- curry - lists.rwth-aachen.de

Lots of problems with cypm
by Andy Jost 04 Apr '19

04 Apr '19

I've had nothing but trouble with cypm. It seems to be required for a certain package I want to use, but even the most basic commands fail, e.g.: % cypm update fatal: destination path '.' already exists and is not an empty directory. CRITICAL Failed to update git repository, return code 128 Others are able to build the package in question, so I'd like to start over. I'd like to remove all traces of cypm and even Curry (pakcs, kics2) from my system (Ubuntu) and start from scratch. How should I go about doing that? Or are there other recommendations for how to approach this. -Andy

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2nd CFP WFLP
by Herbert Kuchen 02 Apr '19

02 Apr '19

========================================================= WFLP 2019: Call for Papers ========================================================= 27th International Workshop on Functional and (Constraint) Logic Programming Cottbus, Germany, September 9-13, 2019 (part of Declare 2019; co-located with INAP and WLP) Important Dates Abstract submission: May 27, 2019 Paper submission: June 3, 2019 Notification of acceptance: July 1, 2019 Camera-ready papers: July 29, 2019 Early registration: August 12, 2019 Online Registration: September 2, 2019 Workshop: September 9-13, 2019 WFLP 2019 The international Workshop on Functional and (constraint) Logic Programming (WFLP) aims at bringing together researchers, students, and practitioners interested in functional programming, logic programming, and their integration. WFLP has a reputation for being a lively and friendly forum, and it is open for presenting and discussing work in progress, technical contributions, experience reports, experiments, reviews, and system descriptions. The 27th International Workshop on Functional and (Constraint) Logic Programming (WFLP 2019) will be held at the Brandenburgische Technische Universität Cottbus Germany. Previous WFLP editions were WFLP 2018 (Frankfurt am Main, Germany), WFLP 2017 (Würzburg, Germany), WFLP 2016 (Leipzig, Germany), WFLP 2014 (Wittenberg, Germany), WFLP 2013 (Kiel, Germany), WFLP 2012 (Nagoya, Japan), WFLP 2011 (Odense, Denmark), WFLP 2010 (Madrid, Spain), WFLP 2009 (Brasilia, Brazil), WFLP 2008 (Siena, Italy), WFLP 2007 (Paris, France), WFLP 2006 (Madrid, Spain), WCFLP 2005 (Tallinn, Estonia), WFLP 2004 (Aachen, Germany), WFLP 2003 (Valencia, Spain), WFLP 2002 (Grado, Italy), WFLP 2001 (Kiel, Germany), WFLP 2000 (Benicassim, Spain), WFLP'99 (Grenoble, France), WFLP'98 (Bad Honnef, Germany), WFLP'97 (Schwarzenberg, Germany), WFLP'96 (Marburg, Germany), WFLP'95 (Schwarzenberg, Germany), WFLP'94 (Schwarzenberg, Germany), WFLP'93 (Rattenberg, Germany), and WFLP'92 (Karlsruhe, Germany). WFLP 2019 will be part of DECLARE 2019 and hence be co-located with INAP 2019 (International Conference on Applications of Declarative Programming and Knowledge Management), WLP 2019 (Workshop on (Constraint) Logic Programming), and QuaProL 2019 (Quantum and Probability Logic). Topics The topics of interest cover all aspects of functional and logic programming. They include (but are not limited to): * Functional programming * Logic programming * Constraint programming * Deductive databases, data mining * Extensions of declarative languages, objects * Multi-paradigm declarative programming * Foundations, semantics, non-monotonic reasoning, dynamics * Parallelism, concurrency * Program analysis, abstract interpretation * Program and model manipulation * Program transformation, partial evaluation, meta-programming * Specification, * Verification * Debugging * Testing * Knowledge representation, machine learning * Interaction of declarative programming with