May 2010 - Haskell - Haskell.org

Call for Papers (ICFEM 2010)
by Huibiao Zhu 12 May '10

12 May '10

*************************************************************** ICFEM 2010 12th International Conference on Formal Engineering Methods *** Call For Papers *** Nov 16-19, 2010 Shanghai, China http://www.sei.ecnu.edu.cn/icfem2010/ *************************************************************** ICFEM brings together 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 that promises to bring practical, tangible benefit. ICFEM 2010 will be organized by Software Engineering Institute, East China Normal University. Any inquiries can be sent to icfem2010(a)sei.ecnu.edu.cn. 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: Formal model-based development and code generation Abstraction and refinement Formal specification and modelling Software verification Formal approaches to software testing Software model checking Formal methods for object and component systems Analysis and models for concurrency Formal methods for cloud computing Tool development and integration Software safety, security and reliability Experiments involving verified systems Applications of formal methods 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 2010 submission page (http://www.sei.ecnu.edu.cn/icfem2010/) handled by the EasyChair conference system. All queries should be sent to the e-mail address icfem2010(a)sei.ecnu.edu.cn. IMPORTANT DATES May 28, 2010: Abstract submission deadline June 4, 2010: Full-paper submission deadline July 30, 2010: Acceptance/rejection notification August 13, 2010: Final version due ORGANIZATION COMMITTEE Conference Chair: Jifeng He (East China Normal University, China) Program Co-Chairs: Jin Song Dong (National University of Singapore, Singapore) Huibiao Zhu (East China Normal University, China) PROGRAM COMMITTEE Yamine AIT AMEUR (LISI/ENSMA, France) Farhad Arbab (CWI and Leiden University, The Netherlands) Nazareno Aguirre (Universidad Nacional de Río Cuarto, Argentina) Bernhard Aichernig (Graz University of Technology, Austria) Keijiro Araki (Kyushu University, Japan) Richard Banach (University of Manchester , UK) Jonathan Bowen (University of Westminster, UK) Karin Breitman (Pontifical Catholic University of Rio de Janeiro, Brazil) 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) Jim Davies (Oxford University, UK) Jin Song Dong ((National University of Singapore, Singapore, Co-Chair) Zhenghua Duan (Xidian University, China) Colin Fidge (Queensland University of Technology, Australia) John Fitzgerald (Newcastle University, UK) Joaquim Gabarro (Universitat Politècnica de Catalunya, Spain) Stefania Gnesi (Istituto di Scienza e Tecnologie dellInformazione A. Faedo, Italy) Mike Hinchey (University of Limerick, Ireland) Thierry Jeron (INRIA , France) Gerwin Klein (NICTA, Australia) Kim Larsen (Aalborg University, Denmark) Michael Leuschel (Heinrich-Heine Universität Düsseldorf, Germany) Xuandong Li (Nanjing University, China) Shaoying Liu (Hosei University, Japan) Zhiming Liu (UNU/IIST, Macau) Tiziana Margaria (University of Potsdam, Germany) Brendan Mahony (DSTO, Australia) Tom Maibaum (McMaster University, Canada) Dominique Mery (LORIA & Université Henri Poincaré Nancy 1, France) Huaikou Miao (Shanghai University, China) Flemming Nielson (Technical University of Denmark, Denmark) Jun PANG (University of Luxembourg, Luxembourg) Geguang Pu (East China Normal University, China) Shengchao Qin (Durham University, UK) Zongyan Qiu (Peking University, China) Anders P. Ravn (Aalborg University, Denmark) Augusto Sampaio (Universidade Federal de Pernambuco, Brazil) Marjan Sirjani (Reykjavik University, Iceland) Graeme Smith (University of Queensland, Australia) Jing Sun (University of Auckland, New Zealand) Jun Sun (National University of Singapore, Singapore) Kenji Taguchi (National Institute of Informatics, Japan) Yih-Kuen Tsay (National Taiwan University, Taiwan) T.H. Tse (University of Hong Kong, Hong Kong) Sergiy Vilkomir (East Carolina University, USA) Heike Wehrheim (University of Paderborn, Germany) Wang Yi (Uppsala University, Sweden) Hai Wang (Aston University, UK) Ji Wang (National University of Defense Technology, China) Xu Wang (UNU/IIST, Macau) Jim Woodcock (University of York, UK) Jian Zhang (Chinese Academy of Sciences, China) Huibiao Zhu, China (East China Normal University, China, Co-Chair) 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

