-independent, BSD-licensed, easy-to-install 2D game engine currently based on OpenGL and GLUT." Alexander McPhail [3]announced the release of vector-buffer. "It provides a buffer that can be turned into a Data.Vector.Storable. The mapM* functions map from the oldest element, not the first." Mark P. Jones [4]announce the availability of 2 openings for post-doctoral researches "to help design, develop, and apply a new strongly typed, pure functional language for systems programming." Trystan Spangler [5]made a second release of his Behavior Driven Development for Haskell, and the tool can now be found in Hackage! Jeremy Shaw [6]announce the release of Happstack 6. "We fully recomend that all Happstack users migrate to the new release." Gregory D. Weber [7]published a new release of Sifflet and sifflet-lib. "Sifflet is a visual, functional programming language and support system for students learning about recursion." Johan Tibell [8]announced the release of two new packages: unordered-containers (Efficient hashing-based container types), and hashable (Efficient hashing of common types). Quotes of the Week * kmc: i started to read the "tutorial" and it was incomprehensible. makes the Gentle Introduction to Haskell look like Teach Yourself PHP in 24 Hours * ConorMcBride: Sometimes it's easier to search for good programs in the space of well typed programs, rather than in the space of ascii turds. * monochrom: best practice haskell is "go with your heart" * accel: one day, it was raining -- I was walking home -- I saw Knuth biking home, wearing a helmet, in the rain -- and I freaked out -- rain was hitting him like any other mortal ... it wasn't bounching off his aura of awesomeness Top Reddit Stories * Type level natural numbers ... ready to merge into GHC mainline: From (hackage.haskell.org) scored 62 with 44 comments. Read on [9]reddit or the [10]original post. * Haskell Web Framework Happstack 6 Released: From (groups.google.com) scored 45 with 3 comments. Read on [11]reddit or the [12]original post. * Well-Typed is hiring: From (well-typed.com) scored 41 with 13 comments. Read on [13]reddit or the [14]original post. * Haskell is Better: slides from Mark Lentczner's talk at Ignite Silicon Valley: From (scribd.com) scored 40 with 43 comments. Read on [15]reddit or the [16]original post. * New, faster hashing-based containers library released: From (blog.johantibell.com) scored 40 with 6 comments. Read on [17]reddit or the [18]original post. * Disciple haskell dialect : strict evaluation as default , destructive update of data structures.: From (disciple.ouroborus.net) scored 35 with 25 comments. Read on [19]reddit or the [20]original post. * Yesod: Warp Speed Ahead: From (docs.yesodweb.com) scored 34 with 8 comments. Read on [21]reddit or the [22]original post. * Faster persistent data structures through hashing: From (blog.johantibell.com) scored 28 with 15 comments. Read on [23]reddit or the [24]original post. * Developing iPhone applications in Haskell â a tutorial: From (gergo.erdi.hu), scored 25 with 6 comments. Read on [25]reddit or the [26]original post. * An Introduction to Agda :: PDF: From (dl.dropbox.com) scored 24 with 4 comments. Read on [27]reddit or the [28]original post. Top StackOverflow Answers * [29]How to tell whether Haskell will cache a result or recompute it? votes: 17 primes, in your code, is not a function, but a constant, in haskellspeak known as a CAF. If it would take a parameter (say, ()), you would get two different versions of the same list back if calling it twice, but as it is a CAF, you get the exact same list back both times; As a top-level definition, primes never gets out of scope, thus the head of the list ... * [30]Specific type inference using uncurry function votes: 17 This has nothing to do with ghci. This is the monomorphism restriction being irritating. If you try to compile the following file: add = uncurry (+) main = do print $ add (1,2 :: Int) print $ add (1,2 :: Double) You will get an error. If you expand: main = do print $ uncurry (+) (1,2 :: Int) print $ uncurry (+) (1,2 :: Double) ... * [31]Haskell: Unexpected output for expression [0, 0.1 .. 1] votes: 15 This is a result of the imprecision of floating point values, it isn't particular to Haskell. If you can't deal with the approximation inherent in floating point then you can use Rational at a high performance cost: > import Data.Ratio Data.Ratio> [0,1%10.. 