other formalisms * Implementation of declarative languages * Advanced programming environments and tools * Software techniques for declarative programming * Applications The primary focus is on new and original research results, but submissions describing innovative products, prototypes under development, application systems, or interesting experiments (e.g., benchmarks) are also encouraged. Survey papers that present some aspects of the above topics from a new perspective, and experience reports are also welcome. Papers must be written and presented in English. Work that already appeared in unpublished or informally published workshop proceedings may be submitted (please contact the PC chair in case of questions). Submission Guidelines Submission is via the Easychair submission website for WFLP 2019: https://easychair.org/conferences/?conf=wflp2019 Authors are invited to submit papers in the following categories: + Regular research paper + Work-in-progress report + System description Regular research papers must describe original work, be written and presented in English, and must not substantially overlap with papers that have been formally published or that are simultaneously submitted to a journal, conference, or workshop with formal proceedings. They will be judged on the basis of significance, relevance, correctness, originality, and clarity. For work-in-progress reports and system descriptions, less formal rules apply, and presentation-only submissions (talk and discussion, but no paper in the formal proceedings) are possible. Please contact the PC chair with any questions. All submissions must be formatted in the Lecture Notes in Computer Science style. Submissions cannot exceed 15 pages including references but excluding well-marked appendices not intended for publication. Reviewers are not required to read the appendices, and thus papers should be intelligible without them. However, all submissions (especially work-in-progress reports and system descriptions) may be considerably shorter than 15 pages. Proceedings All papers accepted for presentation at the conference will be published in informal proceedings publicly available at the Computing Research Repository. According to the program committee reviews, submissions can be directly accepted for publication in the formal post-conference proceedings. The formal post-conference proceedings will be published in both electronic and paper formats by Springer in the Lecture Notes in Computer Science series. After the conference, all authors accepted only for presentation will be invited to revise and/or extend their submissions in the light of the feedback solicited at the conference. Then, after another round of reviewing, these revised papers may also be published in the formal proceedings. Therefore, all accepted papers will be published in open-access, and the authors can also decide to publish their work in the Springer LNCS formal proceedings. Program Committee Maria Alpuente Frasnedo, Universitat Politècnica de València, Spain Sergio Antoy, Portland State University, USA Olaf Chitil, University of Kent, UK Sandra Dylus, University of Kiel, Germany Moreno Falaschi, U. Siena, Italy Michael Hanus, University of Kiel, Germany Herbert Kuchen, University of Münster, Germany (Chair) Julio Mariño Carballo, Universidad Politécnica de Madrid, Spain Manuel Montenegro Montes, Universidad Complutense de Madrid, Spain Kostis Sagonas, Uppsala University, Sweden Sibylle Schwarz, HTWK Leipzig, Germany Dietmar Seipel, University of Würzburg, Germany Josep Silva Galiana, Universitat Politècnica de València, Spain Johannes Waldmann, HTWK Leipzig, Germany Organizing Committee Petra Hofstedt (General Chair), Brandenburg University of Technology, Cottbus, Germany