1 0

SLE 2010 Doctoral Symposium call for abstracts
by evw＠cs.umn.edu 10 May '10

10 May '10

Doctoral Symposium at the 3rd International Conference on Software Language Engineering Call for Submissions October 11, 2010 Eindhoven, The Netherlands http://planet-sl.org/sle2010/ --------------------------------------------------------------------- * Goals * SLE aims to integrate the different sub-communities of the software-language-engineering community to foster cross-fertilisation and strengthen research overall. The Doctoral Symposium at SLE 2010 contributes towards these goals by providing a forum for both early and late-stage PhD students to present their research and get detailed feedback and advice from researchers both in and out of their particular research area. The main objectives of this event are: * to provide PhD students with an opportunity to write about and present their research, * to provide PhD students with constructive feedback on their work from their peers and from established researchers in their own and in different SLE sub-communities, * to build bridges for potential research collaboration, and * to foster integrated thinking about SLE challenges crossing the boundaries between sub-communities. The first edition of the Doctoral Symposium will be held in conjunction with SLE 2010 in Eindhoven, The Netherlands, on October 11, 2010. * Event Format * The Doctoral Symposium is a one-day event consisting of two parts: 1) A Plenary Session in the morning, where selected PhD students give short presentations on their research. The emphasis here is on feedback from fellow PhD students and established researchers in the field and on discussion of the research presented. 2) A Mentoring Session in the afternoon, where students are matched up with one or two established researchers from their own and neighboring sub-communities to receive detailed and specific feedback on their research abstracts. Additionally, there will be a poster session as part of the main SLE conference. Doctoral-Symposium participants will be invited to present a poster on their research as part of this poster session. The doctoral symposium will also include a social event in the evening of October 11. Details of this are currently still under negotiation. * Important Dates * Deadline for submissions July 12, 2010 Deadline for notifications August 27, 2010 Deadline for revisions September 17, 2010 Doctoral Symposium October 11, 2010 * Submissions * Submissions are invited from PhD students working on any topic that falls within the SLE conference remit. Students should read the SLE call for papers for more details on topics of interest. Submissions consist of two parts, a research abstract (maximum 4 pages LNCS format plus references) and a letter of recommendation from the student's supervisor. Research Abstracts should be based on the following outline: 1. Problem Description and Motivation Describe the problem you are addressing and motivate why this is a relevant research problem. 2. Brief Overview of Related Work Focus on demonstrating that your work addresses a significant gap in the current research literature. 3. Proposed Solution Give a high-level overview of your proposed solution to the problem identified in part 1. Describe any hypotheses that you have formulated. 4. Research Method Describe the research method you are using. In particular: What steps will you undertake to validate your hypotheses? It is understood that students at different stages of their research will be able to make more or less detailed and stabilised contributions to each of these sections. Therefore, we provide this outline as more of a guide than a strict requirement. Nonetheless, we encourage even early-stage PhD students to consider using this outline. Letters of recommendation should be provided by the student's supervisor and should include an assessment of the current status of the thesis research and an indication of the expected deadline for thesis submission. In addition, the supervisor should indicate what she/he hopes the student would gain from participation in the Doctoral Symposium. Research abstracts should be submitted using EasyChair at http://www.easychair.org/conferences/?conf=sleds10 . Supervisors should send letters of recommendation by email from their university account directly to sleds10(a)easychair.org . Research abstracts will be published as part of the SLE pre-proceedings and will be archived online, most likely at CEUR-WS.org. * Review of Research Abstracts * Students submitting research abstracts will also be asked to review the abstracts of two other submitted abstracts (in addition to reviews by the Selection Committee) to gain some experience in the review process. * Organisation * Doctoral Symposium Co-Chairs: Eric Van Wyk, University of Minnesota, USA, evw(a)cs.umn.edu Steffen Zschaler, Lancaster University, UK, szschaler(a)acm.org Selection Committee: Colin Atkinson, University of Mannheim, Germany Abraham Bernstein, University of Zurich, Switzerland Mark van den Brand, Eindhoven University, The Netherlands Jordi Cabot, Ecole des Mines de Nantes, France Tony Clark, Thames Valley University, UK Charles Consel, LaBRI / INRIA, France James Cordy, Queens University, Canada Dragan Gasevic, Athabasca University, Canada Jeff Gray, University of Alabama at Birmingham, USA Gorel Hedin, Lund University, Sweden Adrian Johnstone, Royal Holloway, University of London, UK Paul Klint, CWI, The Netherlands Dimitrios Kolovos, University of York, UK Ivan Kurtev, University of Twente, The Netherlands Ralf Laemmel, University of Koblenz-Landau, Germany Julia Lawall, DIKU, Denmark Brian Malloy, Clemson University, USA Richard Paige, University of York, UK Joao Saraiva, University of Minho, Portugal Steffen Staab, University of Koblenz-Landau, Germany Jurgen Vinju, CWI, The Netherlands Jos Warmer, Ordina, The Netherlands Jon Whittle, Lancaster University, UK

