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Spring School in Generic and Indexed Programming
by Jeremy.Gibbons＠comlab.ox.ac.uk 16 Jan '10

16 Jan '10

SPRING SCHOOL ON GENERIC AND INDEXED PROGRAMMING Wadham College, Oxford, 22nd to 26th March 2010 TOPIC "Generic programming" is about making programs more widely applicable via exotic kinds of parametrization - not just along the dimensions of values or of types, but of things such as the shape of data, algebraic structures, strategies, computational paradigms, and so on. "Indexed programming" is a lightweight form of dependently typed programming, constraining flexibility by allowing one to state and check relationships between parameters: that the shapes of two arguments agree, that an encoded value matches to some type, that values transmitted along a channel conforms to some protocol, and so on. The two forces of genericity and indexing balance each other nicely, simultaneously promoting and controlling generality. The EPSRC-funded Generic and Indexed Programming project at Oxford has been exploring their interaction over the period 2006 - 2010; this school is the closing activity of the project. LECTURERS Six lecturers from the Programming Languages community, each an acknowledged expert in their specialism, will cover various aspects of generic and indexed programming. Each will give about four hours' lectures, distributed throughout the week. Nate Foster (Princeton University) "Bidirectional Programming" Ralf Hinze (University of Oxford) "Generic Programming with Adjunctions" Oleg Kiselyov (Fleet Numerical Meteorology and Oceanography Center) "Typed Tagless Interpreters" Simon Peyton Jones (Microsoft Research Cambridge) "Type Functions" Jeremy Siek (University of Colorado at Boulder) "Concepts in C++" Stephanie Weirich (University of Pennsylvania) "Generic Programming with Dependent Types" PREREQUISITES The school is aimed at doctoral students in programming languages and related areas; however, researchers and practitioners will be very welcome, as will strong masters students with the support of a supervisor. It will be assumed that participants have a good understanding of typed functional programming, as in Haskell or O'Caml. DATES Registration deadline: 19th February School: 22nd March (0900) to 26th March (lunchtime) VENUE Lectures will be held and accommodation provided in Wadham College in the centre of Oxford. The college celebrates its 400th anniversary in 2010; notable past members include Sir Christopher Wren, the founder of the Royal Society, and notable present ones Marcus du Sautoy, the mathematician and TV presenter. COSTS Costs will be kept low, thanks to support from EPSRC. There will be a nominal registration fee, and B&B accommodation in college will be about £55 per night. (Precise costs are yet to be determined.) FURTHER INFORMATION Further information, including instructions on how to register, will be available soon at the website: http://www.comlab.ox.ac.uk/projects/gip/school.html

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ANN: haskell-src-exts 1.7.0
by Niklas Broberg 15 Jan '10