1%1] [0 % 1,1 % 10,1 % 5,3 % 10,2 % 5,1 % 2,3 % 5,7 % 10,4 % 5,9 % 10,1 % 1] Just to hammer ... * [32]valid haskell function names votes: 14 From the Haskell report: Haskell uses the Unicode character set. However, source programs are currently biased toward the ASCII character set used in earlier versions of Haskell. Recent versions of GHC seem to be fine with unicode (at least in the form of UTF-8):... * [33]Haskell range notation to generate list. Unexpected output votes: 13 The notation is meant to mimic the usual way to write simple sequences mathematics. The second element is not the step, but in fact the actual second element of the list. The rest is linearly extrapolated from there. Examples: [1,2..10] = [1,2,3,4,5,6,7,8,9,10] [1,3..10] = [1,3,5,7,9] [4,3..0] = [4,3,2,1,0] [0,5..] = [0,5,10,15,20,25,30,35... Top StackOverflow Questions * How to tell whether Haskell will cache a result or recompute it? (votes: 11, answers: 1) [34]read * How can one distribute Haskell programs to non-technical end users? (votes: 8, answers: 2) [35]read * Haskell range notation to generate list. Unexpected output (votes: 8, answers: 2) [36]read * Appropriate uses of Monad `fail` vs. MonadPlus `mzero` (votes: 8, answers: 2) [37]read * Why does Haskell not have an I Monad (for input only, unlike the IO monad)? (votes: 8, answers: 3) [38]read About the Haskell Weekly News To help create new editions of this newsletter, please send stories to dstcruz(a)gmail.com. Until next time, Daniel Santa Cruz References 1. http://haskell.org/ 2. http://permalink.gmane.org/gmane.comp.lang.haskell.cafe/86330 3. http://permalink.gmane.org/gmane.comp.lang.haskell.cafe/86371 4. http://www.haskell.org/pipermail/haskell/2011-February/022585.html 5. http://permalink.gmane.org/gmane.comp.lang.haskell.general/18510 6. http://www.mail-archive.com/haskell-cafe@haskell.org/msg87352.html 7. http://www.mail-archive.com/haskell@haskell.org/msg23319.html 8. http://article.gmane.org/gmane.comp.lang.haskell.general/18515 9. http://www.reddit.com/r/haskell/comments/fnc80/type_level_natural_numbers_r… 10. http://hackage.haskell.org/trac/ghc/ticket/4385 11. http://www.reddit.com/r/haskell/comments/fnit9/haskell_web_framework_happst… 12. http://groups.google.com/group/happs/browse_thread/thread/f72d7ff313ea9fa0 13. http://www.reddit.com/r/haskell/comments/flyyg/welltyped_is_hiring/ 14. http://www.well-typed.com/blog/50 15. http://www.reddit.com/r/haskell/comments/flajs/haskell_is_better_slides_fro… 16. http://www.scribd.com/doc/48773692/Ignite-SV-Haskell-is-Better 17. http://www.reddit.com/r/haskell/comments/fo9gm/new_faster_hashingbased_cont… 18. http://blog.johantibell.com/2011/02/new-faster-containers-library.html 19. http://www.reddit.com/r/haskell/comments/fojb4/disciple_haskell_dialect_str… 20. http://disciple.ouroborus.net/ 21. http://www.reddit.com/r/haskell/comments/flp87/yesod_warp_speed_ahead/ 22. http://docs.yesodweb.com/blog/warp-speed-ahead 23. http://www.reddit.com/r/haskell/comments/fm6gg/faster_persistent_data_struc… 24. http://blog.johantibell.com/2011/02/slides-from-my-hashing-based-containers… 25. http://www.reddit.com/r/haskell/comments/fkqe1/developing_iphone_applicatio… 26. http://gergo.erdi.hu/blog/2011-02-13-developing_iphone_applications_in_hask… 27. http://www.reddit.com/r/haskell/comments/fl0wr/an_introduction_to_agda_pdf/ 28. http://dl.dropbox.com/u/361503/Agda%20and%20dependent%20types.pdf 29. http://stackoverflow.com/questions/5032750/how-to-tell-whether-haskell-will… 30. http://stackoverflow.com/questions/4999020/specific-type-inference-using-un… 31. http://stackoverflow.com/questions/5048920/haskell-unexpected-output-for-ex… 32. http://stackoverflow.com/questions/5023485/valid-haskell-function-names/502… 33. http://stackoverflow.com/questions/5012185/haskell-range-notation-to-genera… 34. http://stackoverflow.com/questions/5032750/how-to-tell-whether-haskell-will… 35. http://stackoverflow.com/questions/5004902/how-can-one-distribute-haskell-p… 36. http://stackoverflow.com/questions/5012185/haskell-range-notation-to-genera… 37. http://stackoverflow.com/questions/5023969/appropriate-uses-of-monad-fail-v… 38. http://stackoverflow.com/questions/5032475/why-does-haskell-not-have-an-i-m…

