- Haskell-Cafe - Haskell.org

Tomorrow: Simon PJ announces Haskell Foundation
by Richard Eisenberg 04 Nov '20

04 Nov '20

Tomorrow (Wednesday Nov 4) at 12:00 UTC, Simon PJ will announce the formation of the Haskell Foundation, an independent, non-profit organization dedicated to broadening Haskell adoption. This will be a part of Haskell eXchange, but this announcement will be free to attend, via YouTube. Much of the presentation will be time for Q&A; questions can be posed both within the Haskell eXchange HopIn platform and via comments on YouTube. Attend at https://youtu.be/MEmRarBL9kw <https://youtu.be/MEmRarBL9kw> Just to forestall any disappointment: I won't be answering any questions here until at least after the announcement -- but do please come and ask questions there and afterwards. Richard

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Journal of Functional Programming - Call for PhD Abstracts
by Graham Hutton 03 Nov '20

03 Nov '20

Dear all, If you or one of your students recently completed a PhD 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 2020. Please share! Best wishes, Graham Hutton ============================================================ CALL FOR PHD ABSTRACTS Journal of Functional Programming Deadline: 30th November 2020 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 PhD student and PhD advisor/supervisor although we encourage them to coordinate. ============================================================ SUBMISSION: Please submit the following information to Graham Hutton <graham.hutton(a)nottingham.ac.uk> by 30th November 2020: o Dissertation title: (including any subtitle) o Student: (full name) o Awarding institution: (full name and country) o Date of PhD 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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Hackage and searching for substrings
by Magnus Therning 02 Nov '20

02 Nov '20

Just now I thought I'd check what kind of lib waargonaut is. Being lazy I typed "waarg" into the package search box and found nothing! Is there a way to make Hackage find waargonaut without having to type the full package name? /M -- Magnus Therning OpenPGP: 0x927912051716CE39 email: magnus(a)therning.org twitter: magthe http://magnus.therning.org/ It is better to keep your mouth shut and appear stupid than to open it and remove all doubt. — Mark Twain

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Intention to take over the pipes-text package
by Peter J. Jones 02 Nov '20

02 Nov '20

(This is a re-post from October 6, 2020 since the original did not make it into the archive.) The pipes-text [1] package on Hackage hasn't been updated in about 4 years and doesn't currently build due to outdated `build-depends'. Patches have been supplied to the GitHub [2] repository but none have been merged. The last commit was on Dec 2, 2016. I have attempted to reach out to the author (Michael Thompson) to offer assistance and have not received any response. As per the instructions on the Haskell Wiki, I'm posting this message to signal my intent to take over the pipes-text package as a maintainer. I have a working fork here [3]. Michael, if you prefer to keep the package under your control I'm more than happy to help you manage the GitHub project and get some patches merged. Otherwise I'll reach out to the Hackage administrators after a reasonable amount of time has passed. [1]: https://hackage.haskell.org/package/pipes-text [2]: https://github.com/michaelt/text-pipes [3]: https://github.com/pjones/pipes-text

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GHC-8.6.3 question.
by David Duke 02 Nov '20

02 Nov '20

Dear colleagues I'm in the process of having to reinstall ghc-8.6.3 in order to use a library (gtk) where the last successful build is 8.6.3. I was able to do that on linux. However I'm now trying to repeat this under OSX. I couldn't find a binary version, so I've been trying to build from source- but i'm hitting an issue on 'make install': stage2/build/libHSghc-8.6.3_p.a: copyFile: does not exist (No such file or directory) I'm not seeing a stage2 directory in my build area, but I'm not seeing any earlier error messages so I'm unclear why the build is failing. If someone familiar with this release and/or th build process could suggest any causes or fixes that would be helpful. thanks, David Duke

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2020 State of Haskell Survey
by Taylor Fausak 01 Nov '20

01 Nov '20

Hi friends! I am very excited to announce the fourth annual state of Haskell survey. It opens today (the 1st) and stays open for two weeks (the 15th). I would greatly appreciate it if you could take 10 minutes to fill it out. Thanks! https://haskellweekly.news/survey/2020.html

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Re: [Haskell-cafe] Split the IsList class for OverloadedLists
by Olaf Klinke 01 Nov '20

01 Nov '20

> Hello Café, > > Right now the IsList class used by the OverloadedLists extension > requires both fromList, to construct something using list syntax, > and > toList, to pattern-match on something using list syntax. > > So types implementing that class are expected to be isomorphic to > lists. > This is a very strong restriction. In particular, this gets in the > way > of implementing IsList for aeson's Value type[1], since there's no > sensible total implementation of toList. > > [1]: That is a recently proposed idea > https://github.com/bos/aeson/issues/813 For constructing values from list syntax, I can understand that only fromList is used and Aeson's Value indeed contains lists. But if both fromList and toList are required, I would expect that fromList.toList=id and I can not see how that can ever be achieved with Aeson Values. Maybe a lightweight quasi-quoter can be syntactically almost as convenient for construction? MonoFoldable and MonoTraversable instances for Value might also be helpful: MonoFoldable gives you a toList function. > > > Proposal: split toList and fromList in two separate classes. > > (And modify the OverloadedLists extension accordingly.) > > Since they rely on an associated type family Item, it would be made > a > standalone family. > > > type family Item (l :: Type) :: Type > > class ToList l where > toList :: l -> [Item l] > > class FromList l where > fromList :: [Item l] -> l > fromListN :: Int -> [Item l] -> l > > > (Note: we can't just replace ToList with Foldable, because these > classes > have different kinds.) > > > - Any objections? An obvious concern is backwards compatibility. Is > that > a deal breaker? Are there other issues with this idea? You would lose the pattern matching functionality, it seems. It reminds me very much of OverloadedStrings and that is not always as convenient as you might think. The issue is that a previously monomorphic piece of syntax suddenly is polymorphic, so in some places with OveroadedStrings one must provide type annotations. And that destroys the brevity one was after. > > - Should that be a GHC proposal[2]? > > - Has this been discussed before? > > [2]: https://github.com/ghc-proposals/ghc-proposals > > > One alternative is to use RebindableSyntax, which already allows > users > to redefine toList and fromList however they want. The issue is it > might > also mess with all other kinds of syntactic sugar just enough that > the > unpleasantness is not worth the trouble. > > For example, if you wanted to use multiple list-like types in one > module, you would want an overloaded version of fromList/fromListN. > You > either roll your own or find a suitable dependency. Either way it's > overhead you might not be willing to pay for, as opposed to > something > that's already in base and Just Works. > > So even with some existing workarounds in mind, the above proposal > seems > a net improvement over the status quo. > > Maybe some day we'll also get to take fromInteger out of Num. > > Regards, > Li-yao >

