- Haskell-Cafe - Haskell.org

Re: [Haskell-cafe] Optimization flag changing result of code execution
by Azeem -ul-Hasan 18 Jul '13

18 Jul '13

I am using GHC 7.6.1 mwc-random 0.12.0.1 vector 0.9.1 primitive 0.4.1 Azeem On 16.03.2013 13:31, Azeem -ul-Hasan wrote: > Nope that isn't the case either. Even if I make use of defaultSeed > through create the problem still remains. The problem seems to be in the > generation of a vector of (a,a) i.e in the part > > V.generateM ((round $ p*(fromIntegral $ l*z)) `div` 2) (\i-> R.uniformR > ((0,0) , (l-1,l-1)) gen) > > in line 16. Thanks again. > I've tried to run you program and I've got approximately same results regardless of optimization level. Which versions of GHC, mwc-random, vector and primitive do you use?

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Haskell Weekly News: Issue 273
by Daniel Santa Cruz 18 Jul '13

18 Jul '13

Welcome to issue 273 of the HWN, an issue covering crowd-sourced bits of information about Haskell from around the web. This issue covers the week of June 30 to July 13, 2013. Quotes of the Week * monochrom: 8-bit word uses less memory, but if it doesn't have to preserve information, I know how to use 0 bits of memory. * byorgey: you know, servers migrate in the summer to their ancestral breeding grounds * emeijer: It must me said on the other hand compiler writers seem to ignore the existence of formal semantics completely, probably because they don't like greek letters. * byorgey: now we have the pig operator <^(++)^> as well as the robot monkey operator (:[]) * chrisdone: i remember when the internet was black and white and you had to upload web pages back onto the internet when you were done with them * raganwald: Immuteability: The property of functional programmers that prevents them from shutting up about pure functional programming. Top Reddit Stories * On taking the last n elements of a list Domain: joachim-breitner.de, Score: 69, Comments: 37 On Reddit: [1] http://goo.gl/E9hRX Original: [2] http://goo.gl/9Uf74 * Comonads are NOT objects Domain: gelisam.blogspot.ca, Score: 62, Comments: 50 On Reddit: [3] http://goo.gl/tgdhh Original: [4] http://goo.gl/i3EDv * ANNOUNCE: Haste, the Haskell to JS compiler, is now on Hackage Domain: hackage.haskell.org, Score: 60, Comments: 27 On Reddit: [5] http://goo.gl/GTpj5 Original: [6] http://goo.gl/Nzpe7 * Postmodern Haskell and OpenGL: Introducing vinyl-gl Domain: arcadianvisions.com, Score: 57, Comments: 6 On Reddit: [7] http://goo.gl/9mVbl Original: [8] http://goo.gl/Zh5jE * ANNOUNCE: haskell-mode 13.07 (& Survey) Domain: projects.haskell.org, Score: 49, Comments: 18 On Reddit: [9] http://goo.gl/gYU24 Original: [10] http://goo.gl/YSmk4 * Why the world needs Haskell Domain: devalot.com, Score: 46, Comments: 22 On Reddit: [11] http://goo.gl/ekD96 Original: [12] http://goo.gl/LBxRP * Cartesian Closed Comic #20: Weird language Domain: ro-che.info, Score: 42, Comments: 10 On Reddit: [13] http://goo.gl/In50H Original: [14] http://goo.gl/tblYa * Do naming practices hurt Haskell? Domain: self.haskell, Score: 38, Comments: 222 On Reddit: [15] http://goo.gl/mnwO9 Original: [16] http://goo.gl/mnwO9 * ANNOUNCE: [17] http://goo.gl/pp0Vf Domain: self.haskell, Score: 37, Comments: 18 On Reddit: [18] http://goo.gl/MRDO7 Original: [19] http://goo.gl/MRDO7 * Skills Matter : In The Brain of Edsko de Vries: Lazy I/O and Alternatives in Haskell Domain: skillsmatter.com, Score: 37, Comments: 14 On Reddit: [20] http://goo.gl/13zlQ Original: [21] http://goo.gl/QSyTu * Attoparsec tutorial - School of Haskell Domain: fpcomplete.com, Score: 35, Comments: 17 On Reddit: [22] http://goo.gl/Riydl Original: [23] http://goo.gl/P2oiy * FP Haskell Center Beta Released and Beta Accounts Activated Domain: fpcomplete.com, Score: 33, Comments: 7 On Reddit: [24] http://goo.gl/Zs3kU Original: [25] http://goo.gl/vgy5m Top StackOverflow Questions * What advantage does Monad give us over an Applicative? votes: 17, answers: 7 Read on SO: [26] http://goo.gl/4L0gj * Encoding “Less Than” with Haskell votes: 11, answers: 1 Read on SO: [27] http://goo.gl/1Qsvn * Why is factorial