[Haskell] PPDP 2013: Call for Papers
of Oxford, UK Yukiyoshi Kameyama University of Tsukuba, Japan Oleg Kiselyov USA Yanhong Annie Liu State University of New York at Stony Brook, USA Stefan Monnier Universite de Montreal, Canada Alan Mycroft University of Cambrige, UK Bruno C. d. S. OliveiraNational University of Singapore, Singapore Alberto Pettorossi Universita di Roma Tor Vergata, Italy Enrico PontelliNew Mexico State University, USA Kristoffer RoseIBM Research, USA Sukyoung Ryu KAIST, South Korea Vitor Santos Costa University of Porto, Portugal Torsten Schaub University Potsdam, Germany Tom Schrijvers Ghent University, Belgium Martin SulzmannHochschule Karlsruhe, Germany Wouter Swierstra Universiteit Utrecht, The Netherlands Tarmo Uustalu Institute of Cybernetics, Estonia Janis Voigtlaender University of Bonn, Germany Meng Wang Chalmers University of Technology, Sweden Jan Wielemaker Universiteit van Amsterdam, The Netherlands Program Chair Tom Schrijvers Department of Applied Mathematics and Computer Science Ghent University 9000 Gent, Belgium General Chair Ricardo Pena Facultad de Informatica Universidad Complutense de Madrid 28040 Madrid, Spain * Confirmation pending ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
[Haskell] PPDP 2013: 2nd Call for Papers
Universite de Montreal, Canada Alan Mycroft University of Cambrige, UK Bruno C. d. S. Oliveira National University of Singapore, Singapore Alberto Pettorossi Universita di Roma Tor Vergata, Italy Enrico PontelliNew Mexico State University, USA Kristoffer RoseIBM Research, USA Sukyoung Ryu KAIST, South Korea Vitor Santos Costa University of Porto, Portugal Torsten Schaub University Potsdam, Germany Tom Schrijvers Ghent University, Belgium Martin SulzmannHochschule Karlsruhe, Germany Wouter Swierstra Universiteit Utrecht, The Netherlands Tarmo Uustalu Institute of Cybernetics, Estonia Janis Voigtlaender University of Bonn, Germany Meng Wang Chalmers University of Technology, Sweden Jan Wielemaker Universiteit van Amsterdam, The Netherlands Program Chair Tom Schrijvers Department of Applied Mathematics and Computer Science Ghent University 9000 Gent, Belgium General Chair Ricardo Pena Facultad de Informatica Universidad Complutense de Madrid 28040 Madrid, Spain ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
[Haskell] PPDP'13: Last call for papers
University of Cambrige, UK Bruno C. d. S. Oliveira National University of Singapore, Singapore Alberto Pettorossi Universita di Roma Tor Vergata, Italy Enrico PontelliNew Mexico State University, USA Kristoffer RoseIBM Research, USA Sukyoung Ryu KAIST, South Korea Vitor Santos Costa University of Porto, Portugal Torsten Schaub University Potsdam, Germany Tom Schrijvers Ghent University, Belgium Martin SulzmannHochschule Karlsruhe, Germany Wouter Swierstra Universiteit Utrecht, The Netherlands Tarmo Uustalu Institute of Cybernetics, Estonia Janis Voigtlaender University of Bonn, Germany Meng Wang Chalmers University of Technology, Sweden Jan Wielemaker Universiteit van Amsterdam, The Netherlands Program Chair Tom Schrijvers Department of Applied Mathematics and Computer Science Ghent University 9000 Gent, Belgium General Chair Ricardo Pena Facultad de Informatica Universidad Complutense de Madrid 28040 Madrid, Spain -- prof. dr. ir. Tom Schrijvers Programming Languages Group Department of Applied Mathematics and Computer Science University of Ghent Krijgslaan 281 S9 9000 Gent Belgium Phone: +32 9 264 4805 http://users.ugent.be/~tschrijv/ ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
[Haskell] Postdoctoral Position in Programming Languages at KU Leuven
Postdoctoral Position in Programming Languages at KU Leuven The Declarative Languages and Artificial Intelligence (DTAI) group of KU Leuven (Belgium) invites applicants for a postdoctoral position in the area of programming languages. This position has been created at the occasion of the new appointment of prof. Tom Schrijvers as research professor at KU Leuven. The position's aim is to reinforce the research activities in functional programming, logic programming and/or programming language theory. To apply you must hold a recent PhD (or be about to graduate) in one of the above areas of programming languages. Candidates are expected to have high-quality publications in peer-reviewed conferences and journals. The postdoc will work closely with prof. Schrijvers and his PhD students, participate in ongoing research activities and enjoy the freedom to develop new lines of research. The position is for 2 x 1 year and can be further extended. The salary is competitive and the starting date negotiable. Moreover, KU Leuven's policy of equal opportunities and diversity applies to this position. Please send your application to prof. Tom Schrijvers (tom dot schrijvers at cs dot kuleuven dot be) by October 15, 2014. Your application should contain: - A cover letter explaining your interest in the position. - Your curriculum vitae. - A short research statement (max. 3 pages). - The names and contact details of three people who can, if asked, write letters of reference. ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