1 0

Well-Typed are hiring
by Duncan Coutts 10 May '10

10 May '10

We are looking to hire a Haskell expert to work with us at Well-Typed as a Haskell consultant. We are seeing an increasing demand for our services, and are thus seeking to expand our capacity. This is an exciting opportunity for someone who is passionate about Haskell and who is keen to improve and promote Haskell in a professional context. The role is quite general and could cover any of the projects and activities that we are involved in as a company. The tasks may involve: * working on the Haskell compilers, libraries and tools; * Haskell application development; * working directly with clients to solve their problems. Well-Typed has a variety of clients. For some we do proprietary Haskell development and consulting. For others, much of the work involves open-source development and cooperating with the rest of the Haskell community: the commercial, open-source and academic users. The position is initially as a contractor for one year with a salary comprised of a base level of 150 GBP per day, plus a profit-dependent component. We offer flexible hours and work from home. Living in England is not required. In the longer term there is the opportunity to become a member of the partnership with a full stake in the business: being involved in business decisions, and fully sharing the risks and rewards. If you are interested, please apply via info(a)well-typed.com. Send us your CV, and tell us why you are interested and why you would be a good fit for the job. We are more than happy to answer informal enquiries. Contact Duncan Coutts or Ian Lynagh for further information, either by email or IRC. The deadline for applications is Friday 11 June 2010. -- Duncan Coutts, Haskell Consultant Well-Typed LLP, http://www.well-typed.com/

1 0

ANN: test-framework 0.3.0
by Max Bolingbroke 08 May '10

08 May '10

I'm pleased to announce the release of version 0.3 of test-framework (http://hackage.haskell.org/package/test-framework-0.3.0) This package provides a nice test runner for HUnit, QuickCheck 1 and QuickCheck 2 tests. To see a detailed example of the runner in action, please check out our website at http://batterseapower.github.com/test-framework The highlights of this release are: * Thanks to the contributions of Rogan Creswick at Galois, you can now get JUnit XML output from the test runner using the --jxml=FILENAME option * There is a new command line option (--plain), which tells the test runner to avoid using any ANSI features - this can be handy if you are (for example) viewing test output in Emacs Cheers, Max