calculation much faster in Haskell than in Java votes: 11, answers: 5 Read on SO: [28] http://goo.gl/QTbrl * Haskell: Can typeclasses define types (ala type traits) votes: 10, answers: 2 Read on SO: [29] http://goo.gl/yLSqT * C++ and Haskell codes differs in execution time on different machines votes: 10, answers: 1 Read on SO: [30] http://goo.gl/LRs3k * GHC.Generics or Data.Data? votes: 10, answers: 1 Read on SO: [31] http://goo.gl/yU6Ri * Constraint subset higher-order constraint votes: 9, answers: 1 Read on SO: [32] http://goo.gl/MTTws * How to make catamorphisms work with parameterized/indexed types? votes: 9, answers: 2 Read on SO: [33] http://goo.gl/FNSZg * How to “change” single values in large objects in elegant way? votes: 9, answers: 1 Read on SO: [34] http://goo.gl/3KuJj * What programming languages have something like Haskell’s `newtype` votes: 9, answers: 4 Read on SO: [35] http://goo.gl/vzUAI * Implementing a zipper for length-indexed lists votes: 8, answers: 1 Read on SO: [36] http://goo.gl/ja6VS * Does Haskell concatenate String literals at compile time? votes: 8, answers: 4 Read on SO: [37] http://goo.gl/sr61q * Combining lenses votes: 8, answers: 2 Read on SO: [38] http://goo.gl/qEbPd Until next time, [38]+Daniel Santa Cruz References 1. http://www.joachim-breitner.de/blog/archives/600-On-taking-the-last-n-eleme… 2. http://www.reddit.com/r/haskell/comments/1i64mt/on_taking_the_last_n_elemen… 3. http://gelisam.blogspot.ca/2013/07/comonads-are-neighbourhoods-not-objects.… 4. http://www.reddit.com/r/haskell/comments/1hficb/comonads_are_not_objects/ 5. http://hackage.haskell.org/package/haste-compiler 6. http://www.reddit.com/r/haskell/comments/1htqi2/announce_haste_the_haskell_… 7. http://www.arcadianvisions.com/blog/?p=388 8. http://www.reddit.com/r/haskell/comments/1hhrfn/postmodern_haskell_and_open… 9. http://projects.haskell.org/pipermail/haskellmode-emacs/2013-June/000188.ht… 10. http://www.reddit.com/r/haskell/comments/1hd21v/announce_haskellmode_1307_s… 11. http://www.devalot.com/articles/2013/07/why-haskell.html 12. http://www.reddit.com/r/haskell/comments/1hzz2d/why_the_world_needs_haskell/ 13. http://ro-che.info/ccc/20.html 14. http://www.reddit.com/r/haskell/comments/1i8e6v/cartesian_closed_comic_20_w… 15. http://www.reddit.com/r/haskell/comments/1i0uiq/do_naming_practices_hurt_ha… 16. http://www.reddit.com/r/haskell/comments/1i0uiq/do_naming_practices_hurt_ha… 17. http://www.reddit.com/r/haskell/comments/1i2a9l/announce_httphackagehaskell… 18. http://www.reddit.com/r/haskell/comments/1i2a9l/announce_httphackagehaskell… 19. http://skillsmatter.com/podcast/home/lazy-io-and-alternatives-in-haskell/jd… 20. http://www.reddit.com/r/haskell/comments/1i438a/skills_matter_in_the_brain_… 21. https://www.fpcomplete.com/school/attoparsec 22. http://www.reddit.com/r/haskell/comments/1hkg3g/attoparsec_tutorial_school_… 23. https://www.fpcomplete.com/blog/2013/06/fp-haskell-center-beta-announcement 24. http://www.reddit.com/r/haskell/comments/1hfbgs/fp_haskell_center_beta_rele… 25. http://stackoverflow.com/questions/17409260/what-advantage-does-monad-give-… 26. http://stackoverflow.com/questions/17578728/encoding-less-than-with-haskell 27. http://stackoverflow.com/questions/17584630/why-is-factorial-calculation-mu… 28. http://stackoverflow.com/questions/17398784/haskell-can-typeclasses-define-… 29. http://stackoverflow.com/questions/17412348/c-and-haskell-codes-differs-in-… 30. http://stackoverflow.com/questions/17502603/ghc-generics-or-data-data 31. http://stackoverflow.com/questions/17502985/constraint-subset-higher-order-… 32. http://stackoverflow.com/questions/17503131/how-to-make-catamorphisms-work-… 33. http://stackoverflow.com/questions/17518749/how-to-change-single-values-in-… 34. http://stackoverflow.com/questions/17591276/what-programming-languages-have… 35. http://stackoverflow.com/questions/17501777/implementing-a-zipper-for-lengt… 36. http://stackoverflow.com/questions/17513273/does-haskell-concatenate-string… 37. http://stackoverflow.com/questions/17528119/combining-lenses 38. https://plus.google.com/105107667630152149014/about

