- Haskell-Cafe - Haskell.org

Reshaping arrays in accelerate
by Lana Black 27 Jun '19

27 Jun '19

Hello cafe, Is there a generic way to reshape an array in accelerate[1] assuming the number of dimensions remains constant? For example, given a matrix, is there a way to add or, more importantly, remove several rows or columns? It seems to me that the API is lacking in this case, but I hope I'm wrong. Thank you. [1]: https://hackage.haskell.org/package/accelerate-1.2.0.1/

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Re: [Haskell-cafe] extra semi-colons
by Johannes Waldmann 27 Jun '19

27 Jun '19

> The rule "alt" allows "(empty alternative)" Ah, yes. But no? The standard says > A case expression must have at least one alternative > and each alternative must have at least one body. Should this be "each non-empty alternative must have ..."? I think the intention is to allow case () of () | False -> () | True -> () (one alternative, two bodies) but to disallow case () of () (one alternative, no body) - J.

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Unexpected result from Data.Compact.inCompact?
by Viktor Dukhovni 27 Jun '19

27 Jun '19

I am seeing surprising results from 'inCompact' after 'compact'. It seems there are additional limitations on what can be compacted, with 'compact' not throwing a 'CompactionFailed' exception in some cases, and yet not compacting the value. Is this expected? When the below is compiled and run: {-# LANGUAGE OverloadedStrings #-} module Main (main) where import Data.Compact import qualified Data.ByteString.Short as S import qualified Data.Map.Strict as M fib :: [Int] fib = 0:1:zipWith (+) fib (tail fib) u = if M.lookup 3 m == Just 2 then () else undefined f3 = head $ drop 3 fib m = M.fromList $ zip [0..9] fib main :: IO () main = do test "explicit ()" () test "computed ()" u test "explicit Int" (42 :: Int) test "computed Int" f3 test "empty string" ("" :: String) test "non-empty string" ("some string" :: String) test "empty short bytestring" S.empty test "non-empty short bytestring" (S.toShort "some bytestring") test "explict empty map" (M.empty :: M.Map Int Int) test "computed fib table" m where test :: String -> a -> IO () test msg val = do putStr (msg ++ ": ") c <- compact val inCompact c (getCompact c) >>= print it outputs: explicit (): False computed (): False explicit Int: False computed Int: True empty string: False non-empty string: True empty short bytestring: True non-empty short bytestring: True explict empty map: False computed fib table: True but the documentation promises: getCompact :: Compact a -> a # Retrieve a direct pointer to the value pointed at by a Compact reference. If you have used compactAdd, there may be multiple Compact references into the same compact region. Upholds the property: inCompact c (getCompact c) == True so when 'compact' does not bottom, I'd expect 'True'. -- Viktor.

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OT: CLR and JVM
by trent shipley 26 Jun '19

26 Jun '19

Is there a typed, functional language with mature versions on Microsoft's CLR and the JVM? A JVM OCaml to go with F# would be ideal. Trent

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(Extended deadline) Formal Methods 2019 - 1st Workshop on Formal Methods for Blockchains, CFP
by Bruno Bernardo 25 Jun '19