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CfP: WLP 2019 - 33rd Workshop on (Constraint) Logic Programming
by Petra Hofstedt (BTU) 04 Feb '19

04 Feb '19

========================================================= WLP 2019: Call for Papers ========================================================= 33rd Workshop on (Constraint) Logic Programming Cottbus, Germany, September 9-13, 2019 (part of Declare 2019; co-located with INAP, WFLP, and QPLogic) Important Dates Abstract submission: May 27, 2019 Paper submission: June 3, 2019 Notification of acceptance: July 1, 2019 Camera-ready papers: July 29, 2019 Early registration: August 12, 2019 Online Registration: September 2, 2019 Workshop: September 9-13, 2019 WLP 2019 The workshops on (constraint) logic programming serve as the scientific forum of the annual meeting of the Society of Logic Programming (GLP, Gesellschaft fuer Logische Programmierung e.V.). They bring together researchers (not only from Germany) interested in logic programming, constraint programming, and related areas like databases, artificial intelligence, and operations research. Previous workshops have been held in Germany, Austria, Switzerland, Egypt, Japan, Denmark, Spain, Brazil, Italy, and France. Contributions are welcome on all theoretical, experimental, and application aspects of logic and constraint logic programming. The topics include, but are not limited to the following areas: + Logic and Constraint Logic Programming Languages and Extensions + Knowledge Representation and Non-monotonic Reasoning + Applications and Application Areas of (C)LP + Implementations WLP 2019 will be part of DECLARE 2019 and hence be co-located with INAP 2019 (International Conference on Applications of Declarative Programming and Knowledge Management), WFLP 2019 (International Workshop on Functional and Logic Programming), and QPLogic 2019 (Quantum and Probability Logic). Submission Guidelines Authors are invited to submit long papers (no longer than 15 pages) or short papers (no longer than 6 pages) in the following categories: + Regular research papers + Application papers + System descriptions We also encourage submissions on ongoing work of PhD students (no longer than 6 pages). Submissions must be unpublished original work and not submitted for publication elsewhere. However, work that already appeared in informally published workshop proceedings may be submitted too. All papers will be judged on the basis of significance, relevance, correctness, originality, and clarity. All submissions must be formatted in the Lecture Notes in Computer Science style. For further information on the submission procedure, please, visit the conference web site: declare19.de Proceedings All papers accepted for presentation at the conference will be published in informal proceedings publicly available at the Computing Research Repository. According to the program committee reviews, submissions can be directly accepted for publication in the formal post-conference proceedings. The formal post-conference proceedings will be published in both electronic and paper formats by Springer in the Lecture Notes in Computer Science series. After the conference, all authors accepted only for presentation will be invited to revise and/or extend their submissions in the light of the feedback solicited at the conference. Then, after another round of reviewing, these revised papers may also be published in the formal proceedings. All accepted papers will be presented during the conference. At least one author of an accepted contribution is expected to register for the conference and present the paper. Program Committee Slim Abdennadher (German University in Cairo, Egypt) Christoph Beierle (FernUniversität in Hagen, Germany) Thomas Eiter (Vienna University of Technology, Austria) Daniel Gall (University of Ulm, Germany) Ulrich Geske (University of Potsdam, Germany) Michael Hanus (University of Kiel, Germany) Petra Hofstedt (BTU Cottbus - Senftenberg, Germany) (co-Chair) Steffen Hölldobler (TU Dresden, Germany) Tomi Jahunen (Aalto University, Finland) Ulrich John (hwtk Berlin) (co-Chair) Ke Liu (BTU Cottbus - Senftenberg, Germany) Sven Löffler (BTU Cottbus - Senftenberg, Germany) Falco Nogatz (University of Würzburg, Germany) Torsten Schaub (University of Potsdam, Germany) Sibylle Schwarz (HTWK Leipzig, Germany) Dietmar Seipel (University of Würzburg, Germany) Hans Tompits (Vienna University of Technology, Austria) Janis Voigtländer (Universität Duisburg-Essen, Germany) Armin Wolf (Fraunhofer FOKUS Berlin, Germany) Organizing Committee Petra Hofstedt (General Chair), Sven Löffler, Katrin Ebert, Brandenburg University of Technology, Cottbus, Germany

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CfP: INAP 2019 - 22nd International Conference on Applications of Declarative Programming and Knowledge Management
by Petra Hofstedt (BTU) 04 Feb '19