2 1

ANNOUNCE: network-protocol-xmpp 0.3
by John Millikin 07 May '10

07 May '10

XMPP[1] is a protocol for asynchronous communication via long-lived XML documents. It is most famous for underlying the Jabber and Wave protocols, but is also used for a variety of cases where security and extensibility are useful. My library, network-protocol-xmpp[2], is an implementation of most of RFC 3920 and a bit of RFC 3921. It supports opening client-to-server and component-to-server sessions, which is useful for implementing XMPP-based clients. This library's interface is very simple: clients may start a session with 'runClient' or 'runComponent', send and receive stanzas, and resume stored sessions. Later, I intend to add additional modules to support features such as MUC or file transmission, but for now I'd like to make sure the core library works. There's an example XMPP client, echo.hs[3], in the Darcs repository. Server-to-server sessions and accepting connection requests are not yet supported, so it's not usable as the foundation of an XMPP server yet. However, given that XMPP prefers to place features on the servers rather than clients, it's likely that writing an XMPP server in Haskell would take a *lot* of effort anyway. You're probably better off just using ejabberd or OpenFire. My thanks go to Stephan Maka, who let me know that this library actually has users, and who contributed most of the Component connection implementation. ---------- Additionally, I'm trying an experiment intended to break the gridlock of Haskell XML libraries. Currently, there are multiple options for XML handling (HXT, HaXml, libxml, tagsoup, xml, xml-basic) but each defines their own data types. This makes it very difficult to mix-and-match -- I can't easily use one library's parser with another's tree manipulation combinators. Simple use cases, such as using HXT for serializing, drag in dozens of dependencies on libraries like HTTP and QuickCheck. A library's poor data type definitions (such as HaXml's lack of support for namespaces) means that an entire set of potentially useful operations is unusable. And a library's choice propagates! In n-p-xmpp 0.2, which used HXT, clients were forced to figure out arrows before they could perform even rudimentary inspection of received stanzas. To fix this, I've created the xml-types[4] package. Its only dependency is the "text" library, and it defines full types for most XML structures[5]. My hope is that other libraries will replace their own types with these, so that (for example) I can parse events with libxml, manipulate them with HXT's arrow API, and write them back out using a custom serialiser without having to jump through type conversion hoops. It might take some time before any major XML libraries are transitioned to these types, but maybe in a year or two there'll be enough to be useful. [1] http://en.wikipedia.org/wiki/Extensible_Messaging_and_Presence_Protocol [2] http://hackage.haskell.org/package/network-protocol-xmpp [3] http://patch-tag.com/r/jmillikin/xmpp/snapshot/current/content/pretty/examp… [4] http://hackage.haskell.org/package/xml-types [5] I haven't included types for inner entity declarations in DTDs, out of laziness, because does anybody actually *use* those?

2 1

5th International School on Rewriting, Call for Participation
by Vincent van Oostrom 05 May '10

05 May '10

************ CALL FOR PARTICIPATION ************ ISR 2010 5th International School on Rewriting July 3-8, 2010, Utrecht, The Netherlands http://www.phil.uu.nl/isr2010/ ************************************************ Background and Organisation --------------------------- Term rewriting is a powerful model of computation underlying much of declarative programming, which is heavily used in symbolic computation in logic and computer science. Applications can be found in theorem proving and protocol verification, but also in fields as diverse as mathematics, philosophy and biology. Following the editions in Nancy (twice, France), Obergurgl (Austria), and Brasilia (Brazil), the 5th International School on Rewriting takes place in Utrecht, The Netherlands. The school is aimed at master and PhD students, researchers and practitioners interested in the study of rewriting concepts and their applications. To accommodate the different backgrounds, we offer two (parallel) tracks: (Basic) A full-fledged introductory course at master/PhD level accompanied with exercise sessions for students without previous exposure to term rewriting; (Advanced) A series of more advanced lectures at PhD/researcher level on recent developments and state-of-the-art applications. Master students can obtain 3ECs for successfully participating in the Basic track. The school is organised under the auspices of IFIP WG 1.6 and takes place as part (course H16) of Utrecht Summer School 2010. The school is planned such that participants can subsequently attend the major yearly conference on rewriting, RTA 2010, or other conferences that are part of the federated logic conference, FLoC 2010, in Edinburgh. ISR 2010 is supported by the Netherlands Organisation for Scientific Research (NWO), Utrecht University and VU University Amsterdam. Lectures and lecturers ---------------------- o Introduction to Term Rewriting (Basic) Aart Middeldorp, Univ. of Innsbruck, Austria Femke van Raamsdonk, VU Amsterdam, The Netherlands o Applications of Rewriting in Design and Analysis of Algorithms (lectures shared between Basic & Advanced) Ashish Tiwari, SRI International, Menlo Park, CA, USA o Tree Automata and Rewriting (Advanced) Ralf Treinen, PPS, Univ. Paris-Diderot, France o Complexity Analysis of Term Rewrite Systems (Advanced) Georg Moser, Univ. of Innsbruck, Austria o Termination of Programs (Advanced) Peter Schneider-Kamp, Univ. of Southern Denmark, Odense, Denmark o Productivity (Advanced) Joerg Endrullis, VU Amsterdam, The Netherlands Dimitri Hendriks, VU Amsterdam, The Netherlands Clemens Grabmayer, Utrecht Univ., The Netherlands o SAT solving for term rewriting (Advanced) Hans Zantema, Eindhoven Univ. of Tech., Radboud Univ. Nijmegen o Coq and rewriting (Advanced) Adam Koprowski, R&D MLstate, Paris, France The Basic and the Advanced track both consist of 26.5 hours of lectures and exercises/labs. Complete program at: http://www.phil.uu.nl/isr2010/ Location and Registration ------------------------- The school takes place in the historical city centre of Utrecht. Utrecht is located in the centre of the Netherlands, and is known for its university, its treaty, the 112m high Dom tower dating back to 1321, its wharves and its canal side terraces. The Netherlands has a sea climate and the average temperature in July is between 20 and 25 degrees Celsius. Utrecht has excellent public transport connections to the rest of the country and to the major international airports of Amsterdam (Schiphol, 30 minutes by train, every 15 minutes) and Frankfurt (3.5 hours by train, 8 times per day). Registration via the link to the program above or via *Courses* -> *Start data* -> *01-15 July 2010* at http://www.utrechtsummerschool.nl/ o Basic track: 200 euro o Advanced track: 250 euro o Housing: 175 euro (saturday and thursday night inclusive) Fees include participation, course material for both tracks, the ISR dinner event, and the Social Programme as offered by the Utrecht Summer School, e.g. world cup semi-finals, but do not include further meals. We have grants available to cover the registration fee for a number of exceptional students. See the registration and/or ISR2010 site for details.

