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F-IDE 2021 - Last Call for Papers - Extended Deadline
by Andrei Paskevich 24 Feb '21

24 Feb '21

****************************************************************** F-IDE 2021: 6th Workshop on Formal Integrated Development Environment Affiliated with NASA Formal Methods 2021 May 24-25, 2021 -- held online https://cister-labs.pt/f-ide2021 ****************************************************************** Keynotes * Prof. Jan Friso Groote, Eindhoven Univ. of Technology, the Netherlands * Benoît Rognier, Edukera, France Important Dates * Abstract submission - extended: Mon, Mar 8, 2021 * Full paper submission - extended: Mon, Mar 15, 2021 * Notification: Mon, Apr 19, 2021 * Camera-ready: Mon, May 3, 2021 * Workshop: May 24-25, 2021 Overview High levels of safety, security, and privacy standards require the use of formal methods to specify and develop compliant software (sub)systems. Any standard comes with an assessment process, which requires a complete documentation of the application to ease the justification of design choices and the review of code and proofs. Ideally, an F-IDE dedicated to such developments should comply with several requirements. The first one is to associate a logical theory with a programming language, in a way that facilitates the tightly coupled handling of specification properties and program constructs. The second is to offer a language and/or an environment simple enough to be usable by most developers, even if they are not fully acquainted with higher-order logics or set theory, in particular by making development of proofs as easy as possible. The third is to offer automated management of application documentation. It may also be expected that developments done with such an F-IDE are reusable and modular. Tools for testing and static analysis may be embedded within F-IDEs to support the assessment process. Topics The workshop is open to contributions on all aspects of a system development process, including specification, design, implementation, analysis, and documentation. It welcomes the presentation of tools, methods, techniques, and experiments. Topics of interest include, but are not limited to, the following: * F-IDE building: design and integration of languages, development of user-friendly front-ends * How to make high-level logical and programming concepts palatable to industrial developers * Integration of object-oriented and modularity features * Integration of static analyzers * Integration of automated proof tools, theorem provers, and testing tools * Documentation tools * Impact of tools on certification * Experience reports on developing F-IDEs * Experience reports on using F-IDEs * Experience reports on formal methods-based assessments in industrial applications Submission Guidelines We accept both long (15 pages) and short (6 pages) paper submissions. The page limit does not include the bibliography. Submitted papers must present original contributions whose main results and conclusions have not been published or submitted elsewhere. Each submission will be reviewed by at least three members of the Program Committee. We expect that one author of every accepted paper will present their work at the workshop. Submitted papers must be written in English and follow the EPTCS LaTeX format (http://style.eptcs.org) Authors are invited to submit the following types of contributions: * Research papers providing new concepts and results * Experience reports * Position papers and research perspectives * Tool presentations Papers should be submitted via EasyChair at F-IDE 2021's workshop page: https://easychair.org/conferences/?conf=f-ide2021. Preliminary proceedings will be made available in electronic form at the workshop. Post-proceedings will be published in the Electronic Proceedings in Theoretical Computer Science (EPTCS). Program Committee * Andrew Reynolds, University of Iowa, USA * Damien Doligez, Inria, France * Bernhard Rumpe, RWTH Aachen University, Germany * Carlo A. Furia, Chalmers University of Technology, Sweden * César Muñoz, NASA Langley, USA * Cinzia Bernardeschi, University of Pisa, Italy * Claudio Sacerdoti Coen, University of Bologna, Italy * Enrico Tassi, Inria, France * François Pessaux, ENSTA ParisTech, France * José Creissac Campos, University of Minho, Portugal * Kenneth Lausdahl, Aarhus University, Denmark * Laurent Voisin, Systerel, France * Lucas Wagner, Collins Aerospace, USA * Makarius Wenzel, sketis.net * Markus A. Kuppe, Microsoft Research, USA * Mattias Ulbrich, Karlsruhe Institute of Technology, Germany * Pierre-Yves Strub, LIX, École Polytechnique, France * Rosemary Monahan, Maynooth University, Ireland * Silvia Lizeth Tapia Tarifa, University of Oslo, Norway * Simão Melo de Sousa, Universidade Beira Interior, Portugal * Stefan Mitsch, Carnegie Mellon University, USA * Stephan Merz, Inria, France * Virgile Prevosto, Institut List, CEA Tech, Université Paris-Saclay, France * Yannick Moy, AdaCore, France * Yi Zhang, Massachusetts General Hospital, USA PC Chairs * Andrei Paskevich, Université Paris-Saclay, France * José Proença, CISTER/ISEP, Portugal Steering Committee * Catherine Dubois, Samovar, ENSIIE, France * Paolo Masci, US National Institute of Aerospace (NIA), USA * Dominique Méry, LORIA, Université de Lorraine, France

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Problem with stack
by Seph Shewell Brockway 24 Feb '21

