- Haskell-Cafe - Haskell.org

Re: [Haskell-cafe] Wincomplete-uni-patterns and bidirectional patterns
by Olaf Klinke 16 Jan '24

16 Jan '24

> > I think the completeness checker works fine in all > > pattern-synonym-free cases, i.e. when you're using only real > > constructors. One can envision a simple recursive divide-and-conquer algorithm, see below. > I don't actually understand why completeness > > annotations are needed for pattern synonyms. > > I remember reading somewhere, but I can't find it now, that GHC's > coverage checker does not look inside pattern synonym definitions at > all, and this is by design: namely to ensure abstraction boundaries. > Looking inside the definition would mean that type checking behaviour > (in a way -- if you count coverage checks as "type checking") of user > code is influenced by invisible implementation details of the > "constructors" they're using. Compare that to 'type' versus 'newtype' on the type level: A type is just an alias, a synonym. The type checker has access to all information on the right hand side of the equality. With extensions like TypeSynonymInstances, A type alias is interchangeable with the aliased type. If what you report is true, they should not have called pattern synonyms a "synonym". > > My own thoughts on this: if GHC would look inside pattern synonym > definitions, then it would be hard to ensure that GHC thinks that > certain things are _not_ complete even if technically they are. For > example, if you have a data type with, say, 3 constructors, but you > hide > some of those (don't export them) and use pattern synonyms to make it > look like 4 constructors, then you might want GHC's coverage checker > to > consider that a data type with 4 constructors, not one with 3. > COMPLETE > pragmas add "positive" information -- "this set is complete, in > addition > to whatever other complete sets GHC might already know" -- and there > is > no way to _subtract_ complete sets from GHC's knowledge base. > > This is mostly me theorising, but perhaps it helps. > > - other Tom > I don't think the number of constructors/patterns is the issue. Likely the problem lies in the fact that while ordinary constructors make up disjoint subsets of the type, with patterns you can define overlapping sets, which makes completeness checks much more complicated. Hence I believe that completeness checks in presence of patterns is equivalent to determine whether a disjunction of logic formulae, which are possibly self-referential, is a tautology. That may well be semi- decidable at best. Olaf

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Re: [Haskell-cafe] Wincomplete-uni-patterns and bidirectional patterns
by Olaf Klinke 16 Jan '24

16 Jan '24

> On Mon, Jan 15, 2024 at 12:00:16PM +0100, Olaf Klinke wrote: > > How can I teach GHC 9 that the pattern is indeed exhaustive? > > Have you tried COMPLETE pragmas? > > > https://ghc.gitlab.haskell.org/ghc/doc/users_guide/exts/pragmas.html#comple… > > Tom Huh, of course that works. Thanks. It never occurred to me to even consider the existence of manual completeness annotation, since completeness checks work so reliably for ordinary constructors. But maybe my types weren't esoteric enough so far. Are there pattern-free cases where the GHC completeness checker is wrong? Of what computational class is the problem? Can I simulate a Turing machine by checking completeness in the presence of patterns? Olaf

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GSoC 2024 Call for Ideas
by Aaron Allen 16 Jan '24

16 Jan '24

Dear Haskellers, Google Summer of Code is a long-running program by Google that supports Open Source projects. Haskell has been involved in the Google Summer of Code program almost since its inception and we are hoping to participate again in 2024! In order to do this we need a collection of ideas for participants to select from. In the past this has included significant improvements to Haskell projects such as GHC, Cabal, and HLS - and it can include your project as well! This is a great opportunity to find new contributors for your project and many past participants have become involved long-term. You can find more info and instructions on how to participate here: https://summer.haskell.org/ideas.html.

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[Haskell] [ANNOUNCE] Haskell Language Server 2.6.0.0 released
by Zubin Duggal 15 Jan '24

15 Jan '24

Binaries for this release are available at https://downloads.haskell.org/~hls/haskell-language-server-2.6.0.0/. These binaries can be installed using [GHCup](https://www.haskell.org/ghcup/), using the vanilla metadata channel. ```bash ghcup --url-source=https://raw.githubusercontent.com/haskell/ghcup-metadata/master/ghcup-vanilla-0.0.8.yaml install hls 2.6.0.0 ``` All of these tarballs have associated GPG signatures. The signature should be from `Zubin Duggal <zubin(a)well-typed.com>` (key ID [588764FBE22D19C4](https://keys.openpgp.org/search?q=588764FBE22D19C4)) The prebuilt binaries in this release support the following GHC versions: - 9.2.8 - 9.4.8 - 9.6.4 - 9.8.1 # Changelog - Bindists for GHC 9.6.4 - A new semantic tokens plugin (#3892, @soulomoon). - Improvements to multiple home unit support with GHC 9.4. Using cabal 3.11+ will load proper multiple home unit sessions by default, fixing a lot of issues with loading and reloading projects that have more than one component (#3462, @wz1000). - Removed implicit-hie, resulting in better behaviour for projects without cradles. - Don't produce diagnostics for disabled plugins (#3941, @fendor). - Many other bug fixes. Happy editing! - Zubin.

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Wincomplete-uni-patterns and bidirectional patterns
by Olaf Klinke 15 Jan '24

15 Jan '24

Dear Cafe, I have a data type with a bidirectional pattern {-# LANGUAGE PatternSynonyms #-} newtype T f t = C (f Double) pattern T :: Double -> T Identity t pattern T x = C (Identity x) Note that pattern T is the only way to construct something of type (T Identity t) for any phantom parameter t. When using the pattern to match in a where clause, the Wincomplete-uni-pattern warns me about non-exhaustive pattern matches that are in fact matched: f a = x where T x = g a :: T Identity () warning: [-Wincomplete-uni-patterns] Pattern match(es) are non- exhaustive in a pattern binding: Patterns not matched: C (Identity _) Minimal complete example is attached. How can I teach GHC 9 that the pattern is indeed exhaustive? GHC seems to have only three issues involving incomplete-uni-patterns, only one of them open, none of which matches my observations. Thanks Olaf

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Fully-funded PhD studentship in functional programming
by Graham Hutton 15 Jan '24

15 Jan '24

Dear all, I'm advertising a fully-funded PhD studentship in functional programming, starting 1st October 2024. Please pass the advert on to anyone who may be intersted in applying. Best wishes, Graham Hutton +-----------------------------------------------------------+ Fully-Funded PhD Studentship Functional Programming Lab School of Computer Science University of Nottingham, UK http://tinyurl.com/fplab-phd Applications are invited for a fully-funded PhD studentship under the supervision of Prof Graham Hutton, starting on 1st October 2024. The successful applicant will join the Functional Programming Lab, an internationally-leading centre for programming language research. The topic for the studentship is open, but should relate to the research interests of Prof Hutton on the mathematics of program construction. The studentship forms part of the recently-funded EPSRC project on Semantics-Directed Compiler Construction, which seeks to develop new techniques for constructing certified compilers from semantics. The studentship is open to home and international students, is fully-funded for three and a half years, and includes a stipend of £18,622 per year and tuition fees. Applicants are expected to have a first-class Masters or Bachelors degree (or equivalent) in Computer Science and/or Mathematics, and an excellent ability and interest in the mathematical foundations of programming, together with experience of programming in a functional language. Further information and advice for prospective applicants is available from http://tinyurl.com/369xwzc7. Funding for this studentship is already in place. To apply, please submit the following items by email to graham.hutton(a)nottingham.ac.uk: (1) a brief covering letter that describes your reasons for wishing to undertake a PhD and any ideas you have about potential topics; (2) a copy of your CV, including your actual or expected degree class(es) and results of all university examinations; (3) an example of your technical writing, such as a report or dissertation; (4) email addresses for two academic referees. Closing date for applications: Friday 9th February 2024. +-----------------------------------------------------------+ — Professor Graham Hutton School of Computer Science University of Nottingham, UK http://www.cs.nott.ac.uk/~pszgmh 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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2nd Call for Participation: BOB 2024 (Berlin, Mar 15, Early Bird until Jan 30)
by Stefan Wehr 15 Jan '24

15 Jan '24

========================================================================= BOB 2024 Conference “What happens if we simply use what’s best?” March 15, 2024, Berlin https://bobkonf.de/2024/ Program: https://bobkonf.de/2024/program.html Registration: https://bobkonf.de/2024/registration.html ========================================================================= BOB conference is a place for developers, architects, and decision-makers to explore technologies beyond the mainstream in software development and to find the best tools available to software developers today. Our goal is for all participants of BOB to return home with new insights that enable them to improve their own software development experience. The program features 14 talks and 8 tutorials on current topics: https://bobkonf.de/2024/program.html Talk subjects includes functional programming, property-based testing, service API design, programming for spacecraft, accessibility, hypermedia, business processes, software analytics, event-based communication and zero-knowledge proofs. BOB will feature tutorials on F#, Haskell, Lean, SwiftUI, Copilot, the K Framework, functional domain modelling, and Liberating Structures. Andreas Rossberg will give the keynote talk. Registration is open - online tickets are all under 200€, and many discount options are available, as are grants for members of groups underrepresented in tech. Early-bird registration runs until Jan 30: https://bobkonf.de/2024/registration.html

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Fastest saturating add?
by amindfv＠mailbox.org 14 Jan '24

14 Jan '24

I have a function that's called many (many) times, which involves a saturating addition (addition without overflow). In other words, I'd like ((254 :: Word8) + 10) to equal 255 (which is maxBound::Word8), not 8 (which is what you get with overflow). My current code, without particular regard to performance, is simply: satAdd :: Word8 -> Word8 -> Word8 satAdd x y = let m = x + y in if m < x then 255 else m This seems like the type of code somebody's already worked on the performance for, though I can't find much Haskell-specific in searches online. Is there a faster way to do this? Thanks! Tom

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restore type from existential
by zoran.bosnjak＠via.si 10 Jan '24

10 Jan '24

Dear haskellers, if for example I have the following (simplified) situation: import GHC.TypeLits type MyTypes = '[ () -- index 0 , Char -- index 1 , Int -- index 2 ] data SNat (n :: Nat) where SZ :: SNat 0 SS :: SNat n -> SNat (n+1) data Wrap where WrapUnsafe :: SNat n -> t -> Wrap t1 = WrapUnsafe SZ () :: Wrap t2 = WrapUnsafe (SS SZ) 'x' :: Wrap t3 = WrapUnsafe (SS (SS SZ)) (1::Int) :: Wrap Is it possible to have an 'unwrap' function? That is: to combine MyType types table and the type index... to get the exact type back. Something in the form: unwrapUnsafe :: Wrap -> t unwrapUnsafe (WrapUnsafe (ix::SNat n) (val::t)) = undefined x1 = unwrapUnsafe t1 x2 = unwrapUnsafe t2 x3 = unwrapUnsafe t3 GHC didn't like any of my attempt. Is it even possible? regards, Zoran

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[ANNOUNCE] GHC 9.6.4 is now available
by Zubin Duggal 09 Jan '24

09 Jan '24

The GHC developers are happy to announce the availability of GHC 9.6.4. Binary distributions, source distributions, and documentation are available on the [release page](https://www.haskell.org/ghc/download_ghc_9_6_4.html). This release is primarily a bugfix release addressing a few issues found in the 9.6 series. These include: * A fix for a bug where certain warnings flags were not recognised (#24071) * Fixes for a number of simplifier bugs (#23952, #23862). * Fixes for compiler panics with certain package databases involving unusable units and module reexports (#21097, #16996, #11050). * A fix for a typechecker crash (#24083). * A fix for a code generator bug on AArch64 platforms resulting in invalid conditional jumps (#23746). * Fixes for some memory leaks in GHCi (#24107, #24118) * And a few other fixes A full accounting of changes can be found in the [release notes]. As some of the fixed issues do affect correctness users are encouraged to upgrade promptly. We would like to thank Microsoft Azure, GitHub, IOG, the Zw3rk stake pool, Well-Typed, Tweag I/O, Serokell, Equinix, SimSpace, Haskell Foundation, 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. Happy hacking! -Zubin [ticket]: https://gitlab.haskell.org/ghc/ghc/-/issues/new [release notes]: https://downloads.haskell.org/~ghc/9.6.4/docs/users_guide/9.6.4-notes.html

