June 2024 - Haskell-Cafe

Call for Papers: SPLASH 2024 Student Research Competition
by Umar Farooq 07 Jun '24

07 Jun '24

======================================================================== SPLASH 2024 Student Research Competition Call for Papers Student Research Competition will be held as part of The ACM Conference on Systems, Programming, Languages, and Applications: Software for Humanity (SPLASH'24) October 20-25, 2024, Pasadena, California, United States https://2024.splashcon.org/track/splash-2024-SRC ======================================================================== ### Important dates Submission Deadline: Mon Jul 8, 2024 Author Notification: Mon Aug 19, 2024 Camera Ready: Sun Sep 1, 2024 The ACM Student Research Competition (SRC) offers a unique opportunity for undergraduate and graduate students to present their research to a panel of judges and conference attendees at SPLASH. The SRC provides visibility and exposes up-and-coming researchers to computer science research and the research community. This competition also gives students an opportunity to discuss their research with experts in their field, get feedback, and sharpen their communication and networking skills. ### Eligibility criteria Participants must have current student status, either graduate or undergraduate, at the time of the competition. Participants in the SRC must also be current ACM (student) members. ### Prizes Winners of the three top places in each category receive prizes of $500 for the first place winner, $300 for the second place winner and $200 for the third place winner, respectively. The top three undergraduate and graduate winners receive an award medal and a one-year complimentary ACM student membership with a subscription to ACM's Digital Library. ### ACM SRC Grand Finals First place winners in each category will be invited to participate in the ACM SRC Grand Finals, an online round of competition between first-place SRC winners from different ACM conferences held in 2024. Grand Finals will be judged by an ACM-appointed panel of judges. Winners of the three top Grand Finals places in each category will receive additional prizes of $500 for the first place winner, $300 for the second place winner and $200 for the third place winner, respectively. Winners of the SRC Grand Finals are recognized at the Annual ACM Awards Banquet along with prestigious ACM award winners, including the winner of the Turing Award. ##### Review Committee Review Committee Chairs: Anders Miltner, Simon Fraser University Jiasi Shen, The Hong Kong University of Science and Technology

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2nd Call for Papers: ACM Workshop on Functional Software Architecture [Deadline June 3]
by Michael Sperber 04 Jun '24

04 Jun '24

====================================================================== *** FUNARCH 2024 -- CALL FOR PAPERS *** Second ACM SIGPLAN Workshop on Functional Software Architecture - FP in the Large 6th September 2024, Milan, Italy Co-located with ICFP 2024 https://functional-architecture.org/events/funarch-2024/ ====================================================================== TIMELINE: Paper submission 3rd June 2024 Author notification 30th June 2024 Camera ready copy 18th July 2024 Workshop 6th Sept 2024 BACKGROUND: "Functional Software Architecture" refers to methods of construction and structure of large and long-lived software projects that are implemented in functional languages and released to real users, typically in industry. The goals for the workshop are: - To assemble a community interested in software architecture techniques and technologies specific to functional programming; - To identify, categorize, and document topics relevant to the field of functional software architecture; - To connect the functional programming community to the software architecture community to cross-pollinate between the two. The workshop follows on from the Functional Software Architecture open space that was held at ICFP 2022 in Slovenia. SCOPE: The workshop seeks submissions in a range of categories: - You're a member of the FP community and have thought about how to support programming in the large, for example by framing functional ideas in architectural terms or vice verse, comparing different languages in terms of their architectural capabilities, clarifying architectural roles played by formal methods, proof assistants and DSLs, or observing how functional concepts are used in other language and architecture communities. Great, submit a research paper! - You're a member of the architecture community, and have thought about how your discipline might help functional programmers, for example by applying domain-driven design, implementing hexagonal architecture, or designing self-contained systems. Excellent, submit a research paper! - You've worked on a large project using functional programming, and it's worked out well, or terribly, or a mix of both; bonus points for deriving architectural principles from your experience. Wonderful, submit an experience report! - You know a neat architectural idiom or pattern that may be useful to others developing large functional software systems. Fabulous, submit an architectural pearl! - You have something that doesn't fit the above categories, but that still relates to functional software architecture, such as something that can be written up, or that could be part of the workshop format like a panel debate or a fishbowl. Superb, submit to the open category! Research papers should explain their research contributions in both general and technical terms, identifying what has been accomplished, explaining why it is significant, and relating it to previous work, and to other languages where appropriate. Experience reports and architectural pearls need not necessarily report original research results. The key criterion for such papers is that they make a contribution from which others can benefit. It is not enough simply to describe a large software system, or to present ideas that are specific to a particular system. Open category submissions that are not intended for publication are not required to follow the formatting guidelines, and can submit in PDF, word or plain text format as preferred. Not knowing what kinds of submissions we will receive, we cannot be specific as to how they will be evaluated. However, submissions that seem likely to stimulate discussion around practices in functional architecture are encouraged. If you are unsure whether your contribution is suitable, or if you need any kind of help with your submission, please email the program chairs at <funarch2024(a)easychair.org>. Papers must be submitted by 3rd June 2024 using the EasyChair submission page: https://easychair.org/my/conference?conf=funarch2024 Formatting: submissions intended for publication must be in PDF format and follow the ACM SIGPLAN style guidelines, using the acmart format and the sigplan sub-format. Please use the review option when submitting, as this enables line numbers for easy reference in reviews. For further details, see SIGPLAN's author information: http://www.sigplan.org/Resources/Author/#acmart-format If your submission is not a research paper, please mark this using a subtitle (Experience Report, Architectural Pearl, Open Category). Length: submissions must adhere to the limits specified below. However, there is no requirement or expectation that all pages are used, and authors are encouraged to strive for brevity. Research papers 5 to 12+ pages Architectural pearls 5 to 12 pages Experience reports 3 to 6 pages Open category 1 to 6 pages Publication: The proceedings of FUNARCH 2024 will be published in the ACM Digital Library, and authors of accepted papers are required to agree to one of the standard ACM licensing options. Accepted papers must be presented at the workshop by one of the authors, but in special cases we may consider remote presentation. The official publication date is the date the 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. PROGRAM CHAIRS: Mike Sperber (Active Group, Germany) Perdita Stevens (University of Edinburgh, UK) PROGRAM COMMITTEE: Annette Bieniusa (University of Kaiserslautern) Jeffrey Young (IOG) Will Crichton (Brown University) Isabella Stilkerich (Schaeffler Technologies AG) Kiko Fernandez-Reyes (Ericsson) Ryan Scott (Galois) Satnam Singh (Groq) Facundo Dominguez (Tweag) Ilya Sergey (University of Singapore) Martin Elsman (University of Copenhagen) Benjamin Pierce (University of Pennsylvania) Matthew Flatt (University of Utah) Nada Amin (Harvard University) Richard Eisenberg (Jane Street) WORKSHOP VENUE: The workshop will be co-located with the ICFP 2024 conference at the Fiera Milano Congressi, Milan, Italy.