24 Feb '21

Hi all, A system update (on Arch Linux) seems to have broken my stack installation. It’s started producing linker errors that look like this: dns > /usr/bin/ld.gold: error: /mnt/data/home/seph/.stack/snapshots/x86_64-linux-tinfo6/0ae0d61c27cd61876740871252be93ed57cf041b2170a9014507e77ea977085d/8.10.4/lib/x86_64-linux-ghc-8.10.4/libHScryptonite-0.27-G0nFpwexMw39Vj7zbfAUBq-ghc8.10.4.so:1:1: invalid character dns > collect2: error: ld returned 1 exit status dns > `gcc' failed in phase `Linker'. (Exit code: 1) This seems to happen no matter what snapshot I’m using, although not necessarily with the same packages. Does anyone have any idea what might be going on? Regards, Seph -- Seph Shewell Brockway, BSc MSc (Glas.) Pronouns: she/her

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[ANN] cabal-install-3.4.0.0
by Emily Pillmore 24 Feb '21

24 Feb '21

The Cabal team is excited to announce the release of cabal-install 3.4. This is the third release of the 3.0 release series, bringing a support for the `Cabal-Version: 3.4` `.cabal` file format. This introduces a number of user-facing features including: - Support for GHC 9.0 - Package sublibrary dependency syntax - Allowing omission of the `default-language` declaration - A mixins field allowing the user to specify a sublibrary - [Many other features]( https://cabal.readthedocs.io/en/latest/file-format-changelog.html#cabal-ver… ) In addition, the `cabal-install` frontend itself has gained a number of new features including: - New `active-repositories` `cabal.project` fields allowing users to specify an order and various ways of combining package repositories - Improvements to `cabal init` - A rework of the `cabal v2-sdist` command. `cabal v1-sdist` is removed as of this version - `source-repository-package` directories are no longer local - A new `list-bin` command - `cabal sandbox` is now removed in favor of default nix-style builds - `cabal list` now accepts regular expressions - More rich `index-state` syntax. `v2-freeze` saves `index-state` I'd also like to thank the many contributors who offered patches, tickets, and other help in the preparation of this release. We appreciate all of your help! For a full set of release notes, see https://github.com/haskell/cabal/blob/master/release-notes/cabal-install-3.…. If you have issues, we'd love to hear about there here: https://github.com/haskell/cabal/issues. Happy hacking! Emily

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Cabal 3.2.0.0, run okay with profiling enabled, but installed exe NO profiling enabled
by YueCompl 23 Feb '21

23 Feb '21

Dear Cafe, I'm not sure it is a bug or just designed behavior? But I can't install profiling-enabled exe with cabal 3.2.0.0, while direct running works correctly. $ cabal --version cabal-install version 3.2.0.0 compiled using version 3.2.0.0 of the Cabal library $ cabal run --enable-profiling --enable-executable-profiling exe:els -- +RTS --info Up to date [("GHC RTS", "YES") ,("GHC version", "8.8.4") ,("RTS way", "rts_thr_p") ,("Build platform", "x86_64-apple-darwin") ,("Build architecture", "x86_64") ,("Build OS", "darwin") ,("Build vendor", "apple") ,("Host platform", "x86_64-apple-darwin") ,("Host architecture", "x86_64") ,("Host OS", "darwin") ,("Host vendor", "apple") ,("Target platform", "x86_64-apple-darwin") ,("Target architecture", "x86_64") ,("Target OS", "darwin") ,("Target vendor", "apple") ,("Word size", "64") ,("Compiler unregisterised", "NO") ,("Tables next to code", "YES") ,("Flag -with-rtsopts", "-maxN31 -qg") ] $ cabal install --enable-profiling --overwrite-policy=always --enable-executable-profiling exe:els && els +RTS --info Wrote tarball sdist to ... Resolving dependencies... Up to date Copying 'els' [("GHC RTS", "YES") ,("GHC version", "8.8.4") ,("RTS way", "rts_thr") ,("Build platform", "x86_64-apple-darwin") ,("Build architecture", "x86_64") ,("Build OS", "darwin") ,("Build vendor", "apple") ,("Host platform", "x86_64-apple-darwin") ,("Host architecture", "x86_64") ,("Host OS", "darwin") ,("Host vendor", "apple") ,("Target platform", "x86_64-apple-darwin") ,("Target architecture", "x86_64") ,("Target OS", "darwin") ,("Target vendor", "apple") ,("Word size", "64") ,("Compiler unregisterised", "NO") ,("Tables next to code", "YES") ,("Flag -with-rtsopts", "-maxN31 -qg") ] $ cabal install --enable-profiling --overwrite-policy=always --enable-executable-profiling exe:els && els +RTS -p Wrote tarball sdist to ... Resolving dependencies... Up to date Copying 'els' els: the flag -p requires the program to be built with -prof els: els: Usage: <prog> <args> [+RTS <rtsopts> | -RTS <args>] ... --RTS <args> els: ... Is there other options to get a profiling enabled exe installed? Thanks with regards, Compl