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Technical Working Group: Call for Volunteers
by Jose Calderon 02 Jan '24

02 Jan '24

Hello, The Haskell Foundation Technical Working Group (TWG) <https://github.com/haskellfoundation/tech-proposals/blob/main/proposals/PRO…> serves as an advisory organization for both the HF management and the Haskell community as a whole, by evaluating specific proposals for projects that can have broad, ecosystem-wide effects. These proposals can be: - Community RFCs that seek the community’s input on a project - Community projects that will be executed primarily by the proposer, but seek administrative or financial support from the HF - HF projects that a community member would like us to execute - Other topics of relevance to the community Volunteers wanted! We presently have three openings on the working group, and we’re seeking volunteers. Members are expected to attend a monthly meeting, to participate in and moderate discussion threads regarding specific proposals, and to evaluate proposals for their technical merits. From time to time, committee members may also be asked to help a community member revise their proposal. The ability to communicate well and respectfully is important for any potential member. These discussions have a real impact on the Haskell ecosystem, so this is an opportunity to give back in a meaningful way. If you are interested, or if you know someone who might be, please get in touch with me at director(a)haskell.foundation! You don’t have to be a long-term Haskeller, or someone who is deeply embedded in Haskell development - we have members with this background already. If you are unsure as to whether you would fit in, please get in touch, and we can have a chat about it. We would like to have members with diverse backgrounds, professional experiences, and knowledge. All self-nominations must be submitted by the end of the day on Jan 12th 2024. Best wishes, Jose

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[TFP (and TFPiE) 2024] Call For Participation (January 9-12, Seton Hall University, NJ, USA)
by Peter Achten 22 Dec '23

22 Dec '23

# TFP 2024 -- Call For Participation (trendsfp.github.io) ## Venue TFPiE and TFP will take place in-person at Seton Hall University, New Jersey in the United States. ## Dates TFPiE Workshop: Tuesday 9th January, 2024 TFP Symposium: Wednesday 10th - Friday 12th January, 2024 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. ## Keynote speakers We are happy to have the following keynotes in the programme: * Jeremy Gibbons, Oxford University * Benjamin Pierce, University of Pennsylvania * John Reppy, University of Chicago ## Programme The programme schedule can be found here: trendsfp.github.io/schedule.html ## Excursion and banquet After lunch on Thursday there is a private guided tour of the Thomas Edison National Historical Park and Museum. Thursday evening we have the TFP banquet at Forno's of Spain. During dinner the winners of the best paper awards of last year's TFP will be announced.

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RFC: Changes to the Haskell Symposium
by J. Garrett Morris 20 Dec '23

20 Dec '23

Dear Haskellers, In recent years, submissions to the Haskell Symposium have dropped precipitously: from 37 in 2017 to just 15 in 2023. This has made it increasingly challenging for the program committee to put together a program that is vibrant and intellectually rigorous. The Haskell Symposium steering committee has developed two proposals to reinvigorate the Symposium. The first is to invite a new category of presentations of work-in-progress results; the second is to submit accepted papers to the Journal of Functional Programming for publication rather than continuing the Symposium's proceedings. A full description of the proposed changes can be found on the Haskell Foundation's GitHub: https://github.com/haskellfoundation/tech-proposals/pull/62. We invite feedback from the community, particularly on how these changes would effect your participation (either as authors or attendees) in the future. Yours, /g J. Garrett Morris PC Co-chair, 2024 Haskell Symposium For the Haskell Symposium Steering Committee

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Call for Participation: BOB 2024 (Berlin, March 15)
by Stefan Wehr 15 Dec '23

15 Dec '23

========================================================================= BOB 2024 Conference “What happens if we simply use what’s best?” March 15, 2024, Berlin https://bobkonf.de/2024/ Program: https://bobkonf.de/2024/program.html Registration: https://bobkonf.de/2024/registration.html ========================================================================= BOB conference is a place for developers, architects, and decision-makers to explore technologies beyond the mainstream in software development and to find the best tools available to software developers today. Our goal is for all participants of BOB to return home with new insights that enable them to improve their own software development experience. The program features 14 talks and 8 tutorials on current topics: https://bobkonf.de/2024/program.html Talk subjects includes functional programming, property-based testing, service API design, programming for spacecraft, accessibility, hypermedia, business processes, software analytics, event-based communication and zero-knowledge proofs. BOB will feature tutorials on F#, Haskell, Lean, SwiftUI, Copilot, the K Framework, functional domain modelling, and Liberating Structures. Andreas Rossberg will give the keynote talk. Registration is open - online tickets are all under 200€, and many discount options are available, as are grants for members of groups underrepresented in tech: https://bobkonf.de/2024/registration.html

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Package takeover request for socks
by Markus Läll 13 Dec '23

13 Dec '23

Hi I would like to take over maintainership of the socks package (as in the SOCKS network proxy protocol). Vincent announced archiving the package in September[1] (I'm also cc'ing him here). The github repository is here[2]. Unless there are objections, my plan is to simply maintain it under my own github account, because when I took over rapid, I created a new github organization for it. But until there are other people interested in contributing, then having an org for each library is not worth it IMO. [1] https://twitter.com/vincenthz/status/1704395906374889934 [2] https://github.com/vincenthz/hs-socks -- Markus Läll

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ICFP 2024: Call for Workshops and Co-Located Events
by ICFP Publicity 12 Dec '23

12 Dec '23

CALL FOR WORKSHOP AND CO-LOCATED EVENT PROPOSALS ICFP 2024 29th ACM SIGPLAN International Conference on Functional Programming September 2 - 7, 2024 Milan, Italy https://icfp24.sigplan.org/ The 29th ACM SIGPLAN International Conference on Functional Programming will be held in Milan, Italy on September 2 - 7, 2024, with the option of virtual participation. ICFP provides a forum for researchers and developers to hear about the latest work on the design, implementations, principles, and uses of functional programming. Proposals are invited for workshops (and other co-located events, such as symposiums) to be affiliated with ICFP 2024 and sponsored by SIGPLAN. These events should be less formal and more focused than ICFP itself, include sessions that enable interaction among the attendees, and foster the exchange of new ideas. The preference is for one-day events, but other schedules can also be considered. The workshops are scheduled to occur on September 2nd (the day before ICFP) and September 6-7th (the two days after ICFP). A separate call for Call for Tutorial, Panel, and Discussion Proposals is going to be circulated later. ---------------------------------------------------------------------- Submission details Deadline for submission: January 11, 2024 Notification of acceptance: January 19, 2024 Prospective organizers of workshops or other co-located events are invited to submit a completed workshop proposal form in plain text format to the ICFP 2024 workshop co-chairs (Chandrakana Nandi and Yannick Forster) via email to chandra(a)certora.com yannick.forster(a)inria.fr by January 11, 2024. (For proposals of co-located events other than workshops, please fill in the workshop proposal form and just leave blank any sections that do not apply.) Please note that this is a firm deadline. Organizers will be notified whether their event proposal is accepted by January 19, 2024, and if successful, depending on the event, they will be asked to produce a final report after the event has taken place that is suitable for publication in SIGPLAN Notices. The proposal form is available at: http://www.icfpconference.org/icfp2024-files/icfp24-workshops-form.txt.docx PC Template: http://www.icfpconference.org/icfp2024-files/pc-template.xlsx Further information about SIGPLAN sponsorship is available at: http://www.sigplan.org/Resources/Proposals/Sponsored/ ---------------------------------------------------------------------- Selection committee The proposals will be evaluated by a committee comprising the following members of the ICFP 2024 organizing committee, together with the members of the SIGPLAN executive committee. Workshop Co-Chair: Chandrakana Nandi (Certora) Workshop Co-Chair: Yannick Forster (Inria) General Chair: Marco Gaboardi (Boston University) Program Chair: Brigitte Pientka (McGill University) ---------------------------------------------------------------------- Further information Any queries should be addressed to the workshop co-chairs (Chandrakana Nandi and Yannick Forster), via email to chandra(a)certora.com end yannick.forster(a)inria.fr

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Issues with static linking of a C ".a" library with cabal
by Hécate 11 Dec '23

11 Dec '23

Hi everyone, I'm hitting a number of roadblocks while trying to embed a ".a" file (and its headers) in Haskell code. The setup is the following: I have a bindings library that handles all of the cAPI FFI declarations, and a consumer that does not directly depend on the underlying C library. As such, I use a combination of extra-bundled-libraries, include-dirs and install-includes stanzas in my cabal file: elifflag(bundled-libsodium) extra-bundled-libraries: Csodium include-dirs: include install-includes: include/sodium.h include/sodium/core.h include/sodium/crypto_aead_aes256gcm.h […] (full file here: https://github.com/haskell-cryptography/libsodium-bindings/blob/37-libsodiu…) It all seemed to work on my day-to-day system, but further tests on a system that did not have libsodium installed system-wide showed that there's still a missing part: |/usr/bin/ld.gold:error:cannotfind-lsodium collect2:error:ldreturned1exitstatus `gcc'failedinphase`Linker'.(Exitcode:1)| At this point I am simply baffled, because I thought that I had the right invocation for all of this to work. What else can I do? Am I missing something obvious? I have opened a ticket here with a bit more details: https://github.com/haskell/cabal/issues/9509 Cheers, Hécate -- Hécate ✨ 🐦: @TechnoEmpress IRC: Hecate WWW:https://glitchbra.in RUN: BSD

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OverloadedStrings, but with compile-time invariants
by Max Ulidtko 10 Dec '23

10 Dec '23

Greetings @cafe, Transparent wrapping of string literals into custom types, driven automatically by type inference, is of course very useful. I'm getting huge mileage off GHC's OverloadedStrings when working with e.g. the Text type: class IsString a where fromString :: String -> a instance IsString Text {- ... -} greeting :: Text greeting = "Hello" But I hope there's possibly room for improvement. I've got a bag of several use-cases; perhaps the simplest is the following. Consider a type called NonEmptyText which is a (wrapper around) Text, but with an added invariant that the contained text is never the empty string "". Depending on codebase, such a type can be very useful too, allowing to offload the burden of keeping track of the invariant onto machine; the typechecker will show me all the spots to handle, current or future ones. IOW, this type enables writing a non-boolean-blind null check, toNonEmptyText :: ToText str => str -> Maybe NonEmptyText — which makes not only the programmer, but also the compiler, aware of the null-check result. I'm focusing the example on Text to somewhat maintain generality of the idea. NonEmpty Char can be an alternative formulation of "non-empty String"; length-indexed vectors could possibly handle this too. But there're all sorts of invariants besides non-emptiness one may wish to express. I'll omit other examples; but to summarize, I've got plenty of practical motivation to get "smart literals". And to the point: IsString as it stands, forces us to write much unsatisfactory instances: instance IsString NonEmptyText where fromString (c:cs) = NonEmptyText.new c cs fromString [] = error "unavoidable runtime panic" -- argh ... despite fromString being invoked, presumably with OverloadedStrings, on a string literal — which is statically known at compile-time. I'd imagine upgrading the interface with GHC's own TypeLits: class KnownSymbol lit => IsString' str lit where fromString' :: proxy lit -> str This 2-parameter formulation of IsString enables pretty straightforward user code, along the lines of: type family MyInvariant (s :: Symbol) :: Constraint where MyInvariant "" = TypeError ('Text "Empty string literal") MyInvariant _s = () instance (MyInvariant lit, KnownSymbol lit) => IsString' NonEmptyText lit where fromString' = nothingImpossible . NeT.fromText . toText . symbolVal where nothingImpossible (Just x) = x nothingImpossible Nothing = error "typelevel invariant violated" text1, text2 :: NonEmptyText text1 = fromString' $ Proxy @"hello, types" text2 = fromString' $ Proxy @"" -- compile error here, as expected! With the primes, this is possible to write today. With AllowAmbiguousTypes, the unwieldy syntax can be abbreviated somewhat, e.g. smartLiteral @"overloaded string literal with compiler-checked invariant" — but is still rather awkward... in the same way that ubiquitous T.pack is annoying enough to want to enable OverloadedStrings and stop seeing it all over the place. The question is, could this IsString' somehow become the IsString that OverloadedStrings is friends with? I guess, not soon, with compatibility in mind... But in principle? Is it even worth trying to pursue the GHC Proposal path? Perhaps a new extension OverloadedTypelevelStrings? Relatedly... Can a GHC Plugin do this? And overall, to zoom out of "XY Problem" pitfalls: am I missing a neater way to have "partial" IsString instances, those that can reject some literals at compile-time? Having this code work is the goal: text1, text2 :: NonEmptyText text1 = "hello, types" text2 = "" -- compile error Best regards, Max

