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ICFP/SPLASH 2025 Workshop Proposal Deadline: Thu, Jan 16
by ICFP Publicity 10 Jan '25

10 Jan '25

ACM SIGPLAN ICFP 2025 and SPLASH 2025 invite proposals for workshops and co-located events to be held in Singapore from Sunday, October 12 to Saturday, October 18, 2025. This joint event will create a forum for researchers, developers, and practitioners to present the latest work in software development, programming languages, functional programming, and emerging new ideas in computing. All co-located events must submit a proposal — workshops, tutorials, symposiums, or side meetings: https://icfpsplash25events.hotcrp.com/ Important Deadlines <https://conf.researchr.org/track/icfp-splash-2025/icfp-splash-2025-workshop…> - Deadline for Proposal Submission for Workshops: January 16, 2025 - Notification of Acceptance: January 31, 2025 - Deadline for Proposal Submission for Tutorials: May 8, 2025 For more information, please see: https://conf.researchr.org/track/icfp-splash-2025/icfp-splash-2025-workshops We look forward to your proposals and hope to see you in Singapore!

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Formal Verification & Modern AI Safety
by Mostafa Touny 10 Jan '25

10 Jan '25

Hello Haskellers, I hope you are doing well. Amazon started to adopt automated theorem provers, to mitigate modern Generative AI hallucination. See "Prevent factual errors from LLM hallucinations with mathematically sound Automated Reasoning checks": https://aws.amazon.com/blogs/aws/prevent-factual-errors-from-llm-hallucinat… This community has ties to formal proofs, type-driven programming, and Logic programming. Do you see any special potential of Haskell for recent AI safety? Sincerely, Mostafa Touny

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[ANN] Darcs 2.18.4 release
by Ben Franksen 09 Jan '25

09 Jan '25

Hello Everyone On behalf of the Darcs [1] team, I would like to announce the release of Darcs 2.18.4 [2]. See [3] for the full release notes. The main reason for this release was to make it build with stack against stackage lts-22.34 on Linux. This in turn should hopefully make it re-appear in the Debian and Ubuntu GNU/Linux distros. Cheers Ben [1] https://darcs.net [2] https://hackage.haskell.org/package/darcs-2.18.4 [3] https://hackage.haskell.org/package/darcs-2.18.4/changelog

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Final call for participation: LMS/BCS-FACS Online Seminar, Annabelle McIver, 15 January 2025
by Andrei Popescu 09 Jan '25

09 Jan '25

LMS/BCS-FACS Seminar 2025 Wednesday 15 January 2025, from 19:00 (GMT) Online via Zoom https://www.lms.ac.uk/events/lms-bcs-facs-seminar-2025 In association with the British Computer Society Formal Aspects of Computing Science (BCS-FACS), the LMS hosts an annual online seminar on aspects of the computer science–mathematics interface. These events are free to anyone who wishes to attend and have attracted high-quality speakers. We are happy to have this verification talk from a wonderful speaker just one day after World Logic Day. Speaker: Annabelle McIver (Macquarie University) Probabilistic Datatypes: automating verification for abstract probabilistic reasoning Abstract: Datatypes - in which data is encapsulated together with methods that access it - play an important role in the organisation of large software projects. Correctness of datatypes has traditionally been carried out using simulation relations to simplify the verification by separating concerns: the datatype can be verified independently from the programs that use it, whilst those programs themselves can be verified using the specifications of the datatype's methods. Use of these principles enables complex programs to be brought within reach of automated proof. When probabilistic choice is included, however, it turns out that obtaining similar simplifications of the verification problem will require distinguishing between "hidden" and "observable" probabilistic behaviour - if demonic choice is allowed in the surrounding program. And that is not required in the non-probabilistic setting: the crucial issue is the potential interaction of probabilistic- and demonic choice. In the main part of this talk I will use examples to explain why the interaction is problematic, and I will suggest how extension of existing pGCL-based automated reasoning-tools, will by taking that interaction into account, enable automated probabilistic abstract reasoning about "hard to crack" probabilistic programs. Registration: To attend remotely via Zoom, please complete the registration form here: https://www.lms.ac.uk/civicrm/event/info?reset=1&id=139 You will receive the link to the meeting upon registration, as well as an automated reminder email sent 24 hours before the event is scheduled to start. For all queries regarding the seminar, please contact lmscomputerscience(a)lms.ac.uk.

