- Haskell-Cafe - Haskell.org

Releasing crypton v2.0.0
by Kazu Yamamoto 26 Sep '26

26 Sep '26

Hello cafe, I have posted a new blog article on "crypton": https://kazu-yamamoto.hatenablog.jp/entry/2026/09/25/110313 --Kazu

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Andrew Hodges to give this year's LMS/BCS-FACS Seminar: "Alan Turing, The Absent Father of Computing" -- 12 November 2026 (London and online)
by Andrei Popescu 25 Sep '26

25 Sep '26

Dear Colleagues, We are delighted to announce that Andrew Hodges will give this year's LMS/BCS-FACS Seminar on Thursday, 12 November 2026, with a talk titled "Alan Turing, The Absent Father of Computing". The seminar also marks an anniversary: Turing's "On Computable Numbers" paper was read to the London Mathematical Society on 12 November 1936, ninety years to the day. The seminar will be held in a hybrid format, with the opportunity to attend in person at De Morgan House in London or remotely via Zoom. Date: Thursday, 12 November 2026 Time: 16:30-17:30 GMT (welcome and refreshments from 16:00; reception from 17:30) Venue: De Morgan House, London, and online via Zoom Registration: Attendance is free, but advance registration is required. Please register for either in-person or online attendance via the event page: https://www.lms.ac.uk/events/lms-bcs-facs-seminar-2026 Speaker: Andrew Hodges (University of Oxford) Title: Alan Turing, The Absent Father of Computing Abstract: Alan Turing (1912-1954) has often been dubbed the 'Father' of computing, this vague word conveying the complex connection between On Computable Numbers in 1936, the digital computing plans of 1945, the first working electronic computers in 1948-51, and computer science thereafter. I will address this complexity, starting with an update on the well-known question of whether and how von Neumann’s EDVAC report of 1945 was related to Turing’s work. But my emphasis will be on what happened after 1945, regarding it as a puzzle that Turing drew so little attention to his own 1936 foundations, despite their relevance to his famous Intelligent Machinery predictions. His extraordinary reticence affected the emergent science and technology of computing, as I will illustrate with some little-known documents. My conclusion is summarised in the title: it is fair to consider him a ‘father’, but he avoided taking either praise or responsibility for his offspring. About the speaker: Andrew Hodges was for many years a tutor and lecturer in mathematics at Oxford University. His research was mainly as a colleague of Roger Penrose in making a new approach to mathematical physics, and in this field he was also a visitor to the Institute for Advanced Study, Princeton, working with Nima Arkani-Hamed. He is now an Emeritus Fellow of Wadham College, Oxford. He is best known as the author of Alan Turing: the Enigma, published in 1983. In the forty years since then he has contributed further to the world of Turing studies, with a website at turing.org.uk. In an unusual career he has also seen various adaptations of this work in the arts and media, most recently in collaborating with the Pet Shop Boys in A man from the future, a musical piece released in October 2026. We hope you will be able to join us, either in London or online. Please feel free to circulate this announcement to colleagues, students, and anyone else who may be interested. Best wishes, Andrei (on behalf of the LMS/BCS-FACS Seminar organisers)

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Save the date for the Haskell Ecosystem and Implementors’ Workshops 2027
by Dominik Schrempf 25 Sep '26

25 Sep '26

Dear Haskellers, The Haskell Foundation is happy to announce that it will again host two workshops as a prelude to ZuriHac in 2027, in collaboration with the OST Eastern Switzerland University of Applied Sciences: Details at https://haskell.foundation/news/2026-09-23/save-the-date-hew-hiw-2027.html. Best, Dominik

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P256 assembler implementation
by Kazu Yamamoto 23 Sep '26