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[ANN] mig-2.1 minimal server library
by Anton Kholomiov 10 Dec '23

10 Dec '23

I'm happy to announce a new release of the mig library. It's a minimal and simple library to build servers. This release adds some goodies for servers that produce HTML: * cookies (new [input Cookie]( https://hackage.haskell.org/package/mig-0.2.1.0/docs/Mig-Core-Types-Route.h…) type and [function to set]( https://hackage.haskell.org/package/mig-0.2.1.0/docs/Mig-Core-Class-Respons…) the cookies) * [type-safe stable URLs]( https://hackage.haskell.org/package/mig-0.2.1.0/docs/Mig-Core-Class-Url.html) from server definition * an example [HtmlTemplate]( https://github.com/anton-k/mig/tree/main/examples/mig-example-apps/HtmlTemp…) on how to use template engine and type-safe URLs with the library Also it adds a stack template to create new hello-world server with stack (on how to use it see the section on how to start [a new mig project]( https://anton-k.github.io/mig/#how-to-start-a-new-project) in the tutorial). Links: * [github](https://github.com/anton-k/mig) * [tutorial](https://anton-k.github.io/mig/) * [hackage for the server library]( https://hackage.haskell.org/package/mig-server) * [hackage for the core library](https://hackage.haskell.org/package/mig) * [examples]( https://github.com/anton-k/mig/tree/main/examples/mig-example-apps#mig-exam… )

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PLDI'24 Artifact Evaluation Committee: Call for nominations
by Ningning Xie 08 Dec '23

08 Dec '23

Dear all, We are looking for motivated students and researchers to be members of the PLDI 2024 Artifact Evaluation Committee (AEC). The artifact evaluation process aims to promote, share and catalog the research artifacts of papers accepted to the PLDI research track. This year, we are accepting self-nominations for the AEC. The self-nomination form is available at: https://forms.gle/wWGfW33qMY2gUqqz7 The first round of nomination ends on Dec 22nd, 2023. As a committee member, the primary responsibilities would be to review the artifacts submitted corresponding to the already accepted papers in the main research track. In particular, you may have to run the associated tool, check whether the results in the main paper can be reproduced, and inspect the data. We expect the bulk of the review work to take place between early February and mid April. Each artifact will take about 8h to review, and reviewers will be assigned about 3 artifacts to review. Come join us in improving the quality of research in our field! Best regards, Manuel Rigger and Ningning Xie

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CGO'24 - Student Research Competition (SRC) and more
by L. Cicolini 08 Dec '23

08 Dec '23

Dear all, The International Symposium on Code Generation and Optimization (CGO) is hosting a Student Research Competition (SRC). Our SRC is a unique opportunity for undergraduate and graduate students to present their original research before a panel of judges and attendees at CGO'24. The winner will be invited to the Grand 2024 ACM SRC competition. If you are an undergraduate or postgraduate student doing research in compiler-related topics, consider applying. We look forward to meeting you! CGO'24 is a compiler conference happening in Edinburgh, March 2nd to 6th 2024. This conference is a great opportunity for anyone interested in compilers to connect with great researchers and professionals and will host four existing workshops: LLVM [1], the BuildIt Framework [2], LATHC [3], and C4ML [4]. Find more information on https://conf.researchr.org/home/cgo-2024 and share this message with anyone who might be interested! Best, Luisa Cicolini [1] LLVM Performance Workshop: https://llvm.org/devmtg/2024-03/ [2] BuildIt: Building DSLs made easy with the BuildIt Framework: https://buildit.so/tutorial/ [3] LATHC: Languages, Architectures, and Tools for Heterogeneous Computing Workshop: https://jnamaral.github.io/LATHC24/ [4] C4ML - Compilers For Machine Learning: https://www.c4ml.org/c4ml-2024

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Haskell.org Call for Nominations (for the terms 2024-2027)
by Ida Bzo 05 Dec '23

05 Dec '23

Dear Haskellers, We are pleased to announce that nominations are now open for the Haskell.org committee. You can nominate yourself or a friend for a three-year term (2024-2027) by sending an email to [committee at haskell.org] by January 10, 2024. Self-nominations and re-nominations are also welcome. Please include any relevant information about yourself or your nominee that you think will help us make our decision. Committee members do not have to be technical experts in Haskell. We are looking for people who are enthusiastic about improving the Haskell community and come from a variety of backgrounds, such as academia, industry, open-source development, and community building. Our goal is to represent the various facets of the Haskell world, including gender, race, location, and industry or research. The committee's responsibilities include setting policies, providing guidance for Haskell.org infrastructure, planning for the long term, and being fiscally responsible with Haskell.org funds and donations. Being a committee member does not require a significant amount of time, but members should be responsive during discussions and should be able to attend monthly calls and participate in the Haskell.org Slack and mailing lists. Candidates for the committee should possess strong leadership, communication, and judgment skills. They must be able to set aside personal or business-related biases and make decisions with the good of the open-source Haskell community in mind. For more information about the committee's roles and responsibilities, please visit https://www.haskell.org/haskell-org-committee/ If you have any questions about the nomination process, please feel free to email us at [committee at haskell.org] or contact one of us individually. λCheers, Ida Bzo

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Download stats not updated on Hackage
by Harendra Kumar 05 Dec '23

05 Dec '23

Hi, It seems the download count for packages on Hackage is stuck for quite some time now. Is this issue known to the Hackage maintainers? -harendra

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Why Choose Digitology.co as Your Digital Marketing Agency in Egypt
by Ihab Mohsen 05 Dec '23

05 Dec '23

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Elevate Safety with ATISystems.com: Your Destination for Cutting-Edge Giant Voice and Outdoor Warning Systems
by Ihab Mohsen 05 Dec '23

05 Dec '23

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garn: a Nix/Cabal/Stack alternative
by Julian Arni 03 Dec '23

03 Dec '23

Dear list, garn is a new take on Nix - configured in Typescript rather than the Nix language, and with a nicer and simpler CLI (thanks optparse-applicative!). The repository is https://github.com/garnix-io/garn, and the website is https://garn.io/. I'm mentioning it here because we just added better Haskell support, which makes it now a plausible alternative to managing your Haskell projects with Nix, Stack or Cabal. An example Haskell project: import * as garn from "https://garn.io/ts/v0.0.18/mod.ts"; import * as pkgs from "https://garn.io/ts/v0.0.18/nixpkgs.ts"; export const project = garn.haskell.mkHaskellProject({ description: "My project", src: ".", executables: ["server", "openapi-generation"] overrideDependencies: { "servant": "0.19.1" }, ghcVersion: "ghc94" }).addExecutable("format")`${pkgs.ormolu}/bin/ormolu --mode inplace $(find . -name '*.hs')` Which allows for `garn build project` to build the project, and `garn enter project` to be in a devshell with cabal, ghc94 and all the dependencies installed, and `garn run project.format` for formatting all files with ormolu. (`garn init` is capable of generating most of that file for you.) # Comparisons First, compared to all of the options below, garn is much less mature - there'll be rougher edges or features not yet supported. It's also still changing very quickly, and backwards compatibility is not, for now, a priority. - Cabal: Like Cabal, garn still uses a cabal file, and in fact expects you to develop with cabal. garn brings in the dependencies itself and makes them known to ghc/cabal, and they're snapshot-based rather than resolver-based. In addition, garn makes it easy to include system (non-Haskell) dependencies, it sandboxes builds and tests for better reproduciblity (making CI in particular quite easy); it allows for shared caches; it supports scripts for project janitoring and management; and it supports devshells. - Stack: Like Stack, garn uses a snapshot-based approach to dependencies. In fact, it's based on the stackage releases. It also supports overriding versions from Hackage, but not yet from git. Unlike Stack, it allows specifying system dependencies (non-Haskell dependencies); it sandboxes builds and tests for better reproduciblity (making CI in particular quite easy); it allows for shared caches; it supports scripts for project janitoring and management; and it supports devshells. - Nix: the focus of garn has been a simplified and more productive user experience when compared to Nix. A typed language means you can get autocompletion, documentation, and type errors in your editor, for example. And, even if Typescript is by no means perfect, it's much easier to program in than Nix, so it becomes more fun to abstract away functionality (e.g.: an addGhcidToProject function). garn "transpiles" to Nix, and Nix can be embedded in garn, so the choice is not binary. # Feedback If you try it out, please let us know what you think, or if you run into any roadblocks. You can email me at this address, or open issues on GitHub, or join the Discord channel at https://discord.com/invite/XtDrPsqpVx. It also happens to be partly written in Haskell; hopefully that makes it more easy and fun to get involved! Cheers, Julian

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ANN: hledger 1.32
by Simon Michael 02 Dec '23

02 Dec '23

G'day all, I'm very pleased to announce hledger 1.32, including work from contributors Jonathan Dowland, S. Zeid, Charlie Ambrose, Jacob Weisz, Peter Sagerson, Philipp Klocke, Stephen Morgan, and bobobo1618. Highlights: More precision control, beancount output, TSV output, --summary-only, strict/idempotent import, CSV rule enhancements, timedot letters, fixes - there's a lot in this one, set aside some time to read the notes. - https://github.com/simonmichael/hledger/releases/1.32 - https://hledger.org/release-notes.html#2023-12-01-hledger-132 - https://hledger.org/install hledger is free, fast, reliable, multicurrency, double-entry, plain text accounting software for unix, mac, windows, and the web; built around human-readable, version-controllable plain text files; inspired by and largely compatible with Ledger CLI; convertible to and from Beancount; written in Haskell for reliability and longevity. For help getting started or more info, see https://hledger.org and join our Matrix/IRC chat or mail list: https://hledger.org/support . Newcomers, experts, contributors, sponsors, feedback are welcome! For more about plain text accounting, see https://plaintextaccounting.org . May you be free from danger; may you have happy, peaceful, prosperous holidays. -Simon

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Request to take over floating-bits package
by Julia Longtin 01 Dec '23

01 Dec '23

This is an attempt to follow the process at wiki.haskell.org/Taking_over_a_package I have set up a git repository at github.com/julialongtin/floating-bits/ , and fixed compatibility issues with ghc-9.4. I would like to be made maintainer of this package in hackage. Julia Longtin

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Does the constraints library give (a :- b) -> Dict (a |- b)?
by Tom Ellis 01 Dec '23