[Haskell] Postdoc Position in Functional and Constraint Programming at KU Leuven
Postdoctoral position in Functional and Constraint Programming at KU Leuven The Declarative Languages and Artificial Intelligence (DTAI) group of KU Leuven (Belgium) invites applicants for a postdoctoral position in the area of functional and constraint programming. The position revolves around domain-specific languages (DSLs) embedded in Haskell for constraint programming. It is part of the EU project GRACeFUL whose overarching theme is tools for collective decision making. The KU Leuven part of the project is under the direction of prof. Tom Schrijvers. To apply you must hold a recent PhD (or be about to graduate) related to either functional or constraint programming. Experience in both areas is an advantage. You will work closely with prof. Schrijvers and his PhD students at KU Leuven, as well as with the GRACeFUL project partners across Europe. The position is for 3 years. The salary is competitive and the starting date negotiable (but no later than February 1). Moreover, KU Leuven's policy of equal opportunities and diversity applies to this position. For the application procedure, see: http://people.cs.kuleuven.be/~tom.schrijvers/postdocposition2.html -- prof. dr. ir. Tom Schrijvers Research Professor KU Leuven Department of Computer Science Celestijnenlaan 200A 3001 Leuven Belgium Phone: +32 16 327 830 http://people.cs.kuleuven.be/~tom.schrijvers/ ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
[Haskell] Postdoctoral Position in Functional Programming
I have a position available for a postdoctoral researcher to join my team at KU Leuven. The position involves working on domain-specific languages (DSLs) embedded in Haskell and building on our earlier work of Monadic Constraint Programming. There is plenty of room for personal input and international collaboration, as well as developing your own research ideas. The position is for 3 years. The salary is competitive and the starting date negotiable. To apply you must hold a recent PhD (or be about to graduate) related to functional programming. The application deadline is January 5, 2015. Send your application (cover letter, cv, 3 references) and any enquiries to tom.schrijv...@cs.kuleuven.be . -- prof. dr. ir. Tom Schrijvers Research Professor KU Leuven Department of Computer Science Celestijnenlaan 200A 3001 Leuven Belgium Phone: +32 16 327 830 http://people.cs.kuleuven.be/~tom.schrijvers/ ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
[Haskell] Leuven Haskell User Group meeting on April 21
You are kindly invited to the special edition of the Leuven Haskell User Group with guest presentation by Amplidata. For details see: https://groups.google.com/d/msg/leuven-haskell/VNcTKtFPGL0/gQhPWtxTbg4J -- prof. dr. ir. Tom Schrijvers Research Professor KU Leuven Department of Computer Science Celestijnenlaan 200A 3001 Leuven Belgium Phone: +32 16 327 830 http://people.cs.kuleuven.be/~tom.schrijvers/ ___ Haskell mailing list Haskell@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell
[Haskell] Leuven Haskell User Group: Season 2
Dear Haskellers, Season 2 of the Leuven Haskell User Group starts on November 17. Join us for an introductory talk on type classes. Everyone is welcome. For more information: http://www.meetup.com/Leuven-Haskell-Users-Group/ http://groups.google.com/forum/#!forum/leuven-haskell See you there! -- prof. dr. ir. Tom Schrijvers Research Professor KU Leuven Department of Computer Science Celestijnenlaan 200A 3001 Leuven Belgium Phone: +32 16 327 830 http://people.cs.kuleuven.be/~tom.schrijvers/ ___ Haskell mailing list Haskell@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell
[Haskell] Postdoctoral position in Functional, Constraint and/or Logic Programming
Prof. Tom Schrijvers invites applications for a postdoctoral position in the area of functional, constraint and logic programming. The position revolves around domain-specific languages (DSLs) embedded in Haskell for constraint programming. It is part of the EU project GRACeFUL whose overarching theme is tools for collective decision making. Responsibilities You will work closely with prof. Schrijvers and his PhD students at KU Leuven, as well as with the GRACeFUL project partners across Europe, in order to conduct research activities for the GRACeFUL project. For more details: https://icts.kuleuven.be/apps/jobsite/vacatures/53613023 -- prof. dr. ir. Tom Schrijvers Research Professor KU Leuven Department of Computer Science Celestijnenlaan 200A 3001 Leuven Belgium Phone: +32 16 327 830 http://people.cs.kuleuven.be/~tom.schrijvers/ ___ Haskell mailing list Haskell@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell
[Haskell] Doctoral or Post-Doctoral Position in Programming Language Theory & Implementation
I am looking for a new member to join my research team in either a doctoral or post-doctoral position. Research topics of particular interest are: * type systems * functional programming * monads, continuations, effect handlers, ... * mechanisation of programming language meta-theory * category theoretical foundations of programming languages * constraint logic programming For more details and application: https://icts.kuleuven.be/apps/jobsite/vacatures/53891815?lang=en For questions about the position, get in touch. -- prof. dr. ir. Tom Schrijvers Research Professor KU Leuven Department of Computer Science Celestijnenlaan 200A 3001 Leuven Belgium Phone: +32 16 327 830 http://people.cs.kuleuven.be/~tom.schrijvers/ ___ Haskell mailing list Haskell@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell
[Haskell] PhD Position in Functional Programming and Programming Language Theory
PHD POSITION IN FUNCTIONAL PROGRAMMING AND PROGRAMMING LANGUAGE THEORY (ref. BAP-2018-431) The group of prof. Tom Schrijvers has expertise in a broad range of topics related to functional programming and programming language theory, including recent contributions to Haskell's type system and the implementation of algebraic effects and handlers The group is part of the Declarative Languages and Artificial Intelligence (DTAI) group of the Department of Computer Science, KU Leuven. The activities of DTAI are centred around research and education in programming languages and artificial intelligence. Other themes of study are in the fields of declarative languages, machine learning, data mining, and knowledge representation. DTAI started in the mid-seventies, closely following the invention of logic programming and became one of the world's leading centres for research in logic programming. Gradually, the scope of its research broadened, including functional programming and more artificial intelligence oriented topics in knowledge representation and machine learning. The use of logic is a common thread to almost all activities. Website unit <https://people.cs.kuleuven.be/~tom.schrijvers/research.html> Project You will work closely with prof. Schrijvers and his team to conduct research in one or several areas of interest in the field of functional programming and programming language theory. Research topics of particular interest are: - type systems - mechanisation of programming language meta-theory - category theoretical foundations of programming languages - monads, continuations, algebraic effects and handlers, ... - recursion schemes and equational reasoning - DSLs Profile We are looking for a candidate who exhibits the following qualities: - You are responsible, can work both independently and in a team, show initiative and seize opportunities. - You can judge the quality of your own work and strive to improve it. - You are comfortable with both theory and practical implementation. - You are a good communicator (writing/presenting). - You get things done. Offer The initial contract is for 1 year and after positive evaluation will be extended to allow completion of a PhD in 4 years. The salary is competitive and the starting date negotiable (ideally September 1 or October 1). Interested? Please include a cover letter and CV in your application; highlight your particular interest and relevant background. For more information please contact Prof. dr. ir. Tom Schrijvers, tel.: +32 16 32 78 30, mail: tom.schrijv...@kuleuven.be. You can apply for this job no later than July 04, 2018 via the online application tool <http://www.kuleuven.be/eapplyingforjobs/light/54703967> KU Leuven seeks to foster an environment where all talents can flourish, regardless of gender, age, cultural background, nationality or impairments. If you have any questions relating to accessibility or support, please contact us at diversiteit...@kuleuven.be. ___ Haskell mailing list Haskell@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell
[Haskell] CfP: Haskell Symposium 2020
