October 2023 - Haskell-Cafe

[ANNOUNCE] Agda 2.6.4
by Andreas Abel 06 Oct '23

06 Oct '23

Dear all, The Agda Team is very pleased to announce the release of Agda 2.6.4. Thanks to everyone who gave us feedback on the release candidates! # Highlights of Agda 2.6.4 * Cubical Agda now displays boundary conditions in interactive mode (PR [#6529](https://github.com/agda/agda/pull/6529)). * An inconsistency in the treatment of large indices has been fixed (Issue [#6654](https://github.com/agda/agda/issues/6654)). * Unfolding of definitions can now be fine-controlled via `opaque` definitions. * Additions to the sort system: `LevelUniv` and `Propω`. * New flag `--erasure` with several improvements to erasure (declared run-time irrelevance). * New reflection primitives for meta-programming. # GHC supported versions Agda 2.6.4 has been tested with GHC 9.6.3, 9.4.7, 9.2.8, 9.0.2, 8.10.7, 8.8.4 and 8.6.5 on Linux, macOS and Windows. # Installation Agda 2.6.4 can be installed using cabal-install or stack: 1. Getting the tarball $ cabal update $ cabal get Agda-2.6.4 $ cd Agda-2.6.4 2. a. Using cabal-install $ cabal install -f +optimise-heavily -f +enable-cluster-counting 2. b. Using stack $ stack --stack-yaml stack-a.b.c.yaml install --flag Agda:optimise-heavily --flag Agda:enable-cluster-counting replacing `a.b.c` with your version of GHC. The flags mean: - optimise-heavily: Turn on extra optimisation for a faster Agda. Takes large resources during compilation of Agda. - enable-cluster-counting: Enable unicode clusters for alignment in the LaTeX backend. Requires the ICU lib to be installed and known to pkg-config. These flags can be dropped from the install if causing trouble. # Standard library You can use standard library v1.7.2 or the `master` branch of the standard library with Agda 2.6.4. This branch is available at https://github.com/agda/agda-stdlib/ # Fixed issues over Agda 2.6.3 https://hackage.haskell.org/package/Agda-2.6.4/changelog Enjoy Agda! Andreas, on behalf of the Agda Team _______________________________________________ Agda mailing list Agda(a)lists.chalmers.se https://lists.chalmers.se/mailman/listinfo/agda

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Meaning of fizzled sparks?
by David Banas 04 Oct '23

04 Oct '23

Hi all, If this code: f5Rslts = map (f5 (n-1) startingMinScore startingMaxScore (otherColor clr) 0) newBoards `using` parList rdeepseq totalMoves = sum $ map snd f5Rslts -- Attempt at parallelization yielded no perf. improvement. is yielding a fizzled spark ratio of about 0.3, does it imply that the sum begins pulling from the list, before the sparks have had a chance to compute the first third of the list elements? Thanks, -db

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CFP, PEPM 2024 ACM SIGPLAN Workshop on Partial Evaluation and Program Manipulation
by Meng Wang 03 Oct '23