04 Feb '19

========================================================= INAP 2019: Call for Papers ========================================================= 22nd International Conference on Applications of Declarative Programming and Knowledge Management Cottbus, Germany, September 9-13, 2019 (part of Declare 2019; co-located with WFLP, WLP, and QPLogic) Important Dates Paper registration: May 27, 2019 Paper submission: June 3, 2019 Notification of acceptance: July 1, 2019 Camera-ready papers: July 29, 2019 Early registration: August 12, 2019 Online Registration: September 2, 2019 Conference: September 9-13, 2019 INAP 2019 INAP is a forum for intensive discussion of applications of important technologies around declarative programming, constraint problem solving, and related computing paradigms. It comprehensively covers the impact of data and knowledge engineering, programmable logic solvers in the internet society, its underlying technologies, and leading edge applications in industry, commerce, government, and societal services. Previous INAP conferences have been held in Japan, Germany, Portugal, and Austria. We invite high quality contributions on the described topics, especially, but not exclusively, on different aspects of declarative programming, constraint processing, data and knowledge management, as well as their use for distributed systems and the web: * data and knowledge engineering / management: deductive databases, rule bases, decision support, expert systems, knowledge discovery; * declarative programming: logic programming, nonmonotonic reasoning, knowledge representation, domain-specific languages; * constraints: constraint systems, (extensions of) constraint (logic) programming, constraint-based modeling and applications; * distributed systems and the web: agents and concurrent engineering, ontologies, semantic web, internet of things; * practical systems: tools for academic and industrial use, knowledge-based web services, logic solvers and applications; * multi-paradigm programming. INAP 2019 will be part of DECLARE 2019 and hence be co-located with WFLP 2019 (International Workshop on Functional and Logic Programming), WLP 2019 (Workshop on (Constraint) Logic Programming), and QPLogic 2019 (Quantum and Probability Logic). Submission Guidelines Authors are invited to submit long papers (no longer than 15 pages) or short papers (no longer than 6 pages) in the following categories: + Regular research papers + Application papers + System descriptions We also encourage submissions on ongoing work of PhD students (no longer than 6 pages). Submissions must be unpublished original work and not submitted for publication elsewhere. However, work that already appeared in informally published workshop proceedings may be submitted too. All papers will be judged on the basis of significance, relevance, correctness, originality, and clarity. All submissions must be formatted in the Lecture Notes in Computer Science style. For further information on the submission procedure, please, visit the conference web site: declare19.de Proceedings All papers accepted for presentation at the conference will be published in informal proceedings publicly available at the Computing Research Repository. According to the program committee reviews, submissions can be directly accepted for publication in the formal post-conference proceedings. The formal post-conference proceedings will be published in both electronic and paper formats by Springer in the Lecture Notes in Computer Science series. After the conference, all authors accepted only for presentation will be invited to revise and/or extend their submissions in the light of the feedback solicited at the conference. Then, after another round of reviewing, these revised papers may also be published in the formal proceedings. All accepted papers will be presented during the conference. At least one author of an accepted contribution is expected to register for the conference and present the paper. Program Committee Salvador Abreu (Universidade de Évora, Portugal) Christoph Beierle (FernUniversität in Hagen, Germany) François Bry (Ludwig-Maximilian-University of Munich, Germany) Vitor Santos Costa (University of Porto, Portugal) Thom Frühwirth (University of Ulm, Germany) Ulrich Geske (University of Potsdam, Germany) Gopal Gupta (UT Dallas, USA) Michael Hanus (University of Kiel, Germany) Petra Hofstedt (BTU Cottbus - Senftenberg, Germany) (Chair) Tomi Jahunen (Aalto University, Finland) Gabriele Kern-Isberner (TU Dortmund University, Germany) Herbert Kuchen (University of Münster, Germany) Sven Löffler (BTU Cottbus - Senftenberg, Germany) Vitor Beires Nogueira (Universidade de Évora, Portugal) Ricardo Rocha (University of Porto, Portugal) Dietmar Seipel (University of Würzburg, Germany) Helmut Simonis (University College Cork, Ireland) Theresa Swift (Universidade Nova de Lisboa, Portugal) Hans Tompits (Vienna University of Technology, Austria) Masanobu Umeda (Kyushu Institute of Technology, Japan) Armin Wolf (Fraunhofer FOKUS Berlin, Germany) Track Chairs Salvador Abreu (Universidade de Évora) - Logic Programming and Extensions Dietmar Seipel (University of Würzburg) - (Deductive) Databases, Rule Bases, Decision Support, Expert Systems, Knowledge Discovery Petra Hofstedt (BTU Cottbus - Senftenberg) - Constraints, Constraint Solvers and Systems Organizing Committee Petra Hofstedt (General Chair), Sven Löffler, Katrin Ebert, Brandenburg University of Technology, Cottbus, Germany

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CfP: WFLP 2019 - 27th International Workshop on Functional and (Constraint) Logic Programming
by Michael Hanus 04 Feb '19