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ANNOUNCE: Aivika v0.6, Aivika Experiment v0.3, Aivika Experiment Chart v0.3
by David Sorokin 17 Jul '13

17 Jul '13

Hi! I’m glad to announce new versions of the Aivika [1] simulation library and its additional packages Aivika Experiment [2] and Aivika Experiment Chart [3]. The library is divided to decrease the dependency on GTK, although all three were tested on Linux, Windows and OS X. They allow developing the wide range of simulation models (SD, DES, AM), simulating them and saving the results in form of charts, tables and so on, automating many routine procedures. The architecture is quite flexible. This is a result of my 4-years work since 2009. I finally find the library a quite mature. Among many languages I tried, Haskell was the most suitable. Many simulation concepts can be naturally expressed in terms of Haskell. Many technical details are hidden either under the façade of monads, or similar structures. So, the ordinary differential equations can be elegantly defined using the recursive do-notation. But the discontinuous processes are well expressed using the continuations, if more precisely, three continuations in one computation. I prepared a 55-page PDF document An Introduction to Aivika Simulation Library [4]. For demonstration, it contains some charts prepared with help of Aivika Experiment Chart. There are the deviation charts and histograms. Thanks, David [1] http://hackage.haskell.org/package/aivika [2] http://hackage.haskell.org/package/aivika-experiment [3] http://hackage.haskell.org/package/aivika-experiment-chart [4] https://github.com/dsorokin/aivika/blob/master/doc/aivika.pdf

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Quoting with template haskell
by Jose A. Lopes 17 Jul '13

17 Jul '13

Hi everyone, I am quite new to template haskell and I am still trying to get the hang of it. How can I achieve something like the following Common Lisp code ? `(,fn ,arg1 ,arg2) Or is there a more Haskelley way of doing this ? Cheers, Jose

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Call for Papers PEPM 2014
by publicityifl＠gmail.com 17 Jul '13