1 0

Latest Haskell Platform for Windows (2010.1.0.0) does not seem to include C++ support
by Jeremy O'Donoghue 05 May '10

05 May '10

Hi list, I've just been helping out a wxHaskell user who has been having problems installing the latest wxHaskell on Windows 7 with the latest haskell Platform. As background, wxHaskell contains a substantial C++ wrapper which is normally compiled from the Cabal script. On Windows machines, this has the result that the GHC internal copy of MinGW is used for compilation. I'm getting the following error: "realgcc.exe: installation problem - cannot exec 'cc1plus': no such file or directory" On checking, Haskell Platform\2010.1.0.0\mingw\libexec\gcc\mingw32\3.4.5 does not contain cc1plus.exe. Previous versions of the platform have done so. Is this an accidental change or a deliberate policy decision? Is there any way to persuade cabal to use another C++ compiler (I have a perfectly good copy of MinGW g++ elsewhere on my machine). Regards Jeremy O'Donoghue -- Jeremy O'Donoghue jeremy.odonoghue(a)gmail.com

4 4

cabal-sort
by Henning Thielemann 05 May '10

05 May '10

I like to announce cabal-sort: If you have a bunch of packages that you want to compile or recompile, then you need an order of compilation that meets the dependencies. Given a number of cabal package files, cabal-sort reads all those files and emits them topologically sorted according to their dependencies. This way you can compile many packages at once, e.g. when a low-level package like transformers has changed. For compiling a couple of packages from their local darcs repositories in the right order, you may run something like $ for dir in `find . -name "*.cabal" | fgrep -v _darcs | xargs cabal-sort --info=dir`; \ do (cd $dir && cabal install); \ done http://hackage.haskell.org/package/cabal-sort

1 0

ANNOUNCE: happstack-hamlet: compile-time HTML templates for the Haskell application server stack
by Jeremy Shaw 04 May '10

04 May '10

Hello, I am pleased to announce the availability of happstack-hamlet: http://hackage.haskell.org/package/happstack-hamlet http://patch-tag.com/r/mae/happstack/snapshot/current/content/pretty/happst… Happstack is a web application development framework. Hamlet provides HTML templates which are checked for correctness at compile time. This package add support for using Hamlet templates with Happstack. A simple demo is available here: http://patch-tag.com/r/mae/happstack/snapshot/current/content/pretty/happst… Please report any issues with the happstack-hamlet package itself to the happs mailing list (You will need to be subscribed): http://groups.google.com/group/happs Big thanks to Michael Snoyman for writing Hamlet! Hamlet homepage: http://docs.yesodweb.com/hamlet/ Happstack homepage: http://www.happstack.com/ happy hacking! - jeremy p.s. Reply-to is set to haskell-cafe

