- Haskell-Cafe - Haskell.org

Re: [Haskell-cafe] Proposal: Professionalizing GHC Development
by Doug McIlroy 05 Apr '18

05 Apr '18

Gershom, An emergent team-building solution (with or without an enabling blockchain protection ring) is all very well, but is it monadic? Doug

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DataHaskell User Survey
by Marco Zocca 05 Apr '18

05 Apr '18

Dear all, the community around datahaskell.org has been slowly but steadily growing since its inception in 2016, and with it the diversity of its members. Its mission is to provide a home for data science and numerical computation students and practitioners who would like to use Haskell in their work and explorations. In order to best represent and serve the community, we'd like to know it in the first place, which is why we have prepared this little questionnaire (10 questions, which should take around 5 minutes to complete): https://www.surveymonkey.com/r/3FBBJWR No personal data are required and the results will only be published in aggregate form at a later stage. The raw data will only be stored and used for producing the aggregate report, after which it will be deleted. Thank you in advance for your time; Best, Marco Zocca github.com/ocramz hackage.haskell.org/user/ocramz

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[Haskell, FP] Anduril Industries is Hiring
by Travis Whitaker 05 Apr '18

05 Apr '18

Anduril Industries (https://www.anduril.com) is hiring. TL;DR: Come write Haskell, Rust, and Nix (and some C++ when necessary) to make autonomous robots and drones go! We're a team of software and hardware engineers from various backgrounds (game development, computer graphics, financial technology, government intelligence, biotechnology) working to improve the state of defense technology. Our strategy involves focusing on product development instead of traditional governmental processes. By funding product development ourselves instead of relying on government funds, we're able to create more focused products faster and with significantly fewer resources. By leveraging hardware and techniques that have only recently become feasible to deploy at scale (e.g. GPGPU computing), we can significantly advance the state of the defense technology market. We're searching for generally competent, mathematically inclined software engineers, and we're especially interested in those with experience in computer vision (first principles techniques and machine learning), sensor fusion, detection and tracking, and statistical parameter estimation. Our team is increasingly applying functional programming and related technologies; we run Haskell and Rust code in production and use Nix to achieve reproducible build environments and keep deployment, CI, and cross-compilation sane. If you like functional programming, interfacing with hardware, and solving problems in detection, tracking, and autonomous vehicle control (land and air), drop me a line at travis(a)anduril.com

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[ANN] Darcs 2.14.0 release
by Guillaume Hoffmann 04 Apr '18

04 Apr '18

Hi all, The Darcs team is pleased to announce the release of Darcs 2.14.0! Darcs is a free, open source revision control system. It is: * Distributed: Every user has access to the full command set, removing boundaries between server and client or committer and non-committers. * Interactive: Darcs is easy to learn and efficient to use because it asks you questions in response to simple commands, giving you choices in your work flow. You can choose to record one change in a file, while ignoring another. As you update from upstream, you can review each patch name, even the full "diff" for interesting patches. * Smart: Originally developed by physicist David Roundy, darcs is based on a unique algebra of patches. Learn more about Darcs on http://darcs.net . # Supported GHC and Cabal versions Darcs 2.14 can be compiled with GHC 8.0, 8.2 and 8.4, and supports Cabal versions from 1.24. # Windows issues Darcs 2.14 received many updates in its support of encoding. However, it may still contain bugs, especially under Windows, a platform for which we have fewer known users. Please let us know if you encounter weird behaviour under Windows. # What's new # ## User Interface ## - fix encoding business, make DARCS_DONT_ESCAPE_8BIT=1 default (Ben Franksen, Ganesh Sittampalam) - show explicit dependencies in `darcs log -s` (Gian Piero Carrubba) - improve bash/zsh completion (Ben, Gian Piero) - no longer print an error message when ctrlc'ing pager (Guillaume Hoffmann) - `darcs help markdown` mentions all files in `_darcs/prefs/` (Guillaume) - add patch index status to `show repo` command (Ben) ## New features ## - per-file conflict marking (Ben) - make it possible to use DARCS_SCP=rsync (Ben) - add --not-in-remote option to unrecord command (Ben) ## Performance ## - plug memory leak and improve efficiency in annotate (Ben) - save unneeded FL/RL reverses in SelectChanges module (Ben) - optimize token replace code and --look-for-replaces (Ben) - no longer show conflicting files on `whatsnew -s`, will reintrodue this feature when it is done efficiently (Guillaume) ## Developer-related ## - separate display and storage of patches (Ben) - support GHC 8.2 and GHC 8.4 (Ganesh) - many refactorings in Darcs.Repository modules and API (Ben, Guillaume) - no longer track build dependencies in Setup.hs, nor use alpha, beta, rc names (Guillaume) - refactor `pull --reorder-patches` (Ben) - refactor SelectChanges (Ben) - remove Patchy typeclass and redundant constaints where possible (Guillaume) - fix build with cabal new-build (Francesco Ariis) - unit and quickcheck tests for inventories (Ben) - throw out all access to bytestring internals from Darcs.Util.ByteString (Ben) - refactor, simplify, and document hunk application (Ben) - drop support of old cache location and SHA1-hashed repos (Guillaume) - rely on GHC's own stack traces for bug reporting (Guillaume) ## Issues resolved in Darcs 2.14 ## - fix mail encoding with '.' or '=' as last character (Timo von Holtz) - issue2526: whatsnew -l --boring should list boring files (Ben) - issue2208: replace detects existing force hunks in working (Ben) - issue2512: author name is written to repository after multiple-choice prompt (Stephan-A. Posselt) - issue2359: convert --export mishandles Unicode filenames (Ben) - issue2545: prevent argument smuggling in SSH repository URLs (Gian Piero) - issue2581: fix rebase pull --reorder (Ben) - issue2575: fix unrevert with rebase (Ben) - issue2579: allow darcs send to work even if no MTA is installed - issue2555: include explicit dependencies in the output of `log -v` (Gian Piero) - issue2569: decoding multibyte characters (Ben) - issue2563: create remote repo in correct format in ssh tests (Ben) - issue2565: create _darcs dir after searching for an existing one (Ben) - issue2567: darcs whatsnew --unified (Ben) - issue2566: avoid renaming across file systems (Ben) - issue2564: delete wrong and irrelevant propConcatPS (Guillaume) - issue2559: remove trailing empty lines in patch header edition (Guillaume) - issue2536: mask out internal matchers in `show files` routing logic (Gian Piero)

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ThEdu'18: Second Call for Extended Abstracts & Demonstrations
by Achim D. Brucker 04 Apr '18

04 Apr '18

(Apologies for duplicates) 2nd Call for Extended Abstracts & Demonstrations ************************************************************************** ThEdu'18 Theorem proving components for Educational software 18 July 2018 http://www.uc.pt/en/congressos/thedu/thedu18 ************************************************************************** affiliated to IJCAR 2018 July 14-17, 2018 Oxford, United Kingdom http://www.ijcar2018.org/ (part of FLoC 2018) ************************************************************************** THedu'18 Scope: Computer Theorem Proving is becoming a paradigm as well as a technological base for a new generation of educational software in science, technology, engineering and mathematics. The workshop brings together experts in automated deduction with experts in education in order to further clarify the shape of the new software generation and to discuss existing systems. Invited Talk Julien Narboux, University of Strasbourg, France Important Dates * Extended Abstracts: 15th April 2018 * Author Notification: 15th May 2018 * Workshop Day: 18 July 2018 Topics of interest include: * methods of automated deduction applied to checking students' input; * methods of automated deduction applied to prove post-conditions for particular problem solutions; * combinations of deduction and computation enabling systems to propose next steps; * automated provers specific for dynamic geometry systems; * proof and proving in mathematics education. Submission We welcome submission of extended abstracts and demonstration proposals presenting original unpublished work which is not been submitted for publication elsewhere. All accepted extended abstracts and demonstrations will be presented at the workshop. The extended abstracts will be made available online. Extended abstracts and demonstration proposals should be submitted via easychair, https://easychair.org/conferences/?conf=thedu18 formatted according to http://www.easychair.org/publications/easychair.zip Extended abstracts and demonstration proposals should be approximately 5 pages in length and are to be submitted in PDF format. At least one author of each accepted extended abstract/demonstration proposal is expected to attend THedu'18 and presents his/her extended abstract/demonstration. Program Committee Francisco Botana, University of Vigo at Pontevedra, Spain Roman Hašek, University of South Bohemia, Czech Republic Filip Maric, University of Belgrade, Serbia Walther Neuper, Graz University of Technology, Austria (co-chair) Pavel Pech, University of South Bohemia, Czech Republic Pedro Quaresma, University of Coimbra, Portugal (co-chair) Vanda Santos, CISUC, Portugal Wolfgang Schreiner, Johannes Kepler University, Austria Burkhart Wolff, University Paris-Sud, France Proceedings The extended abstracts and system descriptions will be available in ThEdu'18 Web-page. After presentation at the conference, selected authors will be invited to submit a substantially revised version, extended to 14--20 pages, for publication by the Electronic Proceedings in Theoretical Computer Science (EPTCS). -- Dr. Achim D. Brucker | Software Assurance & Security | University of Sheffield https://www.brucker.ch | https://logicalhacking.com/blog @adbrucker | @logicalhacking

