October 2026 - Haskell-Cafe

State of Haskell 2026 survey
by Dominik Schrempf 30 Oct '26

30 Oct '26

Dear community! The Haskell Foundation is continuing the tradition of a yearly State of Haskell survey. We hope you’ll take some time (~10 minutes) to tell us about how you use Haskell, so we can better understand and serve the community. https://www.surveymonkey.com/r/3Z9D75V All the best, Dominik

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Mutants at the MCG - 6:00 PM Thurs 12th of November - Tristan Mc Leay - Mutation Testing With Sydtest
by theghostjw＠gmail.com 28 Oct '26

28 Oct '26

Melbourne Compose Group is the monthly in-person meetup for functional programmers in Melbourne, which this month, is on the second Thursday of the month. Our November meeting will be 6:00-8:00 pm Thurs 12th of November at our regular venue, Activity Room 2 at Kathleen Syme Center in Carlton. Arrive from 5:30 for chat and socialising, talks start at 6:30pm. Please [RSVP via Luma](https://luma.com/i1j0ygwy). # Tristan Mc Leay - Mutation Testing With Sydtest Now that use of AI code generation tools has become prevalent, we need a way to keep our agents honest. Is our code well tested? Have we skipped tests? Are the tests sensible or meaningless? All of these could have been problems before AI, but they take on an increased significance when we can produce bigger changes than we might be able to genuinely concentrate on. Mutation testing is a way of checking our test quality as well as our test coverage: instead of just asking whether a line ran during testing, it asks whether changes to that line would have caused the tests to fail. In the case of a typed functional language, that might be swapping an operator, dropping a case, hard-coding a boolean instead of an if or a guard. If the tests continue to pass with a change in place, then the test suite is usually insufficiently sensitive to changes. Sydtest includes a mutation testing framework for GHC, implemented as a GHC plugin alongside driver code. It was designed precisely for this problem - as our coding switches to AI, we need AI to look at our mutation test results to know what to do next. In this presentation, I will take a tour of Sydtest's mutation testing and apply it to a code base. This code base has poor test coverage and was originally hand written but nowadays is essentially agent-coded. As always, newcomers welcome. Hope to see you there :) -Ben Hutchison & John Walker

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Save the date for AmeriHac 2027
by Dominik Schrempf 26 Oct '26

26 Oct '26

Dear fellow Haskellers, I am happy to announce that AmeriHac will take place in New York on Februrary 6-7, 2027. You can now register for the event via Eventbright: https://www.eventbrite.com/e/amerihac-2027-tickets-2003438356054 More details on the event page: https://haskell.foundation/events/2027-amerihac.html All the best, Dominik

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[ANN] Yampa 0.15.1 and yampa-test 0.15.1
by Ivan Perez 24 Oct '26

24 Oct '26

Hi everyone, I'm very happy to announce the release of Yampa 0.15.1 and yampa-test 0.15.1. Yampa is a fast, elegant Functional Reactive Programming implementation. Yampa prides itself in being a long-standing community project. It has now been around for more 20 years! See https://github.com/ivanperez-keera/yampa#features for details on Yampa's features. This release introduces support for MicroHs (thanks to Lennart Augustsson) and several maintenance changes to support newer versions of dependencies. Additionally, all versions of GHC from 7.6.3 to modern to modern versions should work with this release. Special thanks go to @johannes-riecken for a regular contribution to support the Yampa project. For details, see: - https://github.com/ivanperez-keera/Yampa/releases/tag/v0.15.1 The Yampa ecosystem comprises many projects. You can explore the current versions at: - https://hackage.haskell.org/package/Yampa - https://hackage.haskell.org/package/yampa-test - https://hackage.haskell.org/package/yampa-gloss - https://hackage.haskell.org/package/simple-affine-space - https://hackage.haskell.org/package/SpaceInvaders - https://hackage.haskell.org/package/haskanoid # Code The github repos are located at: - https://github.com/ivanperez-keera/Yampa/ - https://github.com/ivanperez-keera/yampa-gloss/ - https://github.com/ivanperez-keera/simple-affine-space/ - https://github.com/ivanperez-keera/SpaceInvaders/ - https://github.com/ivanperez-keera/haskanoid/ *What's coming* In upcoming releases we plan to focus on performance, and on creating demos and examples using different compilers and backends. *Donations* Our project is seeking donations to help continue developing Yampa, create new open source libraries, new material, and give talks. No donation is too small. Any contribution will absolutely help. See https://github.com/sponsors/ivanperez-keera for details. If you can help, please come forward. All the best, Ivan

