June 2016 - Haskell-Cafe

Re: [Haskell-cafe] [Haskell] The Haddock documentation is not showing up on the Hackage
by Henning Thielemann 27 Jun '16

27 Jun '16

On Mon, 27 Jun 2016, KwangYul Seo wrote: > I uploaded a package named enchant on the Hackage last week, but the > Haddock documentation is not showing up yet. The Status field says "Docs > pending" and "Build status unknown". This is certainly not for haskell(a)haskell.org. I am answering to haskell-cafe and cabal-devel. > https://hackage.haskell.org/package/enchant-0.1.0.0 > > enchant uses c2hs as a build tool to generate the FFI binding and > requires libenchant-dev to be installed on the machine. I wonder how I > can tell these build requirements to the Hackage server. I assume that it is not a good idea to install many additional packages on the Haskell server. Thus I think the best you can do is to upload the documentation yourself via the package maintenance site. Here is a script that should help creating the docs locally and upload them to Hackage: https://raw.githubusercontent.com/ekmett/lens/master/scripts/hackage-docs.sh

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Re: [Haskell-cafe] [Haskell] The Haddock documentation is not showing up on the Hackage
by Francesco Ariis 27 Jun '16

27 Jun '16

On Mon, Jun 27, 2016 at 01:28:57PM +0900, KwangYul Seo wrote: > Hi, > > I uploaded a package named enchant on the Hackage last week, but the > Haddock documentation is not showing up yet. The Status field says "Docs > pending" and "Build status unknown". > > https://hackage.haskell.org/package/enchant-0.1.0.0 > > enchant uses c2hs as a build tool to generate the FFI binding and requires > libenchant-dev to be installed on the machine. I wonder how I can tell > these build requirements to the Hackage server. I had a similar problem a few months ago, resolved to upload a 0.1.0.1 version, that triggered the build. p.s.: I am replying in haskell-cafe(a)haskell.org , which is probably more suited (haskell@ is for announcements, etc.)

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Munich Haskell Meeting, 2016-06-29 @ 19:30 Augustiner-Keller
by Christian Neukirchen 25 Jun '16

25 Jun '16

Dear all, Next week, our monthly Munich Haskell Meeting will take place again on Wednesday, June 29 at Augustiner-Keller Arnulfstr. at 19h30. **Please note the different day and location!** For details see here: http://muenchen.haskell.bayern/dates.html (Yes, we got a new domain!) If you plan to join, please add yourself to this dudle so we can reserve enough seats! It is OK to add yourself to the dudle anonymously or pseudonymously. https://dudle.inf.tu-dresden.de/haskell-munich-jun-2016/ Everybody is welcome! cu, -- Christian Neukirchen <chneukirchen(a)gmail.com> http://chneukirchen.org

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User Requirements Survey for CT Software (Beta)
by Murphy, Joie R. (Assoc) 25 Jun '16

25 Jun '16

Hello, My name is Joie Murphy and I am a Summer Research Student at the US National Institute of Standards and Technology (NIST), working with Drs. Spencer Breiner and Eswaran Subrahmanian. We are currently gathering user requirements for category theoretic software to be developed by or with NIST in the future. This questionnaire will give us insight about your past or present use of CT software and your ideal uses for such software. Providing us with the information on how you would like to use this type of software will help us to make the right design choices in development. The survey is available on Google Forms: http://goo.gl/forms/vfOgR26dHnKynHU23 If you have any colleagues who might be willing to fill out this survey, you can forward our message or you can provide us with their contact information at the end of the survey. If you have any questions or concerns, please feel free to contact us by replying to this email. We would like to thank you for your participation in this initial step of the development process. Regards, Joie Murphy

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up-to-date glfw examples
by briand＠aracnet.com 24 Jun '16

24 Jun '16

Hi, I've been looking but the examples are all fairly old and are broken in both imports from glfw and opengl. Just looking for very basic examples that work with the current versions of glfw-b and opengl. Thank you, Brian

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Backtracking when building a bytestring
by David Turner 24 Jun '16