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Exhaustive pattern match warning and GADTs
by William Yager 01 Jun '24

01 Jun '24

Hello cafe, I'm writing a bit of code with state machines that are only allowed to make certain types of transitions between certain classes of states (e.g. "ready" and "unready"). The state types have some type parameters describing which class of state it's currently in. The step functions look vaguely like `step :: state a -> input b -> state c`, with various constraints on `a`, `b`, and `c`. When `state` and `input` are GADTs, you can enforce interesting invariants about the output state, given the input state and event. This all seems to work fine, and seems to be getting me in the direction I want to go. However, I'm running into a roadblock (possibly a bug?). Take the following minimal example: {-# LANGUAGE DataKinds, GADTs #-} module Lib () where data State2 s a where State2T :: s True -> State2 s True State2F :: s False -> State2 s False data OnlyTrue s where TrueState :: OnlyTrue True example :: State2 OnlyTrue s -> () example (State2T TrueState) = () -- Comment this and get non-exhaustive pattern warning -- Uncomment this and get "Inaccessible code" warning -- example (State2F TrueState) = () There is only one possible pattern on the LHS of the equation. If I don't put the (impossible) pattern, GHC gives me a warning about missing a pattern. If I do put the impossible pattern, GHC warns me that the pattern is impossible. Indeed! So why is GHC complaining about it in the first place? I'm using GHC 9.6.5. Around 7-8 years ago, I wrote some similar code, using typeclasses to constraint GADTs, and I remember being very impressed that the completeness checker was smart enough to figure out not to complain about impossible patterns (cf the paper "GADTs meet their match"). This seems like a simpler use case than what I recall doing in the past, but the completeness checker is giving me bad warnings here. Any ideas what might be going wrong? Thanks, Will

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Re: [Haskell-cafe] Issue building with ghc-9.8.2 and packages unix, directory, filepath and os-string
by Daniel Trstenjak 01 Jun '24

01 Jun '24

> The problem is that `--allow-newer` tells cabal to ignore dependencies' upper bounds > completely. If those bounds turn out to be necessary in some cases, the solver will produce a > bad build plan. Looking at the compile error of the unix package, it looks like it gets the wrong combination of filepath and os-string packages, resulting in the missing symbols. This depends on the os-string flag, either the unix package gets the older filepath package containing these symbols or the newer one without them and additionally the os-string package now containing the symbols. This handling with the os-string flag feels wrong to me and therefore cabal can‘t resolve the right dependencies. The unix 2.8.5.0 package has an upper bound for filepath of <1.5, the one with the symbols, but unix 2.8.5.1 has the lower bound filepath >1.4.100, therefore supporting the filepath packages with and without the symbols. It seems if unix 2.8.5.1 would only support the filepath package without the symbols, by having the lower bound filepath >=1.5, then cabal could work out the right dependencies. Is there a reason why the unix 2.8.5.1 does it that way?

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