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Where are rank-3 types necessary in practice for maintaining abstraction?
by Timotej Tomandl 04 Apr '18

04 Apr '18

Hello, So we need rank-2 type in runST :: (forall s. ST <https://hackage.haskell.org/package/base-4.11.0.0/docs/Control-Monad-ST.htm…> s a) -> a, to prevent s from appearing in a. I have been thinking about this for a bit, but I failed to come up with a practical situation, where rank-3 types are necessary for safety of some abstraction. The rank-3 example in here and any other I found, look very synthetic, i.e. limiting computation to id: https://ocharles.org.uk/blog/guest-posts/2014-12-18-rank-n-types.html and compared to the runST example of limiting a scope of a type variable for purposes of safety looks unnatural. Could anyone please point me to a practical example of rank-3 polymorphism, where it is necessary for safety of an abstraction, if it exists? I suspect there is a situation, where rank-3 is necessary for maintaining abstration exists, but I can't think of any. Any ideas about such situations and even better situations where this is used on hackage? Timotej Tomandl

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Database of real faults
by Gabriela Araujo Britto 03 Apr '18

03 Apr '18

Hi, I'd like to know if there exists a database of reproducible real faults in Haskell software, along the lines of defects4j (https://github.com/rjust/ defects4j/), or a related initiative. My intention is to use this for research in mutation testing. Thank you, Gabriela

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2nd CfP: IFL 2018 (30th Symposium on Implementation and Application of Functional Languages)
by Jurriaan Hage 03 Apr '18

03 Apr '18

Hello, Please, find below the second call for papers for IFL 2018. 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 --- ================================================================================ IFL 2018 30th Symposium on Implementation and Application of Functional Languages University of Massachusetts Lowell, MA, USA September 5th-7th, 2018 http://iflconference.org ================================================================================ ### 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 2018 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. Topics of interest to IFL 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 ### Keynote Speakers * Adam Chlipala, Massachusetts Institute of Technology CSAIL * Arjun Guha, University of Massachusetts Amherst ### Submissions and peer-review Differently from previous editions of IFL, IFL 2018 solicits two kinds of submissions: * Regular papers (12 pages including references) * Draft papers for presentations ('weak' limit between 8 and 15 pages) Regular papers will undergo a rigorous review by the program committee, and will be evaluated according to their correctness, novelty, originality, relevance, significance, and clarity. A set of regular papers will be conditionally accepted for publication. Authors of conditionally accepted papers will be provided with committee reviews along with a set of mandatory revisions. Regular papers not accepted for publication will be considered as draft papers, at the request of the author. Draft papers will be screened to make sure that they are within the scope of IFL, and will be accepted for presentation or rejected accordingly. Prior to the symposium: Authors of conditionally accepted papers and accepted presentations will submit a pre-proceedings version of their work that will appear in the draft proceedings distributed at the symposium. The draft proceedings does not constitute a formal publication. We require that at least one of the authors present the work at IFL 2018. After the symposium: Authors of conditionally accepted papers will submit a revised versions of their paper for the formal post-proceedings. The program committee will assess whether the mandatory revisions have been adequately addressed by the authors and thereby determines the final accept/reject status of the paper. Our interest is to ultimately accept all conditionally accepted papers. If you are an author of a conditionally accepted paper, please make sure that you address all the concerns of the reviewers. Authors of accepted presentations 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 post-proceedings. The program committee will evaluate these submissions according to their correctness, novelty, originality, relevance, significance, and clarity, and will thereby determine whether the paper is accepted or rejected. ### Publication The formal proceedings will appear in the International Conference Proceedings Series of the ACM Digital Library. 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 ### Important dates Submission of regular papers: May 25, 2018 Submission of draft papers: July 17, 2018 Regular and draft papers notification: July 20, 2018 Deadline for early registration: August 8, 2018 Submission of pre-proceedings version: August 29, 2018 IFL Symposium: September 5-7, 2018 Submission of papers for post-proceedings: November 7, 2018 Notification of acceptance: December 22, 2018 Camera-ready version: February 10, 2019 ### Submission details All contributions must be written in English. Papers must use the ACM two columns conference format, which can be found at: http://www.acm.org/publications/proceedings-template Authors submit through EasyChair: https://easychair.org/conferences/?conf=ifl2018 ### Peter Landin Prize The Peter Landin Prize is awarded to the best paper presented at the symposium every year. The honored 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. ### Organization and Program committee Chairs: Jay McCarthy & Matteo Cimini, University of Massachusetts Lowell, USA Program Committee: * Arthur Chargueraud, Inria, FR * Ben Delaware, Purdue University, USA * Christos Dimoulas, Northwestern University, USA * David Darais, University of Vermont, USA * Dominic Orchard, University of Kent, UK * Ekaterina Komendantskaya, Heriot-Watt University, UK * Garrett Morris, University of Kansas, USA * Heather Miller, EPFL & Northeastern University, CH & USA * Jeremy Yallop, University of Cambridge, UK * Keiko Nakata, SAP Innovation Center Potsdam, DE * Laura Castro, University of A Coruna, ESP * Magnus Myreen, Chalmers University of Technology, SWE * Natalia Chechina, Bournemouth University, UK * Peter Achten, Radboud Universiteit Nijmegen, NL * Peter-Michael Osera, Grinnell College, USA * Richard Eisenberg, Bryn Mawr College, USA * Trevor McDonell, University of New South Wales, AUS * Yukiyoshi Kameyama, University of Tsukuba, JAP ### Venue The 30th IFL is organized by the University of Massachusetts Lowell. The City of Lowell is located at the heart of the Merrimack Valley just 30 miles northwest of Boston. Lowell can be easily reached by train or taxi. See the website for more information on the venue. ### Acknowledgments This call-for-papers is an adaptation and evolution of content from previous instances of IFL. We are grateful to prior organizers for their work, which is reused here. A part of IFL 2018 format and CFP language that describes conditionally accepted papers has been adapted from call-for-papers of OOPSLA conferences.

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WST 2018 - 2nd Call for Papers (submission: April 15, 2018)
by Salvador Lucas 03 Apr '18

03 Apr '18

========================================================================== WST 2018 - Call for Papers 16th International Workshop on Termination July 18-19, 2017, Oxford, United Kingdom http://wst2018.webs.upv.es/ ========================================================================== The Workshop on Termination (WST) traditionally brings together, in an informal setting, researchers interested in all aspects of termination, whether this interest be practical or theoretical, primary or derived. The workshop also provides a ground for cross-fertilization of ideas from the different communities interested in termination (e.g., working on computational mechanisms, programming languages, software engineering, constraint solving, etc.). The friendly atmosphere enables fruitful exchanges leading to joint research and subsequent publications. The workshop is held as part of the 2018 Federated Logic Conference (FLoC 2018) http://www.floc2018.org/ IMPORTANT DATES: * submission deadline: April 15, 2018 * notification: May 15, 2018 * final version due: May 31, 2018 * workshop: July 18-19, 2018 TOPICS: The 16th International Workshop on Termination welcomes contributions on all aspects of termination. In particular, papers investigating applications of termination (for example in complexity analysis, program analysis and transformation, theorem proving, program correctness, modeling computational systems, etc.) are very welcome. Topics of interest include (but are not limited to): * abstraction methods in termination analysis * certification of termination and complexity proofs * challenging termination problems * comparison and classification of termination methods * complexity analysis in any domain * implementation of termination methods * non-termination analysis and loop detection * normalization and infinitary normalization * operational termination of logic-based systems * ordinal notation and subrecursive hierarchies * SAT, SMT, and constraint solving for (non-)termination analysis * scalability and modularity of termination methods * termination analysis in any domain (lambda calculus, declarative programming, rewriting, transition systems, etc.) * well-founded relations and well-quasi-orders COMPETITION: Since 2003, the catalytic effect of WST to stimulate new research on termination has been enhanced by the celebration of the Termination Competition and its continuously developing problem databases containing thousands of programs as challenges for termination analysis in different categories, see http://termination-portal.org/wiki/Termination_Competition In 2018, the Termination Competition will run in parallel with FLoC 2018. More details will be provided in a dedicated announcement on the competition. PROGRAM COMMITTEE: Cristina Borralleras - U. de Vic Ugo Dal Lago - U. degli Studi di Bologna Carsten Fuhs - Birkbeck, U. of London Samir Genaim - U. Complutense de Madrid Juergen Giesl - RWTH Aachen Raul Gutiérrez - U. Politecnica de València Keiichirou Kusakari - Gifu University Salvador Lucas (chair) - U. Politecnica de Valencia Fred Mesnard - U. de La Reunion Aart Middeldorp - U. of Innsbruck Albert Rubio - U. Politecnica de Catalunya Rene Thiemann - U. of Innsbruck Caterina Urban - ETH Zürich INVITED SPEAKERS: tba SUBMISSION: Submissions are short papers/extended abstracts which should not exceed 5 pages. There will be no formal reviewing. In particular, we welcome short versions of recently published articles and papers submitted elsewhere. The program committee checks relevance and provides additional feedback for each submission. The accepted papers will be made available electronically before the workshop. Papers should be submitted electronically via the submission page: https://easychair.org/conferences/?conf=wst2018 Please, use LaTeX and the LIPIcs style file http://drops.dagstuhl.de/styles/lipics/lipics-authors.tgz to prepare your submission.

