- Haskell-Cafe - Haskell.org

Oxford Haskell User Group
by Callan McGill 23 Mar '18

23 Mar '18

Hi! I am interested in starting a Haskell user group (or functional programming meetup) in Oxford and would like to hear from anyone else wanting to help organise it. Please feel free to get in contact. Best, Callan

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Summer of Code projects
by Luke Lau 23 Mar '18

23 Mar '18

Hello, I’m a beginner-intermediate Haskell programmer and would like to help out this summer with the SoC projects! I have a few questions about some of the project ideas: https://summer.haskell.org/ideas.html#format-preserving-yaml <https://summer.haskell.org/ideas.html#format-preserving-yaml> Would this new library aim to also use the C library behind the scenes, or would there be more interest in making a completely native Haskell version? (Do FFI calls in Haskell have any performance overhead?) https://github.com/haskell/haskell-ide-engine <https://github.com/haskell/haskell-ide-engine> This seems really cool! There are a lot of cool goals on the list I would like to take a stab at. Sharing build cache between HaRe and GHC, to drastically improve refactoring speed. Are there any examples of this being done with any other IDE extensions or build tools? Rewriting the completion system/LSP tests Are there any parts of the LSP specification that are missing or could be implemented better? Also I was curious as to what libraries/tools are used for parsing and analysing, if any at all? I briefly looked through the repository and couldn’t find anything particularly low-level. Thanks!

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Re: [Haskell-cafe] Dropping containers support for old GHC versions
by Adam Bergmark 22 Mar '18

22 Mar '18

I appreciate that it may be hard/undesirable for some to use the latest GHC, but overall I don't think we should need to maintain backwards compatibility indefinitely because of that. Older versions of containers will still work with older GHCs, and other libraries depending on containers will still work as well as long as they support older container versions. But nevertheless, at least it seems there are no objections to dropping 7.0 and 7.2.2 support so far? :) Cheers, Adam On Fri, 9 Mar 2018 at 17:20 Daniel Cartwright <chessai1996(a)gmail.com> wrote: > David, I just checked and you're correct - I believe I was remembering > some other library(ies), though I can't recall which ones. > > On Fri, Mar 9, 2018 at 11:08 AM, David Feuer <david.feuer(a)gmail.com> > wrote: > >> On Mar 9, 2018 10:55 AM, "Daniel Cartwright" <chessai1996(a)gmail.com> >> wrote: >> >> >> On a related note, I find it strange when looking through source code for >> 'containers'/other Haskell libraries and still see notes about supporting >> non-GHC Haskell compilers (e.g. Hugs) >> >> >> I believe we've stripped all references to Hugs and nhc98 from >> containers. If you find any, let us know. I'd be interested in adding >> support for Frege, but the way it deals with numeric literals could be >> problematic. >> >> > _______________________________________________ > Libraries mailing list > Libraries(a)haskell.org > http://mail.haskell.org/cgi-bin/mailman/listinfo/libraries >

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GSoC project
by Sanya Negi 21 Mar '18

21 Mar '18

Hello! I am extremely interested in the project " offline mode for stack " for GSoC, for which I have learnt basic stack and have been learning more. Please guide me as to what other specific things I have to delve into and how to break this problem into pieces to form my proposal. I can't seem to get in touch with the projects mentor Emanuel Borsboom. And as the deadline is reaching, I really need to start forming my proposal now. Soliciting a prompt and positive response. Sanya Negi

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Re: [Haskell-cafe] problem with stack behind proxy
by Yuji Yamamoto 21 Mar '18