01 Dec '23

The constraints library [1] has implied :: forall a b. (a => b) => a :- b from which I can obtain implied' :: Dict (a |- b) -> a :- b implied' Dict = implied but can I get the converse of this, that is coimplied :: (a :- b) -> Dict (a |- b) coimplied = error "Can it be done?" I don't see how. The library itself only mentions "|-" in its definition. Would this combinator violate some guarantee that's essential for the safe use of type classes? I'm a bit confused why the same library allows abstraction over type variables with forall_[2] forall_ :: (forall a. Dict (p a)) -> Dict (Forall p) but not abstraction over "term" variables (i.e. of kind Constraint), as in coimplied. Alternatively, can someone help me achieve my goal another way? That is, I need to be able to dischange the quantified constraint forall i. T0 i => T2 i given that I can already discharge the constraint forall i. T1 i => T2 i and I have available the value forall i. T0 i => Dict (T1 i) >From the latter I can easily get forall i. T0 i :- T1 i But without coimplied I don't know how to proceed. Thanks, Tom [1] https://hackage.haskell.org/package/constraints-0.14/docs/Data-Constraint-F… [2] https://hackage.haskell.org/package/constraints-0.14/docs/Data-Constraint-F…

2 6

[Haskell] [ANNOUNCE] Haskell Language Server 2.5.0.0 released
by Zubin Duggal 01 Dec '23

01 Dec '23

Binaries for this release are available at https://downloads.haskell.org/~hls/haskell-language-server-2.5.0.0/. These binaries can be installed using [GHCup](https://www.haskell.org/ghcup/), using the vanilla metadata channel: ghcup --url-source=https://raw.githubusercontent.com/haskell/ghcup-metadata/master/ghcup-vanilla-0.0.8.yaml install hls 2.5.0.0 All of these tarballs have associated GPG signatures. The signature should be from `Zubin Duggal <zubin(a)well-typed.com>` (key ID [588764FBE22D19C4](https://keys.openpgp.org/search?q=588764FBE22D19C4)) The prebuilt binaries in this release support the following GHC versions: - 9.2.8 - 9.4.8 - 9.6.3 - 9.8.1 # Changelog - Bindists for GHC 9.4.8 - Drop support for GHC 9.0 - Re-add stan plugin - Load default operator fixities in Fourmolu plugin Happy editing! - Zubin

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[ANNOUNCE] Agda 2.6.4.1
by Andreas Abel 30 Nov '23

30 Nov '23

Dear all, The Agda Team is pleased to announce Agda 2.6.4.1. Agda 2.6.4.1 is a minor release of Agda 2.6.4 featuring a few changes: - Make recursion on proofs legal again (regression in 2.6.4). - Improve performance, e.g. by removing debug printing unless built with cabal flag `debug`. - Switch to XDG directory convention. - Reflection: change to order of results returned by `getInstances`. - Fix some internal errors. - Fix some issues with `opaque`. # GHC supported versions Agda 2.6.4.1 has been tested with GHC 9.8.1, GHC 9.6.3, 9.4.7, 9.2.8, 9.0.2, 8.10.7, 8.8.4 and 8.6.5 on Linux, macOS and Windows. # Installation Agda 2.6.4.1 can be installed using cabal-install or stack: 1. Getting the tarball $ cabal update $ cabal get Agda-2.6.4.1 $ cd Agda-2.6.4.1 2. a. Using cabal-install $ cabal install -f +optimise-heavily -f +enable-cluster-counting 2. b. Using stack $ stack --stack-yaml stack-a.b.c.yaml install --flag Agda:optimise-heavily --flag Agda:enable-cluster-counting replacing `a.b.c` with your version of GHC. The flags mean: - optimise-heavily: Turn on extra optimisation for a faster Agda. Takes large resources during compilation of Agda. - enable-cluster-counting: Enable unicode clusters for alignment in the LaTeX backend. Requires the ICU lib to be installed and known to pkg-config. These flags can be dropped from the install if causing trouble. # Standard library You can use standard library v1.7.3 or v2.0 (soon to be released) of the standard library with Agda 2.6.4.1. # Fixed issues over Agda 2.6.4 https://hackage.haskell.org/package/Agda-2.6.4.1/changelog Enjoy Agda! Andreas, on behalf of the Agda Team -- Andreas Abel <>< Du bist der geliebte Mensch. Department of Computer Science and Engineering Chalmers and Gothenburg University, Sweden andreas.abel(a)gu.se http://www.cse.chalmers.se/~abela/

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Strange quirk with {} syntax?
by Noon van der Silk 30 Nov '23

30 Nov '23

Sometimes I have a type like: data A = A1 Int | A2 Int Int Then if I want to do pattern matching and ignore the parameters I do: f (A1 _) = .. f (A2 _ _) = ... But that's annoying; I need to remember how many parameters each one has! Yesterday I learned I can just do this: f A1 {} = ... f A2 {} = ... And GHC is happy. Is this expected? Am I the last to learn about this trick? -- Noon van der Silk, ن http://silky.github.io/ "My programming language is kindness."