24 Jun '16

Hi, I'm working on a network protocol that involves sending frames of data prefixed by their length and a checksum. The only realistic way to work out the length of a frame is to actually write the bytes out, although the length and checksum take up a fixed number of bytes. If I were working in C I'd be filling a buffer, leaving space for the length/checksum, and then go back and fill them in at the end. So this is _almost_ what ByteString.Builder does except for the backtracking bit. Does anyone know if there's an implementation of a thing that's a bit like ByteString.Builder but also allows for this kind of backtracking? Ideally I want to be able to batch up a number of frames into a single buffer, and deal gracefully with overflowing the buffer by allocating some more, much as Builder does. I can't think of a terribly good way of doing this using the existing Builder implementation as it stands, although it looks quite easy to modify it to add this functionality so I might just do that locally if needs be. Cheers, David

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Haskell in Leipzig 2016: Final Call for Papers
by Joachim Breitner 23 Jun '16

23 Jun '16

Haskell in Leipzig September 14-15, 2016 HTKW Leipzig, Germany http://hal2016.haskell.org/ This is the third and last call for submissions for the Haskell in Leipzig workshop. In case you were hesitating whether you want to submit something, the answer is „Yes!“. I’m looking forward to receiving your contribution on July 1st (next Friday). == About HaL == The workshop series “Haskell in Leipzig”, now in its 11th year, brings together Haskell developers, Haskell researchers, Haskell enthusiasts and Haskell beginners to listen to talks, take part in tutorials, and join in interesting conversations. Everything related to Haskell is on topic, whether it is about current research, practical applications, interesting ideas off the beaten track, education, or art, and topics may extend to functional programming in general and its connections to other programming paradigms as well. This year, HaL is colocated with two related conferences, * the Workshop on Functional and (Constraint) Logic Programming (WFLP) and * the Workshop on (Constraint) Logic Programming (WLP), to form the Leipzig Week of Declarative Programming (L-DEC): http://nfa.imn.htwk-leipzig.de/LDEC2016/ In order to accommodate and welcome a more international audience, this year’s HaL will be held in English. == Invited Speaker == Unsure about whether HaL is interesting to you? No need to worry: Alejandro Russo (from Chalmers) is our keynote speaker and will talk about his work on information-flow control (i.e. SecLib, LIO, MAC, HLIO) – a great topic that is of interest to researchers, practitioners and beginners alike. == Submissions == Contributions can take the form of * talks (about 30 minutes), * tutorials (about 90 minutes), * demonstrations, artistic performances, or other extraordinary things. Please submit an abstract that describes the content and form of your presentation, the intended audience, and required previous knowledge. We recommend a length of 2 pages, so that the PC and the audience get a good idea of your submission, but this is not a hard requirement. You can submit your abstract, as an PDF document, at https://easychair.org/conferences/?conf=hal2016 until Friday, July 1, 2016. You will be notified by July 15, 2016. == Program committee == * Andreas Abel, Chalmers and Gothenburg University, Sweden * Heinrich Apfelmus, Leipzig, Germany * Joachim Breitner, Karlsruhe Institute of Technology, Germany (Chair) * Matthias Fischmann, Zerobuzz, Germany * Petra Hofstedt, BTU Cottbus-Senftenberg, Germany * Wolfgang Jeltsch, Institute of Cybernetics at Tallinn University of Technology, Estonia * Andres Löh, Well-Typed LLP, Germany * Alejandro Serrano Mena, Universiteit Utrecht, Netherlands * Neil Mitchell, Standard Chartered Bank, UK * Katie Ots, Facebook, UK * Peter Stadler, University of Leipzig, Germany * Henning Thielemann, Freelancer, Germany * Niki Vazou, University of California, San Diego, USA If you have any questions, please do not hesitate to contact Joachim Breitner <breitner(a)kit.edu>. -- Dr. rer. nat. Joachim Breitner Wissenschaftlicher Mitarbeiter http://pp.ipd.kit.edu/~breitner

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PEPM 2017 Call for Papers
by Jeremy Yallop 23 Jun '16