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vector-sized: (//) Finites to Ints?
by David Banas 03 Apr '18

03 Apr '18

When did the vector-sized (//) operator change from expecting Finites to expecting Ints?

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[ANNOUNCE] GHC 8.4.2-rc1 now available
by Ben Gamari 02 Apr '18

02 Apr '18

Hello everyone, The GHC team is proud to announce the first release candidate of 8.4.2. the source distribution, binary distributions, and documentation are available at https://downloads.haskell.org/~ghc/8.4.2-rc1 This release follows so closely to 8.4.1 due to a number last-minute bug-fixes that didn't quite make it into 8.4.1. This includes fixes for: * #14705, the interpreter being broken on some systems * #14779, where the compiler produces invalid code when used with -g * #14891, where a selection of GHC testsuite cases fail on OS X * #5129, where the simplifier would incorrectly reorder evaluation in under some conditions. Since this is a relatively small bugfix release we are bypassing the alpha releases and moving right to the release candidate stage. If all goes well the final release will be cut next week. Happy testing Cheers, - Ben

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Architecture for reflex based applications
by Robert Klotzner 02 Apr '18

02 Apr '18

Hi there! I did a little write up about structuring reflex applications, which seems to work out really well for me. Check it out here: https://github.com/gonimo/gonimo/blob/master/front/doc/Gonimo-Architecture.… I would love to hear your thoughts! Best regards, Robert

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json-autotype 1.1.2, and type-providers initiative
by Michal J Gajda 02 Apr '18

02 Apr '18

Hi, I am pleased to announce new version of json-autotype. Highlights of the version: 1. GHC 8.4 support. 2. Preliminary support for Elm output (with more Haskell-family languages coming) 3. Peter Simons has joined the team as official maintainer. 4. Ask us anything on Gitter: https://gitter.im/dataHaskell/json-autotype Json-Autotype team, and Data Haskell Frames team is also pleased to announce `type-providers` initiative that aims to provide standard API for type providers for Haskell family of languages. (Please join us on Gitter: https://gitter.im/dataHaskell/type-providers and https://gitter.im/dataHaskell/DataFrames) -- Cheers Michal J. Gajda

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Haskell mailing list etiquette
by Niklas Hambüchen 01 Apr '18

01 Apr '18

Dear mailing list participants, I recently discovered a document that contains, neatly enumerated, all the rules that we as a community follow today when discussing Haskell topics. Please direct Haskell newcomers to it as early as possible, so that they can learn our mode of working upfront, and don't have to discover it bit by bit. For everybody's convenience, I here are the key points: * When possible, refer all matters to committees, for "further study and consideration." Attempt to make the committees as large as possible. * Bring up irrelevant issues as frequently as possible. * Ask endless questions or engage in long correspondence about such orders. Quibble over them when you can. * Haggle over precise wordings of communications, minutes, resolutions. * Refer back to matters decided upon at the last meeting and attempt to re-open the question of the advisability of that decision. * Advocate "caution". Be "reasonable" and urge your fellow-conferees to be "reasonable" and avoid haste which might result in embarrassments or difficulties later on. * Be worried about the propriety of any decision - raise the question of whether such action as is contemplated lies within the jurisdiction of the group or whether it might conflict with the policy of some higher echelon. You can find the full list of rules here (refer to page 28): https://www.cia.gov/news-information/featured-story-archive/2012-featured-s… Best, Niklas

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Proposal: Professionalizing GHC Development
by Gershom B 01 Apr '18

01 Apr '18

Fellow Haskellers, Recently there has been much work into creating a better and more professional GHC development process, including in the form of DevOps infrastructure, scheduled releases and governance, etc. But much remains to be done. There continues to be concern about the lack of use of industry-standard tools. For example, GHC development is tied to Phabricator, which is a custom product originally developed for in-house use by an obscure startup. GHC development is documented on a wiki still -- ancient technology, not appropriate for 2018. Wiki syntax for documentation needs to be replaced by the only modern standard -- github flavored markdown. Trac itself is ancient technology, dating to 2003, well before anybody knew how to program real software. It provides no support for all the most important aspects of software development -- Kanban boards, sprint management, or even burndown charts. What is necessary is an integrated solution that holistically addresses all aspects of development, fostering a DevOps culture, embracing cloud-first, agile-first, test-first, disrupt-first principles, and with an ironclad SLA. Rather than homegrown solutions, we need a GHC development process that utilizes tools and procedures already familiar to regular developers. Cross-sectional feature comparison analysis yields a clear front-runner -- Visual Studio Team Services. VSTS is a recognized Leader in the Gartner Magic Quadrant for Enterprise Agile Planning tools. It lets us migrate from custom git hosting to a more reliable source control system -- Team Foundation Version Control. By enforcing the locking of checked-out files, we can prevent the sorts of overlap between different patches that occur in the current distributed version management system, and coordinate tightly between developers, enabling and fostering T-shaped skills. Team Build also lets us migrate from antiquated makefiles to modern, industry-standard technology -- XML descriptions of build processes that integrate automatically with tracking of PBIs (product backlog items), and one-button release management. In terms of documentation, rather than deal with the subtleties of different markdown implementations and the confusing world of restructured text, we can utilize the full power of Word, including SharePoint integration as well as Office 365 capabilities, and integration with Microsoft Teams, the chat-based workspace for collaboration. This enables much more effective cross-team collaboration with product and marketing divisions. One of the most exciting features of VSTS is powerful extensibility, with APIs offered in both major programming paradigms in use today -- JVM and .NET. The core organizational principle for full application lifecycle management is a single data construct -- the "work item" which documentation informs us "represents a thing," which can be anything that "a user can imagine." The power of work items comes through their extensible XML representation. Work items are combined into a Process Template, with such powerful Process Templates available as Agile, Scrum, and CMMI. VSTS will also allow us to analyze GHC Developer team performance with an integrated reporting data warehouse that uses a cube. Pricing for up to 100 users is $750 a month. Individual developers can also purchase subscriptions to Visual Studio Professional for $45 a month. I suggest we start directing resources towards a transition. I imagine all work to accomplish this could be done within a year, and by next April 1, the GHC development process will be almost unrecognizable from that today. Regards, Gershom

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Re: [Haskell-cafe] Proposal: Professionalizing GHC Development
by David Banas 01 Apr '18

01 Apr '18

What a lovely idea! Might I suggest that, in making this change, we also adopt certain elements from both: - the Cult of Relevance, and - complex drama based managerial hierarchy, so as not to miss out on the wonderful benefits of those two features of modern hive mind development. So glad we’re finally ready to be brave in this new World, -db

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ANN: hledger 1.9
by Simon Michael 31 Mar '18