25 Jun '19

[ Please distribute, apologies for multiple postings. ] ========================================================== 1st Workshop on Formal Methods for Blockchains (FMBC) 2019 https://sites.google.com/view/fmbc/home Porto, Portugal, October 11 Part of the 3rd World Congress on Formal Methods http://formalmethods2019.inesctec.pt/ ------------------------------------------------------------- IMPORTANT DATES -------------------------------- Abstract submission: June 30, 2019 (extended) Full paper submission: July 7, 2019 (extended) Notification: July 31, 2019 Camera-ready: September 2, 2019 Conference: October 11, 2019 -------------------------------- -------------------------------- TOPICS OF INTEREST -------------------------------- Blockchains are decentralized transactional ledgers that rely on cryptographic hash functions for guaranteeing the integrity of the stored data. Participants on the network reach agreement on what valid transactions are through consensus algorithms. Blockchains may also provide support for Smart Contracts. Smart Contracts are scripts of an ad-hoc programming language that are stored in the blockchain and that run on the network. They can interact with the ledger’s data and update its state. These scripts can express the logic of possibly complex contracts between users of the blockchain. Thus, Smart Contracts can facilitate the economic activity of blockchain participants. With the emergence and increasing popularity of cryptocurrencies such as Bitcoin and Ethereum, it is now of utmost importance to have strong guarantees of the behavior of blockchain so ware. These guarantees can be brought by using Formal Methods. Indeed, Blockchain software encompasses many topics of computer science where using Formal Methods techniques and tools are relevant: consensus algorithms to ensure the liveness and the security of the data on the chain, programming languages specifically designed to write smart contracts, cryptographic protocols, such as zero-knowledge proofs, used to ensure privacy, etc. This workshop is a forum to identify theoretical and practical approaches of formal methods for blockchain technology. Topics include, but are not limited to: * Design and implementation of Smart Contract languages * Formal models of blockchain applications or concepts * Formal methods for consensus protocols * Formal methods for blockchain-specific cryptographic primitives or protocols Formal languages for Smart * Verification of Smart Contracts -------------------------------- -------------------------------- SUBMISSION -------------------------------- Submit original manuscripts (not published or considered elsewhere) with a maximum of twelve pages (regular papers), six pages (short papers), and two pages (extended abstract) describing new and emerging ideas or summarizing existing work). Each paper should include a title and the name and affiliation of each author. Authors of selected extended-abstracts are invited to give a short lightning talk of up to 15 minutes. At least one author of an accepted paper is expected to present the paper at the workshop as a registered participant. All accepted contributions will be reviewed once more by the program committee after the workshop and before being included in the post-proceedings. submission link https://easychair.org/conferences/?conf=fmbc19 -------------------------------- -------------------------------- PROCEEDINGS -------------------------------- All submissions will be peer-reviewed by at least three members of the program committee for quality and relevance. Accepted regular papers (full and short papers) will be included in the FM workshop post-proceedings, published as a volume of the Lecture Notes in Computer Science (LNCS) by Springer. -------------------------------- -------------------------------- INVITED SPEAKER --------------------------------------------------------------------------------------------------------- Ilya Sergey - Associate Professor at Yale-NUS College and NUS School of Computing, (Singapore). --------------------------------------------------------------------------------------------------------- -------------------------------- -------------------------------- PROGRAM committee -------------------------------- Program Chairs Bruno Bernardo (bruno(a)nomadic-labs.com <mailto:bruno@nomadic-labs.com>) Néstor Cataño (nestor.catano(a)gmail.com <mailto:nestor.catano@gmail.com>) Diego Marmsoler (diego.marmsoler(a)tum.de <mailto:diego.marmsoler@tum.de>) Program Committee Pietro Abate (Nomadic Labs, France) Ijaz Ahmed (University of Madeira, Portuga) Jonathan Aldrich (Carnegie Mellon University, USA) Bernhard Beckert (Karlsruhe Institute of Technology, Germany) Bruno Bernardo (Nomadic Labs, France) Sukriti Bhattacharya (LIST, Luxembourg) Néstor Cataño (Universidad del Norte, Colombia) Maria Christakis (MPI-SWS, Germany) Léa-Zaynah Dargaye (CEA LIST, France) Georges Gonthier (Inria, France) Neville Grech (University of Athens, Greece / University of Malta, Malta) Davide Grossi (University of Groningen, Netherlands) Sorren Hanvey (Liverpool John Moores University, UK) Andreas Lochbihler (Digital Asset, Swiss) Diego Marmsoler (Technische Universitat Munchen, Germany) Anastasia Mavridou (NASA Ames, USA) Simão Melo de Sousa (Universidade da Beira Interior, Portugal) Fabio Mogavero (Università degli Studi di Napoli, Italy) Peter Csaba Ölveczky (University of Oslo, Norway) Karl Palmskog (University of Texas at Austin, USA) Vincent Rahli (University of Luxembourg, Luxembourg) Steve Reeves (University of Waikato, New Zealand) Camilo Rueda (Pontificia Universidad Javeriana, Colombia) Claudio Russo (Dfinity Foundation, USA) Jorge Sousa Pinto (Universidade do Minho, Portugal) Bas Spitters (Aarhus University, Denmark) Christoph Sprenger (ETH, Zürich) Mark Staples (Data61, Australia) Philip Wadler (University of Edinburgh / IOHK, UK) Xi Wu (The University of Queensland, Australia) Santiago Zanella-Beguelin (Microsoft Research Cambridge, UK) --------------------------------

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extra semi-colons
by Johannes Waldmann 25 Jun '19

25 Jun '19

Dear Cafe, why does ghc accept the extra semi-colon in case () of { () -> (); } or even case () of { ;;; () -> () ;;; } Yes I understand that semicolons like this are introduce by the layout rule L (<n> : ts) (m : ms) = ; : (L ts (m : ms)) if m = n https://www.haskell.org/onlinereport/haskell2010/haskellch10.html#x17-17800… and it's convenient to ignore extra ones. But it's not in the grammar? alts → alt1 ; … ; altn (n ≥ 1) https://www.haskell.org/onlinereport/haskell2010/haskellch3.html#x8-460003.… - J.

