- Haskell-Cafe - Haskell.org

accessing the RTS -M flag value from GHC.RTS.Flags
by Adam Flott 05 Apr '16

05 Apr '16

Given, import GHC.RTS.Flags main = do gcf <- getRTSFlags print (maxHeapSize (gcFlags gcf)) And running on x86-64 in GHC 7.10.3, $ ./ghcflags 0 $ ./ghcflags +RTS -M1M 256 $ ./ghcflags +RTS -M1024K 256 $ ./ghcflags +RTS -M4096K 1024 Is there anyway I can get access to the value stored in the -M flag and depend on that value being correct? I was not able find it in the user's guide or anywhere else for that matter. Thanks, Adam

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[ANN] protobuf-simple: Protocol Buffers library
by Martijn Rijkeboer 05 Apr '16

05 Apr '16

Hello, I've just released protobuf-simple, an Haskell implementation of Google's Protocol Buffers with an emphasis on simplicity. This implementation consists of a library for the encoding and decoding of data and an executable for generating Haskell types from proto files. The code can be found at https://github.com/sru-systems/protobuf-simple Kind regards, Martijn Rijkeboer

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Re: [Haskell-cafe] [ANN] protobuf-simple: Protocol Buffers library
by Martijn Rijkeboer 05 Apr '16

05 Apr '16

Hi Alain, > What version of Protocol Buffer are you supporting (I did not find this > info, sorry) ? Are you planning on supporting the V3 if you don't > already? The protobuf-simple library only supports V2. The version wasn't specified anywhere, my bad. I've just added it to the readme. Currently I have no plans supporting V3, since I have no use for it. However, pull requests are always welcome, providing that the library remains "simple". Kind regards, Martijn Rijkeboer

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Journal of Functional Programming - Call for PhD Abstracts
by Graham Hutton 05 Apr '16

05 Apr '16

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, deadline 30th April 2016. Best wishes, Graham ============================================================ CALL FOR PHD ABSTRACTS Journal of Functional Programming Deadline: 30th April 2016 http://tinyurl.com/jfp-phd-abstracts ============================================================ PREAMBLE: Many students complete PhDs in functional programming each year. As a service to the community, 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 April 2016. 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 1000 words; you may use \emph{...} for emphasis, but we prefer no other markup or formatting in the abstract, but do get in touch if this causes significant problems) 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 send it back to me, and immediately delete it. Please do not use, copy or disclose the information contained in this message or in any attachment. Any views or opinions expressed by the author of this email do not necessarily reflect the views of the University of Nottingham. This message has been checked for viruses but the contents of an attachment may still contain software viruses which could damage your computer system, you are advised to perform your own checks. Email communications with the University of Nottingham may be monitored as permitted by UK legislation.

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Darcs+Pijul Hacking Sprint #11 (May 6th-8th, Helsinki)
by Ganesh Sittampalam 04 Apr '16

04 Apr '16

Dear Hackers, The 11th Darcs Sprint, organised by and jointly with the Pijul team, will be in Helsinki, on Friday May 6th-Sunday May 8th, at Aalto University's startup sauna in the Otaniemi Campus. Please check the details at http://pijul.org/2016/04/02/sprint.html Many thanks to Pierre-Étienne Meunier for organising it. The Darcs planning page is at: http://darcs.net/Sprints/2016-05 Here are three things to know: 1. Everybody is welcome to join us. We'd love to have you, whatever your hacking experience with Pijul or Darcs. Also, if you've got a wacky idea for the future of version control, or a cool use for the Darcs or Pijul libraries, you should join us too. 2. If you're attending please add your name to http://wiki.darcs.net/Sprints/2016-05 3. We may be able to reimburse travel costs (within reason!). Let us know if you'd like a reimbursement, and save your receipts. Many thanks to everybody who participated in our fundraising drives or who gave money on the side. Thanks also to the Software Freedom Conservancy for making fundraising and reimbursements so painless! If you can't join us in person, but you'd like to cheer us on, say hello at http://darcs.net/Donations ! See you next month! Ganesh

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Benchmarking harnesses for a more modern nofib?
by Ryan Newton 04 Apr '16

04 Apr '16

Hi all, Is anyone currently working in, or interested in helping with, a new benchmark suite for Haskell? Perhaps, packaging up existing apps and app benchmarks into a new benchmark suite that gives a broad picture of Haskell application performance today? Background: We run nofib, and we run the shootout benchmarks. But when we want to evaluate basic changes to GHC optimizations or data representation, these really don't give us a full picture of whether a change is beneficial. A few years ago, fibon <https://hackage.haskell.org/package/fibon> tried to gather some Hackage benchmarks. This may work even better with Stackage, where there are 180 benchmark suites among the 1770 packages currently. Also, these days companies are building substantial apps in Hackage. Which substantial apps could or should go into a benchmark suite? I see Warp and other web server benchmarks <http://www.infoq.com/news/2015/04/web-frameworks-benchmark-2015?utm_source=…> all over the web. But is there a harness that can time some of this code while running inside a single-machine, easy-setup benchmark suite? Best, -Ryan

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[ANN] bond-haskell: yet another data serialization library
by Andrey Sverdlichenko 04 Apr '16

04 Apr '16

bond-haskell and bond-haskell-compiler is a pair of packages adding Haskell support to bond serialization framework. Bond is an open source, cross-platform framework for working with schematized data. It supports cross-language serialization/deserialization and powerful generic mechanisms for efficiently manipulating data. It is broadly used at Microsoft in high scale services. For a discussion how Bond compares to similar frameworks (most notably protobufs) see https://microsoft.github.io/bond/why_bond.html Microsoft's bond package or other foreign code is not needed for building or using bond-haskell, all dependencies are published to hackage. For those interested, Microsoft's code is published at https://github.com/Microsoft/bond/

