June 2019 - Haskell-Cafe

ANN brittany-0.12.0.0
by Evan Borden 28 Nov '19

28 Nov '19

Hello, I am happy to announce the release of brittany version 0.12.0.0. This version includes a number of fantastic improvements from many excellent contributors. Additionally brittany will soon be added back to stackage. In the meantime it can be built with the stack.yaml in its source or with cabal v2-build. https://hackage.haskell.org/package/brittany-0.12.0.0 Contributors ============ * Benjamin Kovach @5outh * Doug Beardsley @mightybyte * Evan Borden @eborden * Lennart Spitzner @lspitzner * Matt Noonan @moatt-noonan * Phil Hazelden @ChickenProp * Rupert Horlick @ruhatch * Sergey Vinokurov @sergv New Collaborators ================= You may be wondering why I am sending this message instead of Lennart. Taylor Fausak and I are taking on some of the maintenance for brittany. We will hopefully lift some of the burden from Lennart so he can remain the guiding light and driving force behind the project. Changes ========== This release includes many bug fixes, additional support for a number of syntactic constructs and a few layouting modifications. For full details check the change log on github: https://github.com/lspitzner/brittany/blob/master/ChangeLog.md Again thank you to brittany's fantastic contributors for helping making this release happen. -- Evan

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Call For Papers: Workshop in OCL and Textual Modeling (OCL 2019)
by Achim D. Brucker 29 Jun '19

29 Jun '19

CALL FOR PAPERS 19th International Workshop on OCL and Textual Modeling Co-located with MODELS 2019 ACM/IEEE 22nd International Conference on Model Driven Engineering Languages and System, September 15-20, 2019, Munich, Germany http://oclworkshop.github.io The goal of this workshop is to create a forum where researchers and practitioners interested in building models using OCL or other kinds of textual languages (e.g., OCL, textual MOF, Epsilon, or Alloy) can directly interact, report advances, share results, identify tools for language development, and discuss appropriate standards. In particular, the workshop will encourage discussions for achieving synergy from different modeling language concepts and modeling language use. The close interaction will enable researchers and practitioners to identify common interests and options for potential cooperation. ## Topics of interest Topics of interest include (but are not limited to): - Mappings between textual modeling languages and other languages/formalisms - Mathematical models and/or formal semantics for textual modeling languages - Algorithms, evaluation strategies and optimizations in the context of textual modeling languages for: - validation, verification, and testing, - model transformation and code generation, - meta-modeling and DSLs, and - query and constraint specifications - Alternative graphical/textual notations for textual modeling languages - Evolution, transformation and simplification of textual modeling expressions - Libraries, templates and patterns for textual modeling languages - Tools that support textual modeling languages (e.g., verification of OCL formulae, runtime monitoring of invariants) - Model-driven security using textual modeling languages - Complexity results for textual modeling languages - Quality models and benchmarks for comparing and evaluating textual modeling tools and algorithms - Successful applications of textual modeling languages - Case studies on industrial applications of textual modeling languages - Experience reports: - usage of textual modeling languages and tools in complex domains, - usability of textual modeling languages and tools for end-users - Empirical studies about the benefits and drawbacks of textual modeling languages - Innovative textual modeling tools - Comparison, evaluation and integration of modeling languages - Correlation between modeling languages and modeling tasks We particularly encourage submissions describing applications and case studies of textual modeling as well as test suites and benchmark collections for evaluating textual modeling tools. ## Submissions Four types of submissions will be considered: * Presentation only submission (not included in the workshop proceedings), e.g., for already published work. Authors should submit a short (1 page) abstract of their presentation. * Short papers (between 5 and 7 pages) describing new ideas or position papers. * Tool papers (between 5 and 7 pages) describing tools supporting textual modeling tools * Full papers (between 10 and 14 pages). All submissions should follow the LNCS format guidelines and should be uploaded to [EasyChair](https://easychair.org/conferences/?conf=ocl2019). Accepted papers will be published online in [CEUR](http://www.ceur-ws.org). ## Important Dates - Submission of papers: 14 Jul 2019 - Notification: 25 Aug 2019 - Pre-Workshop CRC: 9 Sep 2019 - Post-Workshop CRC: 5 Oct 2019 -- Prof. Achim Brucker | Chair in Cybersecurity & Head of Group | University of Exeter https://www.brucker.ch | https://logicalhacking.com/blog @adbrucker | @logicalhacking

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Intention to take over package "quipper"
by selinger＠mathstat.dal.ca 27 Jun '19

27 Jun '19

I am writing, as recommended at https://wiki.haskell.org/Taking_over_a_package, to announce my intention to take over the "quipper" package on Hackage. I have contacted the author (miniBill, aka Leonardo Taglialegne) in February 2019, and again this Tuesday, with no response. I am one of the authors of Quipper, and the code in miniBill's "quipper" package was actually written by me and my coauthors. Since the package is both outdated and incomplete, and he is not maintaining it, we would like to assume ownership of the package. Thanks, -- Peter

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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 26 Jun '19

26 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 26 Jun '19

26 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 24 Jun '19

24 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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