23 Sep '26

Hello cafe, I'm currently working on improving the performance of *crypton*, a Haskell cryptography library, and seeing excellent results; for some algorithms, performance is now on par with OpenSSL. The current challenge lies with P256. I do not expect further performance gains from the existing C implementation, so I'm looking for an assembly implementation. While OpenSSL includes an assembly implementation, I cannot adopt it due to its Apache License. If you have any good ideas, please share them via the *crypton* issue tracker. Even if the P256 issue remains unresolved, I plan to release version 2.0.0 in the near future. For the latest status, please refer to the benchmark table in https://github.com/kazu-yamamoto/crypton --Kazu

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Ptero Pro AI Chat — A Free, Open-Source AI Tool for Haskell Developers
by amine kheddache 22 Sep '26

22 Sep '26

Hello Haskell Community, I'm Amine KHD, maintainer of Ptero Pro AI Chat, a free, open-source AI chat platform I wanted to share Ptero with the Haskell community because it can be a useful tool for developers working with functional programming concepts. What Ptero does: - Supports live web search and page extraction - Includes a conversation sidebar with search, pinning, and labels - Offers a developer API for integration into your own applications - Works as a WordPress plugin, or can be used directly at ptero.pro Why it might be useful for Haskell developers: - Explain complex type signatures and monad transformers - Debug compile errors and understand GHC messages - Generate boilerplate for typeclass instances - Assist with refactoring pure functions - Help with learning Haskell concepts like functors, monads, and applicatives Try it here: https://ptero.pro Source code: https://github.com/aminkheddache-dotcom/Ptero It's completely free — no premium plans, no credit card, no paywall. It will always be free. If you find it useful, feedback is always welcome. Best regards, Amine KHD Founder & Lead Developer, Ptero aminekhd(a)ptero.pro https://ptero.pro

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[PLMW@POPL 2027] Call for Attendance & Scholarship Applications
by Ningning Xie 22 Sep '26

22 Sep '26

We are excited to announce that the POPL edition of the Programming Languages Mentoring Workshop (PLMW) is returning for its 15th installment in Mexico City, Mexico! PLMW is designed to help late-stage undergraduate and early-stage PhD students interested in programming languages (PL) research connect with the broader PL community. The workshop includes: - Technical sessions covering both foundational and cutting-edge PL research topics - Mentoring sessions on building a PL research career; covering topics such as how to give a research talk and write a research paper, how to apply to grad school, academic vs. industry research careers, and more - Social sessions to connect with PL researchers and fellow students who share your interests If this sounds exciting to you, we warmly welcome your attendance! We especially encourage women, underrepresented minorities, and people with disabilities to attend. Note, attendance is open to everybody who is registered for workshops for the day. ------------------------------------------------- Call for Travel Scholarship Applications ------------------------------------------------- Our sponsors have generously donated scholarship funds for qualified students who do not have the funds to attend PLMW. These scholarships can cover expenses (airfare, hotel, and registration fees) for attendance at both the workshop and the POPL conference itself. Make sure to apply at the link below by the application deadline for consideration. *Scholarship application deadline*: October 19, 2026 (AoE) *Apply here*: https://popl27.sigplan.org/home/PLMW-POPL-2027#Call-for-Scholarship-Applica… We also strongly recommend applying for the POPL Student Research Competition and student volunteering at POPL if possible. We hope to see you in Mexico City! The PLMW@POPL 2027 Organizing Committee

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Research Fellow positions in the Isabelle development and verification of an "Agentic seL4" system -- application deadline 27 September 2026
by Andrei Popescu 21 Sep '26

