April 2010 - Haskell - Haskell.org

ANNOUNCE: ioctl 0.0.1
by Maciej Piechotka 13 Sep '15

13 Sep '15

A package for type-safe I/O control. Currently only ioctl is supported. Currently simply a extract from my tuntap fork TODO: - Return the integer as well as structure (will break the API) - Port for Windows Network.Socket.IOCtl (as soon as I manage to setup some sane environment on this platform) - Wrapping around DeviceIoControl Example (in hsc): data NotRead = NotRead instance NotRead Int where ioctlReq _ = #const FIONREAD notRead s = ioctlsocket' s NotRead Regards

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Announcing Djinn, version 2004-12-11, a coding wizard
by Lennart Augustsson 07 Apr '11

07 Apr '11

Howdy, y'all! I've written a small program that takes a (Haskell) type and gives you back a function of that type if one exists. It's kind of fun, so I thought I'd share it. It's probably best explained with a sample session. calvin% djinn Welcome to Djinn version 2005-12-11. Type :h to get help. # Djinn is interactive if not given any arguments. # Let's see if it can find the identity function. Djinn> f ? a->a f :: a -> a f x1 = x1 # Yes, that was easy. Let's try some tuple munging. Djinn> sel ? ((a,b),(c,d)) -> (b,c) sel :: ((a, b), (c, d)) -> (b, c) sel ((_, v5), (v6, _)) = (v5, v6) # We can ask for the impossible, but then we get what we # deserve. Djinn> cast ? a->b -- cast cannot be realized. # OK, let's be bold and try some functions that are tricky to write: # return, bind, and callCC in the continuation monad Djinn> type C a = (a -> r) -> r Djinn> returnC ? a -> C a returnC :: a -> C a returnC x1 x2 = x2 x1 Djinn> bindC ? C a -> (a -> C b) -> C b bindC :: C a -> (a -> C b) -> C b bindC x1 x2 x3 = x1 (\ c15 -> x2 c15 (\ c17 -> x3 c17)) Djinn> callCC ? ((a -> C b) -> C a) -> C a callCC :: ((a -> C b) -> C a) -> C a callCC x1 x2 = x1 (\ c15 _ -> x2 c15) (\ c11 -> x2 c11) # Well, poor Djinn has a sweaty brow after deducing the code # for callCC so we had better quit. Djinn> :q Bye. To play with Djinn do a darcs get http://darcs.augustsson.net/Darcs/Djinn or get http://darcs.augustsson.net/Darcs/Djinn/Djinn.tar.gz Then just type make. (You need a Haskell 98 implementation and some libraries.) And then start djinn. For the curious, Djinn uses a decision procedure for intuitionistic propositional calculus due to Roy Dyckhoff. It's a variation of Gentzen's LJ system. This means that (in theory) Djinn will always find a function if one exists, and if one doesn't exist Djinn will terminate telling you so. This is the very first version, so expect bugs. :) Share and enjoy. -- Lennart

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ANN: scan-0.1.0.3, a Haskell style scanner
by Christian Maeder 03 Aug '10

03 Aug '10

Dear Haskell friends, I like to announce a Haskell style scanner at http://hackage.haskell.org/package/scan documented under http://projects.haskell.org/style-scanner/ It's best used in conjunction with hlint http://community.haskell.org/~ndm/hlint/ and gives many suggestions regarding the file format. Feedback is welcome. Thanks Christian (Discussions should only be posted to either haskell-cafe@ or beginners@)

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Parallel Haskell: 2-year project to push real world use
by Duncan Coutts 30 Apr '10

30 Apr '10

GHC HQ and Well-Typed are very pleased to announce a 2-year project funded by Microsoft Research to push the real-world adoption and practical development of parallel Haskell with GHC. We are seeking organisations to take part: read on for details. In the last few years GHC has gained impressive support for parallel programming on commodity multi-core systems. In addition to traditional threads and shared variables, it supports pure parallelism, software transactional memory (STM), and data parallelism. With much of this research and development complete, and more on the way, the next stage is to get the technology into more widespread use. This project aims to do the engineering work to solve whatever remaining practical problems are blocking organisations from making serious use of parallelism with GHC. The driving force will be the *applications* rather than the *technology*. We will work in partnership with a small number of commercial or scientific users who are keen to make use of parallel Haskell. We will work with these partners to identify the issues, major or minor, that are hindering progress. The project is prepared to handle system issues, covering everything from compiler and runtime system through to more mundane platform and tool problems. Meanwhile our partners will contribute their domain-specific expertise to use parallel Haskell to address their application. We are now seeking organisations to take part in this project. Organisations do not need to contribute financially but should be prepared to make a significant commitment of their own time. We expect to get final confirmation of the project funding in June and to start work shortly thereafter. Well-Typed will coordinate the project, working directly with both the participating organisations and the Simons at GHC HQ. If you think your organisation may be interested then get in touch with me, Duncan Coutts, via info(a)well-typed.com. -- Duncan Coutts, Haskell Consultant Well-Typed LLP, http://www.well-typed.com/

