- Haskell-Cafe - Haskell.org

Utrecht Summer School on Advanced Functional Programming 2023
by Swierstra, W.S. (Wouter) 16 Mar '23

16 Mar '23

# Call for Participation SUMMER SCHOOL ON ADVANCED FUNCTIONAL PROGRAMMING Utrecht, the Netherlands, 03 July – 07 July 2023 http://www.afp.school **Please register before June 15th ** ## ABOUT The Advanced Functional Programming summer school has been running for more than ten years. We aim to educate aspiring Haskell programmers beyond the basic material covered by many textbooks. The lectures will cover several more advanced topics regarding the theory and practice of Haskell programming, including topics such as: * lambda calculus; * monads and monad transformers; * lazy evaluation; * generalized algebraic data types; * type families and type-level programming; * concurrency and parallelism. The summer school will be held in Utrecht and consists of a mix of lectures, labs, and a busy social program. ## PREREQUISITES We expect students to have a basic familiarity with Haskell already. You should be able to write recursive functions over algebraic data types, such as lists and trees. There is a great deal of material readily available that covers this material. If you've already started learning Haskell and are looking to take your functional programming skills to the next level, this is the course for you. ## DATES **Registration deadline: June 15th, 2023** School: 03 July – 07 July 2023 ## COSTS 750 euro - Profession registration fee 250 euro - Student registration fee 200 euro - Housing fee We will charge a registration fee of 750 euros (or 250 euros for students) to cover our expenses. If this is problematic for you for any reason at all, please email the organisers and we can try to offer you a discounted rate or a fee waiver. We have a limited number of scholarships or discounts available for students that would not be able to attend otherwise, especially for women and under-represented minorities. ## FURTHER INFORMATION Further information, including instructions on how to register, is available on our website: http://www.afp.school

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Call for Papers, Functional Software Architecture - FP in the Large
by Graham Hutton 16 Mar '23