31 Mar '18

I'm pleased to announce hledger 1.9. The version jump signals some noteworthy changes still landing (normal-positive reports, budget reporting) which are a kind of preview of 2.0. The next major release, on 2018/06/30, will be hledger 2.0. Thank you to release contributors: Eli Flanagan, Peter Simons, Christoph Nicolai, agander, M Parker, Moritz Kiefer, Mykola Orliuk. hledger (http://hledger.org) is a reliable, cross-platform program for tracking money, time or other commodities, using double-entry accounting and simple plain text file formats. It provides command-line, curses and web interfaces, and aims to be a pleasant and practical tool for personal, business or institutional use. What's new ? ------------ Some highlights: * the "financial statement" commands bs/bse/cf/is now show all normal balances as positive numbers, producing more conventional financial reports which are easier to share with others. (experimental) * bal/bs/bse/cf/is can now generate HTML reports * account codes can be used to customize account sorting * numbers in scientific E-notation are supported, eg in journal and CSV data * budget report improvements * general report cleanups More at http://hledger.org/release-notes#hledger-1.9 . Get started ----------- See http://hledger.org/download for all install methods. Often, to get the latest release you will need to build it. Here are some ways to do that: Using the hledger-install script, which requires only bash and will build and install the hledger tools in $HOME/.local/bin/. (Note: building haskell apps can take significant time, memory, and disk space, especially the first time. You can kill and restart the installer without losing progress. If it fails, please help us improve it by reporting the full output): $ curl -O https://raw.githubusercontent.com/simonmichael/hledger/master/hledger-insta… $ less hledger-install.sh # (do security review) $ bash hledger-install.sh # (add -v for more detail; use bash -x to show commands being run) Using hledger-install the more convenient, less secure way: $ curl https://raw.githubusercontent.com/simonmichael/hledger/master/hledger-insta… | bash Using stack: $ stack install hledger-lib-1.9 hledger-1.9 # hledger-ui-1.9 hledger-web-1.9 hledger-api-1.9 Using cabal: $ cabal update $ cabal install hledger-1.9 # hledger-ui-1.9 hledger-web-1.9 hledger-api-1.9 After installation, ensure $HOME/.local/bin is in your $PATH. Now try some commands: $ hledger -h # quick help $ hledger help # list built-in manuals $ hledger add # record some transactions $ hledger # list available commands Now perhaps work through the tutorial at http://hledger.org/step-by-step.html Or review the fine documents, presentations etc. at http://hledger.org and http://plaintextaccounting.org Or say hello and ask questions in the #hledger IRC channel on Freenode: http://irc.hledger.org New users and contributors are always welcome! Give feedback, report bugs, send pull requests, write about it, etc. And if you have been finding hledger useful, consider becoming a sponsor or donor to help to sustain and accelerate our progress (see home page). Our IRC channel is #hledger on Freenode (http://irc.hledger.org)

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Minimizing cascading rebuilds
by ☂Josh Chia (謝任中) 30 Mar '18

30 Mar '18

Hi, In my project, I have multiple packages. One of the packages, packageA, is very fundamental and depended on directly and indirectly by almost all the other packages. It has functions that use some hard-coded data (a ByteString top-level variable) also defined within packageA. This hard-coded data is appended regularly, causing packageA to be rebuilt and thus almost all the other packages to be rebuilt, and building takes a painfully long time. I know I can move this hard-coded data to a file that's read at run-time, but that means one more item to plumb in at run-time (where to find the file), and IO (preventing the functions from being pure), so I would like to keep it hard-coded. Is there an elegant way to prevent or minimize the cascading rebuild of the dependent packages just because the hard-coded data in packageA changed? For analogy, in C or C++, source code gets compiled to .o files, one for each .cpp source file. Multiple .o files get linked into executables. So, unless the interface (.hpp files) also change, an implementation (.cpp file) change does not cause dependents to be recompiled to get new .o files, although dependent executables get relinked. I'm not familiar with the compilation and linking logic in GHC so maybe it has additional complications. BTW, I'm using stack, in case it makes any difference to the nature of the problem. Josh

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Haskell to Ethereum VM ?
by Takenobu Tani 30 Mar '18

30 Mar '18

Hi cafe, Does anyone know about the code generator from Haskell's syntax to Ethereum VM language (bytecode)? That is, what corresponds to Solidity in Haskell. Although Solidity is interesting, it's difficult for me to achieve quality and safety. Does such a project already exist? Regards, Takenobu

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Re: [Haskell-cafe] Accelerating Automatic Differentiation
by Michal J Gajda 29 Mar '18

29 Mar '18

Hi Charlie It certainly looks like exciting project, but the bar is currently placed very high. TensorFlow package not only provides automatic differentiation for whole programs, but also optimizes data processing both on GPU, and reading to achieve large batches. This field has a lot of hot developments, so You would either need to propose something unique to Haskell, or You risk being outclassed by PyTorch and TensorFlow bindings Maybe Dominic suggests something too. Cheers Michal

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ANN: network-2.6.3.5
by evan＠evan-borden.com 28 Mar '18

28 Mar '18

Announcing network-2.6.3.5 * Reverting "Do not closeFd within sendFd" [#271](https://github.com/haskell/network/pull/271) Sorry for any disruption this versioning snafu may have caused. https://hackage.haskell.org/package/network-2.6.3.5

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[Call for Contributions] Haskell Communities and Activities Report, May 2018 edition (34th edition)
by Mihai Maruseac 26 Mar '18

26 Mar '18

Dear all, We would like to collect contributions for the 34th edition of the ============================================================ Haskell Communities & Activities Report http://www.haskell.org/haskellwiki/Haskell_Communities_and_Activities_Report Submission deadline: 30 April 2018 (please send your contributions to hcar at haskell.org, in plain text or LaTeX format, both are equally accepted) ============================================================ This is the short story: * If you are working on any project that is in some way related to Haskell, please write a short entry and submit it. Even if the project is very small or unfinished or you think it is not important enough --- please reconsider and submit an entry anyway! * If you are interested in an existing project related to Haskell that has not previously been mentioned in the HCAR, please tell us, so that we can contact the project leaders and ask them to submit an entry. * If you are working on a project that is looking for contributors, please write a short entry and submit it, mentioning that your are looking for contributors. * Feel free to pass on this call for contributions to others that might be interested. More detailed information: The Haskell Communities & Activities Report is a bi-annual overview of the state of Haskell as well as Haskell-related projects over the last, and possibly the upcoming six months. If you have only recently been exposed to Haskell, it might be a good idea to browse the previous edition --- you will find interesting projects described as well as several starting points and links that may provide answers to many questions. Contributions will be collected until the submission deadline. They will then be compiled into a coherent report that is published online as soon as it is ready. As always, this is a great opportunity to update your webpages, make new releases, announce or even start new projects, or to talk about developments you want every Haskeller to know about! Looking forward to your contributions, Mihai Maruseac FAQ: Q: What format should I write in? A: The usual format is a LaTeX source file, adhering to the template that is available at: http://haskell.org/communities/11-2017/template.tex There is also a LaTeX style file at http://haskell.org/communities/11-2017/hcar.sty that you can use to preview your entry. If you do not know LaTeX or don't want to use it or don't have time to translate your entry into it, then please use plain text, it is better to have an entry in plain-text which we will translate than not have it at all. If you modify an old entry that you have written for an earlier edition of the report, you should soon receive your old entry as a template (provided we have your valid email address). Please modify that template, rather than using your own version of the old entry as a template. Q: Can I include Haskell code? A: Yes. Please use lhs2tex syntax (http://www.andres-loeh.de/lhs2tex/) The report is compiled in mode polycode.fmt. Q: Can I include images? A: Yes, you are even encouraged to do so. Please use .jpg or .png format, then. PNG is preferred for simplicity. Q: Should I send files in .zip archives or similar? A: No, plain file attachments are the way. Q: How much should I write? A: Authors are asked to limit entries to about one column of text. A general introduction is helpful. Apart from that, you should focus on recent or upcoming developments. Pointers to online content can be given for more comprehensive or "historic" overviews of a project. Images do not count towards the length limit, so you may want to use this opportunity to pep up entries. There is no minimum length of an entry! The report aims for being as complete as possible, so please consider writing an entry, even if it is only a few lines long. Q: Which topics are relevant? A: All topics which are related to Haskell in some way are relevant. We usually had reports from users of Haskell (private, academic, or commercial), from authors or contributors to projects related to Haskell, from people working on the Haskell language, libraries, on language extensions or variants. We also like reports about distributions of Haskell software, Haskell infrastructure, books and tutorials on Haskell. Reports on past and upcoming events related to Haskell are also relevant. Finally, there might be new topics we do not even think about. As a rule of thumb: if in doubt, then it probably is relevant and has a place in the HCAR. You can also simply ask us. Q: Is unfinished work relevant? Are ideas for projects relevant? A: Yes! You can use the HCAR to talk about projects you are currently working on. You can use it to look for other developers that might help you. You can use HCAR to ask for more contributors to your project, it is a good way to gain visibility and traction. Q: If I do not update my entry, but want to keep it in the report, what should I do? A: Tell us that there are no changes. The old entry will typically be reused in this case, but it might be dropped if it is older than a year, to give more room and more attention to projects that change a lot. Do not resend complete entries if you have not changed them. Q: Will I get confirmation if I send an entry? How do I know whether my email has even reached its destination, and not ended up in a spam folder? A: Prior to publication of the final report, we will send a draft to all contributors, for possible corrections. So if you do not hear from us within two weeks after the deadline, it is safer to send another mail and check whether your first one was received. -- Mihai Maruseac (MM) "If you can't solve a problem, then there's an easier problem you can solve: find it." -- George Polya

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GSoC Mentoring/Voting
by Aloïs Cochard 26 Mar '18