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REMINDER: Haskell Communities and Activities Report
by Janis Voigtländer 30 Apr '10

30 Apr '10

Dear all, It is not yet too late to contribute to the 18th edition of HCAR. If you haven't already, please write an entry for your new project or update your old entry, and send to me this weekend or early next week. More information about format etc. can be found in the original call: http://www.haskell.org/pipermail/haskell/2010-April/022012.html I am looking forward to receiving your contributions, Janis (current editor) -- Jun.-Prof. Dr. Janis Voigtländer http://www.iai.uni-bonn.de/~jv/ mailto:jv@iai.uni-bonn.de

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Final call for participation: Summer school "Applied Functional Programming", Aug 16-27, Utrecht NL, Application deadline: May 1
by Andres Loeh 27 Apr '10

27 Apr '10

[Feel free to advertise the school to others who might be interested.] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Utrecht Summer School in Computer Science: Applied Functional Programming August 16-27, 2010 Utrecht, The Netherlands ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The summer school is intended as a first or an advanced course on Haskell, consisting of lectures and projects to be solved by the participants, working in teams. We mainly target bachelor and master students, but others who are interested are also welcome to apply. The deadline for applications is *** Saturday, May 1, 2010 ***. More information: http://www.cs.uu.nl/wiki/USCS2010 If you have any questions, feel free to contact me. Cheers, Andres -- Andres Loeh, Universiteit Utrecht mailto:andres@cs.uu.nl mailto:mail@andres-loeh.de http://www.andres-loeh.de

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ANNOUNCE: GHC version 6.12.2
by Ian Lynagh 27 Apr '10

27 Apr '10

============================================================== The (Interactive) Glasgow Haskell Compiler -- version 6.12.2 ============================================================== The GHC Team is pleased to announce a new patchlevel release of GHC. This release contains a number of bugfixes relative to 6.12.1, so we recommend upgrading. Release notes are here: http://haskell.org/ghc/docs/6.12.1/html/users_guide/release-6-12-2.html How to get it ~~~~~~~~~~~~~ The easy way is to go to the web page, which should be self-explanatory: http://www.haskell.org/ghc/ We supply binary builds in the native package format for many platforms, and the source distribution is available from the same place. Packages will appear as they are built - if the package for your system isn't available yet, please try again later. Background ~~~~~~~~~~ Haskell is a standard lazy functional programming language; the current language version is Haskell 98, agreed in December 1998 and revised December 2002. GHC is a state-of-the-art programming suite for Haskell. Included is an optimising compiler generating good code for a variety of platforms, together with an interactive system for convenient, quick development. The distribution includes space and time profiling facilities, a large collection of libraries, and support for various language extensions, including concurrency, exceptions, and foreign language interfaces (C, whatever). GHC is distributed under a BSD-style open source license. A wide variety of Haskell related resources (tutorials, libraries, specifications, documentation, compilers, interpreters, references, contact information, links to research groups) are available from the Haskell home page (see below). On-line GHC-related resources ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Relevant URLs on the World-Wide Web: GHC home page http://www.haskell.org/ghc/ GHC developers' home page http://hackage.haskell.org/trac/ghc/ Haskell home page http://www.haskell.org/ Supported Platforms ~~~~~~~~~~~~~~~~~~~ The list of platforms we support, and the people responsible for them, is here: http://hackage.haskell.org/trac/ghc/wiki/Contributors Ports to other platforms are possible with varying degrees of difficulty. The Building Guide describes how to go about porting to a new platform: http://hackage.haskell.org/trac/ghc/wiki/Building Developers ~~~~~~~~~~ We welcome new contributors. Instructions on accessing our source code repository, and getting started with hacking on GHC, are available from the GHC's developer's site run by Trac: http://hackage.haskell.org/trac/ghc/ Mailing lists ~~~~~~~~~~~~~ We run mailing lists for GHC users and bug reports; to subscribe, use the web interfaces at http://www.haskell.org/mailman/listinfo/glasgow-haskell-users http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs There are several other haskell and ghc-related mailing lists on www.haskell.org; for the full list, see http://www.haskell.org/mailman/listinfo/ Some GHC developers hang out on #haskell on IRC, too: http://www.haskell.org/haskellwiki/IRC_channel Please report bugs using our bug tracking system. Instructions on reporting bugs can be found here: http://www.haskell.org/ghc/reportabug