16 Mar '23

Dear all, We're delighted to announce that the first ACM SIGPLAN Workshop on "Functional Software Architecture - FP in the Large" will be held in Seattle, USA in September 2023, co-located with the ICFP conference. Please share, and submit your best papers, experience reports, and architectural pearls on large-scale functional programming! Best wishes, Mike Sperber and Graham Hutton Program Chairs, FUNARCH 2023 ====================================================================== *** FUNARCH 2023 -- CALL FOR PAPERS *** The First ACM SIGPLAN Workshop on Functional Software Architecture - FP in the Large 8th September 2023, Seattle, Washington, USA Co-located with ICFP 2023 https://tinyurl.com/FUNARCH23 ====================================================================== TIMELINE: Paper submission 1st June 2023 Author notification 28th June 2023 Camera ready copy 18th July 2023 Workshop 8th Sept 2023 (date to be confirmed) BACKGROUND: "Functional Software Architecture" refers to methods of construction and structure of large and long-lived software projects that are implemented in functional languages and released to real users, typically in industry. The goals for the workshop are: - To assemble a community interested in software architecture techniques and technologies specific to functional programming; - To identify, categorize, and document topics relevant to the field of functional software architecture; - To connect the functional programming community to the software architecture community to cross-pollinate between the two. The workshop follows on from the Functional Software Architecture open space that was held at ICFP 2022 in Slovenia. SCOPE: The workshop seeks submissions in a range of categories: - You're a member of the FP community and have thought about how to support programming in the large, for example by framing functional ideas in architectural terms or vice verse, comparing different languages in terms of their architectural capabilities, clarifying architectural roles played by formal methods, proof assistants and DSLs, or observing how functional concepts are used in other language and architecture communities. Great, submit a research paper! - You're a member of the architecture community, and have thought about how your discipline might help functional programmers, for example by applying domain-driven design, implementing hexagonal architecture, or designing self-contained systems. Excellent, submit a research paper! - You've worked on a large project using functional programming, and it's worked out well, or terribly, or a mix of both; bonus points for deriving architectural principles from your experience. Wonderful, submit an experience report! - You know a neat architectural idiom or pattern that may be useful to others developing large functional software systems. Fabulous, submit an architectural pearl! - You have something that doesn't fit the above categories, but that still relates to functional software architecture, such as something that can be written up, or that could be part of the workshop format like a panel debate or a fishbowl. Superb, submit to the open category! Research papers should explain their research contributions in both general and technical terms, identifying what has been accomplished, explaining why it is significant, and relating it to previous work, and to other languages where appropriate. Experience reports and architectural pearls need not necessarily report original research results. The key criterion for such papers is that they make a contribution from which others can benefit. It is not enough simply to describe a large software system, or to present ideas that are specific to a particular system. Open category submissions that are not intended for publication are not required to follow the formatting guidelines, and can submit in PDF, word or plain text format as preferred. If you are unsure whether your contribution is suitable, or if you need any kind of help with your submission, please email the program chairs at <funarch2023(a)easychair.org>. SUBMISSION: Papers must be submitted by 1st June 2023 using EasyChair, via the following link: https://tinyurl.com/FUNARCH23-submit Formatting: submissions intended for publication must be in PDF format and follow the ACM SIGPLAN style guidelines, using the acmart format and the sigplan sub-format. Please use the review option, as this enables line numbers for easy reference in reviews. For further details, see: https://tinyurl.com/sigplan-acmart If your submission is not a research paper, please mark this using a subtitle (Experience Report, Architectural Pearl, Open Category). Length: submissions must adhere to the limits specified below. However, there is no requirement or expectation that all pages are used, and authors are encouraged to strive for brevity. Research papers 5 to 12+ pages Architectural pearls 5 to 12 pages Experience reports 3 to 6 pages Open category 1 to 6 pages Publication: The proceedings of FUNARCH 2023 will be published in the ACM Digital Library, and authors of accepted papers are required to agree to one of the standard ACM licensing options. Accepted papers must be presented at the workshop by one of the authors, but in special cases we may consider remote presentation. The official publication date is the date the proceedings are made available in the ACM Digital Library. This date may be up to two weeks prior to the first day of the workshop. PROGRAM CHAIRS: Mike Sperber Active Group, Germany Graham Hutton University of Nottingham, UK PROGRAM COMMITTEE: Joachim Breitner Germany Manuel Chakravarty Tweak & IOG, The Netherlands Ron Garcia University of British Columbia, Canada Debasish Ghosh LeadIQ, India Lars Hupel Giesecke+Devrient, Germany Andy Keep Meta, USA Shriram Krishnamurthi Brown University, USA Andres Löh Well-Typed, Germany Anil Madhavapeddy University of Cambridge, UK José Pedro Magalhães Standard Chartered, UK Simon Marlow Meta, UK Hannes Mehnert Robur, Germany Erik Meijer USA Ivan Perez KBR / NASA Ames Research Center, USA Stefanie Schirmer DuckDuckGo, Germany Perdita Stevens University of Edinburgh, UK Stefan Wehr Hochschule Offenburg, Germany Scott Wlaschin FPbridge, UK WORKSHOP VENUE: The workshop will be co-located with the ICFP 2023 conference at The Westin Seattle Hotel, Seattle, Washington, United States. ====================================================================== 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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Re: [Haskell-cafe] dynamic web form generation for algebraic data types
by Olaf Klinke 14 Mar '23

14 Mar '23

> > From briefly reading the wiki page > https://wiki.haskell.org/Tangible_Value, it looks like it relies on > Applicative functors for combining values. > So maybe the missing piece for sum-types was Selective functors > https://hackage.haskell.org/package/selective? > > Gustavo Bicalho > Well spotted! I did not know selective applicative functors (SAFs), thanks for mentioning! Indeed `branch` seems to be all that is necessary to get forms for sum types going. In the talk [1] Andrey mentions that SAFs have a bind, but only for enumerable inputs. The papers state that "all effects are declared statically". If we equate "effect" with "form input" then for recursive types like lists this would mean to pre-define an infinite number of fields and have the user select a finite number of them. I wonder whether that is feasible with html forms. Maybe forms (in the html sense) are a red herring for what I am after. Both the Grace and tangible values demos immediately process changes to inputs, there is no distinction between inputting the data and having the data processed: they are event-driven systems. As is JavaScript with its `oninput` and `onchange` functions. So there are two sub-problems here: The first problem is to programmatically generate html elements by JavaScript functions that can build all finite values of a given Generic Haskell type, and nothing else. The second problem is to scrape the thusly generated elements and re-assemble them into a Haskell value on the server side. The second problem is usually solved by html forms, but there may be other means. Olaf [1] https://dl.acm.org/doi/abs/10.1145/3341694#