26 Mar '18

Hi all, I'm a bit confuse about the process regarding voting on GSoC proposals and proposing as mentor. I receive email from Google that seems to talk about a UI that I have never seen (i.e. they speak about some purple button "I want to be mentor"), OTOH there is this GitHub repository where it seems people contributed proposals. It seems like tomorrow is the deadline for the proposal, so I'm curious what will be the next steps for potential mentor as it seems we diverged a bit from the "official Google way". Thanks for the help. -- *Λ\oïs* http://twitter.com/aloiscochard http://github.com/aloiscochard

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GSoC Project Introduction: Accelerate Automatic Differentiation
by Charles Blake 26 Mar '18

26 Mar '18

Dear all, I'm a student interested in the GSoC programme and I wanted to introduce myself and make contact with those involved in potentially mentoring for the 'Implementing Automatic Differentiation in Accelerate' project (https://summer.haskell.org/ideas.html#accelerate-automatic-differentiation) If it would be more appropriate for me to contact those individuals directly then please let me know. My name is Charlie Blake, and I'm currently coming to the end of my CS undergrad degree. Much of my study of late has been focused on functional programming and parallelism - so when I saw this project proposal it jumped out at me! I was expecting to be assisting research at my university (St Andrews University, Scotland) in this field over the summer, but this arrangement has recently fallen through. Hence why I'm unfortunately sending this message rather close to the deadline. Nevertheless, I'm now hoping very much to get on the GSoC program, to which I am very much committed. With regards to the project itself, I'm currently in the process of drawing up a proposal. Although I'm making every effort to read as much as I can about the 'ad' and 'accelerate' libraries, it's still quite hard to get a good sense of the scope of the project. Would, for instance, it be a reasonable goal to expect to be able to implement all of the core 'ad' functionality in my own parallel library in the time-frame? This seems like the natural objective, but I don't want to propose an unrealistically large project if this is not feasible. If anyone has answers to these questions and might further be willing to discuss a draft project proposal with me over the next few days that would be greatly appreciated. Many thanks, Charlie Blake

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Munich Haskell Meeting, 2018-03-28 @ 19:30
by Christian Neukirchen 25 Mar '18

25 Mar '18

Dear all, Next week, our monthly Munich Haskell Meeting will take place again on Wednesday, March 28 at Cafe Puck at 19h30. For details see here: http://muenchen.haskell.bayern/dates.html If you plan to join, please add yourself to this dudle so we can reserve enough seats! It is OK to add yourself to the dudle anonymously or pseudonymously. https://dudle.inf.tu-dresden.de/haskell-munich-mar-2018/ Everybody is welcome! cu, -- Christian Neukirchen <chneukirchen(a)gmail.com> http://chneukirchen.org

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[ANN] brittany-0.9.0.0 (on both hackage&stackage)
by lennart spitzner 25 Mar '18

25 Mar '18

- Implement `IndentPolicyLeft`: A layouting setting that disables "hanging indentation". This indentation mode may become default in the future. Only configurable via config-file for the time being. - (!) commandline interface is reworked slightly to support multiple inputs/outputs (`brittany --write-mode=inplace *.hs`). This removes the --input/--output flags. - Ensure compatibility with stackage - Change default global config path (old configs are still respected) - Improve support for per-project config - Fix several bugs and Improve language extension support full changelog at https://hackage.haskell.org/package/brittany-0.9.0.0/changelog brittany was recently added to stackage, and should hopefully be included in the next LTS release. -- lennart

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GSoC Haddock project
by Quentin Liu 24 Mar '18

24 Mar '18

Hi all, I am Qingbo Liu, a cs student from Colby College, ME. I’m very interested in the Hi Haddock project and would like to work on it for the summer. Currently I have finished a draft proposal and I am revising it (Thank Alex Biehl here for his kind suggestions). If the project would help you and you are willing to spend some time improving the proposal, please take a look at [1]. Any comment is appreciated. [1] https://docs.google.com/document/d/1BcSeLu8X9QwiM5LzYq5UEU5jIFF7hogdDT3UByU… Best Regards, Qingbo Liu

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Incorrect link to Haskell Summer of Code page on Reddit
by Henk-Jan van Tuyl 24 Mar '18

24 Mar '18

L.S., The Reddit forum haskell_proposals links to "Haskell Google Summer of Code site", which is https://ghc.haskell.org/trac/summer-of-code/wiki/WikiStart The linked page contains a suggestion for which shoes to buy for "running, casual wear, lifting". I suppose the subreddit should point to https://summer.haskell.org/ (The Haskell Summer of Code Trac also contains spam in the Tickets.) Regards, Henk-Jan van Tuyl -- Message from Stanford University: Folding@home What if you could share your unused computer power to help find a cure? In just 5 minutes you can join the world's biggest networked computer and get us closer sooner. Watch the video. http://foldingathome.stanford.edu/ -- http://members.chello.nl/hjgtuyl/tourdemonad.html Haskell programming --

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I am interested in doing Offline mode for Stack as GSoC 2018 project
by Akhil Seshan 24 Mar '18

24 Mar '18

Hi, I am Akhil Seshan, B.Tech Computer Science and Engineering Student. I would like to do Offline mode for Stack as the GSoC 2018 project. I have basic knowledge in Haskell/Functional programming but have an intermediate knowledge in Object oriented programming. I used Stack which is used for running Haskell programs. Kindly do let me know the details for moving forward with this as my project,

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Oxford Haskell User Group
by Callan McGill 23 Mar '18

23 Mar '18

Hi! I am interested in starting a Haskell user group (or functional programming meetup) in Oxford and would like to hear from anyone else wanting to help organise it. Please feel free to get in contact. Best, Callan

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Summer of Code projects
by Luke Lau 23 Mar '18

23 Mar '18

Hello, I’m a beginner-intermediate Haskell programmer and would like to help out this summer with the SoC projects! I have a few questions about some of the project ideas: https://summer.haskell.org/ideas.html#format-preserving-yaml <https://summer.haskell.org/ideas.html#format-preserving-yaml> Would this new library aim to also use the C library behind the scenes, or would there be more interest in making a completely native Haskell version? (Do FFI calls in Haskell have any performance overhead?) https://github.com/haskell/haskell-ide-engine <https://github.com/haskell/haskell-ide-engine> This seems really cool! There are a lot of cool goals on the list I would like to take a stab at. Sharing build cache between HaRe and GHC, to drastically improve refactoring speed. Are there any examples of this being done with any other IDE extensions or build tools? Rewriting the completion system/LSP tests Are there any parts of the LSP specification that are missing or could be implemented better? Also I was curious as to what libraries/tools are used for parsing and analysing, if any at all? I briefly looked through the repository and couldn’t find anything particularly low-level. Thanks!

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Re: [Haskell-cafe] Dropping containers support for old GHC versions
by Adam Bergmark 22 Mar '18

22 Mar '18

I appreciate that it may be hard/undesirable for some to use the latest GHC, but overall I don't think we should need to maintain backwards compatibility indefinitely because of that. Older versions of containers will still work with older GHCs, and other libraries depending on containers will still work as well as long as they support older container versions. But nevertheless, at least it seems there are no objections to dropping 7.0 and 7.2.2 support so far? :) Cheers, Adam On Fri, 9 Mar 2018 at 17:20 Daniel Cartwright <chessai1996(a)gmail.com> wrote: > David, I just checked and you're correct - I believe I was remembering > some other library(ies), though I can't recall which ones. > > On Fri, Mar 9, 2018 at 11:08 AM, David Feuer <david.feuer(a)gmail.com> > wrote: > >> On Mar 9, 2018 10:55 AM, "Daniel Cartwright" <chessai1996(a)gmail.com> >> wrote: >> >> >> On a related note, I find it strange when looking through source code for >> 'containers'/other Haskell libraries and still see notes about supporting >> non-GHC Haskell compilers (e.g. Hugs) >> >> >> I believe we've stripped all references to Hugs and nhc98 from >> containers. If you find any, let us know. I'd be interested in adding >> support for Frege, but the way it deals with numeric literals could be >> problematic. >> >> > _______________________________________________ > Libraries mailing list > Libraries(a)haskell.org > http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries >

2 1

GSoC project
by Sanya Negi 21 Mar '18

21 Mar '18

Hello! I am extremely interested in the project " offline mode for stack " for GSoC, for which I have learnt basic stack and have been learning more. Please guide me as to what other specific things I have to delve into and how to break this problem into pieces to form my proposal. I can't seem to get in touch with the projects mentor Emanuel Borsboom. And as the deadline is reaching, I really need to start forming my proposal now. Soliciting a prompt and positive response. Sanya Negi

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Re: [Haskell-cafe] problem with stack behind proxy
by Yuji Yamamoto 21 Mar '18