15 Jan '10

Fellow Haskelleers, As I was asked to start spamming again, I'm hereby pleased to announce the release of haskell-src-exts-1.7.0! * On hackage: http://hackage.haskell.org/package/haskell-src-exts * Via cabal: cabal install haskell-src-exts * Darcs repo: http://code.haskell.org/haskell-src-exts For users of hsx, this version works fine with hsx-0.6.1. Since I haven't sent out one of these announcements in a while, here's the complete CHANGELOG since the previous announcement: ** 1.7.x 1.6.1 --> 1.7.0 =============== * Operators defined on the form (a `op` b) c = ... could not be handled by the (annotated) AST, nor the parser. I had to change the definition of the AST node for InfixMatch to allow a list of right-hand subpatterns, i.e. InfixMatch l (Pat l) (Name l) (Pat l) ... has become InfixMatch l (Pat l) (Name l) [Pat l] ... I also had an epiphany and fixed the issue that would arise with exact printing of prefix definitions including parentheses (e.g. (foo x) y = ...), so that now works too! ** 1.6.x 1.6.0 --> 1.6.1 =============== * UnicodeSyntax now works not only for identifiers, but also for ->, <- and =>, as well as Arrows arrows and kind stars. (And before you send me bug reports for this one, do check that your version of readFile is Unicode aware, i.e. you use GHC 6.12 or the utf8-string version). 1.5.3 --> 1.6.0 =============== * (=~=) turns out to be too general at Functor (for intuitive and not technical reasons), so is specialised to Annotated to closer mirror the original intention. * applyFixities is hoisted to a monad, and now fails on ambiguous infix expressions. ** 1.5.x 1.5.2 --> 1.5.3 =============== * Several small bug fixes in the exact printer, and fail more gracefully if the number of srcInfoPoints doesn't match the needs of the node. 1.5.1 --> 1.5.2 =============== * Fix a bug in the exact printer that made it always print the first token at position (0,0). * In fixing the above, Annotated is now a superclass of ExactP. It was already a superclass in spirit, and nothing can break from this since ExactP is only exported abstractly. 1.5.0 --> 1.5.1 =============== * The pretty printer now introduces parentheses for non-atomic arguments to function application. Note that infix applications are left untouched, no parentheses will be inserted there, as it is assumed that fixities are already properly resolved. * Fix a bug in the pretty printer where view patterns and n+k patterns were not properly parenthesised. 1.4.0 --> 1.5.0 =============== * Add support for acting on LINE pragmas while parsing, i.e. updating the source position according to info given in LINE pragmas. This is done conditionally based on a new flag ignoreLinePragmas in the ParseMode, hence the need to increase the major version. ** 1.4.x 1.3.5 --> 1.4.0 =============== * The AST node for Proc in the simple AST is changed to include a SrcLoc argument, to make it consistent with similar nodes e.g. Lambda. This is specifically needed for transformation of patterns in HSX. ** 1.3.x 1.3.4 --> 1.3.5 =============== * Added an entry point in the parser for statements, and an instance Parseable Stmt to go with it. * Ensured that .Annotated exports all relevant parseXXX(WithYYY) functions. 1.3.3 --> 1.3.4 =============== * Operator fixities are now resolved in patterns. 1.3.2 --> 1.3.3 =============== * Fixes a bug where qualified keywords are rejected even if the extension that enables the keyword in question is not turned on. 1.3.0 --> 1.3.2 =============== (Let's forget 1.3.1 ever existed.) * Fix a bug where declarations of infix operators were not properly merged as FunBinds.

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ANNOUNCE: Functional Programming Bibliography
by James Russell 15 Jan '10

15 Jan '10

I am pleased to announce the Functional Programming Bibliography at http://www.catamorphism.net/ The functional programming bibliography was created in the hope that it will be a useful resource to the functional programming community. The site is still in an early stage of development, and is pretty raw, and incomplete in a number of ways. Keyword categorization, in particular, is still fairly spotty. It currently contains in excess of 1500 references, heavily slanted toward Haskell-related topics, and contains links to publicly available versions of many papers, as well as links to gated versions of some papers. I am eager for suggestions as to how the site could be made more useful. Regards, James Russell

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Signature error because the order
by Luis Cabellos 14 Jan '10

14 Jan '10

Hi, I found than this piece of code causes an error in GHC ( * http://haskell.pastebin.com/m5e3f4a4c* ): data Tree a = Leaf a | Node (Tree a) (Tree a) --prettyShow :: (Show a, Num a) => Tree a -> String -- WORKS prettyShow :: (Num a, Show a) => Tree a -> String -- FAILS prettyShow (Leaf a) = show a prettyShow (Node a b) = (simple a) ++ (simple b) simple :: (Show a, Num a) => Tree a -> String simple (Leaf x) = prettyShow (Leaf x) simple x = "(" ++ prettyShow x ++ ")" With the error: test.lhs:14:0: Couldn't match expected type `Show a' against inferred type `Num a1' When matching the contexts of the signatures for prettyShow :: forall a. (Num a, Show a) => Tree a -> String simple :: forall a. (Show a, Num a) => Tree a -> String The signature contexts in a mutually recursive group should all be identical When generalising the type(s) for prettyShow, simple Failed, modules loaded: none. But if I change the order of *Show* and *Num* in the signature of * prettyShow* it works. It's a GHC problem? it's normal than signature is order-dependent? I use *GHC 6.10.3* Thanks, Luis Cabellos -- LC, ("There is no Dana, only Zuul." - Cazafantasmas [1984])

