- Haskell-Cafe - Haskell.org

ARM builds of GHC
by Vanessa McHale 06 May '19

06 May '19

Hi all, Are there any plans to release/distribute ARM builds of GHC for the 8.8.* series? The most recent GHC to have ARM binaries distributed seems to be 8.4.2, which regrettably has a bug that makes it unsuitable for my purposes. Cheers, Vanessa McHale

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[ANNOUNCEMENT] 11th International School on Rewriting (ISR'19), 1-6 July 2019, MINES ParisTech, France
by Johannes Waldmann 06 May '19

06 May '19

Dear Cafe - if your're using Haskell, you are using (term) rewriting: both first order (pattern matching on algebraic data types) and higher order (lambda calculus). Here is your chance to get the fundamentals right, and see more applications: the 11th International School on Rewriting (ISR'19), 1-6 July 2019, MINES ParisTech, France. https://isr2019.mines-paristech.fr/ Deadline for early registration: May 17 full text of call for participation http://lists.tcs.ifi.lmu.de/pipermail/loginf/2019/001723.html - J.W.

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Call for Participation: Compose Conference [NYC, Jun 22- 23 2019]
by Gershom B 03 May '19

03 May '19

=============================================== Call for Participation Compose Conference 2019 Mon June 24 - Tue June 25 2019 (Unconference on Sat Jun 22 - Sun Jun 23) New York, NY http://www.composeconference.org/2019 =============================================== The practice and craft of functional programming :: Conference Compose is a conference for typed functional programmers, focused specifically on Haskell, OCaml, F#, SML, and related technologies. Typed functional programming has been taken up widely, by industry and hobbyists alike. For many of us it has renewed our belief that code should be beautiful, and that programming can be as enjoyable as it is practical. Compose is about bringing together functional programmers of all levels of skill and experience — from technical leads to novices, and from long-time hackers to students just getting started. It will feature a two days of great and wide-ranging talks * Invited Keynotes Donya Quick - Making Algorithmic Music David Spivak - Compositional Graphical Logic * Accepted Talks and Tutorials Kenny Foner - Functors of the World, Unite! Phillip Carter - The anatomy of the F# tools for Visual Studio Sebastien Mondet - Genspio: Generating Shell Phrases In OCaml Justin Le - Applicative Regular Expressions using the Free Alternative Gaetano Checinski - Buckaroo SAT - Solving a partially revealed SAT problem for Package Management Richard Feldman - From Rails to Elm and Haskell Samuel Gélineau - Stuck macros: deterministically interleaving macro-expansion and typechecking Vaibhav Sagar - Yes, IHaskell Can Do That! Fintan Halpenny - Bowl Full of Lentils Aditya Siram - A Tase Of ATS Ward Wheeler, Alex Washburn, Callan McGill - Phylogenetic Software in Haskell Igor Trindade Oliveira - Type Driven Secure Enclave Development using Idris David Christiansen - Bidirectional Type Checking Chris Smith - Teaching the intersection of mathematics and functional programming Brandon Kase - Fast Accumulation on Streams James Koppel - The Best Refactoring You’ve Never Heard Of Allister Beharry - Using Dependent Types in an F# DSL for Linear Algebra Diego Balseiro - Bridge Haskell and ReasonML in Production * Full abstracts: http://www.composeconference.org/2019/program * Conference Registration: https://www.eventbrite.com/e/new-york-compose-2019-tickets-56751182314 * Unconference Registration: https://www.eventbrite.com/e/new-york-compose-unconference-2019-tickets-603… * Follow @composeconf on twitter for news: https://twitter.com/composeconf * On freenode irc, chat with fellow attendees at #composeconference * Corporate sponsorships are welcome. Current sponsors list forthcoming. * Policies (diversity and anti-harassment): http://www.composeconference.org/conduct * Email us with any questions at info(a)composeconference.org * Please forward this announcement to interested parties and lists.

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Static linking against X11
by Vanessa McHale 01 May '19