21 Mar '18

FYI. If your office's proxy server is authenticated with NTLM authentication, use CNTLM http://cntlm.sourceforge.net/ , a proxy of proxy for NTLM-authenticated server. Actually, my last office uses it :) 2018-03-21 18:46 GMT+09:00 Nikos Karagiannidis <nikoshaskell(a)gmail.com>: > Thank you both for your help! > > I have tried to embed a URI encoded username and password in the > HTTP_PROXY setting but still did not work. > I have managed to find an alternative proxy by talking to the network > department that does not require authentication! > So now "stack upgrade" works for me too! > > I will continue with this workaround for now ... > > many thanks! > Nikos > > > On Wed, Mar 21, 2018 at 6:05 AM, Yuji Yamamoto < > whosekiteneverfly(a)gmail.com> wrote: > >> According to the error, you must set proxy user name and password to pass >> the authentication. >> >> Like this: >> >> HTTP_PROXY = http://username:password@proxy-host:8080 >> <http://proxy-host:8080/> >> HTTPS_PROXY = http:// <http://proxy-host:8080/>username:password@ >> <http://proxy-host:8080/> proxy-host:8080 >> >> Note that you must URI-encode the username or password if they include >> some meta-characters like a colon or an at-sign. >> >> Besides, stack 1.3.2 is too old! >> >> 2018-03-21 2:00 GMT+09:00 Nikos Karagiannidis <nikoshaskell(a)gmail.com>: >> >>> Hi all, >>> >>> I am trying to run stack build, or stack update behind the corporate web >>> proxy and I get the following error: >>> >>> $ stack build >>> Downloading lts-11.1 build plan ...HttpExceptionRequest Request { >>> host = "raw.githubusercontent.com" >>> port = 443 >>> secure = True >>> requestHeaders = [] >>> path = "/fpco/lts-haskell/master//lts-11.1.yaml" >>> queryString = "" >>> method = "GET" >>> proxy = Nothing >>> rawBody = False >>> redirectCount = 10 >>> responseTimeout = ResponseTimeoutDefault >>> requestVersion = HTTP/1.1 >>> } >>> (ProxyConnectException "raw.githubusercontent.com" 443 (Status >>> {statusCode = 407, statusMessage = "Proxy Authentication Required ( >>> Forefront TMG requires authorization to fulfill the request. Access to the >>> Web Proxy filter is denied. )"})) >>> >>> My stack version is: >>> >>> $ stack --version >>> Version 1.3.2, Git revision 3f675146590da4f3edf768b89355f798229da2a5 >>> x86_64 hpack-0.15.0 >>> >>> I have set the HTTP_PROXY and HTTPS_PROXY environment variables to a >>> value of: >>> HTTP_PROXY = http://proxy-host:8080 >>> HTTPS_PROXY = http://proxy-host:8080 >>> >>> Can you help me how to achieve proxy authentication via stack? >>> >>> thank you in advance! >>> >>> Nikos >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "haskell-stack" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to haskell-stack%2Bunsubscribe(a)googlegroups.com. >>> To post to this group, send email to haskell-stack(a)googlegroups.com. >>> To view this discussion on the web visit https://groups.google.com/d/ms >>> gid/haskell-stack/CAN0STeQPzM2SyxyYUiy3o2HS%2BDMw8sWmTcyWZHi >>> -LwLANjY%2BtQ%40mail.gmail.com >>> <https://groups.google.com/d/msgid/haskell-stack/CAN0STeQPzM2SyxyYUiy3o2HS%2…> >>> . >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> >> >> -- >> 山本悠滋 >> twitter: @igrep >> GitHub: https://github.com/igrep >> GitLab: https://gitlab.com/igrep >> Facebook: http://www.facebook.com/igrep >> Google+: https://plus.google.com/u/0/+YujiYamamoto_igrep >> > > -- 山本悠滋 twitter: @igrep GitHub: https://github.com/igrep GitLab: https://gitlab.com/igrep Facebook: http://www.facebook.com/igrep Google+: https://plus.google.com/u/0/+YujiYamamoto_igrep

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[ANN] New QFPL Applied Functional Programming Course 🎉 🎉
by Sean Chalmers 21 Mar '18

21 Mar '18

Hi everyone, After successful trials in Sydney, Melbourne, and Brisbane, we're pleased to present our new **Applied Functional Programming Course**. Designed for those of you beyond the intro stage and hungry for more. This is new course material that is targeted toward programmers who have become proficient with navigating Functional Programming concepts and would like to progress to building a complete application. This course material involves writing a REST application with a database backend. Topics covered include: * Hackage and the general Haskell ecosystem * Cabal files and project structure * Database integration * Configuration * Monad transformers * Testing * Type driven development The assumed Haskell knowledge for this course is that you are comfortable with Applicative, and you are able to write the definition for a function with the type: Applicative f => [f a] -> f [a] As with all of our course material, we invite and encourage you to submit issues and pull-requests. We build these courses for you, so if things aren't working. With either the content or any of the moving parts, we want to know. These courses are run free of charge, in Australia. When and where we run them is based on demand. So if you or your team are keen, then let us know. We can also arrange to run them in-house. Our contact details are here: https://qfpl.io/contact/. More info about both of our current courses is available on our projects page: https://qfpl.io/projects/courses/. Cheers, Sean Chalmers Functional Programming Engineer Queensland FP Lab Data61 / CSIRO Australia

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Call for Submissions: Haskell Symposium 2018
by Nicolas Wu 20 Mar '18

20 Mar '18

================================================================================ ACM SIGPLAN CALL FOR SUBMISSIONS Haskell Symposium 2018 St. Louis, MO, United States 27--28 September, 2018 http://www.haskell.org/haskell-symposium/2018/ ================================================================================ The ACM SIGPLAN Haskell Symposium 2018 will be co-located with the 2018 International Conference on Functional Programming (ICFP), in St. Louis, Missouri, USA. The Haskell Symposium aims to present original research on Haskell, discuss practical experience and future development of the language, and to promote other forms of denotative programming. Topics of interest include: * Language design, with a focus on possible extensions and modifications of Haskell as well as critical discussions of the status quo; * Theory, such as formal semantics of the present language or future extensions, type systems, effects, metatheory, and foundations for program analysis and transformation; * Implementations, including program analysis and transformation, static and dynamic compilation for sequential, parallel, and distributed architectures, memory management, as well as foreign function and component interfaces; * Libraries, that demonstrate new ideas or techniques for functional programming in Haskell; * Tools, such as profilers, tracers, debuggers, preprocessors, and testing tools; * Applications, to scientific and symbolic computing, databases, multimedia, telecommunication, the web, and so forth; * Functional Pearls, being elegant and instructive programming examples; * Experience Reports, to document general practice and experience in education, industry, or other contexts. * System Demonstrations, based on running software rather than novel research results. Regular papers should explain their research contributions in both general and technical terms, identifying what has been accomplished, explaining why it is significant, and relating it to previous work, and to other languages where appropriate. Experience reports and functional pearls need not necessarily report original academic research results. For example, they may instead report reusable programming idioms, elegant ways to approach a problem, or practical experience that will be useful to other users, implementers, or researchers. The key criterion for such a paper is that it makes a contribution from which other Haskellers can benefit. It is not enough simply to describe a standard solution to a standard programming problem, or report on experience where you used Haskell in the standard way and achieved the result you were expecting. More advice is available via the Haskell wiki. System demonstrations should summarize the system capabilities that would be demonstrated. The proposals will be judged on whether the ensuing session is likely to be important and interesting to the Haskell community at large, whether on grounds academic or industrial, theoretical or practical, technical, social or artistic. Please contact the program chair with any questions about the relevance of a proposal. Submission Details ================== Early and Regular Track ----------------------- The Haskell Symposium uses a two-track submission process so that some papers can gain early feedback. Strong papers submitted to the early track are accepted outright, and the others will be given their reviews and invited to resubmit to the regular track. Papers accepted via the early and regular tracks are considered of equal value and will not be distinguished in the proceedings. Although all papers may be submitted to the early track, authors of functional pearls and experience reports are particularly encouraged to use this mechanism. The success of these papers depends heavily on the way they are presented, and submitting early will give the program committee a chance to provide feedback and help draw out the key ideas. Formatting ---------- Submitted papers should be in portable document format (PDF), formatted using the ACM SIGPLAN style guidelines. Authors should use the `acmart` format, with the `sigplan` sub-format for ACM proceedings. For details, see: http://www.sigplan.org/Resources/Author/#acmart-format Functional pearls, experience reports, and demo proposals should be labelled clearly as such. Page Limits ----------- The length of submissions should not exceed the following limits: Regular paper: 12 pages Functional pearl: 12 pages Experience report: 6 pages Demo proposal: 2 pages There is no requirement that all pages are used. For example, a functional pearl may be much shorter than 12 pages. Deadlines --------- Early track: Submission deadline: 30 March 2018 (Fri) Notification: 18 May 2018 (Fri) Regular track and demos: Submission deadline: 8 June 2018 (Fri) Notification: 13 July 2018 (Fri) Deadlines are valid anywhere on Earth. Submission ---------- Submissions should adhere to SIGPLAN's republication policy, as explained on the web. The paper submission deadline and length limitations are firm. There will be no extensions, and papers violating the length limitations will be summarily rejected. Papers should be submitted through easychair at: https://easychair.org/conferences/?conf=haskell2018 Travel Support ============== Student attendees with accepted papers can apply for a SIGPLAN PAC grant to help cover travel expenses. 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 program, see its web page (http://pac.sigplan.org) Proceedings =========== Accepted papers will be included in the ACM Digital Library. Authors must grant ACM publication rights upon acceptance (http://authors.acm.org/main.html) Authors are encouraged to publish auxiliary material with their paper (source code, test data, etc.); they retain copyright of auxiliary material. Accepted proposals for system demonstrations will be posted on the symposium website but not formally published in the proceedings. All accepted papers and proposals will be posted on the conference website one week before the meeting. Publication date: The official publication 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. Program Committee ================= Michael D. Adams University of Utah Patrick Bahr IT University of Copenhagen Olaf Chitil University of Kent Nils Anders Danielsson University of Gothenburg Graham Hutton University of Nottingham Mauro Jaskelioff CONICET/Universidad Nacional de Rosario Oleg Kiselyov Tohoku University Sam Lindley The University of Edinburgh Andres Löh Well-Typed LLP Bruno Oliveira The University of Hong Kong Maciej Piróg University of Wrocław Wren Romano Google Mark Shinwell Jane Street Niki Vazou University of California Marcos Viera Universidad de la República Nicolas Wu (Chair) University of Bristol Ryan Yates University of Rochester Brent Yorgey Hendrix College If you have questions, please contact the chair at: nicolas.wu(a)bristol.ac.uk ================================================================================