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Call for Participation: ICFP 2019
by Sam Tobin-Hochstadt 25 Jun '19

25 Jun '19

===================================================================== Call for Participation ICFP 2019 24th ACM SIGPLAN International Conference on Functional Programming and affiliated events August 18 - August 23, 2019 Berlin, Germany http://icfp19.sigplan.org/ Early Registration until July 18! ===================================================================== ICFP provides a forum for researchers and developers to hear about the latest work on the design, implementations, principles, and uses of functional programming. The conference covers the entire spectrum of work, from practice to theory, including its peripheries. This year, ICFP is co-located with BOBKonf! * Overview and affiliated events: http://icfp19.sigplan.org/home * Program: http://icfp19.sigplan.org/program/program-icfp-2019 * Accepted papers: http://icfp19.sigplan.org/track/icfp-2019-papers * Registration is available via: https://regmaster4.com/2019conf/ICFP19/register.php Early registration ends 18 July, 2019. * Programming contest: https://icfpcontest2019.github.io/ * Student Research Competition: https://icfp19.sigplan.org/track/icfp-2019-Student-Research-Competition * Follow us on Twitter for the latest news: http://twitter.com/icfp_conference In addition to BOBKonf (8/21), there are several events co-located with ICFP: * Erlang Workshop (8/18) * Functional Art, Music, Modeling and Design (8/23) * Functional High-Performance and Numerical Computing (8/18) * Haskell Implementors' Workshop (8/23) * Haskell Symposium (8/22-8/23) * miniKanren Workshop (8/22) * ML Family Workshop (8/22) * OCaml Workshop (8/23) * Programming Languages Mentoring Workshop (8/18) * Scheme Workshop (8/18) * Type-Driven Development (8/18) ### ICFP Organizers General Chair: Derek Dreyer (MPI-SWS, Germany) Artifact Evaluation Co-Chairs: Simon Marlow (Facebook, UK) Industrial Relations Chair: Alan Jeffrey (Mozilla Research, USA) Programming Contest Organiser: Ilya Sergey (Yale-NUS College, Singapore) Publicity and Web Chair: Sam Tobin-Hochstadt (Indiana University, USA) Student Research Competition Chair: William J. Bowman (University of British Columbia, Canada) Workshops Co-Chair: Christophe Scholliers (Universiteit Gent, Belgium) Jennifer Hackett (University of Nottingham, UK) Conference Manager: Annabel Satin (P.C.K.) ### PACMPL Volume 3, Issue ICFP 2019 Principal Editor: François Pottier (Inria, France) Review Committee: Lennart Beringer (Princeton University, United States) Joachim Breitner (DFINITY Foundation, Germany) Laura M. Castro (University of A Coruña, Spain) Ezgi Çiçek (Facebook London, United Kingdom) Pierre-Evariste Dagand (LIP6/CNRS, France) Christos Dimoulas (Northwestern University, United States) Jacques-Henri Jourdan (CNRS, LRI, Université Paris-Sud, France) Andrew Kennedy (Facebook London, United Kingdom) Daan Leijen (Microsoft Research, United States) Kazutaka Matsuda (Tohoku University, Japan) Bruno C. d. S. Oliveira (University of Hong Kong, China) Klaus Ostermann (University of Tübingen, Germany) Jennifer Paykin (Galois, United States) Frank Pfenning (Carnegie Mellon University, USA) Mike Rainey (Indiana University, USA) Chung-chieh Shan (Indiana University, USA) Sam Staton (University of Oxford, UK) Pierre-Yves Strub (Ecole Polytechnique, France) German Vidal (Universitat Politecnica de Valencia, Spain) External Review Committee: Michael D. Adams (University of Utah, USA) Robert Atkey (University of Strathclyde, IK) Sheng Chen (University of Louisiana at Lafayette, USA) James Cheney (University of Edinburgh, UK) Adam Chlipala (Massachusetts Institute of Technology, USA) Evelyne Contejean (LRI, Université Paris-Sud, France) Germán Andrés Delbianco (IRIF, Université Paris Diderot, France) Dominique Devriese (Vrije Universiteit Brussel, Belgium) Richard A. Eisenberg (Bryn Mawr College, USA) Conal Elliott (Target, USA) Sebastian Erdweg (Delft University of Technology, Netherlands) Michael Greenberg (Pomona College, USA) Adrien Guatto (IRIF, Université Paris Diderot, France) Jennifer Hackett (University of Nottingham, UK) Troels Henriksen (University of Copenhagen, Denmark) Chung-Kil Hur (Seoul National University, Republic of Korea) Roberto Ierusalimschy (PUC-Rio, Brazil) Ranjit Jhala (University of California, San Diego, USA) Ralf Jung (MPI-SWS, Germany) Ohad Kammar (University of Oxford, UK) Oleg Kiselyov (Tohoku University, Japan) Hsiang-Shang ‘Josh’ Ko (National Institute of Informatics, Japan) Ondřej Lhoták (University of Waterloo, Canada) Dan Licata (Wesleyan University, USA) Geoffrey Mainland (Drexel University, USA) Simon Marlow (Facebook, UK) Akimasa Morihata (University of Tokyo, Japan) Shin-Cheng Mu (Academia Sinica, Taiwan) Guillaume Munch-Maccagnoni (Inria, France) Kim Nguyễn (University of Paris-Sud, France) Ulf Norell (Gothenburg University, Sweden) Atsushi Ohori (Tohoku University, Japan) Rex Page (University of Oklahoma, USA) Zoe Paraskevopoulou (Princeton University, USA) Nadia Polikarpova (University of California, San Diego, USA) Jonathan Protzenko (Microsoft Research, USA) Tiark Rompf (Purdue University, USA) Andreas Rossberg (Dfinity, Germany) KC Sivaramakrishnan (University of Cambridge, UI) Nicholas Smallbone (Chalmers University of Technology, Sweden) Matthieu Sozeau (Inria, France) Sandro Stucki (Chalmers | University of Gothenburg, Sweden) Don Syme (Microsoft, UK) Zachary Tatlock (University of Washington, USA) Sam Tobin-Hochstadt (Indiana University, USA) Takeshi Tsukada (University of Tokyo, Japan) Tarmo Uustalu (Reykjavik University, Iceland) Benoit Valiron (LRI, CentraleSupelec, Univ. Paris Saclay, France) Daniel Winograd-Cort (University of Pennsylvania, USA) Nicolas Wu (University of Bristol, UK)