01 May '19

Hi all, I'm trying to cross-compile xmobar for aarch64-linux-gnu. The cross compiler that comes with my version of Ubuntu works with a later GLIBC than the host platform, so I figured I'd make a static executable instead - this approach had worked with e.g. cabal-install. Unfortunately, I get the following: Resolving dependencies... Build profile: -w ghc-8.6.4 -O1 In order, the following will be built (use -v for more details): - xmobar-vanessa-0.1.0.0 (exe:xmobar) (first run) Preprocessing executable 'xmobar' for xmobar-vanessa-0.1.0.0.. Building executable 'xmobar' for xmobar-vanessa-0.1.0.0.. Linking /home/vanessa/programming/haskell/done/xmobar-vanessa/dist-newstyle/build/aarch64-linux/ghc-8.6.4/xmobar-vanessa-0.1.0.0/x/xmobar/build/xmobar/xmobar ... /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /usr/local/lib/aarch64-linux-gnu-ghc-8.6.4/rts/libHSrts.a(Linker.o): in function `internal_dlopen': /home/vanessa/cross/ghc-8.6.4/rts/Linker.c:600:0: error: warning: Using 'dlopen' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /home/vanessa/.cabal/store/ghc-8.6.4/network-3.1.0.0-b60cf17d11d7eda024959ae28f710f94d7565bcd8e3372f04f32d2600769c2c1/lib/libHSnetwork-3.1.0.0-b60cf17d11d7eda024959ae28f710f94d7565bcd8e3372f04f32d2600769c2c1.a(HsNet.o): in function `hsnet_getaddrinfo': HsNet.c:(.text+0x10): warning: Using 'getaddrinfo' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/lib/../lib/libX11.a(xcb_io.o): in function `require_socket': /tmp/cpkg-2c6d48cdbb4678ca/libX11-1.6.7/src/xcb_io.c:68:0: error: undefined reference to `xcb_take_socket' /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/lib/../lib/libX11.a(xcb_io.o): in function `poll_for_event': /tmp/cpkg-2c6d48cdbb4678ca/libX11-1.6.7/src/xcb_io.c:245:0: error: undefined reference to `xcb_poll_for_event' /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /tmp/cpkg-2c6d48cdbb4678ca/libX11-1.6.7/src/xcb_io.c:243: undefined reference to `xcb_poll_for_queued_event' /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/lib/../lib/libX11.a(xcb_io.o): in function `poll_for_response': /tmp/cpkg-2c6d48cdbb4678ca/libX11-1.6.7/src/xcb_io.c:284:0: error: undefined reference to `xcb_poll_for_reply64' /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/lib/../lib/libX11.a(xcb_io.o): in function `_XSend': /tmp/cpkg-2c6d48cdbb4678ca/libX11-1.6.7/src/xcb_io.c:499:0: error: undefined reference to `xcb_writev' /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/lib/../lib/libX11.a(xcb_io.o): in function `_XEventsQueued': /tmp/cpkg-2c6d48cdbb4678ca/libX11-1.6.7/src/xcb_io.c:364:0: error: undefined reference to `xcb_connection_has_error' /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/lib/../lib/libX11.a(xcb_io.o): in function `_XReadEvents': /tmp/cpkg-2c6d48cdbb4678ca/libX11-1.6.7/src/xcb_io.c:441:0: error: undefined reference to `xcb_connection_has_error' /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /tmp/cpkg-2c6d48cdbb4678ca/libX11-1.6.7/src/xcb_io.c:400: undefined reference to `xcb_wait_for_event' /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/lib/../lib/libX11.a(xcb_io.o): in function `_XAllocIDs': /tmp/cpkg-2c6d48cdbb4678ca/libX11-1.6.7/src/xcb_io.c:549:0: error: undefined reference to `xcb_generate_id' /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/lib/../lib/libX11.a(xcb_io.o): in function `_XReply': /tmp/cpkg-2c6d48cdbb4678ca/libX11-1.6.7/src/xcb_io.c:609:0: error: undefined reference to `xcb_wait_for_reply64' /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/lib/../lib/libX11.a(ClDisplay.o): in function `XCloseDisplay': /tmp/cpkg-2c6d48cdbb4678ca/libX11-1.6.7/src/ClDisplay.c:71:0: error: undefined reference to `xcb_disconnect' /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/lib/../lib/libX11.a(OpenDis.o): in function `OutOfMemory': /tmp/cpkg-2c6d48cdbb4678ca/libX11-1.6.7/src/OpenDis.c:705:0: error: undefined reference to `xcb_disconnect' /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/lib/../lib/libX11.a(OpenDis.o): in function `XOpenDisplay': /tmp/cpkg-2c6d48cdbb4678ca/libX11-1.6.7/src/OpenDis.c:255:0: error: undefined reference to `xcb_get_setup' /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /tmp/cpkg-2c6d48cdbb4678ca/libX11-1.6.7/src/OpenDis.c:498: undefined reference to `xcb_get_maximum_request_length' /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/lib/../lib/libX11.a(xcb_disp.o): in function `_XConnectXCB': /tmp/cpkg-2c6d48cdbb4678ca/libX11-1.6.7/src/xcb_disp.c:69:0: error: undefined reference to `xcb_parse_display' /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /tmp/cpkg-2c6d48cdbb4678ca/libX11-1.6.7/src/xcb_disp.c:76: undefined reference to `xcb_connect_to_display_with_auth_info' /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /tmp/cpkg-2c6d48cdbb4678ca/libX11-1.6.7/src/xcb_disp.c:81: undefined reference to `xcb_get_file_descriptor' /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /tmp/cpkg-2c6d48cdbb4678ca/libX11-1.6.7/src/xcb_disp.c:84: undefined reference to `xcb_generate_id' /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /tmp/cpkg-2c6d48cdbb4678ca/libX11-1.6.7/src/xcb_disp.c:92: undefined reference to `xcb_connection_has_error' /usr/lib/gcc-cross/aarch64-linux-gnu/8/../../../../aarch64-linux-gnu/bin/ld: /tmp/cpkg-2c6d48cdbb4678ca/libX11-1.6.7/src/xcb_disp.c:78: undefined reference to `xcb_connect' collect2: error: ld returned 1 exit status `aarch64-linux-gnu-gcc' failed in phase `Linker'. (Exit code: 1) I looked in libX11.a with nm /usr/aarch64-linux-gnu/lib/libX11.a | rg 'xcb_take_socket' which yields U xcb_take_socket which, as I understand, means that something is screwed up in the X11 static linking (but I know less about systems programming and linkers than Haskell). Does anyone know how to fix such a problem? Cheers, Vanessa McHale