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CFP: Functional High Performance Computing 2016
by David Duke 03 Apr '16

03 Apr '16

====================================================================== CALL FOR PAPERS FHPC 2016 The 5th ACM SIGPLAN Workshop on Functional High-Performance Computing Nara, Japan September 22, 2016 https://sites.google.com/site/fhpcworkshops/ Co-located with the International Conference on Functional Programming (ICFP 2016) Submission Deadline: Friday, 10 June, 2016 (anywhere on earth) ====================================================================== The FHPC workshop aims at bringing together researchers exploring uses of functional (or more generally, declarative or high-level) programming technology in application domains where high performance is essential. The aim of the meeting is to enable sharing of results, experiences, and novel ideas about how high-level, declarative specifications of computationally challenging problems can serve as maintainable and portable code that approaches (or even exceeds) the performance of machine-oriented imperative implementations. All aspects of performance critical programming and parallel programming are in-scope for the workshop, irrespective of hardware target. This includes both traditional large-scale scientific computing (HPC), as well as work targeting single node systems with SMPs, GPUs, FPGAs, or embedded processors. It is becoming apparent that radically new and well founded methodologies for programming such systems are required to address their inherent complexity and to reconcile execution performance with programming productivity. Experience reports are also welcome. Proceedings: ============ FHPC 2016 seeks to encourage a range of submissions, focussing on work in progress and facilitating early exchange of ideas and open discussion on innovative and/or emerging results. To this end submissions should take the form of short (maximum 6 page) papers. Accepted papers will be published by the ACM and will appear in the ACM Digital Library. * Submissions due: Friday, 10 June, 2016 (anywhere on earth) * Author notification: Friday, 8 July, 2016 * Final copy due: Sunday, 31 July, 2016 Submitted papers must be in portable document format (PDF), formatted according to the ACM SIGPLAN style guidelines (2 column, 9pt format). See http://www.sigplan.org/authorInformation.htm for more information and style files. Papers should be no longer than 6 pages. Contributions to FHPC 2016 should be submitted via Easychair, at the following URL: * https://www.easychair.org/conferences/?conf=fhpc16 The FHPC workshops adhere to the ACM SIGPLAN policies regarding programme committee contributions and republication. Any paper submitted must adhere to ACM SIGPLAN's republication policy. PC member submissions are welcome, but will be reviewed to a higher standard. http://www.sigplan.org/Resources/Policies/Review http://www.sigplan.org/Resources/Policies/Republication 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 programme, see its web page (http://www.sigplan.org/PAC.htm) Programme Committee: ==================== David Duke (co-chair) University of Leeds, UK Yukiyoshi Kameyama (co-chair) University of Tsukuba, Japan Baris Aktemur Özyeğin University, Turkey Marco Aldinucci University of Torino, Italy Jost Berthold Commonwealth Bank, Australia Kei Davis Los Alamos National Laboratory, USA Kento Emoto Kyushu Institute of Technology, Japan Zhenjiang Hu National Institute of Informatics, Japan Ben Lippmeier University of New South Wales, Australia Rita Loogen University of Marburg, Germany Geoffrey Mainland Drexel University, USA Mike Rainey INRIA, France Mary Sheeran Chalmers University of Technology, Sweden Satnam Singh Facebook, UK

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ANNOUNCE: fadno-braids 0.0.2
by Stuart Popejoy 03 Apr '16

03 Apr '16

Braids represented as Haskell types with support for generation and transformations. Artin generators, Birman-Ko-Lee band generators, isotopy/Reidemeister moves, rendering via Diagrams. https://hackage.haskell.org/package/fadno-braids-0.0.2 Thanks, Stuart

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Fastest way to calculate all the ways to interleave two lists
by David Feuer 03 Apr '16

03 Apr '16

I ran into a fun question today: http://stackoverflow.com/q/36342967/1477667 Specifically, it asks how to find all ways to interleave lists so that the order of elements within each list is preserved. The most efficient way I found is copied below. It's nicely lazy, and avoids left-nested appends. Unfortunately, it's pretty seriously ugly. Does anyone have any idea of a way to do this that's both efficient and elegant? {-# LANGUAGE BangPatterns #-} import Data.Monoid import Data.Foldable (toList) import Data.Sequence (Seq, (|>)) -- Find all ways to interleave two lists interleave2 :: [a] -> [a] -> [[a]] interleave2 xs ys = interleave2' mempty xs ys [] -- Find all ways to interleave two lists, adding the -- given prefix to each result and continuing with -- a given list to append interleave2' :: Seq a -> [a] -> [a] -> [[a]] -> [[a]] interleave2' !prefix xs ys rest = (toList prefix ++ xs ++ ys) : interleave2'' prefix xs ys rest -- Find all ways to interleave two lists except for -- the trivial case of just appending them. Glom -- the results onto the given list. interleave2'' :: Seq a -> [a] -> [a] -> [[a]] -> [[a]] interleave2'' !prefix [] _ = id interleave2'' !prefix _ [] = id interleave2'' !prefix xs@(x : xs') ys@(y : ys') = interleave2' (prefix |> y) xs ys' . interleave2'' (prefix |> x) xs' ys -- What the question poser wanted; I don't *think* there's -- anything terribly interesting to do here. interleavings :: [[a]] -> [[a]] interleavings = foldr (concatMap . interleave2) [[]] Thanks, David

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