ation date of accepted papers is the date the proceedings are made available in the ACM Digital Library. This date may be up to two weeks prior to the first day of the conference. The official publication date affects the deadline for any patent filings related to published work. Artifacts = Authors of accepted papers are encouraged to make auxiliary material (artifacts like source code, test data, etc.) available with their paper. They can opt to have these artifacts published alongside their paper in the ACM Digital Library (copyright of artifacts remains with the authors). If an accepted paper's artifacts are made permanently available for retrieval in a publicly accessible archival repository like the ACM Digital Library, that paper qualifies for an Artifacts Available badge (https://www.acm.org/publications/policies/artifact-review-badging#available). Applications for such a badge can be made after paper acceptance and will be reviewed by the PC chair. Program Committee = Arthur Azevedo de Amorim Carnegie Mellon University Manuel Chakravarty Tweag I/O / IOHK Jan Christiansen Flensburg University of Applied Sciences Youyou Cong Tokyo Institute of Technology Pierre-Evariste Dagand CNRS Anton Ekblad Chalmers University of Technology Jurriaan Hage Universiteit Utrecht Graham Hutton University of Nottingham José Pedro Magalhães Standard Chartered Clare Martin Oxford Brookes University Andrey Mokhov Jane Street Shin-Cheng Mu Academia Sinica Nikolaos Papaspyrou National Technical University of Athens Simon Peyton Jones Microsoft Research Cambridge Norman Ramsey Tufts University Exequiel Rivas INRIA Tom Schrijvers (chair) KU Leuven Martin Sulzmann Karlsruhe University of Applied Sciences If you have questions, please contact the chair at: tom.schrijv...@kuleuven.be<mailto:tom.schrijv...@kuleuven.be> ___ Haskell mailing list Haskell@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell
[Haskell] Haskell Symposium 2020 -- Call for Papers: Regular track & demos
on date of accepted papers is the date the proceedings are made available in the ACM Digital Library. This date may be up to two weeks prior to the first day of the conference. The official publication date affects the deadline for any patent filings related to published work. Artifacts = Authors of accepted papers are encouraged to make auxiliary material (artifacts like source code, test data, etc.) available with their paper. They can opt to have these artifacts published alongside their paper in the ACM Digital Library (copyright of artifacts remains with the authors). If an accepted paper's artifacts are made permanently available for retrieval in a publicly accessible archival repository like the ACM Digital Library, that paper qualifies for an Artifacts Available badge (https://www.acm.org/publications/policies/artifact-review-badging#available ). Applications for such a badge can be made after paper acceptance and will be reviewed by the PC chair. Program Committee = Arthur Azevedo de Amorim Carnegie Mellon University Manuel Chakravarty Tweag I/O / IOHK Jan Christiansen Flensburg University of Applied Sciences Youyou Cong Tokyo Institute of Technology Pierre-Evariste Dagand CNRS Anton Ekblad Chalmers University of Technology Jurriaan Hage Universiteit Utrecht Graham Hutton University of Nottingham José Pedro Magalhães Standard Chartered Clare Martin Oxford Brookes University Andrey Mokhov Jane Street Shin-Cheng Mu Academia Sinica Nikolaos Papaspyrou National Technical University of Athens Simon Peyton Jones Microsoft Research Cambridge Norman Ramsey Tufts University Exequiel Rivas INRIA Tom Schrijvers (chair) KU Leuven Martin Sulzmann Karlsruhe University of Applied Sciences If you have questions, please contact the chair at: tom.schrijv...@kuleuven.be ___ Haskell mailing list Haskell@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell
Re: simple question
Cagdas Ozgenc wrote: > books2 :: Database2 -> Person -> [Book] > > books2 db person = head [ snd tuple | tuple <- db, fst tuple == person ] > > borrowers2 :: Database2 -> Book -> [Person] > borrowers2 db book = [ person | (person, books) <- db, book <- books ] You can't pattern match against a variable (like equal x x = True). But that is what you seem to be doing in book <- books. However, Haskell doesn't give you an error in this case (as it would with my equal example) because the book in book <- books is considered a new veriable that is hiding the other book variable. What you wrote is the same as > borrowers2 db book = [ person | (person, books) <- db, x <- books ] where x <- books has no meaning (except maybe the person should have at least one book). Try this instead: > borrowers2 db book = [ person | (person, books) <- db, elem book books] As for books2, use (person, books) <- db instead of tuple. Looks better than fst and snd in my opinion. Tom ___ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
Re: Prob with numeric values