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Trying to find a Haskell unikernel project which is not HaLVM.
by Magicloud Magiclouds 01 May '19

01 May '19

Hi, About half an year ago, while I was digging a sanity check issue in 8.6.1, I accidently got a Trac mentioning a Haskell unikernel project. The name is H prefixed (apparently), and a bit of long. Now I am trying to dig more on that project, but could not find it anywhere. Does anyone have a clue? Thanks. -- 竹密岂妨流水过山高哪阻野云飞 And for G+, please use magiclouds#gmail.com.

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Repa array and Data.Vector.Storable.Mutable.
by PICCA Frederic-Emmanuel 01 May '19

01 May '19

Hello I would like a function which allows to freeze a Mutable Vector into a Repa array. of type Array F DIM2 a It seems to me that the the foreignPtr ownership should be transfer to the Repa Array, but I can not find a way to do this... So what is the proper way to achieve this ? thansk for your help. Frederic

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Agda's BUILTIN Naturals in Haskell
by Georgi Lyubenov 30 Apr '19

30 Apr '19

Hey, Is there any way to do something similar to what Agda does with natural numbers via BUILTIN pragmas? More precisely I want to have correct-by-construction natural numbers, that at runtime are treated as `Integer`s. My initial idea was to abuse rewrite rules to turn `data N = Z | S N` into `Integer` terms somehow, but I'm not sure if this is possible. ======= Georgi

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MPC 2019 deadline extension
by Graham Hutton 30 Apr '19

