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Upcoming maintenance on Haskell services
by Bryan Richter 22 Nov '22

22 Nov '22

Hello folks, On Thursday 24 November at 6 AM UTC, I will start a 4-hour maintenance window for the following Haskell services: 1. downloads.haskell.org 2. gitlab.haskell.org In particular, I expect the following outages: 1. downloads.haskell.org will be read-only for the duration of the window. * No uploads 2. gitlab.haskell.org will be read-only for the duration of the window. * No CI pipelines(!) * No git pushes * No commenting on issues or merge requests 3. gitlab.haskell.org will furthermore be entirely inaccessible very briefly. * There will be 1-2 outages. * Each outage will last a few seconds. The reason for the maintenance is that our hosting sponsor, Equinix Metal, is performing a facilities migration. One of our servers, gitlab-storage, is slated for retirement. All data and services that run on that server must be moved to a new server. I'm sending this first notification to a wide audience as an extra precaution in case something goes wrong. :) In reality, I expect this maintenance to only affect GHC developers and a small group of ecosystem maintainers. In particular, web access of https://downloads.haskell.org should *not* be affected by this maintenance. I will send further updates to a smaller audience. Note: The actual migration will be quick. Most of the maintenance window will be spent waiting for DNS propagation. -Bryan Haskell Foundation DevOps

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10 PhD studentships in Nottingham
by Graham Hutton 21 Nov '22

21 Nov '22

Dear all, The School of Computer Science at the University of Nottingham in the UK is seeking applications for 10 fully-funded PhD studentships: https://tinyurl.com/ten-phd-2022 Applicants in the area of the Functional Programming Lab (tinyurl.com/fp-notts) are strongly encouraged! If you are interested in applying, please contact a potential supervisor as soon as possible; the application deadline is 12th Feb 2023: Thorsten Altenkirch - constructive logic, proof assistants, homotopy type theory, category theory, lambda calculus. Ulrik Buchholtz - homotopy type theory, synthetic homotopy theory, proof assistants, constructive mathematics, and related topics. Graham Hutton - functional programming, haskell, category theory, program verification, program calculation. Nicolai Kraus - homotopy type theory, higher category theory, constructive mathematics, and related topics. Dan Marsden - category theory, logic, finite model theory, diagrammatic reasoning, foundations of computer science. These positions are open to students of any nationality. Best wishes, The FP Lab +-----------------------------------------------------------+ 10 Fully-Funded PhD Studentships School of Computer Science University of Nottingham, UK https://tinyurl.com/ten-phd-2022 Applications are invited from international and home students for 10 fully-funded PhD studentships offered by the School of Computer Science, starting on 1st October 2023. The topics for the studentships are open, but should relate to the interests of one the School's research groups: Computational Optimisation and Learning; Computer Vision; Cyber Security; Functional Programming; Intelligent Modelling and Analysis; Mixed Reality; Uncertainty in Data and Decision Making; Visualisation and Computer Graphics; Cyber-Physical Health and Assistive Robotics Technologies. The studentships are fully funded for 3.5 years and include a stipend of £17,668 per year and tuition fees. Applicants are normally expected to have a first-class class bachelors or masters in Computer Science or another relevant area, and must obtain the support of a potential supervisor in the School prior to submitting their application. If you are interested in applying, please contact a potential supervisor as soon as possible, and at least two weeks prior to the closing date. If the supervisor wishes to support your application, they will direct you to make an official application through the MyNottingham system. Closing date for applications: Sunday 12th February 2023. +-----------------------------------------------------------+ This message and any attachment are intended solely for the addressee and may contain confidential information. If you have received this message in error, please contact the sender and delete the email and attachment. Any views or opinions expressed by the author of this email do not necessarily reflect the views of the University of Nottingham. Email communications with the University of Nottingham may be monitored where permitted by law.

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Cabal 3.10 last call for contributions
by Mikolaj Konarski 17 Nov '22

17 Nov '22

Hi! Would you like cabal 3.10 to have your favourite bugfix, feature or overall spiffiness? If so, please let us help you help yourself. We are going to soft-freeze cabal 3.10 in a month or two and ship a little later, around the GHC 9.6 release date. There is still time to fix your favourite regression https://github.com/haskell/cabal/issues?q=is%3Aopen+label%3A%22regression+i… or add your high priority feature (or argue for bumping the priority of an existing ticket) https://github.com/haskell/cabal/labels/priority%3A%20high%20%3Afire%3A The friendly team of cabal maintainers is at your disposal whether you need a PR review, a design discussion in a ticket, or you just get stuck or urgently need somebody to chat to (the #hackage IRC/matrix room is open). Cabal 3.10 is going to be mostly a bugfix release, so there may or may not be a release candidate for you to try to break. However, brave people are continuously dogfooding the master branch from github artifacts (at the bottom of 'validate' CI jobs) or gitlab pipelines (more flavours, including statically linked Alpine Linux) https://gitlab.haskell.org/haskell/cabal/-/pipelines/59103 Another way you can contribute is by picking up a newcomer-labelled ticket. Yet another is triaging new tickets, e.g., via https://www.codetriage.com/haskell/cabal Don't worry if you feel you'd need to learn a lot --- cabal is a large and constantly changing system, so most of us are forgetting faster than learning. However, purity, types and tests often permit to focus, code-dive and fix or improve a hot subsystem in relative isolation. See you there, Mikolaj