21 Mar '18

FYI. If your office's proxy server is authenticated with NTLM authentication, use CNTLM http://cntlm.sourceforge.net/ , a proxy of proxy for NTLM-authenticated server. Actually, my last office uses it :) 2018-03-21 18:46 GMT+09:00 Nikos Karagiannidis <nikoshaskell(a)gmail.com>: > Thank you both for your help! > > I have tried to embed a URI encoded username and password in the > HTTP_PROXY setting but still did not work. > I have managed to find an alternative proxy by talking to the network > department that does not require authentication! > So now "stack upgrade" works for me too! > > I will continue with this workaround for now ... > > many thanks! > Nikos > > > On Wed, Mar 21, 2018 at 6:05 AM, Yuji Yamamoto < > whosekiteneverfly(a)gmail.com> wrote: > >> According to the error, you must set proxy user name and password to pass >> the authentication. >> >> Like this: >> >> HTTP_PROXY = http://username:password@proxy-host:8080 >> <http://proxy-host:8080/> >> HTTPS_PROXY = http:// <http://proxy-host:8080/>username:password@ >> <http://proxy-host:8080/> proxy-host:8080 >> >> Note that you must URI-encode the username or password if they include >> some meta-characters like a colon or an at-sign. >> >> Besides, stack 1.3.2 is too old! >> >> 2018-03-21 2:00 GMT+09:00 Nikos Karagiannidis <nikoshaskell(a)gmail.com>: >> >>> Hi all, >>> >>> I am trying to run stack build, or stack update behind the corporate web >>> proxy and I get the following error: >>> >>> $ stack build >>> Downloading lts-11.1 build plan ...HttpExceptionRequest Request { >>> host = "raw.githubusercontent.com" >>> port = 443 >>> secure = True >>> requestHeaders = [] >>> path = "/fpco/lts-haskell/master//lts-11.1.yaml" >>> queryString = "" >>> method = "GET" >>> proxy = Nothing >>> rawBody = False >>> redirectCount = 10 >>> responseTimeout = ResponseTimeoutDefault >>> requestVersion = HTTP/1.1 >>> } >>> (ProxyConnectException "raw.githubusercontent.com" 443 (Status >>> {statusCode = 407, statusMessage = "Proxy Authentication Required ( >>> Forefront TMG requires authorization to fulfill the request. Access to the >>> Web Proxy filter is denied. )"})) >>> >>> My stack version is: >>> >>> $ stack --version >>> Version 1.3.2, Git revision 3f675146590da4f3edf768b89355f798229da2a5 >>> x86_64 hpack-0.15.0 >>> >>> I have set the HTTP_PROXY and HTTPS_PROXY environment variables to a >>> value of: >>> HTTP_PROXY = http://proxy-host:8080 >>> HTTPS_PROXY = http://proxy-host:8080 >>> >>> Can you help me how to achieve proxy authentication via stack? >>> >>> thank you in advance! >>> >>> Nikos >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "haskell-stack" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to haskell-stack%2Bunsubscribe(a)googlegroups.com. >>> To post to this group, send email to haskell-stack(a)googlegroups.com. >>> To view this discussion on the web visit https://groups.google.com/d/ms >>> gid/haskell-stack/CAN0STeQPzM2SyxyYUiy3o2HS%2BDMw8sWmTcyWZHi >>> -LwLANjY%2BtQ%40mail.gmail.com >>> <https://groups.google.com/d/msgid/haskell-stack/CAN0STeQPzM2SyxyYUiy3o2HS%2…> >>> . >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> >> >> -- >> 山本悠滋 >> twitter: @igrep >> GitHub: https://github.com/igrep >> GitLab: https://gitlab.com/igrep >> Facebook: http://www.facebook.com/igrep >> Google+: https://plus.google.com/u/0/+YujiYamamoto_igrep >> > > -- 山本悠滋 twitter: @igrep GitHub: https://github.com/igrep GitLab: https://gitlab.com/igrep Facebook: http://www.facebook.com/igrep Google+: https://plus.google.com/u/0/+YujiYamamoto_igrep

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[ANN] New QFPL Applied Functional Programming Course 🎉 🎉
by Sean Chalmers 21 Mar '18