03 Oct '23

Dear Haskellers, Gabriele and I are organising PEPM this year. Over the years, PEPM has grown into a conference of general PL topics and Haskell/FP is strongly represented. We look forward to receiving your submissions. Best regards, Gabriele Keller (Utrecht University, Netherlands) Meng Wang (University of Bristol, UK) ---------------------------------------------------------------------------------------------------------- ** ** CALL FOR PAPERS ** ** PEPM at POPL 2024 ** Workshop on PARTIAL EVALUATION AND PROGRAM MANIPULATION ** 16th of January 2024, London, United Kingdom ** ** Submission Deadline: ** 18 October 2023 ** ** https://popl24.sigplan.org/home/pepm-2024 ** https://easychair.org/conferences/?conf=pepm24 ** ----------------------------------------------------------------------------------------------------------- ACM SIGPLAN Workshop on PARTIAL EVALUATION AND PROGRAM MANIPULATION (PEPM) 2024 =============================================================================== * Website : https://popl24.sigplan.org/home/pepm-2024 * Time : 16th January 2024 * Place : London, United Kingdom (co-located with POPL 2024) The ACM SIGPLAN Workshop on Partial Evaluation and Program Manipulation (PEPM) has a history going back to 1991 and has been co-located with POPL every year since 2006. It originated with the discoveries of useful automated techniques for evaluating programs with only partial input. Over the years, the scope of PEPM has expanded to include a variety of research areas centred around the theme of semantics-based program manipulation — the systematic exploitation of treating programs not only as subjects to black-box execution but also as data structures that can be generated, analysed, and transformed while establishing or maintaining important semantic properties. Scope ----- In addition to the traditional PEPM topics (see below), PEPM 2024 welcomes submissions in new domains, in particular: * Semantics based and machine-learning based program synthesis and program optimisation. * Modelling, analysis, and transformation techniques for distributed and concurrent protocols and programs, such as session types, linear types, and contract specifications. More generally, topics of interest for PEPM 2024 include, but are not limited to: * Program and model manipulation techniques such as: supercompilation, partial evaluation, fusion, on-the-fly program adaptation, active libraries, program inversion, slicing, symbolic execution, refactoring, decompilation, and obfuscation. * Techniques that treat programs/models as data objects including metaprogramming, generative programming, embedded domain-specific languages, program synthesis by sketching and inductive programming, staged computation, and model-driven program generation and transformation. * Program analysis techniques that are used to drive program/model manipulation such as: abstract interpretation, termination checking, binding-time analysis, constraint solving, type systems, automated testing and test case generation. * Application of the above techniques including case studies of program manipulation in real-world (industrial, open-source) projects and software development processes, descriptions of robust tools capable of effectively handling realistic applications, benchmarking. Examples of application domains include legacy program understanding and transformation, DSL implementations, visual languages and end-user programming, scientific computing, middleware frameworks and infrastructure needed for distributed and web-based applications, embedded and resource-limited computation, and security. This list of categories is not exhaustive, and we encourage submissions describing new theories and applications related to semantics-based program manipulation in general. If you have a question as to whether a potential submission is within the scope of the workshop, please contact the programme co-chairs, Gabriele Keller (g.k.keller(a)uu.nl<mailto:g.k.keller@uu.nl>) and Meng Wang (meng.wang(a)bristol.ac.uk<mailto:meng.wang@bristol.ac.uk>). Submission categories and guidelines ------------------------------------ Three kinds of submissions will be accepted: * Regular Research Papers should describe new results, and will be judged on originality, correctness, significance, and clarity. Regular research papers must not exceed 12 pages. * Short Papers may include tool demonstrations and presentations of exciting if not fully polished research, and of interesting academic, industrial, and open-source applications that are new or unfamiliar. Short papers must not exceed 6 pages. * Talk Proposals may propose lectures about topics of interest for PEPM, existing work representing relevant contributions, or promising contributions that are not mature enough to be proposed as papers of the other categories. Talk Proposals must not exceed 2 pages. References and appendices are not included in page limits. Appendices may not necessarily be read by reviewers. Both kinds of submissions should be typeset using the two-column ‘sigplan’ sub-format of the new ‘acmart’ format available at: http://sigplan.org/Resources/Author/ and submitted electronically via EasyChair: https://easychair.org/conferences/?conf=pepm24 Reviewing will be single-blind. Submissions are welcome from PC members (except the two co-chairs). Accepted regular research papers will appear in formal proceedings published by ACM, and be included in the ACM Digital Library. Accepted short papers do not constitute formal publications and will not appear in the proceedings. At least one author of each accepted contribution must attend the workshop (physically or virtually) and present the work. In the case of tool demonstration papers, a live demonstration of the described tool is expected. Important dates --------------- * Paper submission deadline : **Wednesday 18th October 2023 (AoE)** * Author notification : **Wednesday 15th November 2023 (AoE)** * Workshop : **Tuesday 16th January 2024** Best paper award ---------------- PEPM 2024 continues the tradition of a Best Paper award. The winner will be announced at the workshop. Programme committee ------------------- * Chairs: Gabriele Keller (Utrecht University, Netherlands) Meng Wang (University of Bristol, UK)

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Meaning of "GC waiting" in ThreadScope?
by David Banas 03 Oct '23

03 Oct '23

Hi all, When viewing the result of my code execution in ThreadScope, What does it imply when there’s a great amount of time spent in the “GC waiting” phase, but only short little blips of time spent in the “GC” phase? Thanks, -db

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two HLS processes with same name
by Dennis Raddle 03 Oct '23

03 Oct '23

I'm running the HLS plugin in VS Code on MacOS, on an M2 Apple Silicon MacBook Pro. My computer is running low on RAM and the HLS process seems to be fairly large for me (over 1 GB). When I first run VS Code on a Haskell workspace, there is one process called "haskell-language-server-9.2.8". Eventually another process, taking an additional 1 GB, joins it. The two processes have the same name. Is it supposed to work like this? Note about Apple Silicon FYI: I bought this computer in June with 16 GB Integrated RAM. RAM is very expensive in a SoC. I'm discovering that a lot of programs are memory hogs, not sure if it's the latest MacOS or M2, but between running software development stuff and music-related apps, I'm running out of RAM. I just bought a similar MacBook but with 32 GB RAM, and will sell the current one. So eventually I won't worry about an extra GB process or two. Dennis

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Taking over maintainership of `fec`
by Jean-Paul Calderone 02 Oct '23

02 Oct '23

Hello all, I would like to take over maintainership of the `fec` package ( https://hackage.haskell.org/package/fec) fec is a wrapper around a C library for a certain forward erasure code scheme. Neither the C library nor the Haskell bindings have changed much since the package was last published on Hackage but recently I've fixed a multithreading bug that leads to corrupt results and an integer overflow bug that leads to memory corruption and typically a segfault. I would love to make these improvements available via Hackage. I don't think `fec` has much of a user base but I've recently published several cryptographic libraries on Hackage which depend on it and suffer from the two issues mentioned above. I'm also an upstream maintainer of the project (https://github.com/tahoe-lafs/zfec) I have emailed the current maintainer and original author of the Haskell bindings, Adam Langley (cced), about becoming a maintainer but I haven't yet heard back. Thanks, Jean-Paul

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