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[ANN] base16-3.2.1
by Emily Pillmore 16 Nov '22

16 Nov '22

Hi All, I'm announcing `base16-3.2.1`, available on hackage now, which features a QOL contribution from Shea Levy, as well as support for up to GHC 9.4.x. This will be the last in the 3.x series before the next major update, which will feature newtyped Base16 bytestrings and optimized Base16 encoding and decoding loops. The same will happen across the all the BaseN encoding libraries from me. Cheers, Emily

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[ANN] faster-megaparsec
by Olaf Klinke 15 Nov '22

15 Nov '22

Dear Haskellers, megaparsec [1] is a parsing library with excellent error reporting. Being able to emit decent parse error messages is traded off against speed, however. Wouldn't it be nice to have a faster parser for your daily parsing needs, but obtain megaparsec's informative error messages for the rare cases when things go wrong? Thanks to megaparsec's parser type class, MonadParsec, you can have both: I wrote a MonadParsec instance for StateT s Maybe (s being the input stream type such as Text or ByteString) which does not do all the bookkeeping ParsecT needs to do. If you manage to write your parser only using the type class primitives, then you can specialize your parser to StateT s Maybe. Only if that returns Nothing specialize again to ParsecT Void s and parse the input again, thus obtaining a decent error message. The package faster-megaparsec [1,2] provides a convenient function to do just that. Of course StateT s Maybe can not provide all the features ParsecT has: * StateT s Maybe is always backtracking. * It does not know the offset in the stream. * It must hold the entire input stream in memory for a second pass, so no garbage collecting the consumed input while parsing. So if your parsing relies on non-backtracking choice, stream offset or garbage-collecting input while parsing, you can not use faster- megaparsec as a drop-in replacement. Happy parsing! Olaf [1] https://hackage.haskell.org/package/megaparsec [2] https://hackage.haskell.org/package/faster-megaparsec [3] https://hub.darcs.net/olf/faster-megaparsec

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[TFP 2023 2nd Call for Papers] 24th International Symposium on Trends in Functional Programming
by Peter Achten 15 Nov '22