21 Mar '18

Hi everyone, After successful trials in Sydney, Melbourne, and Brisbane, we're pleased to present our new **Applied Functional Programming Course**. Designed for those of you beyond the intro stage and hungry for more. This is new course material that is targeted toward programmers who have become proficient with navigating Functional Programming concepts and would like to progress to building a complete application. This course material involves writing a REST application with a database backend. Topics covered include: * Hackage and the general Haskell ecosystem * Cabal files and project structure * Database integration * Configuration * Monad transformers * Testing * Type driven development The assumed Haskell knowledge for this course is that you are comfortable with Applicative, and you are able to write the definition for a function with the type: Applicative f => [f a] -> f [a] As with all of our course material, we invite and encourage you to submit issues and pull-requests. We build these courses for you, so if things aren't working. With either the content or any of the moving parts, we want to know. These courses are run free of charge, in Australia. When and where we run them is based on demand. So if you or your team are keen, then let us know. We can also arrange to run them in-house. Our contact details are here: https://qfpl.io/contact/. More info about both of our current courses is available on our projects page: https://qfpl.io/projects/courses/. Cheers, Sean Chalmers Functional Programming Engineer Queensland FP Lab Data61 / CSIRO Australia

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Call for Submissions: Haskell Symposium 2018
by Nicolas Wu 20 Mar '18

20 Mar '18

================================================================================ ACM SIGPLAN CALL FOR SUBMISSIONS Haskell Symposium 2018 St. Louis, MO, United States 27--28 September, 2018 http://www.haskell.org/haskell-symposium/2018/ ================================================================================ The ACM SIGPLAN Haskell Symposium 2018 will be co-located with the 2018 International Conference on Functional Programming (ICFP), in St. Louis, Missouri, USA. The Haskell Symposium aims to present original research on Haskell, discuss practical experience and future development of the language, and to promote other forms of denotative programming. Topics of interest include: * Language design, with a focus on possible extensions and modifications of Haskell as well as critical discussions of the status quo; * Theory, such as formal semantics of the present language or future extensions, type systems, effects, metatheory, and foundations for program analysis and transformation; * Implementations, including program analysis and transformation, static and dynamic compilation for sequential, parallel, and distributed architectures, memory management, as well as foreign function and component interfaces; * Libraries, that demonstrate new ideas or techniques for functional programming in Haskell; * Tools, such as profilers, tracers, debuggers, preprocessors, and testing tools; * Applications, to scientific and symbolic computing, databases, multimedia, telecommunication, the web, and so forth; * Functional Pearls, being elegant and instructive programming examples; * Experience Reports, to document general practice and experience in education, industry, or other contexts. * System Demonstrations, based on running software rather than novel research results. Regular 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 functional pearls need not necessarily report original academic research results. For example, they may instead report reusable programming idioms, elegant ways to approach a problem, or practical experience that will be useful to other users, implementers, or researchers. The key criterion for such a paper is that it makes a contribution from which other Haskellers can benefit. It is not enough simply to describe a standard solution to a standard programming problem, or report on experience where you used Haskell in the standard way and achieved the result you were expecting. More advice is available via the Haskell wiki. System demonstrations should summarize the system capabilities that would be demonstrated. The proposals will be judged on whether the ensuing session is likely to be important and interesting to the Haskell community at large, whether on grounds academic or industrial, theoretical or practical, technical, social or artistic. Please contact the program chair with any questions about the relevance of a proposal. Submission Details ================== Early and Regular Track ----------------------- The Haskell Symposium uses a two-track submission process so that some papers can gain early feedback. Strong papers submitted to the early track are accepted outright, and the others will be given their reviews and invited to resubmit to the regular track. Papers accepted via the early and regular tracks are considered of equal value and will not be distinguished in the proceedings. Although all papers may be submitted to the early track, authors of functional pearls and experience reports are particularly encouraged to use this mechanism. The success of these papers depends heavily on the way they are presented, and submitting early will give the program committee a chance to provide feedback and help draw out the key ideas. Formatting ---------- Submitted papers should be in portable document format (PDF), formatted using the ACM SIGPLAN style guidelines. Authors should use the `acmart` format, with the `sigplan` sub-format for ACM proceedings. For details, see: http://www.sigplan.org/Resources/Author/#acmart-format Functional pearls, experience reports, and demo proposals should be labelled clearly as such. Page Limits ----------- The length of submissions should not exceed the following limits: Regular paper: 12 pages Functional pearl: 12 pages Experience report: 6 pages Demo proposal: 2 pages There is no requirement that all pages are used. For example, a functional pearl may be much shorter than 12 pages. Deadlines --------- Early track: Submission deadline: 30 March 2018 (Fri) Notification: 18 May 2018 (Fri) Regular track and demos: Submission deadline: 8 June 2018 (Fri) Notification: 13 July 2018 (Fri) Deadlines are valid anywhere on Earth. Submission ---------- Submissions should adhere to SIGPLAN's republication policy, as explained on the web. The paper submission deadline and length limitations are firm. There will be no extensions, and papers violating the length limitations will be summarily rejected. Papers should be submitted through easychair at: https://easychair.org/conferences/?conf=haskell2018 Travel Support ============== Student attendees with accepted papers can apply for a SIGPLAN PAC grant to help cover travel expenses. PAC also offers other support, such as for child-care expenses during the meeting or for travel costs for companions of SIGPLAN members with physical disabilities, as well as for travel from locations outside of North America and Europe. For details on the PAC program, see its web page (http://pac.sigplan.org) Proceedings =========== Accepted papers will be included in the ACM Digital Library. Authors must grant ACM publication rights upon acceptance (http://authors.acm.org/main.html) Authors are encouraged to publish auxiliary material with their paper (source code, test data, etc.); they retain copyright of auxiliary material. Accepted proposals for system demonstrations will be posted on the symposium website but not formally published in the proceedings. All accepted papers and proposals will be posted on the conference website one week before the meeting. Publication date: The official publication date of accepted papers is the date the proceedings 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 Committee ================= Michael D. Adams University of Utah Patrick Bahr IT University of Copenhagen Olaf Chitil University of Kent Nils Anders Danielsson University of Gothenburg Graham Hutton University of Nottingham Mauro Jaskelioff CONICET/Universidad Nacional de Rosario Oleg Kiselyov Tohoku University Sam Lindley The University of Edinburgh Andres Löh Well-Typed LLP Bruno Oliveira The University of Hong Kong Maciej Piróg University of Wrocław Wren Romano Google Mark Shinwell Jane Street Niki Vazou University of California Marcos Viera Universidad de la República Nicolas Wu (Chair) University of Bristol Ryan Yates University of Rochester Brent Yorgey Hendrix College If you have questions, please contact the chair at: nicolas.wu(a)bristol.ac.uk ================================================================================