21 Sep '26

Dear Colleagues, We are looking to recruit a Research Fellow at the University of Sheffield, UK, for a new project on formal verification with Isabelle, funded by the Advanced Research + Invention Agency (ARIA). The project, jointly undertaken with the University of Surrey and the University of Melbourne, will develop a formally verified reference monitor on top of seL4 for the secure containment of AI agents, including mechanisms for dynamically controlling agents’ capabilities and information flows. It will also use AI techniques to accelerate large-scale formal verification, trained on the seL4 proof base. The position is at Grade 8 (UK Lecturer level), with a salary of £53,301–£58,225, and is initially for 14 months. We have substantial funding for access to state-of-the-art AI models and computing infrastructure. We are interested in candidates with expertise in interactive theorem proving, formal verification, information-flow security, seL4, and optionally neurosymbolic AI and AI-assisted reasoning. Candidates do not need to cover all these areas. Particular preference will be given to candidates with strong Isabelle expertise (or substantial experience with related interactive theorem provers), and to candidates who are available to start as soon as possible. We would also be very interested in hearing from excellent Isabelle researchers who may be at an earlier career stage than would normally be expected for a Grade 8 position. The formal Sheffield advert and application link are available here: https://jobsite.sheffield.ac.uk/job/Research-Fellow-in-AI-Assisted-Formal-V… The application deadline is on 27/09/2026. If you are potentially interested in the position and have any questions, please feel free to contact me at a.popescu(a)sheffield.ac.uk . There are also closely related positions at our partner institutions. For opportunities at the University of Surrey, please contact Brijesh Dongol (b.dongol(a)surrey.ac.uk) for opportunities at the University of Melbourne, please contact Toby Murray (toby.murray(a)unimelb.edu.au) Best wishes, Andrei

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GHC 10.0.1-alpha1 is now available
by Zubin Duggal 20 Sep '26

20 Sep '26

The GHC developers are very pleased to announce the availability of the first alpha prerelease of GHC 10.0.1. Binary distributions, source distributions, and documentation are available at [downloads.haskell.org][] and via [GHCup](https://www.haskell.org/ghcup/). GHC 10.0 will bring a number of new features and improvements, including: * The default language edition is now `GHC2024` ([GHC Proposal #632][ghc2024], #26039). * `Type` and `Constraint` are now completely distinct types, just as much as `Int` and `Bool` (#24279). * The new [QualifiedStrings][] language extension ([GHC Proposal #723][qualified-strings]) allows string literals to be qualified using module qualification syntax, so that `M."my string"` desugars to`M.fromString "my string"`. * The treatment of static forms has been simplified, implementing [GHC Proposal #732][static-forms] (#26556). The free term variables of `(static e)` must now be bound at top level. * `-fpolymorphic-specialisation` is now (re)enabled by default (#23559), * Bytecode can now be written to disk with `-fwrite-byte-code` and packaged into bytecode libraries with `-bytecodelib`, which the interpreter can use to satisfy package dependencies (#26298). * Executables can now be properly statically linked with the new `-fully-static` and `-static-external` flags (#26434). * SIMD support in the AArch64 native code generator (#26536). * A new `poll` I/O manager, which is now the default in the single-threaded RTS on all POSIX platforms except macOS (!9677). * Version 2 of the [GHC Jobserver Protocol][jsem] for GHC's `-jsem` jobserver on Linux and other POSIX platforms (#25087, #27253). This is sadly a necessary breaking change. `-jsem` requires cabal-install 3.18 or later, and is otherwise ignored with a warning, falling back to sequential compilation. * Changes to `base`: * `GHC.Num.{BigNat,Integer,Natural}` are no longer exposed ([CLC #359][clc-359]) and GHC internals in `GHC.Num` are deprecated ([CLC #360][clc-360]). * `Data.List.init` and `Data.List.last` now carry an `x-partial` warning ([CLC #292][clc-292]). * The minimum bootstrap compiler is now GHC 9.10, LLVM versions up to 23 are supported (#26813, #27764), and the Debian 9, Debian 10, Ubuntu 18.04 and Ubuntu 20.04 bindists have been dropped in favour of a new Debian 13 bindist (#25876). * ... and many more A full accounting of changes can be found in the [release notes][]. See the [migration guide][] for guidance on migrating programs to this release. As always, GHC's release status, including planned future releases, can be found on the GHC Wiki [status][]. Given the many changes in this major release, we would very much appreciate testing on downstream workloads. GHC development is sponsored by: * [Juspay](https://juspay.com/) * [QBayLogic](https://qbaylogic.com/) * [Channable](https://www.channable.com/) * [Haskell Foundation](https://haskell.foundation/) * [Serokell](https://serokell.io/) * [Well-Typed](https://well-typed.com/) * [Tweag](https://www.tweag.io/) * [Dotcom-Monitor](https://www.dotcom-monitor.com/) * [LoadView](https://www.loadview-testing.com/) * [Web Hosting Buddy](https://webhostingbuddy.com/) * [Find My Electric](https://www.findmyelectric.com/) * [Standard Chartered](https://www.sc.com) * [UpCloud](https://upcloud.com) * [Mercury](https://mercury.com) We would like to thank these sponsors and other anonymous contributors whose on-going financial and in-kind support has facilitated GHC maintenance and release management over the years. Finally, this release would not have been possible without the hundreds of open-source contributors whose work comprise this release. As always, do give this release a try and open a [ticket][] if you see anything amiss. [downloads.haskell.org] https://downloads.haskell.org/ghc/10.0.1-alpha1 [release notes]: https://downloads.haskell.org/ghc/10.0.1-alpha1/docs/users_guide/10.0.1-not… [migration guide]: https://gitlab.haskell.org/ghc/ghc/-/wikis/migration/10.0 [status]: https://gitlab.haskell.org/ghc/ghc/-/wikis/GHC-status [ticket]: https://gitlab.haskell.org/ghc/ghc/-/issues/new [ghc2024]: https://github.com/ghc-proposals/ghc-proposals/pull/632 [static-forms]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0732-s… [QualifiedStrings]: https://downloads.haskell.org/ghc/10.0.1-alpha1/docs/users_guide/exts/quali… [qualified-strings]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0723-q… [jsem]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0540-j… [clc-292]: https://github.com/haskell/core-libraries-committee/issues/292 [clc-359]: https://github.com/haskell/core-libraries-committee/issues/359 [clc-360]: https://github.com/haskell/core-libraries-committee/issues/360