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2nd CfP: WRS 2011 - 10th International Workshop on Reduction Strategies in Rewriting and Programming
by Santiago Escobar 23 Feb '11

23 Feb '11

Call for Papers WRS 2011 10th International Workshop on Reduction Strategies in Rewriting and Programming http://www.dsic.upv.es/workshops/wrs2011 29 May 2011, Novi Sad, Serbia An RDP 2011 workshop Federated Conference on Rewriting, Deduction, and Programming This workshop promotes research and collaboration in the area of reduction strategies. It encourages the presentation of new directions, developments, and results as well as surveys and tutorials on existing knowledge in this area. Reduction strategies define which (sub)expression(s) should be selected for evaluation and which rule(s) should be applied. These choices affect fundamental properties of computations such as laziness, strictness, completeness, and efficiency, to name a few. For this reason programming languages such as Elan, Maude, OBJ, Stratego, and TOM allow the explicit definition of the evaluation strategy, whereas languages such as Clean, Curry, and Haskell allow its modification. In addition to strategies in rewriting and programming, WRS also covers the use of strategies and tactics in other areas such as theorem and termination proving. Previous editions of the workshop were held in Utrecht (2001), Copenhagen (2002), Valencia (2003), Aachen (2004), Nara (2005), Seattle (2006), Paris (2007), Hagenberg (2008), Brasilia (2009), and Edinburgh (2010); the last one as a joint workshop with the STRATEGIES workshop. Further information can be found at the permanent site for WRS <http://www.dsic.upv.es/~wrs/>. WRS 2011 is planned to be co-located with RTA 2011 (22nd International Conference on Rewriting Techniques and Applications), as a satellite event of RDP, the Federated Conference on Rewriting, Deduction, and Programming. WRS 2011 will be held at Novi Sad, Serbia on 29 May 2011. Submissions and Publication: Before the workshop, authors are invited to submit an extended abstract (max. 5 pages) to be formatted in the EasyChair class style through the EasyChair submission site. Accepted abstracts will be presented at the workshop and included in the preliminary proceedings, available at the workshop. After the workshop, authors will be invited to submit a full paper of their presentation (typically a 15-pages paper), which will be refereed and considered for publication in an electronic journal, such as Electronic Proceedings in Theoretical Computer Science. Beyond original ideas and recent results not published nor submitted elsewhere, we also invite authors to submit a 5-pages abstract describing relevant work that has been or will be published elsewhere, or work in progress. These submissions will be only considered for presentation at the workshop and inclusion in the preliminary proceedings but not in the final proceedings. We envisage publication of a special issue of a journal dedicated to WRS after the event. Important Dates: # Submission: 20 March 2011 # Notification: 4 April 2011 (changed) # Preliminary proceedings version due: 15 April 2011 # Workshop: 29 May 2011 # Submission for final proceedings: 12 September 2011 # Notification: 7 November 2011 # Final version: 21 November 2011 Programme Committee: # Dan Dougherty, Worcester Polytechnic Institute, USA # Santiago Escobar, Universidad Politecnica de Valencia, Spain (chair) # Maribel Fernandez, King's College London, UK # Juergen Giesl, RWTH Aachen, Germany # Bernhard Gramlich, Technische Universit Wien, Austria # Helene Kirchner, Centre de Recherche INRIA Bordeaux, France # Francisco Javier Lopez Fraguas, Universidad Complutense de Madrid, Spain # Salvador Lucas, Universidad Politecnica de Valencia, Spain # Aart Middeldorp, University of Innsbruck, Austria # Jaco van de Pol, University of Twente, The Netherlands # Masahiko Sakai, Nagoya University, Japan # Manfred Schmidt-Schauss, Johann Wolfgang Goethe-Universitat, Germany For more information, please contact Santiago Escobar Universidad Politecnica de Valencia, Spain Email: sescobar(a)dsic.upv.es