6 6

ICFP 2024: Call for Papers
by ICFP Publicity 30 Nov '23

30 Nov '23

PACMPL Volume 7, Issue ICFP 2024 Call for Papers Accepted papers to be invited for presentation at The 29th ACM SIGPLAN International Conference on Functional Programming Milan, Italy ### Important dates (All dates are in 2023 at 11.59pm Anywhere on Earth.) Paper Submission -- Wed 28 Feb 2024 (AOE) Paper Author Response -- Mon 29 Apr 12:00 - Wed 1 May 12:00 2024 Paper Notification --Mon 20 May 2024 ### NEW THIS YEAR ------------------- * Full double blind reviewing ### Scope ------------------- PACMPL issue ICFP 2024 seeks original papers on the art and science of functional programming. Submissions are invited on all topics from principles to practice, from foundations to features, and from abstraction to application. The scope includes all languages that encourage functional programming, including both purely applicative and imperative languages, as well as languages with objects, concurrency, or parallelism. Topics of interest include (but are not limited to): * Language Design: concurrency, parallelism, and distribution; modularity; components and composition; meta-programming; macros; pattern matching; type systems; type inference; dependent types; effect types; gradual types; refinement types; session types; interoperability; domain-specific languages; imperative programming; object-oriented programming; logic programming; probabilistic programming; reactive programming; generic programming; bidirectional programming. * Implementation: abstract machines; virtual machines; interpretation; compilation; compile-time and run-time optimisation; garbage collection and memory management; runtime systems; multi-threading; exploiting parallel hardware; interfaces to foreign functions, services, components, or low-level machine resources. * Software-Development Techniques: algorithms and data structures; design patterns; specification; verification; validation; proof assistants; debugging; testing; tracing; profiling; build systems; program synthesis. * Foundations: formal semantics; lambda calculus; program equivalence; rewriting; type theory; logic; category theory; computational effects; continuations; control; state; names and binding; program verification. * Analysis and Transformation: control flow; data flow; abstract interpretation; partial evaluation; program calculation. * Applications: symbolic computing; formal-methods tools; artificial intelligence; systems programming; distributed systems and web programming; hardware design; databases; scientific and numerical computing; graphical user interfaces; graphics and multimedia; GPU programming; scripting; system administration; security. * Education: teaching introductory programming; mathematical proof; algebra. Submissions will be evaluated according to their relevance, correctness, significance, originality, and clarity. Each submission should explain its contributions in both general and technical terms, clearly identifying what has been accomplished, explaining why it is significant, and comparing it with previous work. The technical content should be accessible to a broad audience. PACMPL issue ICFP 2024 also welcomes submissions in two separate categories — Functional Pearls and Experience Reports — that must be marked as such when submitted and that need not report original research results. Detailed guidelines on both categories are given at the end of this call. In an effort to achieve a balanced, diverse program, each author may be listed as a (co)author on a maximum of four submissions. Submissions from underrepresented groups are encouraged. Authors who require financial support to attend the conference can apply for PAC funding ( http://www.sigplan.org/PAC/) The General Chair and PC Chair may not submit papers. PC members (other than the PC Chair) may submit papers. Please contact the Program Chair if you have questions or are concerned about the appropriateness of a topic. ### Full Double-Blind Reviewing Process ICFP 2024 will use a full double-blind reviewing process (similar to the one used for POPL 2024 but different from the lightweight double-blind process used in previous years). This means that identities of authors will not be made visible to reviewers until after conditional-acceptance decisions have been made, and then only for the conditionally-accepted papers. The use of full double-blind reviewing has several consequences for authors. * Submissions: Authors must omit their names and institutions from their paper submissions. In addition, references to authors’ own prior work should be in the third person (e.g., not “We build on our previous work …” but rather “We build on the work of …”). * Supplementary material: Authors are permitted to provide supplementary material (e.g., detailed proofs, proof scripts, system implementations, or experimental data) along with their submission, which reviewers may (but are not required to) examine. This material may take the form of a single file, such as a PDF or a tarball. Authors must fully anonymize any supplementary material. Links to supplementary material on external websites are not permitted. * Author response: In responding to reviews, authors should not say anything that reveals their identity, since author identities will not be revealed to reviewers at that stage of the reviewing process. * Dissemination of work under submission: Authors are welcome to disseminate their ideas and post draft versions of their paper(s) on their personal website, institutional repository, or arXiv (reviewers will be asked to turn off arXiv notifications during the review period). But authors should not take steps that would almost certainly reveal their identities to members of the Program Committee, e.g., directly contacting PC members or publicizing the work on widely-visible social media or major mailing lists used by the community. The purpose of the above restrictions is to help the Program Committee and external reviewers come to a judgment about the paper without bias, not to make it impossible for them to discover the authors’ identities if they were to try. In particular, nothing should be done in the name of anonymity that weakens the quality of the submission. However, there are occasionally cases where adhering to the above restrictions is truly difficult or impossible for one reason or another. In such cases, the authors should contact the Program Chair to discuss the situation and how to handle it. ### Preparation of submissions ------------------------------- * Deadline: The deadline for submissions is Wednesday, 28 February , 2024, Anywhere on Earth (https://www.timeanddate.com/time/zones/aoe) This deadline will be strictly enforced. * Formatting: Submissions must be in PDF format, printable in black and white on US Letter sized paper and interpretable by common PDF tools. All submissions must adhere to the “ACM Small” template that is available (in both LaTeX and Word formats) from https://www.acm.org/publications/authors/submissions. There is a limit of 25 pages for a full paper or Functional Pearl and 12 pages for an Experience Report; in either case, the bibliography and an optional clearly marked appendix will not be counted against these limits. Submissions that exceed the page limits or, for other reasons, do not meet the requirements for formatting, will be summarily rejected. See also PACMPL’s Information and Guidelines for Authors at https://pacmpl.acm.org/authors.cfm. * Submission: Submissions will be accepted at https://icfp24.hotcrp.com/ Improved versions of a paper may be submitted at any point before the submission deadline using the same web interface. * Author Response Period: Authors will have a 72-hour period, starting at 12:00 (noon) AOE on Monday, 29 April, 2024, to read reviews and respond to them. * Appendix and Supplementary Material: Authors have the option to include a clearly marked appendix and/or to attach supplementary material to a submission, on the understanding that reviewers may choose not to look at such an appendix or supplementary material. Supplementary material may be uploaded as a separate PDF document or tarball. Any supplementary material must be uploaded at submission time, not by providing a URL in the paper that points to an external repository. All supplementary material must be anonymised. * Authorship Policies: All submissions are expected to comply with the ACM Policies for Authorship that are detailed at https://www.acm.org/publications/authors/information-for-authors. * Republication Policies: Each submission must adhere to SIGPLAN’s republication policy, as explained on the web at http://www.sigplan.org/Resources/Policies/Republication. * ORCID: ORCID provides a persistent digital identifier (an ORCID iD) that you own and control, and that distinguishes you from every other researcher: https://orcid.org/. ACM now require an ORCID iD for every author of a paper, not just the corresponding author. So, the author who is filling out the permission form should make sure they have the ORCID iDs for all of their coauthors before filling out the form. Any authors who do not yet have an ORCID iD can go to https://orcid.org/register to have one assigned. ### Review Process ------------------- This section outlines the two-stage process with lightweight double-blind reviewing that will be used to select papers for PACMPL issue ICFP 2024. New this year, ICFP 2024 will adapt a full double-blind reviewing process. More information see below. ICFP 2024 will have an Associate Chair who will help the PC Chair monitor reviews, solicit external expert reviews for submissions when there is not enough expertise on the committee, and facilitate reviewer discussions. PACMPL issue ICFP 2024 will employ a two-stage review process. The first stage in the review process will assess submitted papers using the criteria stated above and will allow for feedback and input on initial reviews through the author response period mentioned previously. As a result of the review process, a set of papers will be conditionally accepted and all other papers will be rejected. Authors will be notified of these decisions on 20 May, 2024. Authors of conditionally accepted papers will be provided with committee reviews along with a set of mandatory revisions. By 11 June, 2024, the authors should provide a second revised submission. The second and final reviewing phase assesses whether the mandatory revisions have been adequately addressed by the authors and thereby determines the final accept/reject status of the paper. The intent and expectation is that the mandatory revisions can feasibly be addressed within three weeks. The second submission should clearly identify how the mandatory revisions were addressed. To that end, the second submission must be accompanied by a cover letter mapping each mandatory revision request to specific parts of the paper. The cover letter will facilitate a quick second review, allowing for confirmation of final acceptance within two weeks. Conversely, the absence of a cover letter will be grounds for the paper’s rejection. ### Information for Authors of Accepted Papers ---------------------------------------------- As a condition of acceptance, final versions of all papers must adhere to the ACM Small format. The page limit for the final versions of papers will be increased by two pages to help authors respond to reviewer comments and mandatory revisions: 27 pages plus bibliography for a regular paper or Functional Pearl, 14 pages plus bibliography for an Experience Report. Authors of accepted submissions will be required to agree to one of the three ACM licensing options, one of which is Creative Commons CC-BY publication; this is the option recommended by the PACMPL editorial board. A reasoned argument in favour of this option can be found in the article Why CC-BY? published by OASPA, the Open Access Scholarly Publishers Association. The other options are copyright transfer to ACM or retaining copyright but granting ACM exclusive publication rights. PACMPL is a Gold Open Access journal, and authors are encouraged to publish their work under a CC-BY license. Gold Open Access guarantees permanent free online access to the definitive version in the ACM Digital Library, and the recommended CC-BY option also allows anyone to copy and distribute the work with attribution. Gold Open Access has been made possible by generous funding through ACM SIGPLAN, which will cover all open access costs in the event authors cannot. Authors who can cover the costs may do so by paying an Article Processing Charge (APC). PACMPL, SIGPLAN, and ACM Headquarters are committed to exploring routes to making Gold Open Access publication both affordable and sustainable. ACM Author-Izer is a unique service that enables ACM authors to generate and post links on either their home page or institutional repository for visitors to download the definitive version of their articles from the ACM Digital Library at no charge. Downloads through Author-Izer links are captured in official ACM statistics, improving the accuracy of usage and impact measurements. Consistently linking to the definitive version of an ACM article should reduce user confusion over article versioning. After an article has been published and assigned to the appropriate ACM Author Profile pages, authors should visit http://www.acm.org/publications/acm-author-izer-service to learn how to create links for free downloads from the ACM DL. The official publication date is the date the papers are made available in the ACM Digital Library. This date may be up to two weeks prior to the first day of the conference. The official publication date affects the deadline for any patent filings related to published work. Authors of each accepted submission are invited to attend and be available for the presentation of that paper at the conference. The schedule for presentations will be determined and shared with authors after the full program has been selected. ### Artifact Evaluation ----------------------- Authors of papers that are conditionally accepted in the first phase of the review process will be encouraged (but not required) to submit supporting materials for Artifact Evaluation. These items will then be reviewed by an Artifact Evaluation Committee, separate from the paper Review Committee, whose task is to assess how the artifacts support the work described in the associated paper. Papers that go through the Artifact Evaluation process successfully will receive a seal of approval printed on the papers themselves. Authors of accepted papers will be encouraged to make the supporting materials publicly available upon publication of the papers, for example, by including them as “source materials” in the ACM Digital Library. An additional seal will mark papers whose artifacts are made available, as outlined in the ACM guidelines for artifact badging. Participation in Artifact Evaluation is voluntary and will not influence the final decision regarding paper acceptance. ### Special categories of papers ------------------------------- In addition to research papers, PACMPL issue ICFP solicits two kinds of papers that do not require original research contributions: Functional Pearls, which are full papers, and Experience Reports, which are limited to half the length of a full paper. Authors submitting such papers should consider the following guidelines. * Functional Pearls - A Functional Pearl is an elegant essay about something related to functional programming. Examples include, but are not limited to: - a new and thought-provoking way of looking at an old idea - an instructive example of program calculation or proof - a nifty presentation of an old or new data structure - an interesting application of functional programming techniques - a novel use or exposition of functional programming in the classroom While pearls often demonstrate an idea through the development of a short program, there is no requirement or expectation that they do so. Thus, they encompass the notions of theoretical and educational pearls. Functional Pearls are valued as highly and judged as rigorously as ordinary papers, but using somewhat different criteria. In particular, a pearl is not required to report original research, but, it should be concise, instructive, and entertaining. A pearl is likely to be rejected if its readers get bored, if the material gets too complicated, if too much-specialised knowledge is needed, or if the writing is inelegant. The key to writing a good pearl is polishing. A submission that is intended to be treated as a pearl must be marked as such on the submission web page and should contain the words “Functional Pearl” somewhere in its title or subtitle. These steps will alert reviewers to use the appropriate evaluation criteria. Pearls will be combined with ordinary papers, however, for the purpose of computing the conference’s acceptance rate. * Experience Reports The purpose of an Experience Report is to describe the experience of using functional programming in practice, whether in industrial application, tool development, programming education, or any other area. Possible topics for an Experience Report include, but are not limited to: - insights gained from real-world projects using functional programming - comparison of functional programming with conventional programming in the context of an industrial project or a university curriculum - project-management, business, or legal issues encountered when using functional programming in a real-world project - curricular issues encountered when using functional programming in education - real-world constraints that created special challenges for an implementation of a functional language or for functional programming in general An Experience Report is distinguished from a normal PACMPL issue ICFP paper by its title, by its length, and by the criteria used to evaluate it. Both in the papers and in any citations, the title of each accepted Experience Report must end with the words “(Experience Report)” in parentheses. The acceptance rate for Experience Reports will be computed and reported separately from the rate for ordinary papers. Experience Report submissions can be at most 12 pages long, excluding bibliography. Each accepted Experience Report will be presented at the conference, but depending on the number of Experience Reports and regular papers accepted, authors of Experience Reports may be asked to give shorter talks. Because the purpose of Experience Reports is to enable our community to understand the application of functional programming, an acceptable Experience Report need not add to the body of knowledge of the functional-programming community by presenting novel results or conclusions. It is sufficient if the report describes an illuminating experience with functional programming, or provides evidence for a clear thesis about the use of functional programming. The experience or thesis must be relevant to ICFP, but it need not be novel. The review committee will accept or reject Experience Reports based on whether they judge the paper to illuminate some aspect of the use of functional programming. Anecdotal evidence will be acceptable provided it is well-argued and the author explains what efforts were made to gather as much evidence as possible. Typically, papers that show how functional programming was used are more convincing than papers that say only that functional programming was used. It can be especially effective to present comparisons of the situations before and after the experience described in the paper, but other kinds of evidence would also make sense, depending on context. Experience drawn from a single person’s experience may be sufficient, but more weight will be given to evidence drawn from the experience of groups of people. An Experience Report should be short and to the point. For an industrial project, it should make a claim about how well functional programming worked and why; for a pedagogy paper, it might make a claim about the suitability of a particular teaching style or educational exercise. Either way, it should produce evidence to substantiate the claim. If functional programming worked in this case in the same ways it has worked for others, the paper need only summarise the results — the main part of the paper should discuss how well it worked and in what context. Most readers will not want to know all the details of the experience and its implementation, but the paper should characterise it and its context well enough so that readers can judge to what degree this experience is relevant to their own circumstances. The paper should take care to highlight any unusual aspects; specifics about the experience are more valuable than generalities about functional programming. If the paper not only describes experience but also presents new technical results, or if the experience refutes cherished beliefs of the functional-programming community, it may be better to submit it as a full paper, which will be judged by the usual criteria of novelty, originality, and relevance. The Program Chair will be happy to advise on any concerns about which category to submit to. ### About PACMPL ---------------- Proceedings of the ACM on Programming Languages (PACMPL https://pacmpl.acm.org/) is a Gold Open Access journal publishing research on all aspects of programming languages, from design to implementation and from mathematical formalisms to empirical studies. Each issue of the journal is devoted to a particular subject area within programming languages and will be announced through publicised Calls for Papers, like this one. ### ICFP Organisers General Chair: Marco Gaboardi (Boston University, USA) Programme Chair: Brigitte Pientka (McGill University, Canada) Associate Programme Chair: Gabriele Keller (Utrecht University, Netherlands) Publicity Chair: Ilya Sergey (National University of Singapore, Singapore) Programme Committee: https://icfp24.sigplan.org/committee/icfp-2024-papers-icfp-papers-and-events -----------------------------------------------------------------------

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[TFP 2024 Final Call for Papers] 25th International Symposium on Trends in Functional Programming
by Peter Achten 30 Nov '23

30 Nov '23

# TFP 2024 -- Call for Papers (trendsfp.github.io) ## Important Dates Submission deadline: pre-symposium, full papers, Saturday 4 November, 2023 (AOE) Submission deadline: pre-symposium, draft papers, Friday 8 December, 2023 (AOE) Notification: pre-symposium full papers, Friday 8 December, 2023 Notification: pre-symposium draft papers, Thursday 14 December, 2023 Registration: Friday 5 January, 2024 TFPIE Workshop: Tuesday 9 January, 2024 TFP Symposium: Wednesday 10 - Friday 12 January, 2024 Submission deadline: post-symposium review, Friday 23 February, 2024 (AOE) Notification: post-symposium submissions, Friday 5 April, 2024 Camera-ready: post-symposium submissions, Friday 3 May, 2024 (AOE) 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 Seton Hall University, in South Orange, NJ 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 4, 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, November 30, 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 23. ## 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 2024 program chair, Jason Hemann. ## 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, each year TFP also awards a prize for the best student paper. 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 the paper's 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 Authors must submit papers to: https://easychair.org/conferences/?conf=tfp24 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 Guidelines web site: https://www.springer.com/gp/computer-science/lncs/conference-proceedings-gu… ## Organizing Committee Jason Hemann PC Chair Seton Hall University, USA Stephen Chang Symposium Chair University of Massachusetts Boston, USA Shajina Anand Local Arrangements Seton Hall University, South Orange, USA Peter Achten Publicity Chair Radboud University Nijmegen, Netherlands

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ByteString and ByteString.Builder questions
by Zoran Bošnjak 30 Nov '23