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directory package copyFile error
by Olaf Klinke 20 Mar '18

20 Mar '18

Dear cafe, not sure whether this is a bug or misusage on my part: I'm using stack lts-9.2, which entails directory-1.3.0.0. I have a file on a samba share, say /mnt/remote/foo. I read the file, modify its contents in my program and save a local copy, say /tmp/foo. Then I try to copy the modified file back to its original place using System.Directory.copyFile "/tmp/foo" "/mnt/remote/foo" Sometimes the copyFile command produces an error like this: /mnt/remote/.copyFile1804289383846930886.tmp: copyFile:atomicCopyFileContents:withReplacementFile:hClose: does not exist (Host is down) When I copy /tmp/foo to /mnt/remote/foo using the shell, everything works fine. Does anyone have an idea what goes wrong? Internally withReplacementFile is used which indeed creates a temporary file to not risk corrupting the original. Is this maybe due to a wrong ordering of IO actions? Thanks Olaf

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Listing Yampa projects
by Ivan Perez 20 Mar '18

20 Mar '18

Dear all, I would like to facilitate transitioning to new versions of Yampa when there are breaking changes in the library. Also, when there is a proposal to deprecate a feature, this will help understand if it's still being used. I've created a github issue so that people can list their projects: https://github.com/ivanperez-keera/Yampa/issues/68 If you have a project, example, or paper that uses yampa and you want to keep it in a working state, please comment. If there's a project, maybe not your own, that you'd like to see working, please say so, even if there is no maintainer at the moment. Cheers Ivan

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Register for BayHac 2018
by Dan Burton 19 Mar '18

19 Mar '18

Registration form: https://goo.gl/forms/1gYlTQVNwPkKGgC02 <https://goo.gl/forms/1gYlTQVNwPkKGgC02> All attendees are requested to register for the event via the registration form. Registration form: https://goo.gl/forms/1gYlTQVNwPkKGgC02 Propose a talk or workshop: https://goo.gl/forms/TZbFNIZu4Q1dEh2g2 More info: https://wiki.haskell.org/BayHac2018 -- Dan Burton

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