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Call for Papers (ICFEM 2011)
by Huibiao Zhu 22 Feb '11

22 Feb '11

************************************************************ ICFEM 2011: 13th International Conference on Formal Engineering Methods CALL FOR PAPERs 25-28 Oct 2011 Radisson BLU Hotel, Durham, UK URL: http://www.scm.tees.ac.uk/icfem2011 ************************************************************ Since 1997, ICFEM has provided a forum for those interested in the application of formal engineering methods to computer systems. Researchers and practitioners, from industry, academia, and government, are encouraged to attend, and to help advance the state of the art. We are interested in work that has been incorporated into real production systems, and in theoretical work thatpromises to bring practical, tangible benefit. ICFEM 2011 is organised by Teesside University and will be held in the historic Durham City in the North East of England (http://www.thisisdurham.com/) AREA AND TOPICS Submissions related to the following principal themes are encouraged, but any topics relevant to the field of formal methods and their support environments will also be considered: * Abstraction and refinement * Formal specification and modelling * Software verification * Program analysis * Software model checking * Formal approaches to software testing * Formal methods for object and component systems * Concurrency and software transaction memory * Formal methods for cloud computing * Software inspection * Formal methods for cyber-physical systems * Tool development and integration * Software safety, security and reliability * Experiments involving verified systems * Applications of formal methods * Formal model-based development and code generation SUBMISSION AND PUBLICATION Submissions to the conference must not have been published or be concurrently considered for publication elsewhere. All submissions will be judged on the basis of originality, contribution to the field, technical and presentation quality, and relevance to the conference. The proceedings will be published in the Springer Lecture Notes in Computer Science series. Papers should be written in English and not exceed 16 pages in LNCS format (see http://www.springer.de/comp/lncs/authors.html for details). Submission should be done through the ICFEM 2011 submission page (https://www.easychair.org/conferences/?conf=icfem2011) handled by the EasyChair conference system. All queries should be sent to the e-mail address icfem2011(a)scm.tees.ac.uk. IMPORTANT DATES 31 March, 2011: Abstract submission deadline 7 April, 2011: Full-paper submission deadline 8 June, 2011: Acceptance/rejection notification 6 July, 2011: Camera-ready version due ORGANIZATION COMMITTEE Honorary Chairs: Marc Cavazza, Teesside University Cliff Hardcastle, Teesside University General Chairs: Phil Brooke, Teesside University, UK Cliff Jones, Newcastle University, UK Program Chairs: Shengchao Qin, Teesside University, UK Zongyan Qiu, Peking University, UK Program Committee: Bernhard K. Aichernig (Graz University of Technology, Austria) Keijiro Araki (Kyushu University, Japan) Farhad Arbab (CWI and Leiden University, The Netherlands) Richard Banach (University of Manchester, UK) Nikolaj Bjorner (Microsoft Research Redmond, USA) Jonathan P. Bowen (University of Westminster, UK) Michael Butler (University of Southampton, UK) Andrew Butterfield (Trinity College Dublin, Ireland) Ana Cavalcanti (University of York, UK) Wei-Ngan Chin (National University of Singapore, Singapore) Florin Craciun (Soter Sys, Romania) Thao Dang (French National Center for Scientific Research, France) Jim Davies (Oxford University, UK) Dino Distefano (Queen Mary College, University of London, UK) Jin-Song Dong (National University of Singapore, Singapore) Zhenhua Duan (Xidian University, China) Colin Fidge (Queensland University of Technology, Australia) J. S. Fitzgerald (Newcastle University, UK) Leo Freitas (Newcastle University, UK) Joaquim Gabarro (Universitat Polit(r)(r)cnica de Catalunya, Spain) Stefania Gnesi (ISTI-CNR, Italy) Anthony Hall (Consultant) Ian J. Hayes (The University of Queensland, Australia) Mike Hinchey (Lero, Ireland) Zhenjiang Hu (National Institute of Informatics, Japan) Michael Jackson (Consultant) Thierry J(r)¶ron (INRIA , France) Gerwin Klein (NICTA, Australia) Laura Kovacs (Vienna University of Technology, Austria) Kim G. Larsen (Aalborg University, Denmark) Peter Gorm Larsen (Aarhus University, Denmark) Michael Leuschel (Heinrich-Heine Universit?t D(r)πsseldorf, Germany) Xuandong Li (Nanjing University, China) Shaoying Liu (Hosei University, Japan) Zhiming Liu (UNU/IIST, Macau) Tiziana Margaria (University of Potsdam, Germany) Stephan Merz (INRIA Nancy & LORIA, France) Huaikou Miao (Shanghai University, China) Peter M(r)πller (ETH Zurich, Switzerland) Jun Pang (University of Luxembourg, Luxembourg) Matthew Parkinson (Microsoft Research Cambridge, UK) Geguang Pu (East China Normal University, China) Shengchao Qin (Teesside University, UK) Zongyan Qiu (Peking University, China) Augusto Sampaio (Universidade Federal de Pernambuco, Brazil) Thomas Santen (Microsoft Innovations Center Aachen, Germany) Wuwei Shen (Western Michigan University, USA) Marjan Sirjani (Reykjavik University, Iceland) Bill Stoddart (Teesside University, UK) Jing Sun (University of Auckland, New Zealand) Jun Sun (Singapore University of Technology and Design, Singapore) Kenji Taguchi (AIST, Japan) Tetsuo Tamai (University of Tokyo, Japan) Yih-Kuen Tsay (National Taiwan University, Taiwan) T.H. Tse (University of Hong Kong, Hong Kong) Viktor Vafeiadis (MPI-SWS, Germany) Miroslav Velev (Aries Design Automation, USA) Laurent Voisin (Systerel, France) Hai H. Wang (Aston University, UK) Ji Wang (National University of Defense Technology, China) Heike Wehrheim (University of Paderborn, Germany) Jim Woodcock (University of York, UK) Wang Yi (Uppsala University, Sweden) Hongli Yang (Beijing University of Technology, China) Naijun Zhan (Chinese Academy of Sciences, China) Jian Zhang (Chinese Academy of Sciences, China) Hong Zhu (Oxford Brookes University, UK) Huibiao Zhu (East China Normal University, China) Steering Committee Keijiro Araki, Japan Jin Song Dong, Singapore Chris George, Canada Jifeng He, China Mike Hinchey, Ireland Shaoying Liu (Chair), Japan John McDermid, UK Tetsuo Tamai, Japan Jim Woodcock, UK