15 Nov '22

# TFP 2023 -- Call for Papers (trendsfp.github.io) ## Important Dates Submission deadline: pre-symposium, full papers, Wednesday 23rd November, 2022 Submission deadline: pre-symposium, draft papers, Friday 16th December, 2022 Notification: pre-symposium submissions, Friday 23rd December, 2022 Registration: Friday 6th January, 2023 TFPIE Workshop: Thursday 12th January, 2023 TFP Symposium: Friday 13th - Sunday 15th January, 2023 Submission deadline: post-symposium review, Friday 17th February, 2023 Notification: post-symposium submissions, Friday 31st March, 2023 The Symposium on Trends in Functional Programming (TFP) is an international forum for researchers with interests in all aspects of functional programming, taking a broad view of current and future trends in the area. It aspires to be a lively environment for presenting the latest research results, and other contributions. This year, TFP will take place in-person at UMass Boston, Massachusetts in the United States. It is co-located with the Trends in Functional Programming in Education (TFPIE) workshop, which will take on the day before the main symposium. Please be aware that TFP has several submission deadlines. The first, November 23, is for authors that wish to have their full paper reviewed prior to the symposium. Papers that are accepted in this way must also be presented at the symposium. The second, December 16, is for authors that wish to present their work or work-in progress at the symposium first without submitting to the full review process for publication. These authors can then take into account feedback received at the symposium and submit a full article for review by the third deadline, February 17. ## Scope The symposium recognizes that new trends may arise through various routes. As part of the Symposium's focus on trends we therefore identify the following five article categories. High-quality articles are solicited in any of these categories: * Research Articles: Leading-edge, previously unpublished research work * Position Articles: On what new trends should or should not be * Project Articles: Descriptions of recently started new projects * Evaluation Articles: What lessons can be drawn from a finished project * Overview Articles: Summarizing work with respect to a trendy subject Articles must be original and not simultaneously submitted for publication to any other forum. They may consider any aspect of functional programming: theoretical, implementation-oriented, or experience-oriented. Applications of functional programming techniques to other languages are also within the scope of the symposium. Topics suitable for the symposium include, but are not limited to: * Functional programming and multicore/manycore computing * Functional programming in the cloud * High performance functional computing * Extra-functional (behavioural) properties of functional programs * Dependently typed functional programming * Validation and verification of functional programs * Debugging and profiling for functional languages * Functional programming in different application areas: security, mobility, telecommunications applications, embedded systems, global computing, grids, etc. * Interoperability with imperative programming languages * Novel memory management techniques * Program analysis and transformation techniques * Empirical performance studies * Abstract/virtual machines and compilers for functional languages * (Embedded) domain specific languages * New implementation strategies * Any new emerging trend in the functional programming area If you are in doubt on whether your article is within the scope of TFP, please contact the TFP 2023 program chair, Stephen Chang. ## Best Paper Awards TFP awards two prizes for the best papers each year. First, to reward excellent contributions, TFP awards a prize for the best overall paper accepted for the post-conference formal proceedings. Second, a prize for the best student paper is awarded each year. TFP traditionally pays special attention to research students, acknowledging that students are almost by definition part of new subject trends. A student paper is one for which the authors state that the paper is mainly the work of students, the students are listed as first authors, and a student would present the paper. In both cases, it is the PC of TFP that awards the prize. In case the best paper happens to be a student paper, then that paper will receive both prizes. ## Instructions to Authors Papers must be submitted at: <https://easychair.org/conferences/?conf=tfp23> Authors of papers have the choice of having their contributions formally reviewed either before or after the Symposium. Further, pre-symposium submissions may either be full (earlier deadline) or draft papers (later deadline). ## Pre-symposium formal review Papers to be formally reviewed before the symposium should be submitted before the early deadline and will receive their reviews and notification of acceptance for both presentation and publication before the symposium. A paper that has been rejected for publication but accepted for presentation may be resubmitted for the post-symposium formal review. ## Post-symposium formal review Draft papers will receive minimal reviews and notification of acceptance for presentation at the symposium. Authors of draft papers will be invited to submit revised papers based on the feedback receive at the symposium. A post-symposium refereeing process will then select a subset of these articles for formal publication. ## Paper categories Draft papers and papers submitted for formal review are submitted as extended abstracts (4 to 10 pages in length) or full papers (20 pages). The submission must clearly indicate which category it belongs to: research, position, project, evaluation, or overview paper. It should also indicate which authors are research students, and whether the main author(s) are students. A draft paper for which all authors are students will receive additional feedback by one of the PC members shortly after the symposium has taken place. ## Format Papers must be written in English, and written using the LNCS style. For more information about formatting please consult the Springer LNCS web site. ## Program Committee Peter Achten, Radboud University Nijmegen, Netherlands Nada Amin, Harvard University, USA Ambrose Bonnaire-Sergeant, Untypable LLC, USA Laura M. Castro, University of A Coruña, Spain Stephen Chang (Chair), University of Massachusetts Boston, US John Clements, Cal Poly, USA Youyou Cong, Tokyo Institute of Technology, Japan Paul Downen, University of Massachusetts Lowell, USA Kathy Gray, Meta Platforms, Inc., UK Ben Greenman, University of Utah, USA Jason Hemann, Seton Hall University, USA Patricia Johann, Appalachian State University, USA Alexis King, Tweag, USA Julia Lawall, Inria-Paris, France Barak Pearlmutter, Maynooth University, Ireland Norman Ramsey, Tufts University, USA Ilya Sergey, National University of Singapore, Singapore Melinda Tóth, Eötvös Loránd University, Hungary Ningning Xie, University of Toronto, Canada

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[ANN] Copilot 3.12
by Ivan Perez 14 Nov '22