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Rebuilding package on hackage to generate documentation
by Ivan Perez 08 Jan '25

08 Jan '25

Hi, I'm trying to trigger a re-build of Yampa on hackage so that the documentation will be generated. I'm being met with the following message: Report not found Build report does not exist Am I doing something wrong? Thanks Ivan

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[ANN] Copilot 4.2
by Ivan Perez 08 Jan '25

08 Jan '25

Hi everyone!! We are really excited to announce Copilot 4.2 [1,2]. Copilot is a stream-based EDSL in Haskell 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. Compilation to Bluespec, to target FPGAs, is also supported. Copilot is NASA Class D open-source software, and is being used at NASA in drone test flights. Through the NASA tool Ogma [3] (also written in Haskell), Copilot also serves as a runtime monitoring backend for NASA's Core Flight System, Robot Operating System (ROS2), FPrime (the software framework used in the Mars Helicopter). This release introduces several big improvements to Copilot: - Specifications can now use the same handler for multiple monitors, provided that the arguments to those handlers always have consistent types and arity. This simplifies the code that uses Copilot, since it's no longer necessary to create multiple boilerplate wrappers around the same handling routines. - The use of structs has been vastly simplified. Before, it was necessary to define class instances for structs, whose implementations were, although repetitive, not intuitive especially for users unfamiliar with Haskell. In Copilot 4.2, it is now possible to define those methods automatically by relying on default method implementations that work well for most cases, although users retain the ability to customize those methods if desired. - We have increased test coverage in `copilot-core`, reaching full coverage of all elements of the public interface that are not automatically generated by GHC. The interface of `copilot-core` has also been simplified, deprecating record fields of an existential type UExpr, which were largely unused outside of Copilot's internals. The new implementation is compatible with versions of GHC from 8.6 to 9.10, as well as Stackage Nightly. This release has been made possible thanks to key submissions from Frank Dedden, Ryan Scott, and Kyle Beech, the last of which is also a first-time contributor to the project. We are grateful to them for their timely contributions, especially during the holidays, and for making Copilot better every day. We also want to thank the attendees of Zurihac 2024 for technical discussions that helped find the right solutions to some of the problems addressed by this release. For details on this release, see [1]. https://github.com/Copilot-Language/copilot/releases/tag/v4.2. As always, we're releasing exactly 2 months since the last release. Our next release is scheduled for Mar 7th, 2025. We want to remind the community that Copilot is now accepting code contributions from external participants again. Please see the discussions and the issues in our github repo [4] to learn how to participate. Current emphasis is on improving the codebase in terms of performance, stability and test coverage, removing unnecessary dependencies, hiding internal definitions, formatting the code to meet our new coding standards, and simplifying the Copilot interface. Users are encouraged to participate by opening issues, asking questions, extending the implementation, and sending bug fixes. Happy Haskelling! Ivan -- [1] https://github.com/Copilot-Language/copilot/releases/tag/v4.2 [2] https://hackage.haskell.org/package/copilot [3] https://github.com/nasa/ogma [4] https://github.com/Copilot-Language/copilot

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POPL 2025 Call for Participation (January 19-25, Denver, Colorado)
by Ningning Xie 08 Jan '25

08 Jan '25

The 52nd ACM SIGPLAN Symposium on Principles of Programming Languages (POPL 2025) will take place in January in Denver, Colorado, the United States. It's going to be an amazing conference - don't miss it - sign up now! https://popl25.sigplan.org/attending/registration Location: Curtis Hotel Denver, 1405 Curtis Street, 80202, Denver, Colorado, United States Dates: - Main conference: Wed 22 - Fri 24 January - Workshops, tutorials, co-located events: Sun 19, Mon 20, Tue 21 and Sat 25 January Accepted papers: https://popl25.sigplan.org/track/POPL-2025-popl-research-papers Full details of the conference and co-located events: https://popl25.sigplan.org/ Sponsors: POPL is supported by generous sponsorship from: - Amazon - Jane Street - Google DeepMind - JetBrains - Microsoft - Epic - Google - Ahrefs

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CGO'25 - early bird registration and student research competition
by Luisa Cicolini 07 Jan '25

07 Jan '25

Dear all, Registrations for the International Symposium on Code Generation and Optimization (CGO) 2025<https://2025.cgo.org/>, taking place in Las Vegas<https://2025.cgo.org/attending/Venue>, from 1st-5th March are now open. The International Symposium on Code Generation and Optimization (CGO) is a premier venue bringing together researchers and practitioners working at the interface of hardware and software on a wide range of optimization and code generation techniques and related issues. The conference spans from purely static to fully dynamic approaches, from pure software-based methods to specific architectural features and support for code generation and optimization. Early registration<https://2025.cgo.org/attending/registration> deadline is on 31st January! We are also hosting a Student Research Competition (SRC)<https://2025.cgo.org/track/cgo-2025-student-research-competition>: a unique opportunity for undergraduate and graduate students to present their original research before a panel of judges and attendees at CGO'25. The winner will be awarded and invited to the 2025 ACM SRC competition. If you know any undergraduate or postgraduate students doing research in compiler-related topics, please invite them to apply - we are excited to welcome young researchers to the community! Best, Luisa Cicolini