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directory package copyFile error
by Olaf Klinke 20 Mar '18

20 Mar '18

Dear cafe, not sure whether this is a bug or misusage on my part: I'm using stack lts-9.2, which entails directory-1.3.0.0. I have a file on a samba share, say /mnt/remote/foo. I read the file, modify its contents in my program and save a local copy, say /tmp/foo. Then I try to copy the modified file back to its original place using System.Directory.copyFile "/tmp/foo" "/mnt/remote/foo" Sometimes the copyFile command produces an error like this: /mnt/remote/.copyFile1804289383846930886.tmp: copyFile:atomicCopyFileContents:withReplacementFile:hClose: does not exist (Host is down) When I copy /tmp/foo to /mnt/remote/foo using the shell, everything works fine. Does anyone have an idea what goes wrong? Internally withReplacementFile is used which indeed creates a temporary file to not risk corrupting the original. Is this maybe due to a wrong ordering of IO actions? Thanks Olaf

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Listing Yampa projects
by Ivan Perez 20 Mar '18

20 Mar '18

Dear all, I would like to facilitate transitioning to new versions of Yampa when there are breaking changes in the library. Also, when there is a proposal to deprecate a feature, this will help understand if it's still being used. I've created a github issue so that people can list their projects: https://github.com/ivanperez-keera/Yampa/issues/68 If you have a project, example, or paper that uses yampa and you want to keep it in a working state, please comment. If there's a project, maybe not your own, that you'd like to see working, please say so, even if there is no maintainer at the moment. Cheers Ivan

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Register for BayHac 2018
by Dan Burton 19 Mar '18

19 Mar '18

Registration form: https://goo.gl/forms/1gYlTQVNwPkKGgC02 <https://goo.gl/forms/1gYlTQVNwPkKGgC02> All attendees are requested to register for the event via the registration form. Registration form: https://goo.gl/forms/1gYlTQVNwPkKGgC02 Propose a talk or workshop: https://goo.gl/forms/TZbFNIZu4Q1dEh2g2 More info: https://wiki.haskell.org/BayHac2018 -- Dan Burton

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CfP: Workshop on Functional High-Performance Computing 2018 at ICFP
by Kei Davis 19 Mar '18

19 Mar '18

CALL FOR PAPERS FHPC 2018 7th ACM SIGPLAN Workshop on Functional High-Performance Computing September 29, 2018, St. Louis, Missouri, USA https://icfp18.sigplan.org/track/FHPC-2018-papers The 7th ACM SIGPLAN Workshop on Functional High-Performance Computing (FHPC’18) is being held as in previous years in conjunction with the International Conference on Functional Programming (ICFP’18) together with numerous other workshops/symposia, and as a first, colocated with Strange Loop, in St. Louis, Missouri, USA. Workshop Objectives The FHPC’18 workshop seeks to bring together researchers and practitioners exploring uses of functional (or more generally, declarative or high-level) programming systems or concepts in application domains where high performance is essential. The aim of the meeting is to enable sharing of results, experiences, and novel ideas about how high-level, declarative specifications of computationally challenging problems can serve as maintainable and portable code that approaches (or even exceeds) the performance of machine-oriented (low-level) imperative implementations. All aspects of performance-critical programming and parallel programming are in scope for the workshop, irrespective of hardware target. This includes both traditional large-scale distributed-memory scientific computing (HPC), as well as work targeting single node systems with SMPs, GPUs, FPGAs, or embedded processors. FHPC 2018 seeks to encourage a range of submissions, focusing on work in progress and facilitating early exchange of ideas and open discussion on innovative and/or emerging results. Original research, experience reports, case studies, and evaluations of programming systems are all welcome. Work on incorporation of functional programming concepts into more traditional (imperative) HPC applications is explicitly solicited. This year FHPC provides authors the opportunity to submit for evaluation any relevant artifacts that accompany their papers. The dissemination of artifacts promotes reproducibility, and enables authors to build on top of each others’ work, while it can also help to more unambiguously resolve questions about cases not considered by the original authors. For the purpose of FHPC, we plan to reward selected artifacts with additional presentation time in a dedicated slot during the workshop, for example, for demonstrating (i) reproducibility of results or (ii) practical usage of the framework (visualization, demos, etc). Artifact Details The artifact-evaluation committee (AEC) will accept any artifact that authors wish to submit. Obviously, the better the artifact is packaged, the more likely the AEC can actually work with it. We ask the authors to provide provide the title of the FHPC paper submission, together with three files: * a .pdf file that provides detailed instructions to the reviewers about how to install the artifact and what to look for in the evaluations * an archive .zip or .tar.gz containing the artifact * the submitted FHPC’18 paper (.pdf file) The artifact evaluation process is intended to encourage an open and constructive communication (via HotCRP) between (anonymous) reviewers and authors. Submission of an artifact does not constitute tacit permission to make its content public. AEC members will be instructed that they may not publicise any part of your artifact during or after completing evaluation, nor retain any part of it after evaluation. Thus, you are free to include models, data files, proprietary binaries, and similar items in your artifact. The AEC organisers strongly encourage you to anonymise any data files that you submit. Publication The proceedings of FHPC’18 will be published by the ACM Digital Press. Important Dates * Submission Deadline: June 8, 2018 anywhere on Earth. * Notification: early July (TBD) * Camera ready: late July (TBD) * Final version of proceedings available: Sept. 9 * FHPC 2018: Saturday Sept. 29, 2018. Official website, submissions, registration details https://icfp18.sigplan.org/track/FHPC-2018-papers Previous FHPC websites https://icfp17.sigplan.org/track/FHPC-2017-papers https://sites.google.com/site/fhpcworkshops/ ICFP and related workshops https://conf.researchr.org/home/icfp-2018 https://icfp18.sigplan.org Strange Loop https://www.thestrangeloop.com/ Questions or comments? fhpc18(a)gmail.com Kei Davis and Mike Rainey, co-chairs

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The Racket School 2018: Create your own language
by Sam Tobin-Hochstadt 19 Mar '18

19 Mar '18

The Racket School 2018: Create your own language 9–13 July • Salt Lake City The Racket team has spent over thirty years developing and refining a coherent intellectual tradition for studying and building programming languages. This year’s school will introduce participants to Racket’s framework for language-oriented programming, which the summer school faculty recently spelled out in a a cover article in the Communications of the ACM. [https://tinyurl.com/RacketCACM] Concretely, the 2018 Racket Summer School will cover the following topics: • the spectrum of programming languages; • modules and syntax, or languages as libraries; • DrRacket’s support for language-oriented programming; • a domain-specific language for adding types to languages; • tools and techniques for implementing notational conveniences; and • research challenges in language-oriented programming. If these topics intrigue you, attend the Racket Summer School: http://summer-school.racket-lang.org/2018/ This is not your run-of-the-mill summer school. We will do our best to make it exciting, entertaining, and useful to a broad spectrum of attendees, both academic and industrial. P.S. We will send you your first problem set in June, a month before the summer school to whet your appetite.