14 Nov '22

Dear all, I'm very excited to announce Copilot 3.12. Copilot is a stream-based DSL for writing and monitoring embedded C programs, with an emphasis on correctness and hard realtime requirements. Copilot is typically used as a high-level runtime verification framework, and supports temporal logic (LTL, PTLTL and MTL), clocks and voting algorithms. Among others, Copilot has been used at the Safety Critical Avionics Systems Branch of NASA Langley Research Center for monitoring test flights of drones. It also serves as a runtime monitoring backend for the requirements elicitation tool FRET (https://github.com/NASA-SW-VnV/fret/) via Ogma ( https://github.com/nasa/ogma) The main changes in this release are as follows: - A new library copilot-prettyprinter exposes functions related to the Copilot Core pretty-printing backend. Pre-existing functions included as part of copilot-core are now deprecated. - The C99 backend now produces an additional header file with struct declarations. This file is used by the C implementation file generated by Copilot to define structs before the declarations of the handlers, avoiding potential forward declarations that the C compiler cannot resolve. Users of Copilot can choose to import the same new type declaration header file before the standard Copilot header file in their hand-written code, or use external definitions that declare compatible structs. Note that, in the former case, the header file that declares the structs must be included before the header file that declares the externs, handlers and step function. - The custom type equality module in copilot-core is now deprecated in favour of the definition of type equality in base. - copilot-theorem now includes support for proofs by bisimulation necessary for future extensions to Copilot. - copilot-core now complies with the coding rules established as part of the process of compliance with higher NASA's requirements for software with higher assurance classifications. Current emphasis is on improving the codebase in terms of stability and test coverage, removing unnecessary dependencies, hiding internal definitions, and formatting the code to meet our new coding standards. Users are encouraged to participate by opening issues and asking questions via our github repo (https://github.com/copilot-language/copilot) I'd also like to take this opportunity to announce that Copilot is now available on Debian. As a consequence of this effort, Copilot will also be available to Ubuntu users in the near future. We would like to publicly thank the Debian Haskell Group and, most especially, Scott Talbert, for continued effort making Copilot available on Debian-based distros. This will be extremely useful to a great portion of our users, who need to use Copilot as a runtime verification system targeting C, but do not need to become proficient in Haskell. We hope to continue this effort by making Copilot easily available on other distributions and OSs. Happy Haskelling, The Copilot team

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Sam Staton giving this year's LMS/BCS-FACS Evening Seminar (online) -- registration open until this Wednesday at 5PM, UTC
by Andrei Popescu 14 Nov '22

14 Nov '22

EVENT: Annual LMS/BCS-FACS Evening Seminar SPEAKER: Sam Staton, University of Oxford TITLE: Programming-based foundations for statistics DATE: Thursday, 17 November 2022, Starting time: 18:00 UTC VENUE: Online via Zoom EVENT PAGE: https://www.lms.ac.uk/events/lectures/lms-bcs-facs-evening-seminars REGISTRATION LINK: https://www.lms.ac.uk/civicrm/event/register?id=88&reset=1 Prior registration is required for attendance -- the registration site will close on Wednesday, 16 November, at 17:00 SYNOPSIS Probabilistic programming is a popular tool for statistics and machine learning. The idea is to describe a statistical model as a program with random choices. The program might be a simulation of a system, such as a physics model, a model of viral spread, or a model of electoral behaviour. We can now carry out statistical inference over the system, for example, by running a Monte Carlo simulation – running the simulation 100,000’s of times. As I will discuss in this talk, the idea of treating statistical models as computer programs also has a foundational appeal. If we can understand statistical models as programs, then the foundations of probability and statistics can be discussed in terms of program semantics. There is a chance of new foundational perspectives on statistics, in terms of programming languages and their formal methods. As I will explain, this programming-based foundation for statistics is attractive because there are some intuitively simple scenarios, such as inference over function spaces, which have an easy programming implementation, but for which the traditional mathematical interpretation is complicated. SPEAKER BIOGRAPHY Sam Staton is a Professor of Computer Science and Royal Society University Research Fellow at the University of Oxford. There he currently runs an ERC grant "Better Languages for Statistics". Before arriving in Oxford in 2015, Sam spent time in Nijmegen, Paris, and Cambridge. His PhD was in Cambridge with Marcelo Fiore (2007). Sam's main research is in programming language theory, but he is also interested in logic and category theory. He has recent contributions in probabilistic programming languages, and quantum computing and programming languages. Webpage: https://www.cs.ox.ac.uk/people/samuel.staton/main.html

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[ANN] updated vim's cabal syntax file
by coot＠coot.me 13 Nov '22

13 Nov '22

vim-9.0.0849 comes with an updated cabal syntax file which supports a few more fields. If you want to see the changes, check out the few recent commits: https://github.com/coot/haskell-vim-scripts/commits/master/syntax/cabal.vim… Cheers, Marcin

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Numerical Recipes in Haskell?
by Jonathan Drews 12 Nov '22

12 Nov '22

Hi: New member here. I am looking for a book similar to "Numerical Recioes in C" but for Haskell. https://www.amazon.com/Numerical-Recipes-Scientific-Computing-Second/dp/052… Does such a book exist? I've looked and can't seem to find one. I am new to Haskell and don't have much programming experience. I am using the No Starch press book "Learn Physics with Functional Programming: A Hands-on Guide to Exploring Physics with Haskell". It's very well written. -- Kind regards, Jonathan

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