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[ANN] zlib-0.6.2.3
by Emily Pillmore 21 Feb '21

21 Feb '21

Hello Everyone, I'm pleased to announce zlib-0.6.2.3, which adds support for the bytestring-0.11 work, and unblocks a decent number of packages to the next bytestring versions. I would also like to announce that two new maintainers have been added to the zlib team: Andrew Lelechenko (bodigrim), and myself (topos). Cheers, Emily

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Munich Virtual Haskell Meeting, 2021-02-23 @ 19:30
by Leah Neukirchen 21 Feb '21

21 Feb '21

Dear all, Next week, our monthly Munich Haskell Meeting will take place again on Tuesday, Feburary 23 on Google Meet at 19:30 CET. **Due to meetup limitations in Bavaria, this meeting will take place online!** For details see here: https://muenchen.haskell.bayern/dates.html A Google Meet link to join the room is provided on the page. Everybody is welcome, especially the Haskellers from Bavaria that do not usually come to our Munich meetings due to travel distance! cu, -- Leah Neukirchen <leah(a)vuxu.org> https://leahneukirchen.org/

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dyre-0.9.0 release candidate and call for testing
by Fraser Tweedale 21 Feb '21

21 Feb '21

Dyre is a tool for Haskell program configuration by (re)compilation. After years of project dormancy, I am pleased to announce a Dyre 0.9 release candidate[1]. If you are interested and able to test this candidate release, you can report results at [2]. For more details including changelog, see the accompanying blog post[3]. [1] https://hackage.haskell.org/package/dyre-0.9.0/candidate [2] https://github.com/willdonnelly/dyre/issues/39 [3] https://frasertweedale.github.io/blog-fp/posts/2021-02-21-dyre-0.9-rc.html Thanks, Fraser

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More Efficient Recursion
by A. Mc. 21 Feb '21

21 Feb '21

Hello, I'm just starting off, but I'm wondering if anyone has any suggestions. I've made a recursive function that's goal is to handle a base raised to a very large power. modLoop :: Integer -> Integer -> Integer -> Integer -> Integer -> Integer modLoop iterator exponent result base modulus | (iterator == exponent) = result | (iterator < exponent) = modLoop (iterator + 1) (exponent) (mod (result * base) modulus) base modulus | (iterator > exponent) = (-1) However, it flat breaks or takes a long time when using large numbers. I need to get better at using strict functions, however, I compiled with ghc -o (as it tends to implement the strict version - ?) and I still have the same problem. What's a better way? Thanks in advance and thank you for your time.

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help with existential type signature?
by Ken T Takusagawa 20 Feb '21

20 Feb '21

{- I am experimenting with type-level naturals and with moving values known at runtime to type space. Is there a type signature that I can add to f1 below so that this will compile (maybe also requiring some additional LANGUAGE pragmas)? If I were to change the return value of f1 from "x" to "show x", then the program does compile, suggesting that there's nothing inherently wrong with "x". But I'd prefer the option to compose the output of f1 with other computations separately, e.g., "show . f1" . Thanks, Ken -} {-# LANGUAGE KindSignatures, ScopedTypeVariables, DataKinds, Rank2Types #-} import qualified GHC.TypeLits as TypeLits; import Data.Proxy(Proxy); main = undefined; data Foo (fn :: TypeLits.Nat) = Mkfoo deriving (Show); --f1 :: TypeLits.SomeNat -> ? ; f1 mynat = case mynat of { TypeLits.SomeNat (_ :: Proxy n) -> let { x :: Foo n; x = Mkfoo; } in x }; {- typelits.hs:27:8: error: * Couldn't match expected type `p' with actual type `Foo n' because type variable `n' would escape its scope This (rigid, skolem) type variable is bound by a pattern with constructor: TypeLits.SomeNat :: forall (n :: TypeLits.Nat). TypeLits.KnownNat n => Proxy n -> TypeLits.SomeNat, in a case alternative at smalltypelits2.hs:24:3-33 * In the expression: x In the expression: let x :: Foo n x = Mkfoo in x In a case alternative: TypeLits.SomeNat (_ :: Proxy n) -> let x :: Foo n x = Mkfoo in x * Relevant bindings include x :: Foo n (bound at smalltypelits2.hs:26:5) f1 :: TypeLits.SomeNat -> p (bound at smalltypelits2.hs:23:1) | 27 | } in x | ^ -}

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Grapheme length?
by amindfv＠mailbox.org 20 Feb '21

20 Feb '21

Does there exist a Haskell library or function for getting grapheme lengths of String/Text values? e.g. right now, Prelude.length ("ä" :: String) == 2 Data.Text.length ("ä" :: Text) == 2 But I'd like, either for String or Text, to get 1 instead (there are 2 code points but only 1 grapheme). Thanks, Tom

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