17 Jul '13

Hello, Please, find below the first call for papers for PEPM 2014. Please forward these to anyone you think may be interested. Apologies for any duplicates you may receive. best regards, Jurriaan Hage Co-chair of PEPM 2014 ----------------------------- C A L L F O R P A P E R S ----------------------------- ======= PEPM 2014 =========== ACM SIGPLAN 2014 WORKSHOP ON PARTIAL EVALUATION AND PROGRAM MANIPULATION Mon-Tue, January 20-21, 2014 San Diego, California, USA co-located with POPL'14 Sponsored by ACM SIGPLAN http://www.program-transformation.org/PEPM14 SCOPE The PEPM Symposium/Workshop series aims at bringing together researchers and practitioners working in the areas of program manipulation, partial evaluation, and program generation. PEPM focuses on techniques, theory, tools, and applications of analysis and manipulation of programs. The 2014 PEPM workshop will be based on a broad interpretation of semantics-based program manipulation and continue last years' successful effort to expand the scope of PEPM significantly beyond the traditionally covered areas of partial evaluation and specialization and include practical applications of program transformations such as refactoring tools, and practical implementation techniques such as rule-based transformation systems. In addition, the scope of PEPM covers manipulation and transformations of program and system representations such as structural and semantic models that occur in the context of model-driven development. In order to reach out to practitioners, a separate category of tool demonstration papers will be solicited. Topics of interest for PEPM'14 include, but are not limited to: Program and model manipulation techniques such as: supercompilation, partial evaluation, fusion, on-the-fly program adaptation, active libraries, program inversion, slicing, symbolic execution, refactoring, decompilation, and obfuscation. Program analysis techniques that are used to drive program/model manipulation such as: abstract interpretation, termination checking, binding-time analysis, constraint solving, type systems, automated testing and test case generation. Techniques that treat programs/models as data objects including metaprogramming, generative programming, embedded domain-specific languages, program synthesis by sketching and inductive programming, staged computation, and model-driven program generation and transformation. Application of the above techniques including case studies of program manipulation in real-world (industrial, open-source) projects and software development processes, descriptions of robust tools capable of effectively handling realistic applications, benchmarking. Examples of application domains include legacy program understanding and transformation, DSL implementations, visual languages and end-user programming, scientific computing, middleware frameworks and infrastructure needed for distributed and web-based applications, resource-limited computation, and security. To maintain the dynamic and interactive nature of PEPM, we will continue the category of `short papers' for tool demonstrations and for presentations of exciting if not fully polished research, and of interesting academic, industrial and open-source applications that are new or unfamiliar. Student attendants with accepted papers can apply for a SIGPLAN PAC grant to help cover travel expenses and other support. PAC also offers other support, such as for child-care expenses during the meeting or for travel costs for companions of SIGPLAN members with physical disabilities, as well as for travel from locations outside of North America and Europe. For details on the PAC programme, see its web page. All accepted papers, short papers included, will appear in formal proceedings published by ACM Press. In addition to printed proceedings, accepted papers will be included in the ACM Digital Library. A special issue for Science of Computer Programming is planned with recommended papers from PEPM'14. PEPM has also established a Best Paper award. The winner will be announced at the workshop. SUBMISSION CATEGORIES AND GUIDELINES Regular Research Papers must not exceed 12 pages in ACM Proceedings style (including appendix). Tool demonstration papers and short papers must not exceed 6 pages in ACM Proceedings style (including appendix). At least one author of each accepted contribution must attend the workshop and present the work. In the case of tool demonstration papers, a live demonstration of the described tool is expected. Suggested topics, evaluation criteria, and writing guidelines for both research tool demonstration papers will be made available on the PEPM'14 Web-site. Papers should be submitted electronically via the workshop web site. Authors using LaTeX to prepare their submissions should use the new improved SIGPLAN proceedings style (sigplanconf.cls, 9pt template). IMPORTANT DATES Abstract due: Sat, September 28, 2013 Paper submission: Sat, October 5, 2013, 23:59, GMT Author notification: Mon, November 11, 2013 Camera-ready papers due: * to be announced * INVITED SPEAKERS to be announced PROGRAM CHAIRS Wei Ngan Chin (National University of Singapore, Singapore) Jurriaan Hage (Utrecht University, Netherlands) PROGRAM COMMITTEE velyne Contejean (LRI, CNRS, Universit Paris-Sud, France) Cristina David (University of Oxford, UK) Alain Frisch (LexiFi, France) Ronald Garcia (University of British Columbia, Canada) Zhenjiang Hu (National Institute of Informatics, Japan) Paul H J Kelly (Imperial College, UK) Oleg Kiselyov (Monterey, USA) Naoki Kobayashi (University of Tokyo, Japan) Jens Krinke (University College London, UK) Ryan Newton (University of Indiana, USA) Alberto Pardo (Universidad de la Repblica, Uruguay) Sungwoo Park (Pohang University of Science and Technology, South Korea) Tiark Rompf (Oracle Labs & EPFL, Switzerland) Sukyoung Ryu (KAIST, South Korea) Kostis Sagonas (Uppsala University, Sweden) Max Schaefer (Nanyang Technological University, Singapore) Harald S¿ndergaard (The University of Melbourne, Australia) Eijiro Sumii (Tohoku University, Japan) Eric Van Wyk (University of Minnesota, USA) Jeremy Yallop (University of Cambridge, UK)

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ANNOUNCE: module-management-0.9.3 - clean import lists, split and merge modules
by David Fox 16 Jul '13