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PhD studentships in Nottingham (deadline 1st March)
by Graham Hutton 21 Feb '11

21 Feb '11

+------------------------------------------------------------------+ PhD Studentships in Functional Programming School of Computer Science University of Nottingham, UK The Functional Programming Lab (FP Lab) in the School of Computer Science at the University of Nottingham is seeking to appoint up to two new PhD students, starting on 1st October 2011. The topics for the studentships are open, but will be within the general area of functional programming. The studentships are for 3.5 years, include a maintenance grant of 13,590 UK pounds per year and UK/EU tuition fees, and are open to UK and EU applicants. Particularly strong candidates from outside the EU may also be considered, subject to additional funds being available. Applicants will require a first-class Honours degree (or equivalent) in Computer Science, Mathematics, and/or Physics, experience in functional programming, and an aptitude for mathematical subjects. A higher degree (e.g. Masters) would be desirable. Additionally, experience in one or more of the following will be particularly welcome: formal semantics, type theory, program verification, theorem provers, domain-specific languages, languages for physical modelling, programming language implementation and tools. Successful applicants will work under the supervision of Dr Graham Hutton or Dr Henrik Nilsson in the FP Lab in Nottingham, a leading centre for research on functional programming. The group currently comprises 5 academic staff, 1 research fellow, and 10 PhD students. In order to apply, please submit the following to Dr Graham Hutton (gmh(a)cs.nott.ac.uk) or Dr Henrik Nilsson (nhn(a)cs.nott.ac.uk) by 1st March 2011: an up-to-date copy of your CV (including the results of all your University examinations to date) along with a brief covering letter that describes your experience in functional programming, your reasons for wishing to pursue a PhD in this area, and any ideas you have regarding possible research directions. Note: applicants to the FP Lab should follow the procedure above, rather than applying directly to the School or University, e.g. in response to a general advert for PhD studentships. Closing date for applications: 1st March 2011. +------------------------------------------------------------------+