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[CFP]Agile and Functional Data Pipelines workshop
by mgajda＠mimuw.edu.pl 01 Nov '20

01 Nov '20

Dear Friends, The emerging interest in the rigorous and agile data science and functional ETL pipelines has driven the developments of many new libraries, frameworks and methodologies. We invite industry practitioners and academics to present their latest work on agile functional data pipelines as a workshop at the EDI'2021 conference. Call for papers =============== The following would be accepted: - Exposures of methodologies for building agile functional data pipelines - Presentations of frameworks used for data pipelines in industry and academia - Experience reports from building of data pipelines in industry and academia - Benchmarks and optimization of agile data pipeline frameworks - Solutions to data integration and exchange problems within ETL pipelines. In particular, we encourage: - Agile functional data methodologists - Authors of ETL frameworks, streaming libraries and databases, reactive streaming, streaming benchmarks, high-performance workflow engines - Position papers on the use of agile and functional data methodologies - Descriptions of environments for interactive and live programming with data - Benchmarks of state-of-the-art solutions for agile functional data pipelines. Details at https://afdp.github.io Important dates =============== Abstract registration deadline : December 15th, 2020 Submission deadline : December 22nd, 2020 Acceptance notification : January 12th 2021 Final manuscripts : January 23rd, 2021 Presentation at the conference : March 23rd-26th 2021 Submission instructions ======================= Original, unpublished papers are solicited for presentation at the AFDP workshop. Prospective authors are invited to submit papers (electronically, PDF only) that are no longer than 6 pages for full papers, including all figures and references. For work-in-progress, we also solicit extended abstracts for presentations. The submitted paper must be formatted according to the guidelines of Procedia Computer Science. All accepted papers will be published in Procedia Computer Science. Location ======== This workshop will be held as a part of [The 4th International Conference on Emerging Data and Industry 4.0 (EDI40)](http://cs-conferences.acadiau.ca/EDI40-21/) held on March 23 - 26, 2021 in Warsaw, Poland. -- Best regards MichaB

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Re: [Haskell-cafe] Panmusic?
by Johannes Waldmann 31 Oct '20

31 Oct '20

> Is anyone working on the universal music notation > converter in Haskell? https://github.com/music-suite/music-suite http://music-suite.github.io/docs/ref/ I think this intends to be "the pandoc of music". I was looking into lilypond parsing for that, see my fork https://github.com/jwaldmann/lilypond-parse#goals but I'm currently stalled on this, for lack of time - and for the thorough mess that lilypond makes of mixing lexing, parsing, and semantics. It's as bad as TeX ... - J.

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Split the IsList class for OverloadedLists
by Li-yao Xia 30 Oct '20

30 Oct '20

Hello Café, Right now the IsList class used by the OverloadedLists extension requires both fromList, to construct something using list syntax, and toList, to pattern-match on something using list syntax. So types implementing that class are expected to be isomorphic to lists. This is a very strong restriction. In particular, this gets in the way of implementing IsList for aeson's Value type[1], since there's no sensible total implementation of toList. [1]: That is a recently proposed idea https://github.com/bos/aeson/issues/813 Proposal: split toList and fromList in two separate classes. (And modify the OverloadedLists extension accordingly.) Since they rely on an associated type family Item, it would be made a standalone family. type family Item (l :: Type) :: Type class ToList l where toList :: l -> [Item l] class FromList l where fromList :: [Item l] -> l fromListN :: Int -> [Item l] -> l (Note: we can't just replace ToList with Foldable, because these classes have different kinds.) - Any objections? An obvious concern is backwards compatibility. Is that a deal breaker? Are there other issues with this idea? - Should that be a GHC proposal[2]? - Has this been discussed before? [2]: https://github.com/ghc-proposals/ghc-proposals One alternative is to use RebindableSyntax, which already allows users to redefine toList and fromList however they want. The issue is it might also mess with all other kinds of syntactic sugar just enough that the unpleasantness is not worth the trouble. For example, if you wanted to use multiple list-like types in one module, you would want an overloaded version of fromList/fromListN. You either roll your own or find a suitable dependency. Either way it's overhead you might not be willing to pay for, as opposed to something that's already in base and Just Works. So even with some existing workarounds in mind, the above proposal seems a net improvement over the status quo. Maybe some day we'll also get to take fromInteger out of Num. Regards, Li-yao

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