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Re: [Haskell-cafe] Configuring cabal to tell HPC to ignore certain functions
by Ryan Scott 30 Dec '24

30 Dec '24

Hi Ivan, Short answer: I'm not aware of a way to automate the process of excluding certain definitions from cabal-generated HPC coverage reports. Long answer: there is a way to manually modify HPC coverage reports using the hpc overlay command. Sadly, most the existing documentation on this command [1] is pretty sparse, so the only way I was able to discover this was by reading the original HPC paper [2] (in that paper, `hpc overlay` is called `hpc-makemtix`) and by finding an example of how to use `hpc overlay` in GHC's test suite [3]. To translate that example into prose: suppose you have the following program (hpc001.hs): main = print (const "Hello" "World") Here, the expression "World" is never evaluated, so by default HPC will claim that there is no coverage for it. This is pretty silly, however, so we'd like to instruct HPC not to warn about "World". To do so, first compile the example above with coverage enabled and run it: $ ghc -fhpc hpc001.hs $ ./hpc001 This should generate an hpc001.tix file. If you run `hpc markup hpc001.tix` and look at the resulting HTML report, you'll see that it warns about "World". Let's fix that. To do so, we have to define an HPC overlay file. The example given in GHC's test suite (sample_overlay.ovr) is: module "Main" { inside "main" { tick "\"World\"" on line 1; } } While I can't find a reference for the syntax that HPC overlay files use, this particular example is pretty self-explanatory: don't report about the expression "World" on line 1, which is found inside the `main` function in the `Main` module. In order to make use of this overlay file, we first have to convert it to a .tix file: $ hpc overlay sample_overlay.ovr > sample_overlay1.tix Then we have to combine it with our original .tix file: $ hpc combine hpc_sample.tix sample_overlay1.tix > total1.tix If we run `hpc markup total1.txt`, we now see that HPC no longer warns about "World", just as we'd hoped for. That is where my understanding of this feature ends, however. In particular, I'm not aware of a better way to generate overlay files (other than to write them by hand, which still feels somewhat laborious), and I'm not aware of any deeper integration with cabal so that these overlay files would be picked up and automatically applied (e.g., for reporting coverage on Hackage). Given that the HPC documentation for `hpc overlay` [1] labels this as an experimental feature, I'd be surprised if such tooling or integration existed. I agree that it would be cool if did, however. Best, Ryan ----- [1] https://hpc-bin.readthedocs.io/en/latest/hpc.html#hpc-overlay-and-hpc-draft [2] https://dl.acm.org/doi/abs/10.1145/1291201.1291203 [3] https://gitlab.haskell.org/ghc/ghc/-/blob/e39c8c993c1da534c5893ca418d1fa4cb…

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[ghc-proposals] Allow reserved identifiers as fields ...
by Anthony Clayden 27 Dec '24

27 Dec '24

And Merry Christmas to all. I counsel against allowing reserved ids to be anything other than reserved ids. "... is fraught with peril, unduly complicates the parser, and harms readability. " says a language implementer I asked. But wanting to use field names dictated outside this language's control is a realistic requirement, for which there are several general approaches. The ghc proposal as it stands seems ad-hoc and very specific to one user organisation. Furthermore, this just ain't true: > ... SQL schemas. anyone working with those is stuck deciding between special-casing its naming, and consistently naming *everything* weirdly, ... SQL consistently supports things like embedded spaces, fields starting upper-case [**], embedded dots or other graphics -- by no means just names that clash with reserved ids. How does it do that? And this answer seems particularly relevant when these ids are going to feed into `HasField` constraints as a type-level String: put the id between quotes. > orgNotification."type" doesn't look too ugly to my eye. And to spj's repeated point: I could envisage allowing fields in `data` decls and record syntax to be quoted. (Again you couldn't use punning nor field-name as function.) The approach is sufficiently general it could be extended to `#"Label naming"`. [**] I'm particularly keen on field names starting upper case, because they're injective/part of the structure, like data constructors. AntC (Why am I posting to the cafe, not github? I seem to be blocked from posting on any topic, either on github or gitlab -- even for pages where I'm the sole author. I'd be grateful if somebody could post the above to the PR.)

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