23 Jun '16

CALL FOR PAPERS Workshop on PARTIAL EVALUATION AND PROGRAM MANIPULATION (PEPM 2017) http://conf.researchr.org/home/PEPM-2017 Paris, France, January 16th - 17th, 2017 (co-located with POPL 2017) PEPM is the premier forum for discussion of semantics-based program manipulation. The first ACM SIGPLAN PEPM symposium took place in 1991, and meetings have been held in affiliation with POPL every year since 2006. PEPM 2017 will be based on a broad interpretation of semantics-based program manipulation, reflecting the expanded scope of PEPM in recent years beyond the traditionally covered areas of partial evaluation and specialization. Specifically, PEPM 2017 will include practical applications of program transformations such as refactoring tools, and practical implementation techniques such as rule-based transformation systems. In addition, the scope of PEPM covers manipulation and transformations of program and system representations such as structural and semantic models that occur in the context of model-driven development. In order to maintain the dynamic and interactive nature of PEPM and to encourage participation by practitioners, we also solicit submissions of short papers, including tool demonstrations, and of posters. Scope ----- Topics of interest for PEPM 2017 include, but are not limited to: * Program and model manipulation techniques such as: supercompilation, partial evaluation, fusion, on-the-fly program adaptation, active libraries, program inversion, slicing, symbolic execution, refactoring, decompilation, and obfuscation. * Program analysis techniques that are used to drive program/model manipulation such as: abstract interpretation, termination checking, binding-time analysis, constraint solving, type systems, automated testing and test case generation. * Techniques that treat programs/models as data objects including metaprogramming, generative programming, embedded domain-specific languages, program synthesis by sketching and inductive programming, staged computation, and model-driven program generation and transformation. * Application of the above techniques including case studies of program manipulation in real-world (industrial, open-source) projects and software development processes, descriptions of robust tools capable of effectively handling realistic applications, benchmarking. Examples of application domains include legacy program understanding and transformation, DSL implementations, visual languages and end-user programming, scientific computing, middleware frameworks and infrastructure needed for distributed and web-based applications, embedded and resource-limited computation, and security. This list of categories is not exhaustive, and we encourage submissions describing applications of semantics-based program manipulation techniques in new domains. If you have a question as to whether a potential submission is within the scope of the workshop, please contact the programme chairs. Submission categories and guidelines ------------------------------------ Three kinds of submissions will be accepted: Regular Research Papers, Short Papers and Posters. * Regular Research Papers should describe new results, and will be judged on originality, correctness, significance and clarity. Regular research papers must not exceed 12 pages in ACM Proceedings style (including appendix). * Short Papers may include tool demonstrations and presentations of exciting if not fully polished research, and of interesting academic, industrial and open-source applications that are new or unfamiliar. Short papers must not exceed 6 pages in ACM Proceedings style (including appendix). * Posters should describe work relevant to the PEPM community, and must not exceed 2 pages in ACM Proceedings style. We invite poster submissions that present early work not yet ready for submission to a conference or journal, identify new research problems, showcase tools and technologies developed by the author(s), or describe student research projects. At least one author of each accepted contribution must attend the workshop and present the work. In the case of tool demonstration papers, a live demonstration of the described tool is expected. Suggested topics, evaluation criteria, and writing guidelines for both research tool demonstration papers will be made available on the PEPM 2017 web site. Student participants with accepted papers can apply for a SIGPLAN PAC grant to help cover travel expenses and other support. 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 programme, see its web page. Publication and special issue ----------------------------- All accepted papers, short papers and posters included, will appear in formal proceedings published by ACM Press. Accepted papers will be included in the ACM Digital Library. Authors of selected papers from PEPM 2016 and PEPM 2017 will also be invited to expand their papers for publication in a special issue of the journal Computer Languages, Systems and Structures (COMLAN, Elsevier). Best paper award ---------------- PEPM 2017 continues the tradition of a Best Paper award. The winner will be announced at the workshop. Submission ---------- Papers should be submitted electronically via HotCRP. https://pepm17.hotcrp.com/ Authors using LaTeX to prepare their submissions should use the new improved SIGPLAN proceedings style, and specifically the sigplanconf.cls 9pt template. Important Dates --------------- For Regular Research Papers and Short Papers: * Abstract submission : Tuesday 13th September 2016 * Paper submission : Friday 16th September 2016 * Author notification : Monday 24th October 2016 * Camera ready : Monday 28th November 2016 For Posters: * Poster submission : Sunday 30th October 2016 * Author notification : Friday 10th November 2016 * Camera ready : Monday 28th November 2016 PEPM workshop: * Workshop : Monday 16th - Tuesday 17th January 2017 The proceedings will be published 2 weeks pre-conference. AUTHORS TAKE NOTE: The official publication date 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 your conference. The official publication date affects the deadline for any patent filings related to published work. (For those rare conferences whose proceedings are published in the ACM Digital Library after the conference is over, the official publication date remains the first day of the conference.). PEPM'17 Programme Co-Chairs ------------------- Ulrik Schultz (University of Southern Denmark), ups(a)mmmi.sdu.dk Jeremy Yallop (University of Cambridge), jeremy.yallop(a)cl.cam.ac.uk