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Re: [Haskell] [Haskell-cafe] ANN: unordered-containers - a new, faster hashing-based containers library
by Johan Tibell 20 Feb '11

20 Feb '11

On Sat, Feb 19, 2011 at 4:49 PM, wren ng thornton <wren(a)freegeek.org> wrote: > How does, or will, this package differ from Milan Straka's > http://hackage.haskell.org/package/hashmap ? It's a continuation of that work. The unordered-containers implementation is more space efficient and a bit faster. Milan also uses a Patricia trie in his implementation. I plan to switch to a hash-array mapped trie (HAMT) in the future. It's about 25% faster for lookups but at the moment quite a bit slower for inserts. Once we got some new faster array copy primops in GHC we can hopefully improve the insert time a lot. A HAMT also has much lower space overhead per entry. Johan

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ANN: unordered-containers - a new, faster hashing-based containers library
by Johan Tibell 19 Feb '11

19 Feb '11

Hi all, I am delighted to announce the release of preview versions of two new packages: unordered-containers 0.1 Efficient hashing-based container types. http://hackage.haskell.org/package/unordered-containers hashable 1.1 Efficient hashing of common types. http://hackage.haskell.org/package/hashable These packages address a need for faster container types in Haskell, especially for string types like ByteString and Text. The package achieves better performance by using hashing and a Patricia trie (also known as a radix tree), instead of a balanced tree, in its implementation. The provided HashMap type is three times faster than Data.Map for lookups and twice as fast for inserts, for all key types I've tried, including ByteString, String, and Int. I'm calling this a preview release, even though the code hash been well tested both for correctness and performance, as the API is quite basic and doesn't provide a HashSet type yet. One thing you'll notice is that the API is split into a value-strict and a value-lazy version, making it easier to use in a strict setting. If you want to contribute, please get copies of the source trees from here: * git clone https://github.com/tibbe/unordered-containers.git * git clone https://github.com/tibbe/hashable.git Alternatively, just fork the projects on GitHub: http://github.com/tibbe As I mentioned in my talk on hashing-based containers earlier this week, I'm working on an even faster version, based on hash-array mapped tries, but it won't be ready until GHC 7.2. Johan

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WGP 2011: Call for Papers
by Shin-Cheng Mu 19 Feb '11