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GHC 9.14.2-rc2 is now available
by Zubin Duggal 17 Sep '26

17 Sep '26

The GHC developers are very pleased to announce the availability of the second release candidate for GHC 9.14.2. Binary distributions, source distributions, and documentation are available at [downloads.haskell.org][] and via [GHCup](https://www.haskell.org/ghcup/). See also the [previous announcement of 9.14.2-rc1][rc1]. The changes since the first release candidate are: * Several fixes to the specialiser and demand analyser for miscompilations causing incorrect runtime results, crashes, or hangs (#27626, #27627, #27629, #27703, #27704, #27705, #27717). * Fixes for a number of runtime system bugs: * a missing memory barrier in the parallel garbage collector, which could crash or silently corrupt the heap on weakly-ordered architectures such as AArch64 (#27477). * a use-after-free with TSOs (#26716, #26717). * an "unknown/strange object" crash in the compacting collector when collecting the large data constructors that the bytecode interpreter allocates (#27649). * a segfault when querying the label of an unlabelled thread (#27618). * a crash when capturing or resuming a delimited continuation that adjusts the asynchronous exception masking state (#27651). * stack corruption when returning large unboxed tuples in GHCi (#27633). * Further fixes to the AArch64 native code generator, addressing bugs that caused incorrect runtime results from subword operations (#27430, #27533, #27537, #27538, #27539, #27550). * `toException` for `SomeException` no longer drops the attached `ExceptionContext`, and a `catchSTM` handler no longer breaks `retry` or asynchronous exception delivery (#27455, #27657). * Reduced memory usage with multiple home units (#26423, #27308, #27500, #27748). * Fixes for panics and spurious out-of-scope errors involving type arguments in pattern synonym right-hand sides (#27440, #27583, #27586). * The pattern-match checker now recognises `considerAccessible` under ticks, and no longer emits a spurious `-Wincomplete-uni-patterns` warning under `-finfo-table-map` (#27314, #27360). * The deprecation warning for static forms, added in rc1, no longer fires on free type variables (#27664). * A fix for a regression preventing modules from being loaded into GHCi after startup (#27202, #27640). * A fix for representation-polymorphism checks producing a coercion that fails Core Lint (#27639). * Support for LLVM up to version 23 (#27764). * Updates for libffi (3.8.0), `directory` (1.3.11.0), `file-io` (0.1.6), `haskeline` (0.8.5.0) and `os-string` (2.0.10). GHC 9.14.2 is a bug-fix release fixing many issues of a variety of severities and scopes, including: * Version 2 of the [GHC Jobserver Protocol][jsem] for GHC's `-jsem` jobserver on Linux and other POSIX platforms (#25087, #27253). This is sadly a necessary breaking change: `-jsem` requires cabal-install 3.18 or later, and is otherwise ignored with a [warning][jsem-warning], falling back to sequential compilation. * A new deprecation warning for static forms that mention nested let-bound variables. This will become an error in GHC 10.0 ([GHC Proposal #732][static-forms], #26718). * A fix for a CorePrep miscompilation that could project a field out of an absent dictionary, resulting in a segfault (#25924). * A fix for demand analysis giving an absent demand to an argument that was still used by the function's stable unfolding, which could cause a runtime crash (#26416). * Numerous fixes for register allocation and Cmm register-conflict analysis bugs, preventing incorrect code generation and corruption of vector registers when spilling and reloading (#26411, #26526, #26537, #26542, #26550, #26668). * Many NCG fixes on AArch64: `MOVK` clobbering live values (#26980), register clobbering and an incorrect overflow bit in `MUL2` (#27046, #27047), and incorrect sign extension (#26978) and unsigned right shift (#26979) at subword widths. * A fix for a stack alignment bug on x86 that could cause segfaults or corrupted registers when using AVX/AVX-512 vector code (#26595, #26822). * Fixes for several black hole handling bugs that could lead to deadlocks or crashes in multithreaded programs, showing up as hangs or "END_TSO_QUEUE object entered" errors (#26922, #26936). * Fixes for many other runtime system crashes and races (#26341, #26573, #26640, #27007, #27008, #27009, #27082). * A fix for an "unknown/strange object" crash in the compacting garbage collector (#27434). * Fixes for split sections on Windows (#26696, #26494) and the LLVM backend (#26770). * Fixes for the Wasm backend (#26916, #27257), and the RISC-V (#27300, #27303, #27306) and PowerPC (#23969, #24145, #26828) native code generators. * The JavaScript backend now supports more than 128 registers, fixing runtime `ReferenceError` failures for functions taking very many arguments (#26558). * Correctness and performance improvements in the bytecode interpreter (#12953, #26287, #26946, #26995, #27001). * Fixes for several compiler panics, including issues with SetLevels (#26681), the type-class specialiser (#26682), `mkTick` (#26772, #27121), CoreToStg (#27182, #27386), the pattern-match checker (#25926, #27124), module graph reachability (#26568), and continuation trimming for bottoming functions (#27261). * Fixes for several cases where the compiler could hang or loop, including with negative type literals (#26861), deep subsumption (#26823), and when simplifying the right-hand sides of rewrite rules (#26323, #26826). * A fix for cast worker/wrapper incorrectly firing on INLINE functions (#26903). * A fix for exponential-time desugaring of nested `case` expressions (#27383, #20251). * A fix for a regression that caused overloaded functions to no longer be specialised as effectively as in previous releases, hurting runtime performance (#26831). * A fix for associated type family and data family instance changes not triggering recompilation (#26183, #26705). * Fixes for Explicit Level Imports and Template Haskell staging (#26088, #26098, #26099, #26616, #27385). * Improvements to determinism of compiler output, including the order in which `:info` lists instances (#26846, #26858, #26877, #27532). * Additions for GHCi and GHC API users: the `-fimport-loaded-targets` flag (#26866), custom external interpreter commands (#26652), `decodeStackWithIpe` and related stack-decoding helpers (#27065), an optional `SrcLoc` on `StackAnnotation` (#26806), and a `gc_sync_elapsed_ns` counter in `RTSStats` (#26944). * ... and many more. A full accounting of these fixes can be found in the [release notes][]. As always, GHC's release status, including planned future releases, can be found on the GHC Wiki [status][]. This release candidate will have a two-week testing period. If all goes well the final release will be available the week of 1 October 2026. GHC development is sponsored by: * [Juspay](https://juspay.com/) * [QBayLogic](https://qbaylogic.com/) * [Channable](https://www.channable.com/) * [Haskell Foundation](https://haskell.foundation/) * [Serokell](https://serokell.io/) * [Well-Typed](https://well-typed.com/) * [Tweag](https://www.tweag.io/) * [Dotcom-Monitor](https://www.dotcom-monitor.com/) * [LoadView](https://www.loadview-testing.com/) * [Web Hosting Buddy](https://webhostingbuddy.com/) * [Find My Electric](https://www.findmyelectric.com/) * [Standard Chartered](https://www.sc.com) * [UpCloud](https://upcloud.com) * [Mercury](https://mercury.com) We would like to thank these sponsors and other anonymous contributors whose on-going financial and in-kind support has facilitated GHC maintenance and release management over the years. Finally, this release would not have been possible without the hundreds of open-source contributors whose work comprise this release. As always, do give this release a try and open a [ticket][] if you see anything amiss. [release notes]: https://gitlab.haskell.org/ghc/ghc/-/blob/ghc-9.14/docs/users_guide/9.14.2-… [status]: https://gitlab.haskell.org/ghc/ghc/-/wikis/GHC-status [downloads.haskell.org] https://downloads.haskell.org/ghc/9.14.2-rc2 [jsem]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0540-j… [static-forms]: https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0732-s… [jsem-warning]: https://downloads.haskell.org/ghc/9.14.2-rc2/docs/users_guide/using-warning… [rc1]: https://www.haskell.org/ghc/blog/20260730-ghc-9.14.2-rc1-released.html [ticket]: https://gitlab.haskell.org/ghc/ghc/-/issues/new