1 0

ANN: has-0.4 Entity based records
by HASHIMOTO, Yusaku 04 May '10

04 May '10

Hello, I'm pleased to announce the release of my new library, named "has", written to aim to ease pain at inconvinience of Haskell's build-in records. With the has, You can reuse accessors over records to write generic function, combine records with another. Repository is at GitHub: http://github.com/nonowarn/has Uploaded on Hackage: http://hackage.haskell.org/package/has So you can install this by "cabal install has" You can use the has in three steps (without counting installation). 1. Write {-# OPTIONS_GHC -fglasgow-exts #-} top of your code, import Data.Has module. > {-# OPTIONS_GHC -fglasgow-exts #-} > import Data.Has 2. Define entities. "Entity" is data to index field in records. You can define an entity in one line. > data Foo = Foo; type instance TypeOf Foo = Int (I lied) Before semicolon, declares entity. After semicolon, specifies the type to which the entity points. Define some entities for later examples. > data Bar = Bar; type instance TypeOf Bar = Double > data Baz = Baz; type instance TypeOf Baz = String > data Quux = Quux; type instance TypeOf Quux = Bool 3. Define Records by concatinating fields of entities. > type MyRecord = FieldOf Foo :&: FieldOf Bar :&: FieldOf Baz This is almost same as writing < data MyRecord = MyRecord { foo :: Int < , bar :: Double < , baz :: String < } To construct a value of record, remove colons and replace entities in record with values, and uncapitalize some words. > aRecord :: MyRecord > aRecord = fieldOf 42 & fieldOf 3.14 & fieldOf "string" And you can play with it. To read/write/modify a value of field in records, you can use functions with names stealed from data-accessor. But uses value-level entities instead of accessors. < Foo ^. aRecord -- Reading < Foo ^= 4649 $ aRecord -- Writing < Foo ^: (*2) $ aRecord -- Modifying If we have another record type contains Foo field, You can still access the field in the same way. > type AnotherRecord = FieldOf Bar :&: FieldOf Foo > anotherRecord :: AnotherRecord > anotherRecord = fieldOf 2.71 & fieldOf 31 < Foo ^. anotherRecord -- And this also works Using these functions and Has constraint, You can write generic functions over records. > fooIsGreaterThan :: (Has Foo r) => r -> Int -> Bool > fooIsGreaterThan r x = (Foo ^. r) > x < aRecord `fooIsGreaterThan` 40 -- evaluated to True < anotherRecord `fooIsGreaterThan` 40 -- evaluated To False Even if you defined another record by combining records by (:&:), you can still access the field, and apply to generic functions. > type MoreRecord = FieldOf Baz :&: FieldOf Quux > type CombinedRecord = AnotherRecord :&: MoreRecord > combinedRecord :: CombinedRecord > combinedRecord = (fieldOf 1.618 & fieldOf 39) & (fieldOf "sowaka" & fieldOf True) > -- We can omit parentheses > -- (even place parens anyware in record) < combinedRecord `fooIsGreaterThan` 40 -- This yet works The Has constraint provides not only genericity but also safety. If the record doesn't satisfy the constraint, the type checker rejects it. > predicateOnRecords :: (Has Foo r, Has Quux r) => r -> Bool > predicateOnRecords r = fooIsGreaterThan r 30 && (Quux ^. r) < predicateOnRecords combinedRecord -- This is OK < predicateOnRecords aRecord -- This yields compile error More examples included in package[1] [1]: http://github.com/nonowarn/has/tree/master/examples/ This library is inspired by HList[2], and interfaces are stealed from data-accessors[3]. And lenses[4], fclabels[5], and records[6] devote themselves to similar purposes. [2]: http://hackage.haskell.org/package/HList [3]: http://hackage.haskell.org/package/data-accessor [4]: http://hackage.haskell.org/package/lenses [5]: http://hackage.haskell.org/package/fclabels [6]: http://hackage.haskell.org/package/records Enjoy! -nwn

1 0