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Just released: cabal 3.10.1.0
by Mikolaj Konarski 13 Mar '23

13 Mar '23

Dear cabal users and contributors, The cabal team is proud to announce the release of cabal 3.10.1.0. This is mainly a bugfix release, but it has some new features and enhancements as well. The thread about the release, including troubleshooting and porting discussions, is at https://discourse.haskell.org/t/just-released-cabal-3-10-1-0/5978 The changelogs and release notes are at https://github.com/haskell/cabal/blob/master/release-notes/cabal-install-3.… and, if your code depends on the Cabal library, at https://github.com/haskell/cabal/blob/master/release-notes/Cabal-3.10.1.0.md Two backward (in)compatibility notes may be of particular interest: the XDG Base Directory Specification (conditionally) replacing ~/.cabal and the `--enable-documentation` option by default added to all `cabal haddock` invocations. Please look them up at the links above. Let me finish by thanking our esteemed benefactors, past and present, contributing code, devops, testing, feedback, comments. Representing these are the authors of all PRs included in the 3.10.1.0 release, honourably mentioned in the list of fame below. Abastro Alexander Biehl Alexey Radkov amigalemming Andrea Bedini Andreas Abel Andreas Klebinger Artem Pelenitsyn Ben Gamari Bodigrim Brandon Chinn Bryan Richter Byron Johnson Cheng Shao chowells79 Cmdv Colton Clemmer cydparser Daniel Gröber deltaspace0 Evgenii Akentev fendor Francesco Ariis Francesco Gazzetta Gautier DI FOLCO Georgi Lyubenov Gershom Bazerman Guillaume Genestier Hécate Moonlight Ikko Ashimine instinctive Jade Lovelace James Hobson Jan Synáček Jappie Klooster Javier Neira John Ericson Kobayashi Marcin Szamotulski Martijn Bastiaan Matthew Pickering Max Amanshauser Miezhiko Mike Pilgrem Musab Guma'a Patrick Dougherty Paweł Dybiec Pierre Le Marre Robert Vollmert Ross Paterson Saad Ahmed Sergey Vinokurov sheaf Sören Tempel Sylvain Henry Tom McLaughlin Troels Henriksen Vilius Panevėžys Vladislav Zavialov Wismill

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[ANNOUNCE] GHC 9.6.1 is now available
by Ben Gamari 12 Mar '23

12 Mar '23

The GHC team is very pleased to announce the availability of GHC 9.6.1. As usual, binaries and source distributions are available at downloads.haskell.org: https://downloads.haskell.org/ghc/9.6.1/ Beginning with GHC 9.6.1, GHC can be built as a cross-compiler to WebAssembly and JavaScript. This is an important step towards robust support for compiling Haskell to the Web, but there are a few caveats to be aware of in the 9.6 series: - Both the Javascript and WebAssembly backends are still at an early stage of development and are present in this release as a technology preview - Using GHC as a cross-compiler is not as easy as we would like it to be; in particular, there are challenges related to Template Haskell - GHC is not yet run-time retargetable; a given GHC binary targets exactly one platform, and both WebAssembly and JavaScript are considered platforms for this purpose. Cross-compilers must be built from source by their users We hope to lift all of these limitations in future releases. Additionally, 9.6.1 includes: - Significant latency improvements in the non-moving garbage collector - Efficient runtime support for delimited continuations - Improvements in compiler error messages - Numerous improvements in the compiler's memory usage See the [release notes] for a comprehensive accounting of changes in this release. As always, one can find a migration guide to aid in transitioning from older releases on the [GHC Wiki][migration-guide]. We have also recently started extending our release process to cover a wider set of Linux distributions. In particular, we now offer Rocky 8 and Ubuntu 20.04 binary distributions which cover RedHat-derivative and distributions using older glibc releases (namely 2.27), respectively. Thanks to everyone who has contributed code, documentation, testing, and tickets to this release process. As this release represents upstream GHC's first step towards supporting web targets, we are very excited to have this release out the door! Cheers, - Ben [ticket]: https://gitlab.haskell.org/ghc/ghc/issues/ [migration-guide]: https://gitlab.haskell.org/ghc/ghc/-/wikis/migration/9.6 [release notes]: https://downloads.haskell.org/ghc/9.6.1/docs/users_guide/9.6.1-notes.html