19 Feb '11

====================================================================== CALL FOR PAPERS WGP 2011 7th ACM SIGPLAN Workshop on Generic Programming Tokyo, Japan Sunday, September 18th, 2011 http://flolac.iis.sinica.edu.tw/wgp11/ Collocated with the International Conference on Functional Programming (ICFP 2011) ====================================================================== Goals of the workshop --------------------- Generic programming is about making programs more adaptable by making them more general. Generic programs often embody non-traditional kinds of polymorphism; ordinary programs are obtained from them by suitably instantiating their parameters. In contrast with normal programs, the parameters of a generic program are often quite rich in structure; for example they may be other programs, types or type constructors, class hierarchies, or even programming paradigms. Generic programming techniques have always been of interest, both to practitioners and to theoreticians, and, for at least 20 years, generic programming techniques have been a specific focus of research in the functional and object-oriented programming communities. Generic programming has gradually spread to more and more mainstream languages, and today is widely used in industry. This workshop brings together leading researchers and practitioners in generic programming from around the world, and features papers capturing the state of the art in this important area. We welcome contributions on all aspects, theoretical as well as practical, of * generic programming, * programming with (C++) concepts, * meta-programming, * programming with type classes, * programming with modules, * programming with dependent types, * polytypic programming, * adaptive object-oriented programming, * component-based programming, * strategic programming, * aspect-oriented programming, * family polymorphism, * object-oriented generic programming, * and so on. Organizers ---------- Co-Chair Jaakko Järvi, Texas A&M University, USA Co-Chair Shin-Cheng Mu, Academia Sinica, Taiwan Programme Committee ------------------- Dave Abrahams, BoostPro Computing, USA Magne Haveraaen, Universitetet i Bergen, Norway Akimasa Morihata, Tohoku University, Japan Pablo Nogueira, Universidad Politécnica de Madrid, Spain Ulf Norell, Chalmers University of Technology and University of Gothenberg, Sweden Ross Paterson, City University London, UK Rinus Plasmeijer, Radboud University Nijmegen, The Netherlands Sibylle Schupp, Technische Universität Hamburg-Harburg, Germany Andrew Sutton, Kent State University, USA Tarmo Uustalu, Institute of Cybernetics, Estonia Important Information --------------------- We plan to have formal proceedings, published by the ACM. Submission details Deadline for submission: Monday 2011-06-06 Notification of acceptance: Tuesday 2011-07-01 Final submission due: Monday 2011-07-25 Workshop: Sunday 2011-09-18 Authors should submit papers, in postscript or PDF format, formatted for A4 paper, to the WGP11 EasyChair instance by the above deadline. The length should be restricted to 12 pages in standard (two-column, 9pt) ACM format. Accepted papers are published by the ACM and will additionally appear in the ACM digital library. History of the Workshop on Generic Programming ---------------------------------------------- This year: * Tokyo, Japan 2011 (affiliated with ICFP11) Earlier Workshops on Generic Programming have been held in * Baltimore, Maryland, US 2010 (affiliated with ICFP10) * Edinburgh, UK 2009 (affiliated with ICFP09) * Victoria, BC, Canada 2008 (affiliated with ICFP), * Portland 2006 (affiliated with ICFP), * Ponte de Lima 2000 (affiliated with MPC), * Marstrand 1998 (affiliated with MPC). Furthermore, there were a few informal workshops * Utrecht 2005 (informal workshop), * Dagstuhl 2002 (IFIP WG2.1 Working Conference), * Nottingham 2001 (informal workshop), There were also (closely related) DGP workshops in Oxford (June 3-4 2004), and a Spring School on DGP in Nottingham (April 24-27 2006, which had a half-day workshop attached). Additional information: The WGP steering committee consists of J. Gibbons, R. Hinze, P. Jansson, J. Järvi, J. Jeuring, B. Oliveira, S. Schupp, and M. Zalewski

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ANNOUNCE: Sifflet visual programming language, release 1.2.3
by gdweber＠iue.edu 18 Feb '11

18 Feb '11

Sifflet and sifflet-lib 1.2.3 are now available on Hackage. This is a compatibility release for GHC 7 and Haskell Platform 2011.2. Sifflet is a visual, functional programming language and support system for students learning about recursion. Sifflet programmers define functions by drawing diagrams, and the Sifflet interpreter uses the diagrams to show how function calls are evaluated. Sifflet-lib is the library containing many modules of the sifflet application. What's New ---------- February 18, 2011: Version 1.2.3 provides compatibility with GHC 7 (remaining backward-compatible with GHC 6.12.3) and Haskell Platform 2011.2. About Sifflet ------------- Sifflet is a visual, functional programming language intended as an aid for learning about recursion. * A picture explains Sifflet better than words: please see the screenshot showing how to evaluate 3!: http://mypage.iu.edu/~gdweber/software/sifflet/home.html * Features: - Visual editor. - Visual tracer/debugger which shows how recursive and other function calls are evaluated. To support active learning and avoid screen clutter, Sifflet displays only as much of the computation as the user requests. - A carefully crafted tutorial with 31 pictures and about as many pages. - Number, string, and list data types. - A small collection of primitive functions. - Runnable examples of compound functions. - Sifflet functions can be exported to Scheme, Python 3, and Haskell. * Download: http://hackage.haskell.org/package/sifflet-lib http://hackage.haskell.org/package/sifflet * Home page: http://mypage.iu.edu/~gdweber/software/sifflet/home.html * Tutorial: http://mypage.iu.edu/~gdweber/software/sifflet/doc/tutorial.html -- ___ ___ __ _ / _ \ / _ \| | | | Gregory D. Weber, Associate Professor / /_\// / | | | /\ | | Indiana University East / /_\\/ /__| | |/ \| | http://mypage.iu.edu/~gdweber/ \____/\_____/\___/\__/ Tel. (765) 973-8420; FAX (765) 973-8550

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