> Hello, > > I m having some difficulties with the following thing: > > I've made a class which looks somehow like this: > class A a where >inc::a->a > > > now, when I want to make a instance of it with type Int and define the > function inc like this: > > instance A Int where > inc a = a + 1 > > I can't make a call to it when I enter the folowing > > inc 5 > > (When I type inc 5::Int it does the job perfectly, because I explicitly say > 5 is an Integer, but how can I tell the program 5 is an Int?ithout > saying it explicitly in the prompt) > > What s being the problem here?? Am I overlooking something here? > If you can help me... don't hesitate to contact me > > Thx, > > a haskell-lover This appears to be a question based on the exam of our declarative languages course. Please consult Bart Demoen, Remko Troncon or me with your questions. Cheers, Tom ___ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
Re: name of List.nub function
On Fri, May 24, 2002 at 10:00:35AM -0700, Brian Huffman wrote: > Hi, > > This is just for fun, really, but does anyone know how the nub function from > the standard List module got its name? (It is the function that removes > duplicates from a list, in case you are not familiar with it.) I looked up > the word "nub" in the online Merriam-Webster dictionary (www.m-w.com) and it > gives: > > 1 : KNOB, LUMP > 2 : NUBBIN > 3 : GIST, POINT The first result for nub in dictionary.com gives: nub Pronunciation Key (nb) n. 1. A protuberance or knob. 2. A small lump. 3. The essence; the core: the nub of a story I think essence is the right meaning, removing all duplicates. Cheers, -- Tom ___ Haskell mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell
[Haskell] CHR 2006: 2nd Call for Papers
Apologies if you receive multiple copies Second Call for Papers Third Workshop on Constraint Handling Rules CHR 2006 July 9, 2006 S. Servolo, Venice, Italy Co-located with the International Colloquium on Automata, Languages and Programming (ICALP 2006) http://www.cs.kuleuven.be/~toms/CHR2006/ Introduction The Constraint Handling Rules (CHR) language has become a major declarative specification and implementation language for constraint reasoning algorithms and applications. Algorithms are often specified using inference rules, rewrite rules, sequents, proof rules or logical axioms that can be directly written in CHR. Its clean semantics facilitates program design, analysis and transformation. See the CHR website (http://www.cs.kuleuven.be/~dtai/projects/CHR/) for more information. Previous Workshops on Constraint Handling Rules were organized in May 2004 in Ulm (Germany) and in October 2005 in Sitges (Spain). Topics of Interest -- The workshop calls for full papers and short papers describing ongoing work, on all aspects of CHR, including topics such as: - (Logical) Algorithms - Applications - Comparisons with Related Approaches - Constraint Solvers - Critical Assessment - Expressivity and Complexity - Implementations and Optimization - Language Extensions (Types, Modules) - Program Analysis - Program Transformation and Generation - Programming Environments (Debugging) - Programming Pearls - Retractable Constraints - Semantics Awards -- The best paper receives the CHR Best Paper Award. It is chosen among all submissions for its outstanding quality in both presentation and scientific contribution and for its impact on the field of CHR. Submission Information -- All papers must be written in English and not exceed 15 pages in Springer LNCS format. The authors are encouraged, although not obliged, to submit their papers already in Springer LNCS format. General information about the Springer LNCS series and the LNCS authors' instructions are available at the Springer LNCS/LNAI home page. Submissions should be sent to [EMAIL PROTECTED] and mention 'CHR 2006 Submission' in the subject. Every submission should include the names and e-mail addresses of the authors (with the corresponding author indicated), the paper abstract in ASCII format and the actual paper in postscript or PDF format. The submission should also indicate whether it is a full paper or a short paper. Accepted papers will be published in a technical report. Important dates --- * submission: May 7, 2006 * notification of acceptance: June 9, 2006 * final version due:June 23, 2006 * workshop date:July 9, 2006 Organization Program Committee: * Alessandra Raffaeta, Universita Ca' Foscari di Venezia * François Fages, INRIA Rocquencourt * Gregory Duck, NICTA Victoria Laboratory * Henning Christiansen, Roskilde University * Jacques Robin, Universidade Federal de Pernambuco * Martin Sulzmann, National University of Singapore * Maurizio Gabbrielli, Universita di Bologna * Thom Fruehwirth, Universitaet Ulm * Tom Schrijvers, Katholieke Universiteit Leuven Workshop Coordinators: [EMAIL PROTECTED] Tom Schrijvers (contact person) Department of Computer Science K.U.Leuven http://www.cs.kuleuven.be/~toms/ Thom Fruehwirth Fakultaet fuer Informatik Universitaet Ulm http://www.informatik.uni-ulm.de/pm/fileadmin/pm/home/fruehwirth/___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
Re: [Haskell] MTL violates coverage condition?
