- Haskell-Cafe - Haskell.org

Problem with ghc-9.2.2 on Windows
by Ben Franksen 28 Apr '22

28 Apr '22

Hi everyone I have a strange problem with ghc-9.2.2 on Windows. I recently updated the cabal file for darcs to allow building with ghc-9.2, which required only a few minor changes. But when I ran the tests using our github CI I noticed two regressions vs. ghc-9.0.2 on Windows. It turned out that both tests (shell scripts) try to run the darcs executable under test with a restricted PATH environment variable; the idea is to test what happens if darcs tries to run some external program which cannot be found in the PATH. The problem is that executing darcs under these circumstances fails immediately without any error message. In fact it seems to fail *before the main procedure is executed*. I tested this by printing some text to stderr in main before doing anything else and the text is not printed. The error cannot be reproduced with a simple example program, which seems to indicate that the problem may be caused by a library. But I am not aware of any way a library can influence code that is executed before main. Any kind of input on how to diagnose this problem further would be appreciated. I this were on Linux I'd use strace to find out if anything is trying to run an external program before main but this happens on Windows only and the only access I have to a Windows machine to run tests on is via the github CI. BTW, using `cabal freeze` I found these differences in library versions between the ghc-9.0 and ghc-9.2 builds. If I am not mistaken they are all "boot" libraries i.e. ones that come with ghc. ben@home[1]:.../darcs/screened>diff cabal.project.freeze-ghc-9.0 cabal.project.freeze-ghc-9.2 2c2 < constraints: any.Cabal ==3.4.1.0, --- > constraints: any.Cabal ==3.6.3.0, 25c25 < any.base ==4.15.1.0, --- > any.base ==4.16.1.0, 34c34 < any.binary ==0.8.8.0, --- > any.binary ==0.8.9.0, 37c37 < any.bytestring ==0.10.12.1, --- > any.bytestring ==0.11.3.0, 51c51 < any.containers ==0.6.4.1, --- > any.containers ==0.6.5.1, 61c61 < any.deepseq ==1.4.5.0, --- > any.deepseq ==1.4.6.1, 73c73 < any.filepath ==1.4.2.1, --- > any.filepath ==1.4.2.2, 76,78c76,78 < any.ghc-bignum ==1.1, < any.ghc-boot-th ==9.0.2, < any.ghc-prim ==0.7.0, --- > any.ghc-bignum ==1.2, > any.ghc-boot-th ==9.2.2, > any.ghc-prim ==0.8.0, 81a82 > haskeline +examples +terminfo, 113c114 < any.parsec ==3.1.14.0, --- > any.parsec ==3.1.15.0, 137c138 < any.stm ==2.5.0.0, --- > any.stm ==2.5.0.2, 148c149 < any.template-haskell ==2.17.0.0, --- > any.template-haskell ==2.18.0.0, 163c164 < any.time ==1.9.3, --- > any.time ==1.9.3 || ==1.11.1.1, Cheers Ben -- I would rather have questions that cannot be answered, than answers that cannot be questioned. -- Richard Feynman

2 2

Second CfP: FMBC 2022 - 4th International Workshop on Formal Methods for Blockchains
by Zaynah Dargaye 27 Apr '22