04 Feb '19

========================================================= WFLP 2019: Call for Papers ========================================================= 27th International Workshop on Functional and (Constraint) Logic Programming Cottbus, Germany, September 9-13, 2019 (part of Declare 2019; co-located with INAP, WLP, and QPLogic) Important Dates Abstract submission: May 27, 2019 Paper submission: June 3, 2019 Notification of acceptance: July 1, 2019 Camera-ready papers: July 29, 2019 Early registration: August 12, 2019 Online Registration: September 2, 2019 Workshop: September 9-13, 2019 WFLP 2019 The international Workshop on Functional and (constraint) Logic Programming (WFLP) aims at bringing together researchers, students, and practitioners interested in functional programming, logic programming, and their integration. WFLP has a reputation for being a lively and friendly forum, and it is open for presenting and discussing work in progress, technical contributions, experience reports, experiments, reviews, and system descriptions. The 27th International Workshop on Functional and (Constraint) Logic Programming (WFLP 2019) will be held at the Brandenburgische Technische Universität Cottbus Germany. Previous WFLP editions were WFLP 2018 (Frankfurt am Main, Germany), WFLP 2017 (Würzburg, Germany), WFLP 2016 (Leipzig, Germany), WFLP 2014 (Wittenberg, Germany), WFLP 2013 (Kiel, Germany), WFLP 2012 (Nagoya, Japan), WFLP 2011 (Odense, Denmark), WFLP 2010 (Madrid, Spain), WFLP 2009 (Brasilia, Brazil), WFLP 2008 (Siena, Italy), WFLP 2007 (Paris, France), WFLP 2006 (Madrid, Spain), WCFLP 2005 (Tallinn, Estonia), WFLP 2004 (Aachen, Germany), WFLP 2003 (Valencia, Spain), WFLP 2002 (Grado, Italy), WFLP 2001 (Kiel, Germany), WFLP 2000 (Benicassim, Spain), WFLP'99 (Grenoble, France), WFLP'98 (Bad Honnef, Germany), WFLP'97 (Schwarzenberg, Germany), WFLP'96 (Marburg, Germany), WFLP'95 (Schwarzenberg, Germany), WFLP'94 (Schwarzenberg, Germany), WFLP'93 (Rattenberg, Germany), and WFLP'92 (Karlsruhe, Germany). WFLP 2019 will be part of DECLARE 2019 and hence be co-located with INAP 2019 (International Conference on Applications of Declarative Programming and Knowledge Management), WLP 2019 (Workshop on (Constraint) Logic Programming), and QPLogic 2019 (Quantum and Probability Logic). Topics The topics of interest cover all aspects of functional and logic programming. They include (but are not limited to): * Functional programming * Logic programming * Constraint programming * Deductive databases, data mining * Extensions of declarative languages, objects * Multi-paradigm declarative programming * Foundations, semantics, non-monotonic reasoning, dynamics * Parallelism, concurrency * Program analysis, abstract interpretation * Program and model manipulation * Program transformation, partial evaluation, meta-programming * Specification, * Verification * Debugging * Testing * Knowledge representation, machine learning * Interaction of declarative programming with other formalisms * Implementation of declarative languages * Advanced programming environments and tools * Software techniques for declarative programming * Applications The primary focus is on new and original research results, but submissions describing innovative products, prototypes under development, application systems, or interesting experiments (e.g., benchmarks) are also encouraged. Survey papers that present some aspects of the above topics from a new perspective, and experience reports are also welcome. Papers must be written and presented in English. Work that already appeared in unpublished or informally published workshop proceedings may be submitted (please contact the PC chair in case of questions). Submission Guidelines Submission is via Easychair submission website for WFLP 2019: https://easychair.org/conferences/?conf=wflp2019 Authors are invited to submit papers in the following categories: + Regular research paper + Work-in-progress report + System description Regular research papers must describe original work, be written and presented in English, and must not substantially overlap with papers that have been formally published or that are simultaneously submitted to a journal, conference, or workshop with formal proceedings. They will be judged on the basis of significance, relevance, correctness, originality, and clarity. For work-in-progress reports and system descriptions, less formal rules apply, and presentation-only submissions (talk and discussion, but no paper in the formal proceedings) are possible. Please contact the PC chair with any questions. All submissions must be formatted in the Lecture Notes in Computer Science style. Submissions cannot exceed 15 pages including references but excluding well-marked appendices not intended for publication. Reviewers are not required to read the appendices, and thus papers should be intelligible without them. However, all submissions (especially work-in-progress reports and system descriptions) may be considerably shorter than 15 pages. Proceedings All papers accepted for presentation at the conference will be published in informal proceedings publicly available at the Computing Research Repository. According to the program committee reviews, submissions can be directly accepted for publication in the formal post-conference proceedings. The formal post-conference proceedings will be published in both electronic and paper formats by Springer in the Lecture Notes in Computer Science series. After the conference, all authors accepted only for presentation will be invited to revise and/or extend their submissions in the light of the feedback solicited at the conference. Then, after another round of reviewing, these revised papers may also be published in the formal proceedings. Therefore, all accepted papers will be published in open-access, and the authors can also decide to publish their work in the Springer LNCS formal proceedings. Program Committee Maria Alpuente Frasnedo, Universitat Politècnica de València, Spain Sergio Antoy, Portland State University, USA Olaf Chitil, University of Kent, UK Sandra Dylus, University of Kiel, Germany Moreno Falaschi, U. Siena, Italy Michael Hanus, University of Kiel, Germany Herbert Kuchen, University of Münster, Germany (Chair) Julio Mariño Carballo, Universidad Politécnica de Madrid, Spain Manuel Montenegro Montes, Universidad Complutense de Madrid, Spain Kostis Sagonas, Uppsala University, Sweden Sibylle Schwarz, HTWK Leipzig, Germany Dietmar Seipel, University of Würzburg, Germany Josep Silva Galiana, Universitat Politècnica de València, Spain Johannes Waldmann, HTWK Leipzig, Germany Organizing Committee Petra Hofstedt (General Chair), Sven Löffler, Katrin Ebert, Brandenburg University of Technology, Cottbus, Germany