Does 'MonadState s m => MonadState s (ReaderT r m)', found in Control.Monad.Reader violate the coverage condition as I believe it does? Yes, it does. Can one write a function using this library to force the type inference engine to loop indefinitely? If not, what mitigating conditions prevent it? Can I write a similar declaration in my library and compile it with -fallow-undecidable-instances and without worry? The coverage condition is a sufficient condition for termination of the type checker. Another sufficient condition is the Terminating Weak Coverage condition (Definition 14). This condition is met by that instance, as well as yours. If you want to get non-terminating, you must write a funny instance like: MonadState s m => MonadState (MymonadT s) (MymonadT m) and then set up a constraint MonadState x (MymonadT x) I did not try it, but GHC should run out of stack on this one or give up. I'm currently working with Martin Sulzmann on a relaxed set of conditions for FDs and type functions. Cheers, Tom -- Tom Schrijvers Department of Computer Science K.U. Leuven Celestijnenlaan 200A B-3001 Heverlee Belgium tel: +32 16 327544 e-mail: [EMAIL PROTECTED] url: http://www.cs.kuleuven.be/~toms/ ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
Re: [Haskell] indirectly recursive dictionaries
{-
Recursive instance heads as in ...
 instance C0 (x,Bool) => C0 x
... are Ok if we allow for typechecking scheme as described in "SYB with class".
The main idea is to assume C0 x in proving the preconditions of the
body of the clause.
This is also works for mutual recursion among type classes and
instances to the extent exercised in ditto paper.
What about the below example though?
Here recursion detours through an extra class in a way that leads to
nonterminating typechecking with GHC 6.10.1.
Does anyone agree that a constraint resolution scheme like the one
mentioned could be reasonably expected to cover this case?
Regards,
Ralf
-}
{-# OPTIONS -fglasgow-exts #-}
{-# OPTIONS -fallow-overlapping-instances #-}
{-# OPTIONS -fallow-undecidable-instances #-}
-- Direct recursion terminates (typechecking-wise)
class C0 x
 where
 m0 :: x -> ()
 m0 = const undefined
instance (C0 x, C0 y) => C0 (x,y)
instance C0 Bool
instance C0 (x,Bool) => C0 x
foo :: ()
foo = m0 (1::Int)
-- Indirect recursion does not terminate (typechecking-wise)
class C1 x
 where
 m1 :: x -> ()
 m1 = const undefined
instance (C1 x, C1 y) => C1 (x,y)
instance C1 Bool
instance (C2 x y, C1 (y,Bool)) => C1 x
class C2 x y | x -> y
instance C2 Int Int
The cyclic dictionaries approach is a bit fragile. The problem appears to
be here that GHC alternates exhaustive phases of constraint reduction and
functional dependency improvement. The problem is that in your example you
need both for detecting a cycle.
This can happen:
C1 Int
==> 3rd C1 inst
C2 Int y, C1 (y,Bool)
==> 1st C1 inst
C2 Int y, C1 y, C1 Bool
==> 2nd C1 inst
C2 Int y, C1 y
==> 3rd C1 inst
C2 Int y, C2 y z, C1 (z,Bool)
==>
...
where all the constraint are different because fresh variables are
introduced.
What you want to happen is:
C1 Int
==> 3rd C1 inst
C2 Int y, C1 (y,Bool)
==> 1st C1 inst
C2 Int y, C1 y, C1 Bool
==> 2nd C1 inst
C2 Int y, C1 y
==> C2 FD improvement {Int/y} <<<<
C2 Int Int, C1 Int
==> C1 Int cycle detected
C2 Int Int
==> C2 1st instance
{}
It seems that you want improvement to happen at a higher priority than GHC
does now.
Tom
--
Tom Schrijvers
Department of Computer Science
K.U. Leuven
Celestijnenlaan 200A
B-3001 Heverlee
Belgium
tel: +32 16 327544
e-mail: tom.schrijv...@cs.kuleuven.be
url: http://www.cs.kuleuven.be/~toms/___
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[Haskell] FLOPS 2012: 1st Call for Papers
First Call For Papers = *Eleventh International Symposium on Functional and Logic Programming (FLOPS 2012)* May 23-25, 2012 Kobe, Japan [http://www.org.kobe-u.ac.jp/flops2012/] _Submission deadline : December 9, 2011_ FLOPS is a forum for research on all issues concerning declarative programming, including functional programming and logic programming, and aims to promote cross-fertilization and integration between the two paradigms. Previous FLOPS meetings were held in Fuji Susono (1995), Shonan Village (1996), Kyoto (1998), Tsukuba (1999), Tokyo (2001), Aizu (2002), Nara (2004), Fuji Susono (2006), Ise (2008), and Sendai (2010). Topics == FLOPS solicits original papers in all areas of functional and logic programming, including (but not limited to): - Declarative Pearls: new and excellent declarative programs with illustrative applications. - Language issues: language design and constructs, programming methodology, integration of paradigms, interfacing with other languages, type systems, constraints, concurrency and distributed