30 Apr '19

====================================================================== DEADLINE EXTENSION TO *10 MAY* -- MPC 2019 13th International Conference on Mathematics of Program Construction 7-9 October 2019, Porto, Portugal Co-located with Formal Methods 2019 https://tinyurl.com/MPC-Porto ====================================================================== TIMELINE: Abstract submission 7th May 2019 (AoE) (extended) Paper submission 10th May 2019 (AoE) (extended) Author notification 14th June 2019 Camera ready copy 12th July 2019 Conference 7-9 October 2019 KEYNOTE SPEAKERS: Assia Mahboubi INRIA, France Annabelle McIver Macquarie University, Australia BACKGROUND: The International Conference on Mathematics of Program Construction (MPC) aims to promote the development of mathematical principles and techniques that are demonstrably practical and effective in the process of constructing computer programs. MPC 2019 will be held in Porto, Portugal from 7-9 October 2019, and is co-located with the International Symposium on Formal Methods, FM 2019. Previous conferences were held in Königswinter, Germany (2015); Madrid, Spain (2012); Québec City, Canada (2010); Marseille, France (2008); Kuressaare, Estonia (2006); Stirling, UK (2004); Dagstuhl, Germany (2002); Ponte de Lima, Portugal (2000); Marstrand, Sweden (1998); Kloster Irsee, Germany (1995); Oxford, UK (1992); Twente, The Netherlands (1989). SCOPE: MPC seeks original papers on mathematical methods and tools put to use in program construction. Topics of interest range from algorithmics to support for program construction in programming languages and systems. Typical areas include type systems, program analysis and transformation, programming language semantics, security, and program logics. The notion of a 'program' is interpreted broadly, ranging from algorithms to hardware. Theoretical contributions are welcome, provided that their relevance to program construction is clear. Reports on applications are welcome, provided that their mathematical basis is evident. We also encourage the submission of 'programming pearls' that present elegant and instructive examples of the mathematics of program construction. SUBMISSION: Submission is in two stages. Abstracts (plain text, maximum 250 words) must be submitted by 7th May 2019. Full papers (pdf, formatted using the llncs.sty style file for LaTex) must be submitted by 10th May 2019. There is no prescribed page limit, but authors should strive for brevity. Both abstracts and papers will be submitted using EasyChair. Papers must present previously unpublished work, and not be submitted concurrently to any other publication venue. Submissions will be evaluated by the program committee according to their relevance, correctness, significance, originality, and clarity. Each submission should explain its contributions in both general and technical terms, clearly identifying what has been accomplished, explaining why it is significant, and comparing it with previous work. Accepted papers must be presented in person at the conference by one of the authors. The proceedings of MPC 2019 will be published in the Lecture Notes in Computer Science (LNCS) series, as with all previous instances of the conference. Authors of accepted papers will be expected to transfer copyright to Springer for this purpose. After the conference, authors of the best papers from MPC 2019 and MPC 2015 will be invited to submit revised versions to a special issue of Science of Computer Programming (SCP). For any queries about submission please contact the program chair, Graham Hutton <graham.hutton(a)nottingham.ac.uk>. PROGRAM COMMITTEE: Patrick Bahr IT University of Copenhagen, Denmark Richard Bird University of Oxford, UK Corina Cîrstea University of Southampton, UK Brijesh Dongol University of Surrey, UK João F. Ferreira University of Lisbon, Portugal Jennifer Hackett University of Nottingham, UK William Harrison University of Missouri, USA Ralf Hinze University of Kaiserslautern, Germany Zhenjiang Hu National Institute of Informatics, Japan Graham Hutton (chair) University of Nottingham, UK Cezar Ionescu University of Oxford, UK Mauro Jaskelioff National University of Rosario, Argentina Ranjit Jhala University of California, USA Gabriele Keller Utrecht University, The Netherlands Ekaterina Komendantskaya Heriot-Watt University, UK Chris Martens North Carolina State University, USA Bernhard Möller University of Augsburg, Germany Shin-Cheng Mu Academia Sinica, Taiwan Mary Sheeran Chalmers University of Technology, Sweden Alexandra Silva University College London, UK Georg Struth University of Sheffield, UK CONFERENE VENUE: The conference will be held at the Alfândega Porto Congress Centre, a 150 year old former custom's house located in the historic centre of Porto on the bank of the river Douro. The venue was renovated by a Pritzer prize winning architect and has received many awards. LOCAL ORGANISERS: José Nuno Oliveira University of Minho, Portugal For any queries about local issues please contact the local organiser, José Nuno Oliveira <jno(a)di.uminho.pt>. ====================================================================== This message and any attachment are intended solely for the addressee and may contain confidential information. If you have received this message in error, please contact the sender and delete the email and attachment. Any views or opinions expressed by the author of this email do not necessarily reflect the views of the University of Nottingham. Email communications with the University of Nottingham may be monitored where permitted by law.

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PPDP'19 Deadline extension
by Ekaterina Komendantskaya 28 Apr '19

28 Apr '19

DEADLINE EXTENSION TO *10 MAY* - PPDP 2019 21st International Symposium on Principles and Practice of Declarative Programming 7–9 October 2019, Porto, Portugal Collocated with FM'19 http://ppdp2019.macs.hw.ac.uk ====================================================================== Important Dates --------------- Title and abstract registration 4 May 2019 (AoE) (extended) Paper submission 10 May 2019 (AoE) (extended) Rebuttal period (48 hours) 10 June 2019 (AoE) (extended) Author notification 20 June 2019 (extended) Final paper version 15 July 2019 Conference 7–9 October 2019 About PPDP ---------- The PPDP 2019 symposium brings together researchers from the declarative programming communities, including those working in the functional, logic, answer-set, and constraint handling programming paradigms. The goal is to stimulate research in the use of logical formalisms and methods for analyzing, performing, specifying, and reasoning about computations, including mechanisms for concurrency, security, static analysis, and verification. See http://ppdp2019.macs.hw.ac.uk for further information and information. Invited Speakers ---------------- Amal Ahmed Northeastern University, USA Title: TBA Naoki Kobayashi The University of Tokyo, Japan Title: 10 Years of the Higher-Order Model Checking Project Submission page: ---------------- https://easychair.org/conferences/?conf=ppdp19

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Type information in MVars
by Georgi Lyubenov 28 Apr '19

28 Apr '19

Hi, There are obviously a lot of cool tricks you can do with phantom parameters, but they are all lost when you start looking at a `MVar` holding a type with a phantom parameter. Is there any way to track this type-level information, while still being able to write/read values from multiple threads? ======= Georgi

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