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CFP: Haskell meeting in Leipzig/Germany, June 4
by Johannes Waldmann 27 Apr '10

27 Apr '10

This is the fifth in our series of yearly local meetings. For the full announcement, see: http://www.iba-cg.de/hal5.html . If you want to give a tutorial, or a technical talk, email the programme committee (details on web page). We will also compile a list of "most wanted" topics for tutorials and talks. The primary language is German but we can switch to English if requested/agreed upon by audience and speaker. Best regards, Johannes Waldmann, HTWK Leipzig.

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ANN: operational-0.2.0.0
by Heinrich Apfelmus 26 Apr '10

26 Apr '10

Dear Haskellers, I'm pleased to announce the *release* of operational-0.2.0.0 , a tiny library for implementing monads by specifying their operational semantics. This library is based on "The Operational Monad Tutorial", first published in Issue 15 on The Monad.Reader. http://themonadreader.wordpress.com/2010/01/26/issue-15/ The *main abstraction* is a type Program corresponding to a list of primitive instructions which are then interpreted with operational semantics given by the user; the monad laws hold automatically. Monad transformers can also be implemented and will automatically satisfy the lifting laws. The library comes with *excessive documentation*, including a proof of the monad laws. Elaborate example code demonstrates previously difficult to implement monads, like a CGI monad that models a web session but does not require the CGI script to run in a persistent process. The newest addition is a program for playing tic-tac-toe that demonstrates a monad for implementing different players, like humans or AI. *Get it* from hackage http://hackage.haskell.org/package/operational or browse the project website and documentation http://projects.haskell.org/operational/ Changes ------- version 0.1.0.0 -> version 0.2.0.0 * changed name of view type to `ProgramView` * added instances for mtl classes * new function `liftProgram` to embed `Program` in `ProgramT` * new example TicTacToe.hs * various documentation updates Regards, Heinrich Apfelmus -- http://apfelmus.nfshost.com

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ANNOUNCE: graphviz 2999.9.0.0
by Ivan Lazar Miljenovic 26 Apr '10

26 Apr '10

I'm pleased to announce the latest version of my graphviz library that provides Haskell bindings to the Graphviz graph visualisation suite. There are numerous changes in this release, the most important of which are: * graphviz now has an FAQ and an improved README as well as its own homepage: http://projects.haskell.org/graphviz/ (as prompted by Eric Kow). * Add support for record labels; values are automatically escaped/unescaped. The `Record` and `MRecord` shapes have been added for use with these labels. Requested by Minh Thu and Eric Kow. * Add support for HTML-like values (this replaces the wrong and completely broken URL datatype). Strings are automatically escaped/unescaped. * Various parsing improvements (including a slight parsing speed increase!). In particular, graphviz is now able to parse almost all Dot graphs found on my system (including samples shipped with Graphviz, Linux kernel documentation and various other package documentations). A list of the breakages and why: * /usr/share/sgml/docbook/xsl-stylesheets/roundtrip/template.dot seems to be a binary file and thus can't be read. * /usr/share/graphviz/graphs/directed/Latin1.gv uses Latin1 encoding; at the moment graphviz uses the system's locale encoding (or whatever GHC < 6.10 defaults to). * /usr/share/doc/boost-*/html/libs/graph/example/graphviz_test.dot (various boost versions) has subgraphs in edges; graphviz currently can't cope with these. * /usr/src/linux-2.6.33-gentoo-r1/Documentation/blockdev/drbd/drbd-connection-state-overview.dot uses incorrect syntax for the "minlen" attribute (it is meant to be an integer but actually contains a floating point value). The plans for the next release (which I don't plan on even starting for a while) are to focus on improving printing and parsing performance, using a state-based printer and parser (as part of Dot syntax is state-based) and force usage of UTF-8 (via text or utf8-string). -- Ivan Lazar Miljenovic Ivan.Miljenovic(a)gmail.com IvanMiljenovic.wordpress.com

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