16 Jul '13

I am pleased to announce the first release of module-management, a package for cleaning import lists, and splitting and merging modules. You can see a description at the top of the documentation for Language.Haskell.Modules (once it appears) here: http://hackage.haskell.org/package/module-management It is worth noting that the split and merge operations cause global changes to the module tree, all the modules that import the split or merged modules get their import lists adjusted. For this reason, before these operations can run the caller needs to specify the "moduVerse", the set of modules to scan for import changes. A number of bugs in GHC's -ddump-minimal-imports feature cropped up while I was writing this, and when the fixes for these issues make it into the compiler things will work a bit more smoothly, particularly if you are using NoImplicitPrelude or type families. http://hackage.haskell.org/trac/ghc/ticket/7963 http://hackage.haskell.org/trac/ghc/ticket/7969 http://hackage.haskell.org/trac/ghc/ticket/8000 http://hackage.haskell.org/trac/ghc/ticket/8011 There are workarounds for 7963 and 7969. Not surprisingly, template haskell can cause problems, but frequently it does not. CPP directives do not work. I hope you find this useful - all feedback is welcome! -david

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FP Complete Accepting Submissions for Haskell Competition
by Natalia Muska 16 Jul '13

16 Jul '13

We are excited to share we are accepting submissions for our *FP Haskell Competition<https://www.fpcomplete.com/business/competition/competition-overview> *. Your code and tutorials can earn you $1,000 in cash prizes each month. We're looking for sample Haskell projects that solve specific real-world engineering and business problems. There is no limit to how many projects you can submit or how many times you can win. - $1,000 cash prize for the winning entry each month - $500 each to the 3 runners-ups - There may be none at all if none meet the winning criteria The contest kicks off August 1, 2013. To participate, you'll need to sign up for our FP Haskell Center Beta<https://www.fpcomplete.com/business/haskell-center/overview>. We look forward to seeing your submissions and highlighting the talent of this great Haskell community. if you have any questions, please contact us at competition(a)fpcomplete.com. -- Natalia Muska Marketing Manager FP Complete, Inc. Natalia(a)fpcomplete.com 865-506-6513 skype: natalia.s.muska

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TH splicing and recompilation checking
by Johannes Waldmann 16 Jul '13

16 Jul '13

Hi. we are using template Haskell to splice in some code that is produced by reading and transforming the contents of another file. now, if this "other file" is touched (by editing), but not the main file, then ghc (and cabal) do not realize that the main file does need to be recompiled. is there a way to tell them about the dependency? (example main file: https://github.com/apunktbau/co4/blob/master/CO4/Test/Queens.hs) - J.W.

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Call for Papers IFL 2013
by publicityifl＠gmail.com 16 Jul '13