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pakcs installation gave "inappropriate ioctl" error; I tried to rebuild `pakcs`; now I can't even build `pakcs`
by Jeffrey Brown 03 Dec '18

03 Dec '18

[This email is duplicated in markdown form here <https://github.com/JeffreyBenjaminBrown/curry-studies/blob/9ce2c82c4649835c…> [0].] `pakcs` started giving me this error, no matter where I ran it from: jeff@jeff-inspiron-2017:~/logic/curry/rslt$ pakcs [FATAL ERROR: at Sun Dec 2 17:07:26 2018 Could not open resource database "/home/jeff/logic/curry/install/pakcs-2.0.2/bin/cypm": Inappropriate ioctl for device] jeff@jeff-inspiron-2017:~/logic/curry/rslt$ cd .. After installing `pakcs` (from `pakcs-2.0.2-amd64-Linux.tar.gz`), I had made a copy of the folder. I figured the original must have got corrupted, so I deleted it and replaced it with the copy that I made after first installing. I still got the same "inappropriate ioctl" error. So I tried running `make` again, without first running `make clean`. I got this error <https://github.com/JeffreyBenjaminBrown/curry-studies/blob/a59cf8ee1a6d469d…> [1]. Then I ran `make clean`, and got no apparent errors <https://github.com/JeffreyBenjaminBrown/curry-studies/blob/a59cf8ee1a6d469d…> [2]. But I still can't `make` the project <https://github.com/JeffreyBenjaminBrown/curry-studies/blob/a59cf8ee1a6d469d…> [3]. [0] https://github.com/JeffreyBenjaminBrown/curry-studies/blob/9ce2c82c4649835c… [1] https://github.com/JeffreyBenjaminBrown/curry-studies/blob/a59cf8ee1a6d469d… [2] https://github.com/JeffreyBenjaminBrown/curry-studies/blob/a59cf8ee1a6d469d… [3] https://github.com/JeffreyBenjaminBrown/curry-studies/blob/a59cf8ee1a6d469d… -- Jeff Brown | Jeffrey Benjamin Brown Website <https://msu.edu/~brown202/> | Facebook <https://www.facebook.com/mejeff.younotjeff> | LinkedIn <https://www.linkedin.com/in/jeffreybenjaminbrown>(spammy, so I often miss messages here) | Github <https://github.com/jeffreybenjaminbrown>

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Haskell-related summer internship in Germany
by Finn Teegen 30 Nov '18

30 Nov '18

Our department (PL and compiler construction) again offers a summer internship in 2019 sponsored by DAAD Rise Germany [1]. Undergraduate students enrolled at North American, British and Irish universities are eligible to make an application. We'd be very happy to host a motivated student, who is keen to improve our compiler for the functional logic programming language Curry in terms of performance. For more information you may have a look at our project poster [2]. If you have any questions, feel free to mail any of the contact persons. Please also spread the news to your students and classmates. Cheers, Sandra and Finn [1]: https://www.daad.de/rise/en/rise-germany/ [2]: https://www-ps.informatik.uni-kiel.de/~sad/DAADRise.pdf