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Announcement: Haskell the Craft of Functional Programming. Interactive online text
by Simon Thompson 17 Oct '26

17 Oct '26

Haskell the Craft of Functional Programming. Interactive online text <https://simonjohnthompson.github.io/haskellcraft/> Preface - Haskell: The Craft of Functional Programming<https://simonjohnthompson.github.io/haskellcraft/> simonjohnthompson.github.io<https://simonjohnthompson.github.io/haskellcraft/> [favicon-8114d1fc.png]<https://simonjohnthompson.github.io/haskellcraft/> This is a substantially revised version of the third edition (2011) of Haskell: the Craft of Functional Programming bringing the book up to date with changes in Haskell and its infrastructure: implementations, editor support, discussion channels etc. More substantially it is now available online, and is freely available under a Creative Commons licence. The book is also available as a PDF, <https://github.com/simonjohnthompson/haskellcraft/blob/main/Book/root.pdf> haskellcraft/Book/root.pdf at main · simonjohnthompson/haskellcraft<https://github.com/simonjohnthompson/haskellcraft/blob/main/Book/root.pdf> github.com<https://github.com/simonjohnthompson/haskellcraft/blob/main/Book/root.pdf> [apple-touch-icon-180x180-a80b8e11abe2.png]<https://github.com/simonjohnthompson/haskellcraft/blob/main/Book/root.pdf> as part of the github repository for the text. <https://github.com/simonjohnthompson/haskellcraft/> [haskellcraft.png] simonjohnthompson/haskellcraft<https://github.com/simonjohnthompson/haskellcraft/> github.com<https://github.com/simonjohnthompson/haskellcraft/> The book is supported by a YouTube video lecture course: Introduction to Functional Programming. <https://www.youtube.com/playlist?list=PLqu19-ygE4ocMda7XgriK0BHL8vmlyKPU> [hqdefault.jpg] Introduction to functional programming in Haskell<https://www.youtube.com/playlist?list=PLqu19-ygE4ocMda7XgriK0BHL8vmlyKPU> youtube.com<https://www.youtube.com/playlist?list=PLqu19-ygE4ocMda7XgriK0BHL8vmlyKPU> Comments, and github issues and pull requests very welcome. Enjoy! Simon Simon Thompson | Professor Emeritus of Logic and Computation | University of Kent, UK Professor Emeritus of Computer Science | Eötvös Loránd University, Budapest s.j.thompson(a)kent.ac.uk | M +44 7986 085754 | W www.cs.kent.ac.uk/~sjt London and South East University Group, a charity and company limited by guarantee registered in England (company number 00986729). Registered Office: Old Royal Naval College, Park Row, Greenwich, London SE10 9LS

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2nd Call for Contributions: BOB 2027 (Berlin, Feb 26 - Deadline Nov 2)
by Michael Sperber 13 Oct '26