computing. - Foundations: logic and semantics, rewrite systems and narrowing, type theory, proof systems. - Implementation issues: compilation techniques, memory management, program analysis and transformation, partial evaluation, parallelism. - Applications: case studies, real-world applications, graphical user interfaces, Internet applications, XML, databases, formal methods and model checking. The proceedings will be published as an LNCS volume. The proceedings of the previous meeting (FLOPS 2010) were published as LNCS 6009. PC co-Chairs - Tom Schrijvers (Ghent University, Belgium) - Peter Thiemann (University of Freiburg, Germany) PC Members == - Salvador Abreu (University of Evora, Portugal) - Thorsten Altenkirch (University of Nottingham, UK) - Sebastian Brand (NICTA, Australia) - Giuseppe Castagna (CNRS Univ Paris 7, France) - Sebastian Fischer (Germany) - Marco Gavanelli (University of Ferrara, Italy) - Joxan Jaffar (National University of Singapore, Singapore) - Barry Jay (University of Sydney, Australia) - Andy King (University of Kent, UK) - Claude Kirchner (INRIA, France) - Neelakantan R. Krishnaswami (Microsoft Cambridge, UK) - Yulya Lierler (University of Kentucky, USA) - Keiko Nakata (Tallinn University of Technology, Estonia) - Peter Schneider-Kamp (University of Southern Denmark, Denmark) - Olin Shivers (Northeastern University, USA) - Paul Tarau (University of Northern Texas, USA) - Kazunori Ueda (Waseda University, Japan) - Meng Wang (Chalmers Technical University, Sweden) General Chair and Local co-Chairs = - Naoyuki Tamura (Kobe University, Japan) - Mutsunori Banbara (Kobe University, Japan) - Katsutoshi Hirayama (Kobe University, Japan) Submission == Submissions must be unpublished and not submitted for publication elsewhere. Work that already appeared in unpublished or informally published workshops proceedings may be submitted. Submissions should fall into one of the following categories: - Regular research papers: they should describe new results and will be judged on originality, correctness, and significance. - System descriptions: they should contain a link to a working system and will be judged on originality, usefulness, and design. Submissions must be written in English and can be up to 15 pages long, though pearls are typically considerably shorter. Authors are required to use LaTeX2e and the Springer llncs class file, available at [http://www.springer.de/comp/lncs/authors.html]. Regular research papers should be supported by proofs and/or experimental results. In case of lack of space, this supporting information should be made accessible otherwise (e.g., a link to a web page, or an appendix). Papers should be submitted electronically at [https://www.easychair.org/conferences/?conf=flops2012]. Important Dates === - Submission deadline : December 9, 2011 - Author notification : February 3, 2012 - Camera-ready copy : March 2, 2012 Place and Related Events Takikawa Memorial Hall, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 Japan. The 23rd International Conference on Rewriting Techniques and Applications (RTA 2012) and satellite workshops including WFLP 2012 will be held in the week after FLOPS at Nagoya, Japan. Some Previous FLOPS === - FLOPS 2010, Sendai: [http://www.kb.ecei.tohoku.ac.jp/flops2010/] - FLOPS 2008, Ise: [http://www.math.nagoya-u.ac.jp/~garrigue/FLOPS2008/] - FLOPS 2006, Fuji Susono: [http://hagi.is.s.u-tokyo.ac.jp/FLOPS2006/] Sponsors - Japan Society for Software Science and Technology (JSSST) SIGPPL In Cooperation with === - ACM SIGPLAN (pending
[Haskell] FLOPS 2012: final call for papers & deadline extension
Final Call For Papers = _EXTENDED SUBMISSION DEADLINE : December 16, 2011_ *Eleventh International Symposium on Functional and Logic Programming (FLOPS 2012)* May 23-25, 2012 Kobe, Japan [http://www.org.kobe-u.ac.jp/flops2012/] FLOPS is a forum for research on all issues concerning declarative programming, including functional programming and logic programming, and aims to promote cross-fertilization and integration between the two paradigms. Previous FLOPS meetings were held in Fuji Susono (1995), Shonan Village (1996), Kyoto (1998), Tsukuba (1999), Tokyo (2001), Aizu (2002), Nara (2004), Fuji Susono (2006), Ise (2008), and Sendai (2010). Topics == FLOPS solicits original papers in all areas of functional and logic programming, including (but not limited to): - Declarative Pearls: new and excellent declarative programs with illustrative applications. - Language issues: language design and constructs, programming methodology, integration of paradigms, interfacing with other languages, type systems, constraints, concurrency and distributed computing. - Foundations: logic and semantics, rewrite systems and narrowing, type