30 Nov '23

Hi all, if I understand correctly, the ByteString.Builder is used to efficiently construct sequence of bytes from smaller parts. However, for inspecting data (take, head, index...), a plain ByteString is required. What if the byte sequence manipulation task requires both, for example: - receive ByteString from the network (e.g: Network.Socket.ByteString.recv :: ... -> IO ByteString) - inspect and manipulate data (pure function) - resend to the network (e.g: Network.Socket.ByteString.sendMany :: ... -> [ByteString] -> IO ()) ... where a pure data manipulation could be something like: - extract some segments out of the original sequence - create and add some segments of bytes - reorder - concatinate It is somewhat inconvenient to use 2 different types for the task, namely the ByteString and the Builder... where both represent a sequence of bytes. I have tryed to define a Bytes type where both representations are available: import qualified Data.ByteString as BS import qualified Data.ByteString.Lazy as Bsl import qualified Data.ByteString.Builder as Bld data Bytes = Bytes { toByteString :: ByteString , toBuilder :: Builder , length :: Int } instance Semigroup Bytes ... instance Monoid Bytes ... -- create fromByteString :: ByteString -> Bytes fromByteString bs = Bytes { toByteString = bs , toBuilder = Bld.byteString bs , length = BS.length bs } -- inspect function example head :: Bytes -> Word8 head = BS.head . toByteString -- prepare to send data over the network toChunks :: Bytes -> [ByteString] toChunks = Bsl.toChunks . Bld.toLazyByteString . toBuilder The fields of Bytes are non-strict, so the expectation was that lazy evaluation will suspend unnecessary calculations and to have efficient inspection (via ByteString part) and efficient concatination (via Builder part). I have performed some benchmarks (not sure if they are exactly to the point), but the results of Bytes are not so good: Inspect test using ByteString: OK (0.50s) 5.51 ms ± 342 μs using Bytes: OK (0.17s) 62.0 ms ± 3.0 ms Construct test using Builder: OK (0.21s) 5.29 ms ± 361 μs using Bytes: OK (0.17s) 21.3 ms ± 1.6 ms naive: OK (0.81s) 49.6 ms ± 4.1 ms Here is the full code: https://gist.github.com/zoranbosnjak/7887d843056f07bac6061d20970e1d6a My questions are: 0) Where does the big timing difference comming from? Thunks? 1) Is there any simple way (INLINE pragmas... or some other tricks) to get the performance back with the current implementation? 2) Would DList [ByteString] or any other type be any better over the ByteString.Builder in this case? 3) What would be the most efficient (and reasonable) implementation to support this kind of data processing (inspecting and concatination) in some uniform way? In other words: Is it worth to have uniformity here? 4) Is the Network.Socket.ByteString.sendMany function the way to go in cases where the byte sequence is constructed from segment or is there any better (faster) way? regards, Zoran

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Mutual scoping question
by Todd Wilson 28 Nov '23

28 Nov '23

Hello, Cafe: Is there a preferred way to define two top-level mutually recursive functions, f and g, that both use a common local function h such that h is (1) only defined once and (2) does not escape the scope of f and g? I suppose it could be done like this: fg = let f ... = ... f,g,h ... g ... = ... f,g,h ... h ... = ... h ... in (f,g) f = fst fg g = snd fg but is there something more elegant than this that I'm not seeing? Todd Wilson

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Re: [Haskell-cafe] [Haskell] ANT 2024 CFP (December 4, 2023 (extended)): The 15th International Conference on Ambient Systems, Networks and Technologies (ANT) , Hasselt, Belgium, April 23-25, 2024
by Jeremy Gibbons 27 Nov '23

27 Nov '23

I don’t know what Ivan’s relationship to the list is (for the record, I am not a list administrator myself, just a member of the community). But Ivan makes a good point. The three Haskell mailing lists have a specific purpose: "to discuss issues related to Haskell”. In the last year you appear to have posted 53 adverts for five conferences, called "Ambient Systems, Networks and Technologies", "Emerging Data and Industry", "Information and Communication Technologies in Healthcare", "Emerging Ubiquitous Systems and Pervasive Networks", "Sustainable Energy Information Technology", and "Mobile Systems and Pervasive Computing”. I don’t see that any of these are “related to Haskell”. Has there ever been any paper mentioning Haskell at any of these conferences? Do their calls for papers mention functional programming? If these conferences are not “related to Haskell”, then their announcements do not belong on the Haskell mailing list. Jeremy PS Diverting from the announcements list to haskell-cafe, the discussion list. > On 27 Nov 2023, at 07:28, Ali BENZERBADJ <ali.benzerbadj(a)univ-temouchent.edu.dz> wrote: > > Dear Ivan, > I would like to ask you to introduce yourself first, please. Are you the admin of the mailing list? I assume that Haskell is the one who assesses the relevance of announcements. If the topic doesn't interest you, just ignore it, and that's it. > > Yours sincerely. > > On Sun, 26 Nov 2023 at 23:07, Ivan Perez <ivanperezdominguez(a)gmail.com <mailto:ivanperezdominguez@gmail.com>> wrote: > Ali, > > None of the CfPs you've sent to this mailing list over the past year appear even remotely related to Haskell. I doubt people on this list will find them relevant or interesting. > > Could you please stop sending CfPs to haskell and haskell-cafe? > > Thanks > > Ivan > > On Sun, 26 Nov 2023 at 11:19, Ali BENZERBADJ <ali.benzerbadj(a)univ-temouchent.edu.dz <mailto:ali.benzerbadj@univ-temouchent.edu.dz>> wrote: > *************************************************************************** > The 15th International Conference on Ambient Systems, Networks and Technologies (ANT) > Hasselt, Belgium > April 23-25, 2024 > > *************************************************************************** > Conference Website: http://cs-conferences.acadiau.ca/ant-24/ <http://cs-conferences.acadiau.ca/ant-24/> > Workshops: http://cs-conferences.acadiau.ca/ant-24/#workshop <http://cs-conferences.acadiau.ca/ant-24/#workshop> > > Important Dates > - Workshops Proposals Due: October 20, 2023 > - Paper Submission Due: December 4, 2023 (extended) > - Acceptance Notification: January 15, 2024 > - Camera-Ready Submission: February 9, 2024 > > ANT 2024 accepted papers will be published by Elsevier Science in the open-access Procedia Computer Science series on-line. Procedia Computer Science is hosted by Elsevier on www.Elsevier.com <http://www.elsevier.com/> and on Elsevier content platform ScienceDirect (www.sciencedirect.com <http://www.sciencedirect.com/>), and will be freely available worldwide. All papers in Procedia will be indexed by Scopus (www.scopus.com <http://www.scopus.com/>) and by Thomson Reuters' Conference Proceeding Citation Index (http://thomsonreuters.com/conference-proceedings-citation-index/ <http://thomsonreuters.com/conference-proceedings-citation-index/>). All papers in Procedia will also be indexed by Scopus (www.scopus.com <http://www.scopus.com/>) and Engineering Village (Ei) (www.engineeringvillage.com <http://www.engineeringvillage.com/>). This includes EI Compendex (www.ei.org/compendex <http://www.ei.org/compendex>). Moreover, all accepted papers will be indexed in DBLP (http://dblp.uni-trier.de/ <http://dblp.uni-trier.de/>). The papers will contain linked references, XML versions and citable DOI numbers. You will be able to provide a hyperlink to all delegates and direct your conference website visitors to your proceedings. Selected papers will be invited for publication, in the special issues of: > > > - International Journal of Ambient Intelligence and Humanized Computing (IF: 4.594), by Springer (http://www.springer.com/engineering/journal/12652 <http://www.springer.com/engineering/journal/12652>) > - International Journal Personal and Ubiquitous Computing (IF:3.006), Springer (https://www.springer.com/journal/779 <https://www.springer.com/journal/779>) > - International Journal on Transportation Research Part A: Policy and Practice (IF: 3.992), by Elsevier (https://www.journals.elsevier.com/transportation-research-part-a-policy-and… <https://www.journals.elsevier.com/transportation-research-part-a-policy-and…>) > > > ANT 2024 will be held in Hasselt, Belgium. ANT 2024 is co-organized & co-hosted by the Hasselt University, Belgium. Since 1973 Hasselt University is located on the Campus Diepenbeek, which occupies an attractive 150 acre site in the middle of Limburg's green belt. It is 2 kms west of the town centre of Diepenbeek, a residential town of 17.717 inhabitants, and 4 kms east of Hasselt which has a population of about 69.529 and is the administrative and commercial centre of the province. Brussels is 90 kms away (to the South-West), Antwerp lies 90 kms to the West, Liège (in the French-speaking part of Belgium) 45 kms to the South, Maastricht (in the Netherlands) 25 kms to the East, Aachen (in Germany) 60 kms to the South-East. > > ANT 2024 will be held in conjunction with the 7th International Conference on Emerging Data and Industry (EDI40). > > Conference Tracks > - Agent Systems, Intelligent Computing and Applications > - Big Data and Analytics > - Cloud Computing > - Context-awareness and Multimodal Interfaces > - Emerging Networking, Tracking and Sensing Technologies > - Human Computer Interaction > - Internet of Things > - Mobile Networks, Protocols and Applications > - Modelling and Simulation in Transportation Sciences > - Multimedia and Social Computing > - Service Oriented Computing for Systems & Applications > - Smart, Sustainable Cities and Climate Change Management > - Smart Environments and Applications > - Systems Security and Privacy > - Systems Software Engineering > - Vehicular Networks and Applications > - General Track > > > General Chairs > > Atta Badii, University of Reading, UK > Albert Zomaya, The University of Sydney, Australia > > Program Chairs > > Hossam Hassanein, Queen's University, Canada > Ansar-Ul-Haque Yasar, Hasselt University, Belgium > > Workshops Chair > > Stephane Galland, UTBM, France > > Vice Chairs > > Muhammad Adnan, Hasselt University, Belgium > Manzoor Ahmed, Hubei Engineering University, Xiaogan, China > Akramul Azim, Ontario Tech University, Canada > Ayoub Bahnasse, Hassan II University, Morocco > Nik Bessis, Edge Hill University, UK > Samia Bouzefrane, CEDRIC Lab Conservatoire National des Arts et Metiers, France > Junsung Choi, Chungbuk National University, Republic of Korea > Robertas Damasevicius, Kaunas University of Technology, Lithuania > Antonella Galizia, Principal Scientist, CNR, Italy > Mohammad Ghanim, Ministry of Transport, Qatar > Stefano Guarino, IAC-CNR Rome, Italy > Faouzi Kammoun, Ecole Superieure Privee d'Ingenierie et de Technologies, Tunis > Bouabdellah Kechar, Oran 1 Ahmed BenBella University, Algeria > Ridha Khedri, McMaster University, Canada > Flavio Lombardi, Roma Tre University of Rome, Italy > Yazan Mualla, UTBM, France > Aneta Poniszewska-Maranda, Lodz University of Technology, Poland > Khair Eddin Sabri, The University of Jordan, Jordan > Cristina Seceleanu, Malardalen University, Sweden > Khaled Shaaban, Utah Valley University, USA > Kamran Siddique, Xiamen University Malaysia, Malaysia > Mohamed Tabaa, EMSI, Morocco > Igor Tchappi, University of Luxembourg, Luxembourg > > Technical Program Committee > > http://cs-conferences.acadiau.ca/ant-24/#programCommittees <http://cs-conferences.acadiau.ca/ant-24/#programCommittees> > > Publicity Chairs > > Ali Benzerbadj, University of Ain Temouchent Belhadj Bouchaib, Algeria > Wim Ectors, Hasselt University, Belgium > Siddardha Kaja, Air Canada, Canada > Orven E. Llantos, MSU-IIT, Philippines > Farhan Ullah, Northwestern Polytechnical University, China > > International Journals Chairs > > Haroon Malik, Marshall University, USA > Michael Sheng, Macquarie University, Australia > > Advisory Committee > > Reda Alhajj, University of Calgary, Canada > Sajal K. Das, The University of Texas at Arlington, USA > Erol Gelenbe, Imperial College, UK > Ibad Kureshi, Inlecomm Systems, Belgium > Vincenzo Loia, University of Salerno, Italy > Peter Sloot, Universiteit van Amsterdam, Netherlands > Ralf Steinmetz, Technische Universitaet Darmstadt, Germany > Katia Sycara, Carnegie Mellon University, USA > Peter Thomas, Manifesto Research, Australia > > International Liaison Chairs > > Soumaya Cherkaoui, Sherbrooke University, Canada > Paul Davidsson, Malmo University, Sweden > David Taniar, Monash University, Australia > > Steering Committee Chair and Founder of ANT > > Elhadi Shakshuki, Acadia University, Canada > > -- > Ali Benzerbadj > Lecturer, University of Ain Temouchent > Ain Temouchent, Algeria > Research Laboratory in Industrial Computing and Networks (RIIR) > Research team :"Networks and QoS" > University of Oran 1 Ahmed Ben Bella, Oran, Algeria > Mob(s): +213 6 61622162 > E-mail(s):.benzerbadj@univ-temouchent.edu.dz <mailto:ali.benzerbadj@univ-temouchent.edu.dz>, ali_benz(a)yahoo.fr <mailto:ali_benz@yahoo.fr>, > _______________________________________________ > Haskell mailing list > Haskell(a)haskell.org <mailto:Haskell@haskell.org> > http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell <http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell> > > > -- > Ali Benzerbadj > Lecturer, University of Ain Temouchent > Ain Temouchent, Algeria > Research Laboratory in Industrial Computing and Networks (RIIR) > Research team :"Networks and QoS" > University of Oran 1 Ahmed Ben Bella, Oran, Algeria > Mob(s): +213 6 61622162 > E-mail(s):.benzerbadj@univ-temouchent.edu.dz <mailto:ali.benzerbadj@univ-temouchent.edu.dz>, ali_benz(a)yahoo.fr <mailto:ali_benz@yahoo.fr>, > _______________________________________________ > Haskell mailing list > Haskell(a)haskell.org > http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell Jeremy.Gibbons(a)cs.ox.ac.uk Oxford University Department of Computer Science, Wolfson Building, Parks Road, Oxford OX1 3QD, UK. +44 1865 283521 http://www.cs.ox.ac.uk/people/jeremy.gibbons/