13 Oct '26

Please send us your Haskell proposal! ================================================================================ BOB Conference 2027 "What happens when we use what's best for a change?" https://bobkonf.de/2027/cfc.html Berlin, Feb 26 Call for Contributions Deadline: November 2, 2026 ================================================================================ You are actively engaged in advanced software engineering methods, solve ambitious problem with software and are open to cutting-edge innovation? Attend this conference, meet people that share your goals, and get to know the best software tools and technologies available today. We strive to offer a day full of new experiences and impressions that you can use to immediately improve your daily life as a software developer. If you share our vision and want to contribute, submit a proposal for a talk or tutorial! NOTE: The conference fee will be waived for presenters. Travel expenses will not be covered (for exceptions see "Speaker Grants"). Shepherding ----------- The program committee offers shepherding to all speakers. Shepherding provides speakers assistance with preparing their sessions. Specifically: - advice on structure and presentation - review of talk slides Speaker Grants -------------- BOB has Speaker Grants available to support speakers from groups under-represented in technology. We specifically seek women speakers, speakers of color, disabled speakers, and speakers who would not normally be able to attend the conference for financial reasons. Topics ------ We are looking for talks about best-of-breed software technology, e.g.: - functional programming - persistent data structures and databases - event-based modelling and architecture - "fancy types" (dependent types, gradual typing, linear types, ...) - formal methods for correctness and robustness - abstractions for concurrency and parallelism - metaprogramming - probabilistic programming - math and programming - controlled side effects - program synthesis - AI beyond chatbots, vibecoding, and agents - linked data - symbolic AI - next-generation IDEs - effective abstractions for data analytics - ... everything really that isn’t mainstream, but you think should be - ... including rough ideas that are worth discussing. Presenters should provide the audience with information that is practically useful for software developers. Challenges ---------- Furthermore, we seek contributions on successful approaches for solving hard problems, for example: - bias in machine-learning systems - digital transformation in difficult settings - accessibiltity - systems with critical reliability requirements - ecologically sustainable software development We're especially interested in experience reports. Other topics are also relevant, e.g.: - introductory talks on technical background - overviews of a given field - demos and how-tos Requirements ------------ We accept proposals for presentations of 45 minutes (40 minutes talk + 5 minutes questions), as well as 90 minute tutorials for beginners. The language of presentation should be either English or German. Your proposal should include (in your presentation language of choice): - An abstract of max. 1500 characters. - A short bio/cv - Contact information (including at least email address) - A list of 3-5 concrete ideas of how your work can be applied in a developer's daily life - additional material (websites, blogs, slides, videos of past presentations, …) Organisation ------------ - Direct questions to konferenz at bobkonf dot de - Proposal deadline: November 2, 2026 - Notification: November 23, 2026 - Program: November 30, 2026 Submit here: https://pretalx.com/bob-2027/submit/ Program Committee ----------------- (more information here: https://bobkonf.de/2027/programmkomitee.html) - Matthias Fischmann, Wire - Matthias Neubauer, SICK AG - Nicole Rauch, Softwareentwicklung und Entwicklungscoaching - Michael Sperber, Active Group - Stefan Wehr, Hochschule Offenburg Scientific Advisory Board - Annette Bieniusa, TU Kaiserslautern - Torsten Grust, Uni Tübingen - Peter Thiemann, Uni Freiburg

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cabal-install 3.18.2.0 released
by Francesco Ariis 13 Oct '26

13 Oct '26

The Cabal team is happy to announce the release of `cabal-install` 3.18.2.0 and its related libraries. ## What is new This is a point release, which fixes several bugs in `3.18.1.0`, notably: - `cabal-install` properly cleans temporary files in `/tmp/`. - `Cabal` the library correctly points to `CabalSpecV3_18` as the latest specification. The full changelog for the tool [1] and the libraries [2] are available on GitHub. Read “Known issues” section for regressions still unfixed. [1] https://github.com/haskell/cabal/blob/master/release-notes/cabal-install-3.… [2] https://github.com/haskell/cabal/blob/master/release-notes/Cabal-3.18.2.0.md If you are updating from `3.16`, check the changelogs for `3.18.1.0` too (tool [3], libraries [4]) [3] https://github.com/haskell/cabal/blob/master/release-notes/cabal-install-3.… [4] https://github.com/haskell/cabal/blob/master/release-notes/Cabal-3.18.1.0.md ## Where to get it You can get `cabal-install`: * From our website [5]. The binaries are signed by "Francesco Ariis <fa-ml(a)ariis.it>" (fingerprint: `DAFB 4D8A F684 1435 18D5 051F A9AF 0AAA 6B87 EC51`; the key is hosted on keyserver.ubuntu.com) * From GHCup [6] (“vanilla” channel). * Compiling it yourself with `cabal update && cabal install cabal-install-3.18.2.0`. [5] https://downloads.haskell.org/cabal/cabal-install-3.18.2.0/ [6] https://www.haskell.org/ghcup/ ## Who contributed Code contributions by: Andrea Bedini, Andreas Klebinger, Artem Pelenitsyn, Bodigrim, Curtis Chin Jen Sem, Francesco Ariis, Ilya Baryshnikov, Mikolaj Konarski, Tushar Adhatrao. Many thanks to reviewers, Quality Assurance testers, devops and everyone who made this release possible. ## Feedback For feedback, questions, help, you can find us: * In our GitHub repository [7]. * In our Matrix channel [8]. [7] https://github.com/haskell/cabal/issues [8] https://matrix.to/#/#hackage:matrix.org -- Cabal release team (Artem, Francesco, Ilya, Mikołaj) ## Nightlies Do you want to try new features and help Cabal? Fetch nightlies `cabal-install` snapshots! Get them from GitHub [9] or use `ghcup` invocation below: [9] https://github.com/haskell/cabal/releases/tag/cabal-head ghcup install cabal -u https://github.com/haskell/cabal/releases/download/cabal-head/cabal-head-Li… head