27 Apr '22

FMBC 2022 Second Call for Papers [ Please distribute, apologies for multiple postings. ] ======================================================================== 4th International Workshop on Formal Methods for Blockchains (FMBC) - First Call https://fmbc.gitlab.io/2022 August 11, 2022, Haifa, Israel Co-located with the The Federated Logic Conference 2022 (FLoC 22 -- https://www.floc2022.org/) as a satellite workshop of the 34th International Conference on Computer-Aided Verification (CAV 2022 -- http://i-cav.org/2022/) ----------------------------------------------------------------- Important dates --------------------- Abstract submission: May 3, 2022 Full paper submission: May 10, 2022 Notification: June 15, 2022 Camera-ready: July 13, 2022 Workshop: August 11, 2022 Deadlines are Anywhere on Earth -- https://en.wikipedia.org/wiki/Anywhere_on_Earth. ---------------------- ---------------------- 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 software. 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: * Formal models of Blockchain applications or concepts * Formal methods for consensus protocols * Formal methods for Blockchain-specific cryptographic primitives or protocols * Design and implementation of Smart Contract languages * Verification of Smart Contracts ---------------------- ---------------------- SUBMISSION --------------------- Submit original manuscripts (not published or considered elsewhere) with a page limit of 12 pages for full papers and Systematization of Knowledge (SoK) papers, 6 pages for short papers, and 2 pages for tool papers (excluding bibliography and short appendix of up to 5 additional pages). Alternatively, you may also submit an extended abstract of up to 3 pages (including a bibliography) summarizing your ongoing work in the area of formal methods and blockchain. Authors of selected extended abstracts are invited to give a short lightning talk. -------------------- -------------------- 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 workshop proceedings. , published as a volume of the OpenAccess Series in Informatics (OASIcs <https://www.dagstuhl.de/en/publications/oasics/>) by Dagstuhl. ---------------------- ---------------------- INVITED SPEAKER --------------------- Massimo Bartoletti, Professor, Università degli Studi di Cagliari, Italy ---------------------- ---------------------- PROGRAM COMMITTEE --------------------- PC CO-CHAIRS * Zaynah Dargaye (Nomadic Labs, France) (zaynah.dargaye(a)nomadic-labs.com) * Clara Schneidewind, (MPI-SP, Germany) (clara.schneidewind(a)mpi-sp.org) PC MEMBERS Wolfgang Ahrendt (Chalmers University of Technology, Sweden) Leonardo Alt (Ethereum Foundation, Germany) Lacramioara Astefanoaei (Nomadic Labs, France) Roberto Blanco (MPI-SP, Germany) Joachim Breitner (Germany) Achim Brucker (University of Exeter, UK) Ethan Cecchetti (University of Maryland, USA) Manuel Chakravarty (IOHK & Tweag, Netherlands) Jing Chen (Algorand Inc, USA) Jérémie Decouchant (TU Delft, Netherlands) Antonella Del Pozzo (Université Paris-Saclay & CEA & List, France) Dana Drachsler Cohen (Technion, Israel) Cezara Dragoi (INRIA & ENS & CNRS & PSL, France) Ansgar Fehnker (Twente, Netherlands) Dominik Harz (Interlay & Imperial College London, UK) Lars Hupel (INNOQ, Germany) Igor Konnov (Informal Systems, Austria) Paul Laforgue (Nomadic Labs, France) Julian Nagele (Bank of America, USA) Russel O’Connor (Blockstream) Maria Potop-Butucaru (LIP6, France) Albert Rubio (Complutense University of Madrid, Spain) César Sanchez (IMDEA, Spain) Sun Meng (Peking University, China) Simon Thompson (IO Global, UK) Josef Widder (Informal Systems, Austria)

1 0

Shutting down a Yesod/warp application
by Olaf Klinke 27 Apr '22

27 Apr '22

Dear Cafe, this topic has been discussed [1,2] a decade ago. What is the current state of affairs in this matter? It still seems to be addressed neither in yesod nor warp [*]. We have two use cases: (1) A shutdown route that allows admins to cleanly shut down the web application. (2) We want certain exceptions to terminate the application and have the surrounding monitoring (systemd, docker, ...) re-start the application. For (2) we are safe, I think, because the worker threads are forked from the main thread [3] calling warp, so propagating the exceptions up to the top bypasses warp and yesod's very comprehensive exception handlers. But any exception thrown while answering a request (such as (1)) is caught by default. Thanks Olaf [1] https://groups.google.com/g/yesodweb/c/VoenrabRUBQ [2] https://stackoverflow.com/questions/7881327/how-do-i-implement-a-shutdown-c… [3] https://mail.haskell.org/pipermail/haskell-cafe/2022-March/135132.html [*] Warp offers setOnException and setOnExceptionResponse. But does re- throwing certain exceptions from there terminate warp?