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Two PhD positions in theoretical computer science
by Alexandra Silva 14 Jan '10

14 Jan '10

Vacancies for PhD positions in theoretical computer science =========================================================== Leiden Institute of Advanced Computer Science (LIACS) of Leiden University and Centrum Wiskunde & Informatica (CWI) in Amsterdam are looking for two PhD students for working in the NWO funded research project CoRE: Coinductive Calculi of Regular Expressions The purpose of the project is to use the theory of coalgebras and Kleene algebras for automatic reasoning and verification of quantitative and probabilistic systems, interactive systems and advanced functional programs. We are looking for excellent candidates with a background (Master degree) in mathematics, computer science or a related degree and who have strong interest in the mathematical foundations of computer science. Conditions of employment ------------------------ There are two PhD positions available. One candidate will be employed at LIACS in the Foundations of Software Technology (FAST) group. The other will be employed at CWI in the Coordination Languages group (SEN3) in the sub-group `Coalgebraic Models of Computation' led by Prof. Jan Rutten. Both groups provide a dynamic and productive work environment, are in close collaboration with each other and are involved in several national and international research projects. Both PhD candidates will be appointed for a period of four years and will receive salary based on a full-time employment. The salary and labour agreements are in accordance with the CAO for Dutch universities and research institutes. How to Apply? ------------- You are invited to send your application letter together with a curriculum vitae (including a list of master courses), an abstract of your master thesis or a list of publications, and the names and contact addresses of two potential referees. Please send your application before 1 March 2010 to: Marcello Bonsangue <marcello(a)liacs.nl> and Milad Niqui <M.Niqui(a)cwi.nl>

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ANN: HaXml-1.20.1
by Malcolm Wallace 13 Jan '10

13 Jan '10

I am pleased to announce a new, stable, release of HaXml. (Actually, 1.20 has been available for some time, but I am just getting round to the announcement, and a fresh bugfix means a version bump to 1.20.1.) HaXml-1.20.1 ------------ http://haskell.org/HaXml http://hackage.haskell.org/package/HaXml If you have been using the previous stable version, 1.13.x, you are strongly encouraged to upgrade, as no further bugfixes will be back- propagated. (Ideally, Cabal and Hackage should also now cease to recommend 1.13.x as a preferred version, but I do not know how to change that. A simple "cabal install HaXml" will unfortunately still find 1.13.x, so please use "cabal install HaXml-1.20.1" with explicit version number.) There have been significant API changes since 1.13.x, and a brief migration guide is included on the website. In summary: * There is a SAX-like stream parser. * Ordinary parsing of XML documents can now also be lazy. * Some types have changed. * Some old classes have been re-arranged into a single new class. Regards, Malcolm

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AST 2010 reminder--call for papers and presentations
by John Hughes 12 Jan '10

12 Jan '10

Just a reminder: the submission deadline for AST 2010 (Automation of Software Test 2010, associated with ICSE 2010 in Cape Town) is only a week away. If you're planning to submit a paper or a presentation for the workshop, then now's the time to be putting it together! http://www.cs.allegheny.edu/ast2010/ John Hughes

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Job at Mylife
by Julien Verlaguet 12 Jan '10

12 Jan '10

Dear Haskell Programmers, Our company, MyLife, is continuing to seek OCaml programmers to expand our team in the Silicon Valley. We develop back-end people search technologies and the vast majority of our code is written in Objective Caml and runs on Linux. We love that as it provides us with an opportunity to tackle on big challenges with great productivity. We are now looking for talented and passionate people to share the fun in Mountain View, California. The primary requirements for the job are: - proficiency in a functional programming language and eventually OCaml - familiarity with Linux and shell scripting - proficiency in written English, as much of our team communications are written (brainstorms, bug reports, etc.) - ability to understand end-user requirements and translate them into robust software that gets the job done The ideal candidate will have a good nose for hunting bugs, diagnosing performance problems, and hacking his/her way through colleagues' code. Please contact us at ocaml-job(a)mylife.com if you are interested or might be interested in the future. Julien