theory, proof systems. - Implementation issues: compilation techniques, memory management, program analysis and transformation, partial evaluation, parallelism. - Applications: case studies, real-world applications, graphical user interfaces, Internet applications, XML, databases, formal methods and model checking. The proceedings will be published as an LNCS volume. The proceedings of the previous meeting (FLOPS 2010) were published as LNCS 6009. PC co-Chairs - Tom Schrijvers (Ghent University, Belgium) - Peter Thiemann (University of Freiburg, Germany) PC Members == - Salvador Abreu (University of Evora, Portugal) - Thorsten Altenkirch (University of Nottingham, UK) - Sebastian Brand (NICTA, Australia) - Giuseppe Castagna (CNRS Univ Paris 7, France) - Sebastian Fischer (Germany) - Marco Gavanelli (University of Ferrara, Italy) - Joxan Jaffar (National University of Singapore, Singapore) - Barry Jay (University of Sydney, Australia) - Andy King (University of Kent, UK) - Claude Kirchner (INRIA, France) - Neelakantan R. Krishnaswami (Microsoft Cambridge, UK) - Yulya Lierler (University of Kentucky, USA) - Keiko Nakata (Tallinn University of Technology, Estonia) - Peter Schneider-Kamp (University of Southern Denmark, Denmark) - Olin Shivers (Northeastern University, USA) - Paul Tarau (University of Northern Texas, USA) - Kazunori Ueda (Waseda University, Japan) - Meng Wang (Chalmers Technical University, Sweden) General Chair and Local co-Chairs = - Naoyuki Tamura (Kobe University, Japan) - Mutsunori Banbara (Kobe University, Japan) - Katsutoshi Hirayama (Kobe University, Japan) Submission == Submissions must be unpublished and not submitted for publication elsewhere. Work that already appeared in unpublished or informally published workshops proceedings may be submitted. Submissions should fall into one of the following categories: - Regular research papers: they should describe new results and will be judged on originality, correctness, and significance. - System descriptions: they should contain a link to a working system and will be judged on originality, usefulness, and design. Submissions must be written in English and can be up to 15 pages long, though pearls are typically considerably shorter. Authors are required to use LaTeX2e and the Springer llncs class file, available at [http://www.springer.de/comp/lncs/authors.html]. Regular research papers should be supported by proofs and/or experimental results. In case of lack of space, this supporting information should be made accessible otherwise (e.g., a link to a web page, or an appendix). Papers should be submitted electronically at [https://www.easychair.org/conferences/?conf=flops2012]. Important Dates === - Submission deadline : December 16, 2011 (EXTENDED) - Author notification : February 3, 2012 - Camera-ready copy : March 2, 2012 Place and Related Events Takikawa Memorial Hall, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 Japan. The 23rd International Conference on Rewriting Techniques and Applications (RTA 2012) and satellite workshops including WFLP 2012 will be held in the week after FLOPS at Nagoya, Japan. Some Previous FLOPS === - FLOPS 2010, Sendai: [http://www.kb.ecei.tohoku.ac.jp/flops2010/] - FLOPS 2008, Ise: [http://www.math.nagoya-u.ac.jp/~garrigue/FLOPS2008/] - FLOPS 2006, Fuji Susono: [http://hagi.is.s.u-tokyo.ac.jp/FLOPS2006/] Sponsors - Japan Society for Software Science and Technology (JSSST) SIGPPL In Cooperation with
[Haskell] PhD position at Ghent University
The Programming Languages Group of Ghent University invites applicants for a PhD position. This position centers around the modular treatment of side-effects in purely functional programs and models. It is part of the project "Modular handling of effects in purely functional programs and models" under the direction of Tom Schrijvers. The successful applicant has a master degree in Computer Science or equivalent. Ideally, she/he will also have a strong, documented interest in doing research. Strong problem-solving and programming skills are essential. Prior knowledge of purely functional programming (e.g., Haskell) and models of side-effects (e.g., monads) is an advantage. The PhD position is for 4 years. It starts between January and October 2012. The position is a fully-funded post. The salary is compatible with other Belgian PhD rates and among the better ones in Europe and abroad. For more information, see: http://users.ugent.be/~tschrijv/phdposition2.html -- prof. dr. ir. Tom Schrijvers Programming Languages Group Department of Applied Mathematics and Computer Science University of Ghent Krijgslaan 281 S9 9000 Gent Belgium Phone: +32 9 264 4805 http://users.ugent.be/~tschrijv/ ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