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PAgE'27 Call for Papers (co-located with POPL'27)
by Ningning Xie 16 Sep '26

16 Sep '26

PAgE 2027 Call for Papers https://popl27.sigplan.org/home/page-2027 PAgE (Principles of Agentic Engineering) aims to bring together the formal methods and AI communities to advance the principles of safe agentic engineering. It will feature peer-reviewed papers and invited talks from experts in the field. We welcome submissions describing research results, artifacts, datasets, case studies, and experience reports. Topics of interest include, but are not limited to: - Specifications and type-safe interfaces for tool use - Memory and state management for agents - Reliability & groundedness in planning and tool use - Static & dynamic analysis and verification of agentic plans - Safe integration with software engineering workflows - Testing and debugging of agentic workflows - Runtimes, compilers and virtual machines for agentic programs - Evaluation methods and benchmarks for trustworthy agents and agentic software, including safety, reliability, and cost/latency tradeoffs - Safety, security, and privacy of multi-agent systems - Neuro-symbolic and formal methods approaches for agent reasoning and control We also welcome submissions that explore the use of AI agents in the research and development process itself, including agent-assisted ideation, implementation, experimentation, artifact generation, and writing. Such submissions should clearly describe the workflow used, the extent of human oversight, and any lessons learned regarding reliability, reproducibility, and safety. We encourage submissions describing work in progress, position papers, experience reports, negative results (with detailed analysis and hypotheses for future improvements), demos, artifact or dataset descriptions, and talk proposals. Accepted submissions will be presented at the workshop but will not appear in the ACM Digital Library. You are free to submit work for presentation that is or will be published elsewhere. Please ensure that all submissions are anonymized for review. Submissions may be up to 8 pages, excluding bibliography, and should use the standard SIGPLAN conference two-column format.

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