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Open Position (PhD student or Postdoc), U Tübingen, Germany
by Torsten Grust 11 Jan '10

11 Jan '10

[ Dear Haskellers! This job opening may sound a bit database-ish on a first read, but there is lots of Haskell and functional programming inside. Please contact me if you're in doubt. Best wishes, --Torsten ] Join us on the fringes between database and programming languages The Database Systems Research Group (Prof. Torsten Grust) at the Wilhelm-Schickard-Institute for Computer Science of Eberhard Karls Universität Tübingen, Germany, opens a position for a Research Assistant (PhD student or Postdoc level, three-year, full-time) in the Ferry research project[1]. Ferry explores how far we can push the idea of relational database engines that support the super-fast execution of programs written in a variety of programming languages. Our current focus is on LINQ, Ruby, and Philip Wadler's Links, but consider this list as open-ended. = DATABASE-SUPPORTED PROGRAM EXECUTION = We search for, design, and implement new compilation strategies that map data types and idioms prevalent in (functional) programming and scripting languages into efficient database queries. Ferry targets off-the-shelf SQL database systems as well as a number of off-beat database engines (e.g., X100, MonetDB, or kdb+). We build on technology developed in the context of our project Pathfinder[2]. Implementation languages are Haskell, O'Caml and C. This demo video[3] provides a flavor of the ideas behind Ferry. Ferry is supported by the DFG (German Research Foundation). = REQUIREMENTS = We are looking forward to grow our team and welcome applications of highly motivated candidates with an excellent university degree (Master in Computer Science or a closely related field) who are willing to develop and shape the future of Ferry. If you are a database person, that's great. If you are into (functional) programming languages, that's perfect. (Yes, we love SQL /and/ Haskell.) Last but not least, we hope that you like systems building as much as we do. The position has no teaching obligations -- if you would like to get involved with teaching nevertheless, please let us know. Good knowledge of English (research and publication) is a requirement, a reasonable command of German will be helpful. = JOB DETAILS AND APPLICATION = Successful candidates will sign a contract with the Universität Tübingen under the current regulations applicable to employees in Public Service (TV-L). This is a three-year full-time position. The exact start date in the time frame March till May 2010 is negotiable. You will be working in Tübingen, the traditional university town in the Neckar valley (Stuttgart region). Our group offers an informal, open, and fun working environment. Universität Tübingen aims at increasing the number of female employees and thus especially welcomes applications of female candidates. Applications of disabled candidates will be given priority, depending on their suitability. Please send your complete application in PDF format via e-mail to Prof. Torsten Grust (torsten.grust(a)uni-tuebingen.de) The deadline for applications is Feburary 19, 2010. Inquiries with respect to this position may be directed to Prof. Torsten Grust +49 7071 / 29 75477 torsten.grust(a)uni-tuebingen.de www-db.informatik.uni-tuebingen.de [1] http://www.ferry-lang.org/ [2] http://www.pathfinder-xquery.org/ [3] http://bit.ly/4GKEhQ (MP4, approx. 10MB), or http://www.youtube.com/watch?v=JRKmRiW_v4Q&fmt=18 (YouTube) -- | Prof. Dr. Torsten Grust torsten.grust(a)uni-tuebingen.de | | www-db.informatik.uni-tuebingen.de | | Database Systems - Universität Tübingen (Germany) |

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ANNOUNCE: Palindromes 0.2
by Johan Jeuring 10 Jan '10

10 Jan '10

Palindromes 0.2 ============================================== Palindromes is a package for finding palindromes in files. Palindromes 0.2 is now available on hackage. Visit the homepage http://www.jeuring.net/Palindromes/ In version 0.2, the following features have been added: - Read from standard input, via the flag -i - More flexible flag handling - Read multiple files - Specify minimum length of palindromes returned, via the flag -m int For more information, consult the README file in the distribution. -- Johan Jeuring

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