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[oleg.grenrus@iki.fi: Re: Easy type-level math]
by Lana Black 22 Jun '16

22 Jun '16

Forwarding Oleg's message to the list. ----- Forwarded message from Oleg Grenrus <oleg.grenrus(a)iki.fi> ----- Date: Tue, 21 Jun 2016 05:27:13 +0300 From: Oleg Grenrus <oleg.grenrus(a)iki.fi> To: Lana Black <lanablack(a)amok.cc> Subject: Re: [Haskell-cafe] Easy type-level math X-Mailer: iPhone Mail (13F69) ghc-typelits-natnormalise can dismiss equality constraints, like `n + m ~ m + n`. OP needs to conjure KnownNat dictionary though, and that plugin cannot do. You can do it unsafely and manually with `reifyNat` from `reflections`: http://hackage.haskell.org/package/reflection-2.1.2/docs/Data-Reflection.ht… - Oleg > On 21 Jun 2016, at 03:12, Lana Black <lanablack(a)amok.cc> wrote: > > GHC currently lacks an ability to normalize type level arithmetic equations. There is a plugin however [1] that implements this feature. I believe that's what you are looking for. > > [1] ‎https://hackage.haskell.org/package/ghc-typelits-natnormalise > > From: Станислав Черничкин > Sent: Monday, June 20, 2016 11:37 PM > To: haskell-cafe(a)haskell.org > Subject: [Haskell-cafe] Easy type-level math > > With DataKinds and TypeOperators and GHC.TypeLits and, probably, KindSignatures I have: > > test :: (KnownNat i, KnownNat (i + 4)) => MyType i ((i + 4) + 4) > > and it's typecheck perfectly. > > But what I really want to have is: > > test :: (KnownNat i) => MyType i (i +8) > > and it does not typecheck. > > Does not ((i + 4) + 4) == (i +8)? > > Does not (KnownNat i) implies (KnownNat (i + 4))? > > Did I miss something about Haskell? > > -- > Thanks, Stanislav Chernichkin. > > _______________________________________________ > Haskell-Cafe mailing list > To (un)subscribe, modify options or view archives go to: > http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe > Only members subscribed via the mailman list are allowed to post. ----- End forwarded message -----

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Help with triple stack monad
by Christopher Howard 22 Jun '16

22 Jun '16

Hi, I was expanding on my earlier learning, to try a triple monad stack: {-# LANGUAGE GeneralizedNewtypeDeriving #-} <...snip...> import System.Random import Control.Monad.Random import Control.Monad.State.Lazy import Control.Monad.Reader newtype ReaderStateRandom r s g a = RSR { rSR :: ReaderT r (StateT s (Rand g)) a } deriving (Monad, MonadReader r, MonadState s) However, it seems that I must implement MonadRandom myself, as there is no instance for this sort of arrangement already. Probably this is trivial, but I'm having trouble wrapping my mind around how to do it. Would anybody perhaps assist me in implementing one function, to help guide me in the correct direction? instance MonadRandom (ReaderStateRandom r s g) where getRandom = ...? -- http://justonemoremathproblem.com To protect my privacy, please use PGP encryption. It's free and easy to use! My public key ID is 0x340EA95A (pgp.mit.edu)

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