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The PAKCS REPL consider something undefined, but the module defining it is loaded
by Jeffrey Brown 29 Nov '18

29 Nov '18

New StackOverflow question! https://stackoverflow.com/questions/53547365/the-pakcs-repl-consider-someth… -- Jeff Brown | Jeffrey Benjamin Brown Website <https://msu.edu/~brown202/> | Facebook <https://www.facebook.com/mejeff.younotjeff> | LinkedIn <https://www.linkedin.com/in/jeffreybenjaminbrown>(spammy, so I often miss messages here) | Github <https://github.com/jeffreybenjaminbrown>

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Specifying default rules: Why and how?
by Jeffrey Brown 23 Nov '18

23 Nov '18

I posted this question on Stackoverflow[1] yesterday and haven't received any answers yet. I've duplicated the question below, but an answer posted to StackOverflow would be more useful to future students, if you're so inclined. Thanks! --- In section 3.5.6 of the Curry tutorial (pdf) <https://www.informatik.uni-kiel.de/~curry/tutorial/tutorial.pdf>, we are advised to use default rules to "regain control after a failed search". The following example is given. (For clarity I have added a type signature and curried the input.) lookup :: k -> [(k,v)] -> Maybe v lookup key (_++[(key,value)]++_ ) = Just value lookup’default _ _ = Nothing I can't get that to compile unless I replace the ’ with a '. Once I do, it behaves like this: test> test.lookup 1 [(2,3)] *** No value found! Question 1: What is the default declaration for? Why would you need to specify that a particular clause is the default one? Won't it be arrived at one way or another, once the others fail? Question 2: How is it written? Should it be written at all? If instead I drop the string 'default: lookup :: k -> [(k,v)] -> Maybe v lookup key (_++[(key,value)]++_ ) = Just value lookup _ _ = Nothing it behaves as intended: test> test.lookup 1 [(2,3)] Nothing test> Has the 'default syntax changed since the tutorial was written? Has it been removed altogether? [1] https://stackoverflow.com/questions/53357361/specifying-default-rules-in-th… -- Jeff Brown | Jeffrey Benjamin Brown Website <https://msu.edu/~brown202/> | Facebook <https://www.facebook.com/mejeff.younotjeff> | LinkedIn <https://www.linkedin.com/in/jeffreybenjaminbrown>(spammy, so I often miss messages here) | Github <https://github.com/jeffreybenjaminbrown>

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What speed to expect doing logic on graphs represented by maps
by Jeffrey Brown 19 Nov '18

19 Nov '18

I want to write something resembling an editor for a graph database. I'm wondering if Curry will be fast enough. The data defining the graph would resemble the following: type Address = Int data Graph = Graph { address :: Map String Address content :: Map Address String -- `address` and `content` are inverses children :: Map Label (Set Address) parents :: Map Label (Set Address) } I would define rules such as: descendent :: Graph -> Index -> Index descendent g i -- If j is i's child, then j is i's descendent. | Set.member j $ Map.lookup i $ children g = j descendent g i -- If j is i's descendent and k is j's child, then k is i's descendent. | descendent g i j & (Set.member k $ Map.lookup k $ children g) = k I'll use hash maps unless their space requirements stop me. I'm hoping the resulting code will quickly (say, in under a second) answer queries over a few million nodes, along the lines of "the descendents of X and Y, minus any descendents of Z or W". If an unbounded number of generations proves computationally difficult, I would not be bothered by needing to impose depth limits, ala "the first two generations of descendents of X and Y, minus the first seven generations of descendents of Z or W". The graph would be sparse: with an average number of children well under five, and few cycles. Is this kind of performance a reasonable thing to expect from Curry? If so, using which compiler? If not, can you recommend another language? I know Haskell, and prefer it immensely to any other language. I am reluctant to write a full application in a pure logic language like Mercury, but I will if need be. -- Jeff Brown | Jeffrey Benjamin Brown Website <https://msu.edu/~brown202/> | Facebook <https://www.facebook.com/mejeff.younotjeff> | LinkedIn <https://www.linkedin.com/in/jeffreybenjaminbrown>(spammy, so I often miss messages here) | Github <https://github.com/jeffreybenjaminbrown>

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