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How long does it take to add an entry to https://www.haskell.org/community/?
by Benjamin L. Russell 24 Jun '19

24 Jun '19

Twenty-three days ago, I added an entry to the list of Haskell communities at https://www.haskell.org/community/ and submitted a pull request to have the page (https://github.com/haskell-infra/www.haskell.org/blob/master/community.mark…) updated; however, the page still has not been updated. In addition, it seems that there are 3 other pull requests for the same page by other users that have also not been applied, the earliest of which dates from March 16. How long does it take to add an entry to https://www.haskell.org/community/? (I'm assuming that submitting a pull request to "Update community.markdown" on Github is the correct procedure for those users without write access to the page.) -- Benjamin L. Russell -- Benjamin L. Russell / DekuDekuplex at Yahoo dot com http://dekudekuplex.wordpress.com/ Computer Science Document Translator/Editor "Furuike ya, kawazu tobikomu mizu no oto." -- Matsuo Basho^

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Munich Haskell Meeting, 2019-06-25 @ 19:30
by Leah Neukirchen 23 Jun '19

23 Jun '19

Dear all, Next week, our monthly Munich Haskell Meeting will take place again on Tuesday, June 25 at **Hirschgarten (self-service area)** at 19h30. The weather should be nice! 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-jun-2019/ Everybody is welcome! cu, -- Leah Neukirchen <leah(a)vuxu.org> https://leahneukirchen.org/

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Re: [Haskell-cafe] [ANNOUNCE] GHC 8.8.1-alpha2 is now available
by Ben Gamari 22 Jun '19

22 Jun '19

George Colpitts <george.colpitts(a)gmail.com> writes: > Will 8.8.1 use llvm 7.0.1? I don't see it mentioned in the release notes. > Yes, this release will target LLVM 7. I'll add a mention to the release notes. Cheers, - Ben

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