2 1

Position of Lecturer or Senior Lecturer in Cybersecurity at University of Sheffield
by Andrei Popescu 26 Apr '22

26 Apr '22

Greetings, The Department of Computer Science at University of Sheffield has an open position of Lecturer or Senior Lecturer in Cybersecurity. Details can be found here: https://www.jobs.ac.uk/job/COY785/lecturer-senior-lecturer-in-cybersecurity Note that "formalisation and proof of system security properties" is listed as a topic of interest. Women are particularly encouraged to apply. All applicants will be given equal consideration. Best wishes, Andrei

1 0

Munich Haskell Meeting, 2022-04-28 @ 19:30
by Leah Neukirchen 26 Apr '22

26 Apr '22

Dear all, This week, our monthly Munich Haskell Meeting will take place again on Thursday, April 28 at Augustiner-Gaststätte Rumpler at 19:30 CEST. 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-apr-2022/ Everybody is welcome! cu, -- Leah Neukirchen <leah(a)vuxu.org> https://leahneukirchen.org/

1 0

Near Semi Ring problem
by Henry Laxen 23 Apr '22

23 Apr '22

Dear Group, Many years ago I read a fascinating article which I can't seem to find anymore. It was about writing down (in english) the numbers from one to a billion? and being able to retrieve the nth letter. ie: onetwothreefourfive...ninehundredninetymillion....ninetynineonebillion I remember it used near semi rings and automatic differentiation, but no matter how I use those words to search (both google and duckduck) I can't find it. Do any of you have a pointer. I believe the code was written in haskell too. Best wishes, Henry Laxen

2 1

Haskell.org outage
by Ben Gamari 18 Apr '22

18 Apr '22

Hello everyone, Unfortunately Haskell.org, downloads.haskell.org, and hoogle.haskell.org are currently down. We are currently investigating the cause. Updates will be posted as they are available. Cheers, - Ben

1 1

Ord/Ix and Bounded?
by Zemyla 17 Apr '22

17 Apr '22

Are there any laws relating Bounded to Ord and Ix? For instance, any reasonable type should say minBound <= x == True for all x maxBound >= x == True for all x inRange (minBound, maxBound) x == True for all x

2 2

Retro/indie Haskell to appreciate
by Vanessa McHale 13 Apr '22

13 Apr '22

I’m looking to appreciate “retro” Haskell projects, things from before stabilization/company use. Such as: fgl https://web.engr.oregonstate.edu/~erwig/fgl/haskell/ <https://web.engr.oregonstate.edu/~erwig/fgl/haskell/> WWWBrowser https://cth.altocumulus.org/~hallgren/wwwbrowser.html <https://cth.altocumulus.org/~hallgren/wwwbrowser.html> Balsa/Teak (languages) http://apt.cs.manchester.ac.uk/projects/tools/balsa/ <http://apt.cs.manchester.ac.uk/projects/tools/balsa/> BlueSpec compiler https://github.com/B-Lang-org/bsc <https://github.com/B-Lang-org/bsc> The CABAL spec (Common Architecture for Building Applications and Tools) https://www.haskell.org/cabal/proposal/index.html <https://www.haskell.org/cabal/proposal/index.html> Frag (that one Haskell game) https://wiki.haskell.org/Frag Hugs string extensions https://www.haskell.org/hugs/pages/users_guide/here-documents.html <https://www.haskell.org/hugs/pages/users_guide/here-documents.html> I guess darcs/c2hs/happy/alex count, they have history! Bonus points for Makefiles to build the project Professor-HTML project page Hugs support Haskell 1.4 etc. support

9 10

The planned monomorphisation of Data.List
by Tom Ellis 13 Apr '22

13 Apr '22

There is a plan to monomorphise the contents of Data.List. I have written up an executive summary on the GitHub thread where it is being discussed. If you have an opinion that you would like to be taken into account then please leave a comment on that GitHub thread. https://github.com/haskell/core-libraries-committee/issues/22#issuecomment-…

1 0