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ANN: hledger-1.29
by Simon Michael 11 Mar '23

11 Mar '23

I'm pleased to announce hledger 1.29 ! https://github.com/simonmichael/hledger/releases/1.29 https://hledger.org/install https://hledger.org/release-notes.html#hledger-1-29 Highlights: Tag checking, flexible multi-period start dates, flexible cost/conversion posting combining, new commands list, hledger manual reorg, easier close command, 10% more Ledger file compatible. Thank you to release contributors Chris Lemaire, Caleb Maclennan, Jonathan Dowland, J. B. Rainsberger, Michael Grünewald, Robert Nielsen, and Yann Büchau. What is hledger ? - Fast, reliable, free, multicurrency, double-entry, plain text accounting[1] software that runs on unix, mac, windows, and the web - Built around human-readable, version-controllable plain text files - Inspired by and largely compatible with Ledger CLI[2]; convertible to and from Beancount[3] - Written in Haskell for correctness and longevity. For help getting started, or more info, see https://hledger.org and join our chat via Matrix or IRC: https://hledger.org/support Newcomers, experts, contributors, sponsors, feedback are welcome! Aloha, -Simon [1] https://plaintextaccounting.org [2] https://ledger-cli.org [3] https://beancount.github.io

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ANN: Haskell Tiny Game Jam 2023 Results
by Simon Michael 10 Mar '23

10 Mar '23

We are very pleased to announce.. the results of Haskell Tiny Game Jam 2023 ! Congratulations and thanks to all participants! - 55 entries in 4 categories from 28 entrants in 3 weeks - 109 reviews, 5 winners and 6 honourable mentions from 2 judges - Shell script to browse and play the games on all major platforms (single binary coming later maybe) - Readable source versions, useful development tips, informative blog posts This was the first Haskell game dev contest. The prize.. glory! Also fun, learning, and advancing Haskell's suitability for game dev and programming in the small. We invite you to come and play, read, and get inspired for the next one! https://github.com/haskell-game/tiny-games-hs

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ANN: atomic-modify-general
by David Feuer 10 Mar '23

10 Mar '23

I just put together a new package, atomic-modify-general, for generalizations of the `atomicModifyIORef` operation. In particular: 1. Versions that allow a result of an arbitrary type (not necessarily a pair), where the caller passes in an extraction function. These work with `Array` and `SmallArray` from `primitive` as well as `IORef`. 2. A version that works with record types (not just pairs) whose first field is the new value to install in the `IORef`. This uses implementation details of the `atomicModifyMutVar#` primop as well as GHC's heap object layout to achieve better performance. Please try it out and let me know how it goes, and what extras you may want! Hackage: https://hackage.haskell.org/package/atomic-modify-general-0.1.0.0

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Nearly lens examples
by Geraldus 10 Mar '23

10 Mar '23

Dear all! Do you have good usage examples of *nearly* lens, especially in composition with other lenses / prisms? Sincerely yours, Arthur.

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PhD or Postdoc Position at LMU Munich about Verified Modal Logics
by Andrei Popescu 09 Mar '23

09 Mar '23

We are looking for a PhD student (4 years) or postdoctoral researcher (3 years) to work on the Isabelle formalization of modal model theory. The work will take place within the Chair of Theoretical Computer Science at LMU Munich under Jasmin Blanchette's supervision with the participation of two external experts: Cláudia Nalon (University of Brasília) and Sophie Tourret (Inria Nancy). Modal logics are extensions of classical logics with operators that allow for the qualification of truth. Model theory for modal logics is concerned with the interplay between the language (syntax, i.e., the set of its formulas) and its meaning (semantics, i.e., the structures over which the language is interpreted). There are, however, different ways of characterizing meaning for modal sentences and also several (well-established) results that allow for restriction on the sets of structures being considered. This project concerns the formalization in Isabelle of those results for general Kripke structures for generalized modal operators (i.e., of any arity). The goal is to produce a library that could then be used (and possibly extended) for specific applications, in particular those related to proof theory. The position is categorized as TV-L E13 according to the German salary scale. It includes some teaching obligations. The starting date is flexible. Please contact Jasmin Blanchette (jasmin.blanchette(a)ifi.lmu.de) for more information or if you want to apply. The application deadline is 15 April 2023.

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