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Technical Leadership Committee of the Haskell Foundation
by Dominik Schrempf 13 Oct '26

13 Oct '26

Dear fellow Haskellers! The Haskell Foundation is proud to announce that the Technical Leadership Committee has officially launched! The Technical Leadership Committee is a new committee responsible for formulating a technical vision for the Haskell Foundation, and allocate resources towards achieving this vision. The committee will be proactive (rather than reactive to outside proposals) and favour action and experimentation. Our inaugural members are: - Julian Ospald (Chair) - Simon Marlow (Board Liaison) - Joshua Miller - Rodrigo Mesquita Committee members were chosen for their demonstrated technical expertise, historical community involvement, and bold vision for the future of Haskell. You can head on over to https://haskell.foundation/technical-leadership/ to learn more about the committee members, and stay tuned for news as the committee really gets going! Best, Dominik

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CAR T Cell Therapy Market Forecast to 2035
by abhaybhardwaj282＠gmail.com 09 Oct '26

09 Oct '26

The Global CAR T Cell Therapy Market Report is a comprehensive report on the CAR T Cell Therapy market, offering key insights on business strategies, current trends, and presenting qualitative and quantitative analysis of the CAR T Cell Therapy market. This report offers in-depth research insights on key and significant aspects of the CAR T Cell Therapy market, providing an in-depth analysis of key drivers, restraints, restraints, growth prospects, threats, and risks. The report also includes an in-depth analysis of the competitive landscape and regional scope of the CAR T Cell Therapy market. The global CAR T Cell Therapy market report employs an extremely extensive and perceptive process that analyzes statistical data relating to services and products offered in the market. The research study is a pivotal document in understanding the needs and wants of the clients. The report is comprised of significant data about the leading companies and their marketing strategies. The CAR T Cell Therapy industry is witnessing an expansion and change of dynamics owing to the entry of several new players. The study outlines the rapidly evolving and growing market segments along with valuable insights into each element of the industry. The industry has witnessed the entry of several new players, and the report aims to deliver insightful information about their transition and growth in the market. Mergers, acquisitions, partnerships, agreements, product launches, and joint ventures are all outlined in the report. Key Companies Profiled in the Report are Autolus Bluebird Bio Bristol Myers Squibb Carsgen Therapeutics Cellectis Gilead Sciences Innovative Cellular Therapeutics Noile-Immune Biotech Novartis Shanghai GeneChem CAR T-cell therapy market (5th Edition): Industry Trends and Global Forecasts, Till 2035: Distribution by Target Antigens (CD19, BCMA, CD20, CD19/22, and Other Target Antigens), Target Indication (Acute Lymphoblastic Leukemia, Diffuse Large B-cell Lymphoma, Follicular Lymphoma, Large B-cell Lymphoma, Mantle Cell Lymphoma, Multiple Myeloma, and Others) The research report offers a comprehensive regional analysis of the market with regards to production and consumption patterns, import/export, market size and share in terms of volume and value, supply and demand dynamics, and presence of prominent players in each market. Regional Analysis Covers: North America Europe Asia Pacific Latin America Middle East & Africa Rest of the World To know more about the report, visit @ https://www.rootsanalysis.com/reports/car-t-cell-therapy-market/269.html Furthermore, the report provides analytical data in an organized format segmented into charts, tables, graphs, figures, and diagrams. This enables readers to understand the market scenario in an easy and beneficial manner. Moreover, the report aims to impart a prospective outlook and draw an informative conclusion to assist the reader in making lucrative business decisions. The report, in conclusion, provides a detailed analysis of the segments expected to dominate the market, the regional bifurcation, the estimated market size and share, and comprehensive SWOT analysis and Porter’s Five Forces Analysis. Thank you for reading our report. For further queries, please connect with us, and our team will provide you the report best suited to your requirements.

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Revised online edition of Haskell: the Craft of Functional Programming
by Simon Thompson 08 Oct '26

08 Oct '26

I am delighted to announce a fully revised online edition of Haskell: the Craft of Functional Programming, https://simonjohnthompson.github.io/haskellcraft/<https://simonjohnthompson.github.io/haskellcraft/?fbclid=IwZXh0bgNhZW0CMTAA…> London and South East University Group, a charity and company limited by guarantee registered in England (company number 00986729). Registered Office: Old Royal Naval College, Park Row, Greenwich, London SE10 9LS

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