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Folded long string literals and CPP?
by Viktor Dukhovni 23 Nov '23

23 Nov '23

It looks like there's some sort of syntax conflict between CPP and long string literals folded across multiple lines. Is there a way to have both CPP and folded long string literals? $ cat /tmp/foo.hs {-# LANGUAGE CPP #-} module Main(main) where hello :: String hello = "Hello\ \ World!" main :: IO () main = print hello ---- $ ghci /tmp/foo.hs GHCi, version 9.8.1: https://www.haskell.org/ghc/ :? for help [1 of 2] Compiling Main ( /tmp/foo.hs, interpreted ) /tmp/foo.hs:5:25: error: [GHC-21231] lexical error in string/character literal at character 'W' | 5 | hello = "Hello\ | ^ Failed, no modules loaded. λ> Leaving GHCi. When I run the input through "cpp -E" I get: {-# LANGUAGE CPP #-} module Main(main) where hello :: String hello = "Hello \ World!" main :: IO () main = print hello Clearly not what I want, so the subsequent lexical error from GHC is not surprising, but is there a workaround that allows folding long strings across lines and retaining the layout. Given that the CPP lexer also recognises quoted strings, it looks like a difficult to reconcile mismatch. There would need be some other sort of joiner understood by GHC, where each string fragment is fully enclosed in quotes. Would the below be acceptable? {-# LANGUAGE CPP #-} module Main(main) where hello :: String hello = ##"Hello"\ ##"World!" main :: IO () main = print hello This is turned by CPP into either (version-dependent): {-# LANGUAGE CPP #-} module Main(main) where hello :: String hello = ##"Hello" ##"World!" main :: IO () main = print hello or: {-# LANGUAGE CPP #-} module Main(main) where hello :: String hello = ##"Hello" ##"World!" main :: IO () main = print hello which (or some suitable variant?) GHC could then also recognise as multiple fragments of the same single string literal? -- Viktor.

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Re: [Haskell-cafe] A question about type families conflicting instances
by Darryn 23 Nov '23

23 Nov '23

On Wednesday, 22 November 2023 10:30:01 PM ACDT haskell-cafe-request(a)haskell.org wrote: > > Thank you to anyone in advance who can help; I do really appreciate it. > > I think a simple redefinition of "Formable" takes care of the described > obstacle. Do you have other requirements that make it impractical? > > -- > Viktor. > Hi Viktor. Thanks again for taking a look at this and giving me advice. I hadn't thought of the problem like this, using kind representation. The short answer is that I'm not sure yet whether there are any other requirements that bear on this, given the exploratory nature of the little project, but having just played with your modifications and then worked it back to the main code, this solution looks excellent at this stage. Really appreciate it. Regards, D.

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A question about type families conflicting instances
by Darryn 22 Nov '23

22 Nov '23

Sir/Madam, I have familiarity with Haskell and have recently returned to using it on a small project, and have just taken a crack at using type families for the first time. I've used functional dependencies more in the past. My example below is a greatly simplified version of what I'm trying to do; for context, the overall purpose is a clean representation of logical forms across languages for abstract case analysis for theorem-proving for certain multimodal logics. The idea represented here is a unified representation for sentential forms and labelled sentential forms. The instance for the latter would be defined in terms of the instance for the former, but to keep it as simple as possible, the snippet here just has a separate (nonsense) implementation of three functions f1,f2,f3 that represent the pattern. I understand that that I'm running into overlapping instances but am unsure about how to correct it, and I couldn't find anything to address this in a search of the haskell-cafe archive (which is not to say that it isn't there, just that I couldn't find and/or recognise it). I'm sure it will be a simple matter to point me in the right direction here for people with more experience. Thank you to anyone in advance who can help; I do really appreciate it. ------------------------------------------------------------------------------- {-# LANGUAGE TypeFamilies, TypeFamilyDependencies, MultiParamTypeClasses, FlexibleInstances #-} -- A simplified model for sentences. data S a = SA a (S a) | SB a (S a) | SC String deriving (Eq, Show) -- A simplified model for what will be abstract case analysis: data Form a b = FA a b | FB deriving (Eq, Show) -- A simplified a model for the case analysis class: class (F a ~ b) => Formable a b where type F a = t | t -> a f1 :: b -> Form a b f2 :: b -> b f3 :: b -> Bool -- Simple test instance of Formable for S: instance Formable a (S a) where type F a = S a f1 (SA a y) = FA a y f1 (SB a y) = FA a y f1 (SC x) = FB f2 (SA a y) = SA a y f2 (SB a y) = SA a y f2 (SC x) = SC "nothing" f3 (SA a y) = False f3 (SB a y) = False f3 (SC _) = True -- Some test instances all work fine: -- > f1 (SA "a" (SB "b" (SC "c"))) -- > f2 (SA "a" (SB "b" (SC "c"))) -- > f3 (SA "a" (SB "b" (SC "c"))) -- A model of a wrapper for sentences to iadd integer labels: data W a = W Int (S a) deriving (Eq, Show) -- Test instance modelling an instance for labelled sentences: instance Formable a (W a) where type F a = W a f1 (W k (SA a y)) = FA a (W k y) f1 (W k (SB a y)) = FA a (W k y) f1 (W k (SC x)) = FB f2 (W k x) = W (1+k) x f3 (W k (SA a y)) = False f3 (W k (SB a y)) = False f3 (W k (SC _)) = True -- Intend to re-implement f1,f2,f3 in terms of the instance for S once -- I can convince GHC to let both instances stand. ------------------------------------------------------------------------------- Everything is dandy if either of the two instances, for S and for W, are provided, but GHC is not at all impressed with the idea of having both. GHCi reports the following error. Test.hs:29:10: error: Conflicting family instance declarations: F a = S a -- Defined at Test.hs:29:10 F a = W a -- Defined at Test.hs:51:10 Regards, D.

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Re: [Haskell-cafe] Haskell Usage
by Adrian Cochrane 16 Nov '23

16 Nov '23

Hi from New Zealand! My Haskell usage is more hobbyist than academic or industrial, but I've got a massive personal project written in Haskell (a browser engine). And I'm actively for one of my upcoming contracts (a converter between metadata formats) to use Haskell! I find I'm more productive in Haskell, and that my code is of generally higher quality. Its certainly not a popular language (neither is Erlang) though, which I have to actively plan for when suggesting it for a project. But given the dominance of C/C++, does that count for much? On 16/11/2023 1:00 am, haskell-cafe-request(a)haskell.org wrote: > Send Haskell-Cafe mailing list submissions to > haskell-cafe(a)haskell.org > > To subscribe or unsubscribe via the World Wide Web, visit > http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe > or, via email, send a message with subject or body 'help' to > haskell-cafe-request(a)haskell.org > > You can reach the person managing the list at > haskell-cafe-owner(a)haskell.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Haskell-Cafe digest..." > > > Today's Topics: > > 1. Haskell Usage (Henrique Caldeira) > 2. Re: Haskell Usage (Brandon Allbery) > 3. Re: Haskell Usage (Henning Thielemann) > 4. Re: Haskell Usage (Jo Durchholz) > 5. Re: Haskell Usage (MigMit) > 6. Re: Haskell Usage (Ivan Perez) > 7. Re: Haskell Usage (Jared Tobin) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Tue, 14 Nov 2023 21:27:57 +0000 (GMT+00:00) > From: Henrique Caldeira <h.caldeira(a)ua.pt> > To: haskell-cafe(a)haskell.org > Subject: [Haskell-cafe] Haskell Usage > Message-ID: <aae4e8e1-bf10-4bd5-bf58-9566b2a0be04(a)ua.pt> > Content-Type: text/plain; charset="utf-8" > > Good Evening from Portugal, > > I write to you about the usage of Haskell because I had a professor recommending me Erlang instead because Haskell was "more for academic purposes", which left me wondering if all my time spent was spent only for curiosity sake. > > I want to know how true my professor's statement is. > > I am very passionate about Haskell, although I admit the ecosystem can be confusing sometimes (for example, when to use cabal or stack, which versions of packages to use in order to avoid conflicts, or simply installing them through nixos or arch can be a learning process). > > Would love to hear your thoughts about all of this and thank you with all my heart. > > Lastly, all these wonderings are asked in a curious, "wanting to learn more" mindset. > > Kind regards, > Henrique Caldeira >

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How to use the GPU in Apple M2 from Haskell?
by David Banas 16 Nov '23

16 Nov '23

Does anyone have a good reference for explicitly accessing the GPU in the new Apple M2 chip from a user Haskell program?