16 Jul '13

Hello, Please, find below the third call for papers for IFL 2013. Please forward these to anyone you think may be interested. Apologies for any duplicates you may receive. best regards, Jurriaan Hage Publicity Chair of IFL CALL FOR PAPERS 25th SYMPOSIUM ON IMPLEMENTATION AND APPLICATION OF FUNCTIONAL LANGUAGES - IFL 2013 RADBOUD UNIVERSITY NIJMEGEN, THE NETHERLANDS ACM In-Cooperation / ACM SIGPLAN AUGUST 28 - 30 2013 "Landgoed Holthurnsche Hof" http://ifl2013.cs.ru.nl We are proud to announce that the 25th edition of the IFL series returns to its roots at the Radboud University Nijmegen in the Netherlands. The symposium is held from 28th to 30th of August 2013. Scope ----- The goal of the IFL symposia is to bring together researchers actively engaged in the implementation and application of functional and function-based programming languages. IFL 2013 will be a venue for researchers to present and discuss new ideas and concepts, work in progress, and publication-ripe results related to the implementation and application of functional languages and function-based programming. Following the IFL tradition, IFL 2013 will use a post-symposium review process to produce the formal proceedings which will be published in the ACM Digital Library. All participants of IFL 2013 are invited to submit either a draft paper or an extended abstract describing work to be presented at the symposium. At no time may work submitted to IFL be simultaneously submitted to other venues; submissions must adhere to ACM SIGPLAN's republication policy: http://www.sigplan.org/Resources/Policies/Republication The submissions will be screened by the program committee chair to make sure they are within the scope of IFL, and will appear in the draft proceedings distributed at the symposium. Submissions appearing in the draft proceedings are not peer-reviewed publications. Hence, publications that appear only in the draft proceedings do not count as publication for the ACM SIGPLAN republication policy. After the symposium, authors will be given the opportunity to incorporate the feedback from discussions at the symposium and will be invited to submit a revised full article for the formal review process. From the revised submissions, the program committee will select papers for the formal proceedings considering their correctness, novelty, originality, relevance, significance, and clarity. Invited Speaker --------------- Lennart Augustsson, currently employed by the Standard Chartered Bank, well-known for his work on Haskell, parallel Haskell, Cayenne, and Bluespec, is the invited speaker of IFL 2013. He will be talking about practical applications of functional programming. Submission Details ------------------ Submission deadline draft papers: July 31 Notification of acceptance for presentation: August 2 Early registration deadline: August 7 Late registration deadline: August 14 Submission deadline for pre-symposium proceedings: August 21 25th IFL Symposium: August 28-30 Submission deadline for post-symposium proceedings: November 11 Notification of acceptance for post-symposium proceedings: December 18 Camera-ready version for post-symposium proceedings: February 3 2014 Prospective authors are encouraged to submit papers or extended abstracts to be published in the draft proceedings and to present them at the symposium. All contributions must be written in English. Papers must adhere to the standard ACM two columns conference format. For the pre-symposium proceedings we adopt a 'weak' page limit of 12 pages. For the post-symposium proceedings the page limit of 12 pages is firm. A suitable document template for LaTeX can be found at: http://www.acm.org/sigs/sigplan/authorInformation.htm Papers are to be submitted via the conference's EasyChair submission page: https://www.easychair.org/conferences/?conf=ifl2013 Topics ------ IFL welcomes submissions describing practical and theoretical work as well as submissions describing applications and tools in the context of functional programming. If you are not sure whether your work is appropriate for IFL 2013, please contact the PC chair at rinus(a)cs.ru.nl. Topics of interest include, but are not limited to: - language concepts - type systems, type checking, type inferencing - compilation techniques - staged compilation - run-time function specialization - run-time code generation - partial evaluation - (abstract) interpretation - metaprogramming - generic programming - automatic program generation - array processing - concurrent/parallel programming - concurrent/parallel program execution - embedded systems - web applications - (embedded) domain specific languages - security - novel memory management techniques - run-time profiling performance measurements - debugging and tracing - virtual/abstract machine architectures - validation, verification of functional programs - tools and programming techniques - (industrial) applications Peter Landin Prize ------------------ The Peter Landin Prize is awarded to the best paper presented at the symposium every year. The honoured article is selected by the program committee based on the submissions received for the formal review process. The prize carries a cash award equivalent to 150 Euros. Programme committee ------------------- - Thomas Arts, Quviq, Gothenburg, Sweden - Andrew Butterfield, Trinity College, Dublin, Ireland - Edwin Brady, University of St. Andrews, UK - Clemens Grelck, University of Amsterdam, Netherlands - Adam Granicz, IntelliFactory, Budapest, Hungary - Jeremy Gibbons, University of Oxford, UK - Fritz Henglein, University of Copenhagen, Denmark - Stephan Herhut, Intel Labs, Santa Clara, US - Ralf Hinze (co-chair), University of Oxford, UK - Zoltan Horvath, Eotvos Lorand University, Budapest, Hungary - Zhenjiang Hu, University of Tokyo, Japan - Mauro Jaskelioff, Universidad Nacional de Rosario, Argentina - Johan Jeuring, University of Utrecht, Netherlands - Rita Loogen, University of Marburg, Germany - Marco T. Morazan, Seton Hall University, New Jersey, US - Dominic Orchard, University of Cambridge, UK - Rinus Plasmeijer (chair), Radboud University Nijmegen, Netherlands - Tim Sheard, Portland State University, US - Sam Tobin-Hochstadt, Northeastern University / Indiana University, US - Peter Thiemann, University of Freiburg, Germany - Simon Thompson, University of Kent, UK Venue ----- The 25th IFL is organized by the Radboud University Nijmegen, Model Based Software Development Department at the Nijmegen Institute for Computing and Information Sciences. The event is held in the Landgoed Holthurnsche Hof, a rural estate in the woodlands surrounding Nijmegen. It can be reached quickly and easily by public transport.

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What does it mean to derive "equations of restricted from" in Haskell?
by Daryoush Mehrtash 16 Jul '13

16 Jul '13

In John Hughes's "The Design of Pretty printing library" paper, he says: "The implementations which we are trying to derive consist of equations of > a restricted form. We will derive implementations by proving their > constituent equations from the specification. By itself this is no > guarantee that the implemented functions satisfy the specification because > we might not have proved enough equation But if we also check that the > derived definitions are terminating and exhaustive then this property is > guaranteed" What does "restricted form" mean? What is the meaning and significance of "definitions are terminating and exhaustive"? -- Daryoush Weblog: http://onfp.blogspot.com/

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