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Vim + literal Haskell + dollar symbols
by Ivan Perez 19 Mar '18

19 Mar '18

Hi cafe, The lhaskell edit mode for lhs2tex documents in vim gets confused when a dollar is used in code. This also makes the spellchecker ignore text paragraphs (until a matching $ is found). Where should this be reported? This list is named as maintainer in the Ubuntu package vim-runtime's lhaskell.vim syntax file: " Maintainer: Haskell Cafe mailinglist <haskell-cafe(a)haskell.org> " Original Author: Arthur van Leeuwen <arthurvl(a)cs.uu.nl> " Last Change: 2010 Apr 11 " Version: 1.04 Cheers Ivan

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vim syntax file
by Marcin Szamotulski 19 Mar '18

19 Mar '18

Hello, I am looking for the maintainer of the haskell vim syntax script. The header points to the haskell-cafe mailing lists. I added @Spell and @NoSpell groups so it's easier to spell check haskell in vim. I hope others will find it useful :) Best regards, Marcin Szamotulski

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S-REPLS 9: Call for talks
by Martin Berger 19 Mar '18

19 Mar '18

============================================================================ S-REPLS 9 (#srepls) South of England Regional Programming Language Seminar series Friday 25 May 2018, 10:00 - 19:00 University of Sussex, Brighton, Fulton building, Room A (FUL-A) http://users.sussex.ac.uk/~mfb21/srepls9 Call for talks ============================================================================ Overview S-REPLS is a regular, informal and friendly meeting for those based in the South of England with a professional interest - whether it be academic or commercial - in the semantics, implementation, and use of programming languages, and related areas. Attendance is free! Lunch and refreshments will be provided. Submitting a talk S-REPLS talks are typically 20-30 minutes long on any topic related to programming languages. We are currently requesting talk suggestions for S-REPLS 9 at the University of Sussex in Brighton. Submissions from industrial professionals and junior researchers (postdocs and students), as well as descriptions of work in progress, are especially welcome. Please email <M.F.Berger(a)sussex.ac.uk> with the title "S-REPLS 9 talk suggestion", a draft title, and an abstract by 17:00 on April 25th 2018.

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Scala: Type synonyms for implicits?
by Thomas Jakway 18 Mar '18

18 Mar '18

Posting this here since some of you are Scala programmers:https://stackoverflow.com/questions/49353695/type-synonyms-for-… A type-level question you won't encounter in Haskell.

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Call for Tutorial Proposals: ICFP 2018
by Lindsey Kuper 18 Mar '18

18 Mar '18

CALL FOR TUTORIAL PROPOSALS ICFP 2018 23rd ACM SIGPLAN International Conference on Functional Programming September 23-29, 2018 St. Louis, Missouri, United States http://conf.researchr.org/home/icfp-2018 The 23rd ACM SIGPLAN International Conference on Functional Programming will be held in St. Louis, Missouri, United States on September 23-29, 2018. ICFP provides a forum for researchers and developers to hear about the latest work on the design, implementations, principles, and uses of functional programming. Proposals are invited for tutorials to be presented during ICFP and its co-located workshops and other events. These tutorials are the successor to the CUFP tutorials from previous years, but we also welcome tutorials whose primary audience is researchers rather than practitioners. Tutorials may focus either on a concrete technology or on a theoretical or mathematical tool. Ideally, tutorials will have a concrete result, such as "Learn to do X with Y" rather than "Learn language Y". Tutorials may occur in parallel to both ICFP and its co-located workshops, from September 23 through September 29. Additionally, ICFP is co-located with Strange Loop this year, and this will be taken into account when scheduling tutorials. ---------------------------------------------------------------------- Submission details Deadline for submission: April 9, 2018 Notification of acceptance: April 16, 2018 Prospective organizers of tutorials are invited to submit a completed tutorial proposal form in plain text format to the ICFP 2018 workshop co-chairs (Christophe Scholliers and David Christiansen), via email to icfp-workshops-2018(a)googlegroups.com by April 9, 2018. Please note that this is a firm deadline. Organizers will be notified if their event proposal is accepted by April 16, 2018. The proposal form is available at: http://www.icfpconference.org/icfp2018-files/icfp18-tutorials-form.txt ---------------------------------------------------------------------- Selection committee The proposals will be evaluated by a committee comprising the following members of the ICFP 2018 organizing committee. Workshop Co-Chair: Christophe Scholliers (University of Ghent) Workshop Co-Chair: David Christiansen (Galois, Inc.) General Chair: Robby Findler (Northwestern University) Program Chair: Matthew Flatt (University of Utah) ---------------------------------------------------------------------- Further information Any queries should be addressed to the workshop co-chairs (Christophe Scholliers and David Christiansen), via email to icfp-workshops-2018(a)googlegroups.com

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[Announcement]: New release of ppTable: Pretty Print containers in a tabular format
by Guru Devanla 17 Mar '18

17 Mar '18

Hello Haskell-Cafe, I am happy to announce a new release of the ppTable library that lets you print records in list/vectors/maps in a pretty tabular format. https://hackage.haskell.org/package/pptable The new release also handles nested record structures by displaying the headers in a multi-hierarchical fashion. As they say in Python 'Flat is better than nested'. But for now, nested works too! I am willing and happy to get any feedback and suggestions on the library API and implementation itself. Thank you very much Guru

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Documenting Examples for a library
by Guru Devanla 17 Mar '18

17 Mar '18

Hello, I am close to releasing a new version of the https://hackage.haskell.org/package/pptable library I have been working on off late. I am a little confused on what approach I need to take regarding providing good documentation and working examples. Please, note that I am not referring to the API documentation attached to the code. For API documentation I will continue to use haddock and generate documentation as I build. The approaches I have in mind to provide clear examples are as follows: 1. Provide a README.md and document all usage examples in markdown format. Allow github to produce the HTML. 2. Create and ship an Example.hs file along with library. Using a .hs file allows haddock to build the documentation as part of the package. I took this approach for the previous release. Here is an example: https://hackage.haskell.org/package/pptable-0.2.0.0/docs/Text-PrettyPrint-T…. 3. Using Example.lhs. I like this approach since it lets me load the code in ghci and test out the examples seamlessly. But, I am hitting roadblocks with this, since I am not able to include this file as part of my stack project. `stack haddock` fails too. When I include .lhs file in a stack project, I get the following error File name does not match module name: Saw: ‘Main’ Expected: ‘Text.PrettyPrint.Tabulate.Example’ I like (3) because I can make sure my examples run successfully, (using stack ghci Example.lhs), before I publish them. With options (1) and (2), I need to manually copy/past code into ghci to make sure there are no errors. Is there a better way to do this? Please could the group provide any recommendations and guidance on what approach I should be taking and why. Thanks

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[Google Summer of Code 2018] Student Applications are now open
by Jasper Van der Jeugt 15 Mar '18

15 Mar '18

Hey all, As we've previously announced through different channels, Haskell.org was accepted into Google Summer of Code 2018 [1]. Students application have now opened. Students can submit their proposal at the Summer of Code Dashboard [2]. We are also seeking mentors for possible projects. This year, we would like to assign a back-up mentor for each student. If you are interested in mentoring, please contact us [3] so we can add you to the mentor list directly. Having good mentors is an important factor in making the students feel welcome and guiding them to a succesful completion of their projects. If you would like to apply but you don't know how to start your proposal, have a look at our ideas list [4] and this great guide [5]. Lastly, we recognize that inclusion is an important part of our mission to promote Haskell. Therefore, we strongly encourage applications from people in communities that are underrepresented in functional programming, including but not limited to women; people of color; people in gender, sexual and romantic minorities; people with disabilities; people residing in Asia, Africa, or Latin America; and people who have never taken part in similar programs before. Kind regards, Jasper Van der Jeugt & George Wilson on behalf of the Haskell.org Committee [1]: https://summerofcode.withgoogle.com/organizations/5706672807346176/ [2]: https://summerofcode.withgoogle.com/ [3]: https://summer.haskell.org/contact.html [4]: https://summer.haskell.org/ideas.html [5]: http://write.flossmanuals.net/gsocstudentguide/writing-a-proposal/

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Using Backpack for initial and final encodings
by David Laing 15 Mar '18

15 Mar '18

Hi everyone, Ed Kmett recently pointed me towards his usage of Backpack to write some code in the tagless final style, and I've been playing with it and riffing on it for a while. There's a solution to the expression problem in there involving classy Prisms (and now Backpacky Prisms) that seems pretty neat. I've written it up here: https://qfpl.io/posts/backpack-for-initial-and-final-encodings/ Hopefully some of you find it interesting. Cheers, Dave

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