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Re. Haskell Usage
by Rishiyur Nikhil 15 Nov '23

15 Nov '23

> Haskell was "more for academic purposes", The Bluespec Hardware Design Languages BSV (Bluespec SystemVerilog) and BH (Bluespec Haskell) digital hardware circuit design have been in industrial production and commercial use for over 20 years now. They have been used inside ST Micro, Texas Instruments, IBM, Qualcomm, Google, Galois and other companies, for ASIC and FPGA products and for high-level hardware prototyping and architecture exploration. The BSV and BH languages are themselves heavily inspired by Haskell. The 'bsc' compiler for BSV and BH is written entirely in Haskell, and has been in continuous use/development/maintenance/improvement for 20 years, and constitutes about 125K lines of Haskell. The 'bsc' compiler was open-sourced a few years ago and continues to be actively used and maintained: https://github.com/B-Lang-org/bsc The Haskell code for the compiler is in the src/ directory. Nikhil

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Haskell Usage
by Henrique Caldeira 15 Nov '23

15 Nov '23

Good Evening from Portugal, I write to you about the usage of Haskell because I had a professor recommending me Erlang instead because Haskell was "more for academic purposes", which left me wondering if all my time spent was spent only for curiosity sake. I want to know how true my professor's statement is. I am very passionate about Haskell, although I admit the ecosystem can be confusing sometimes (for example, when to use cabal or stack, which versions of packages to use in order to avoid conflicts, or simply installing them through nixos or arch can be a learning process). Would love to hear your thoughts about all of this and thank you with all my heart. Lastly, all these wonderings are asked in a curious, "wanting to learn more" mindset. Kind regards, Henrique Caldeira

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Journal of Functional Programming - Call for PhD Abstracts
by Graham Hutton 13 Nov '23

13 Nov '23

Dear all, If you or one of your students recently completed a PhD (or Habilitation) in the area of functional programming, please submit the dissertation abstract for publication in JFP: simple process, no refereeing, open access, 200+ published to date, deadline 30th November 2023. Please share! Best wishes, Graham Hutton ============================================================ CALL FOR PHD ABSTRACTS Journal of Functional Programming Deadline: 30th November 2023 http://tinyurl.com/jfp-phd-abstracts ============================================================ PREAMBLE: Many students complete PhDs in functional programming each year. As a service to the community, twice per year the Journal of Functional Programming publishes the abstracts from PhD dissertations completed during the previous year. The abstracts are made freely available on the JFP website, i.e. not behind any paywall. They do not require any transfer of copyright, merely a license from the author. A dissertation is eligible for inclusion if parts of it have or could have appeared in JFP, that is, if it is in the general area of functional programming. The abstracts are not reviewed. Please submit dissertation abstracts according to the instructions below. We welcome submissions from both the student and the advisor/supervisor although we encourage them to coordinate. Habilitation dissertations are also eligible for inclusion. ============================================================ SUBMISSION: Please submit the following information to Graham Hutton <graham.hutton(a)nottingham.ac.uk> by 30th November 2023. o Dissertation title: (including any subtitle) o Student: (full name) o Awarding institution: (full name and country) o Date of award: (month and year; depending on the institution, this may be the date of the viva, corrections being approved, graduation ceremony, or otherwise) o Advisor/supervisor: (full names) o Dissertation URL: (please provide a permanently accessible link to the dissertation if you have one, such as to an institutional repository or other public archive; links to personal web pages should be considered a last resort) o Dissertation abstract: (plain text, maximum 350 words; you may use \emph{...} for emphasis, but we prefer no other markup or formatting; if your original abstract exceeds the word limit, please submit an abridged version within the limit) Please do not submit a copy of the dissertation itself, as this is not required. JFP reserves the right to decline to publish abstracts that are not deemed appropriate. ============================================================ PHD ABSTRACT EDITOR: Graham Hutton School of Computer Science University of Nottingham Nottingham NG8 1BB United Kingdom ============================================================ 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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Trouble installing example code for Parallel and Concurrent Programming in Haskell
by David Banas 12 Nov '23

12 Nov '23

I just picked up a copy of “Parallel and Concurrent Programming in Haskell”. And I’m trying to follow the instructions on p.4 for getting the examples installed, but having trouble: [23-11-10 9:49] dbanas@Davids-Air-M2:~/prj % cabal unpack parconc-examples Downloading parconc-examples-0.4.8 Downloaded parconc-examples-0.4.8 Unpacking to parconc-examples-0.4.8/ [23-11-10 9:50] dbanas@Davids-Air-M2:~/prj % pushd parconc-examples-0.4.8 ~/prj/parconc-examples-0.4.8 ~/prj ~ [23-11-10 9:50] dbanas@Davids-Air-M2:~/prj/parconc-examples-0.4.8 % cabal install --only-dependencies cabal: Could not resolve dependencies: [__0] trying: parconc-examples-0.4.8 (user goal) [__1] next goal: base (dependency of parconc-examples) [__1] rejecting: base-4.17.2.0/installed-4.17.2.0 (conflict: parconc-examples => base>=4.5 && <4.14) [__1] skipping: base-4.19.0.0, base-4.18.1.0, base-4.18.0.0, base-4.17.2.0, base-4.17.1.0, base-4.17.0.0, base-4.16.4.0, base-4.16.3.0, base-4.16.2.0, base-4.16.1.0, base-4.16.0.0, base-4.15.1.0, base-4.15.0.0, base-4.14.3.0, base-4.14.2.0, base-4.14.1.0, base-4.14.0.0 (has the same characteristics that caused the previous version to fail: excluded by constraint '>=4.5 && <4.14' from 'parconc-examples') [__1] rejecting: base-4.13.0.0, base-4.12.0.0, base-4.11.1.0, base-4.11.0.0, base-4.10.1.0, base-4.10.0.0, base-4.9.1.0, base-4.9.0.0, base-4.8.2.0, base-4.8.1.0, base-4.8.0.0, base-4.7.0.2, base-4.7.0.1, base-4.7.0.0, base-4.6.0.1, base-4.6.0.0, base-4.5.1.0, base-4.5.0.0, base-4.4.1.0, base-4.4.0.0, base-4.3.1.0, base-4.3.0.0, base-4.2.0.2, base-4.2.0.1, base-4.2.0.0, base-4.1.0.0, base-4.0.0.0, base-3.0.3.2, base-3.0.3.1 (constraint from non-upgradeable package requires installed instance) [__1] fail (backjumping, conflict set: base, parconc-examples) After searching the rest of the dependency tree exhaustively, these were the goals I've had most trouble fulfilling: base, parconc-examples Thanks, -db

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[ANNOUNCE] GHC 9.4.8 is now available
by Zubin Duggal 10 Nov '23

10 Nov '23

The GHC developers are happy to announce the availability of GHC 9.4.8. Binary distributions, source distributions, and documentation are available on the [release page](/download_ghc_9_4_8.html). This release is primarily a bugfix release addressing a few issues found in the 9.4 series. These include: * A fix for a recompilation checking bug where GHC may miss changes in transitive dependencies when deciding to relink a program (#23724). * A fix for a code generator bug on AArch64 platforms resulting in invalid conditional jumps (#23746). * Support for `-split-sections` on Windows. * Enabling `-split-sections` for various Linux and Windows binary distributions, enabling GHC to produce smaller binaries on these platforms. * And a few other fixes A full accounting of changes can be found in the [release notes]. As some of the fixed issues do affect correctness users are encouraged to upgrade promptly. We would like to thank Microsoft Azure, GitHub, IOG, the Zw3rk stake pool, Well-Typed, Tweag I/O, Serokell, Equinix, SimSpace, Haskell Foundation, 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. Happy compiling! -Zubin [ticket]: https://gitlab.haskell.org/ghc/ghc/-/issues/new [release notes]: https://downloads.haskell.org/~ghc/9.4.8/docs/users_guide/9.4.8-notes.html

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[ANN] mig-0.2 library to build servers and clients
by Anton Kholomiov 09 Nov '23

09 Nov '23

I’m happy to announce the latest release of mig-0.2 <https://github.com/anton-k/mig> library. It is a library to write composable servers for simple / boring haskell. The main focus of this release is the ability to serve Swagger UI from the server with ease and ability to create clients from the same code as servers. I’m happy to confirm that both goals are reached with this release. The tutorial for the library <https://anton-k.github.io/mig/> was created. Also there are many other improvements: - OpenApi schema for servers - swagger servers support (we can add swagger to server with one line of code: withSwagger def server ) - clients from the same code as servers - redesign of internal types - redesign of DSL for routes - many ergonomic improvements - packages for extra utils - split of mig package to several packages: - mig <https://hackage.haskell.org/package/mig> - core - mig-wai <https://hackage.haskell.org/package/mig-wai> - rendering servers to wai apps - mig-client <https://hackage.haskell.org/package/mig-client> - clients - mig-extra <https://hackage.haskell.org/package/mig-extra> - extra utils - mig-server <https://hackage.haskell.org/package/mig-server> - mig servers with batteries - mig-swagger-ui <https://hackage.haskell.org/package/mig-swagger-ui> - swagger ui server - tutorial and quickstart guide <https://anton-k.github.io/mig/> on github pages - CI for repo with formatter, build and tests and update of docs on github pages The internal type for Servers was redesigned so that we assemble the handler function with API description at the same time. In the first release it was just a handler function under the hood. As a refresher mig <https://github.com/anton-k/mig> is a family of libraries to write lightweight, simple, type-safe and composable servers. It strives to be in the middle ground between scotty and servant. To be composable, flexible and type-safe as servant and simple and lightweight in concepts as scotty. One thing that interesting to think about as Server is a first-class value and all servers have the same type and we have just a small number of functions to compose them (they are link server to path and make alternative routes with Monoid) it’s interesting to explore the possibility of creation small grain-like servers for typical tasks. For example, a server can be a function from interfaces (logging, DB or something else) to server value and we can join them together on various paths. This idea is interesting to consider. Thanks to Ambros for contribution. Also I’d like to thank the authors of packages servant, servant-swagger-ui and servant-openapi3 packages for inspiration for my work in this release. Many lines of code are influenced by those packages. Links: - github <https://github.com/anton-k/mig> - tutorial <https://anton-k.github.io/mig/> - mig on hackage <https://hackage.haskell.org/package/mig> also see packages mig-server <https://hackage.haskell.org/package/mig-server> and mig-client <https://hackage.haskell.org/package/mig-client>. - examples <https://github.com/anton-k/mig/tree/main/examples/mig-example-apps> Cheers, Anton

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[ANN] Copilot 3.17
by Ivan Perez 09 Nov '23

09 Nov '23

Hi everyone!! We are very excited to announce Copilot 3.17 [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. Copilotis being used at NASA in drone test flights. Through the NASA tool Ogma [1] (also written in Haskell), Copilot also serves as a runtime monitoring backend for NASA's Core Flight System, Robot Operating System (ROS2), and FPrime (the software framework used in the Mars Helicopter) applications. This release introduces compatibility with what4 versions up to 1.5.1, and replaces several functions in copilot-core. The second change is a breaking change: the functions replaced have been deprecated and new alternatives introduced instead. As always, we're releasing exactly 2 months since the last release. Our next release is scheduled for Jan 7th, 2024. In our last announcement, we mentioned that Copilot has received full approval for release as NASA Class D open-source software. Current emphasis is on increasing test coverage for the two remaining libraries without tests (copilot-libraries and copilot-theorem), 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 [3]. There have been many updates on the Copilot front in the last few months. We'll be able to announce more soon. Stay tuned. Happy Haskelling! Ivan [1] https://github.com/nasa/ogma [2] https://github.com/Copilot-Language/copilot/releases/tag/v3.17 [3] https://github.com/Copilot-Language/copilot [4] https://hackage.haskell.org/package/copilot

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Call for Contributions: BOB 2024 [March 15, Deadline Nov 17]
by Stefan Wehr 03 Nov '23

03 Nov '23

======================================================================== BOB Conference 2024 "What happens when we use what's best for a change?" https://bobkonf.de/2024/cfc.html Berlin, Mar 17 Call for Contributions Deadline: November 17, 2023 ======================================================================== 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, and speakers who are not 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 - next-generation IDEs - effective abstractions for data analytics - … everything really that isn’t mainstream, but you think should be - … includeing rough ideas 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 17, 2023 - Notification: December 5, 2023 - Program: December 12, 2023 Submit here: https://pretalx.com/bob-2024/submit/ Program Committee ----------------- (more information here: https://bobkonf.de/2024/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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