February 2008 - Haskell

please HELP me to understand this code:| quickly:((
by xxxyyyzzz 13 Feb '08

13 Feb '08

(tomorrow I have an exam :|..and I really don't like what I see:P ) http://www.nabble.com/file/p15443214/haskell.jpg -- View this message in context: http://www.nabble.com/please-HELP-me-to-understand-this-code%3A%7C-quickly%… Sent from the Haskell - Haskell mailing list archive at Nabble.com.

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Unifying Theories of Programming 2008 - call for papers
by Andrew Butterfield 13 Feb '08

13 Feb '08

CALL FOR PAPERS Unifying Theories of Programming 2008 Trinity College, Dublin, Ireland September 8th--10th, 2008 https://www.cs.tcd.ie/utp08/ mailto:utp08@easychair.org Important Dates --------------- Full Paper Submission 14th April Author Notification 26th May Final Paper 16th June Symposium 8th-10th September Following on the success of the first International Symposium on Unifying Theories of Programming (UTP) held at Walworth Castle in 2006, we are pleased to announce the second, to be held in Dublin in September 2008. Based on the pioneering work on unifying theories of programming of Tony Hoare, He Jifeng, and others, the aims of this Symposium series are to continue to reaffirm the significance of the ongoing UTP project, to encourage efforts to advance it by providing a focus for the sharing of results by those already actively contributing, and to raise awareness of the benefits of such unifying theoretical frameworks among the wider computer science and software engineering communities. Of particular interest is how unification may be used to meet the goals and difficulties to be encountered in the Grand Challenges of Computing, with particular reference to the UK's "GC6: Dependable Systems Evolution", its international cousin the "Verified Software Initiative", and their plan to develop a Verified Software Repository. To this end the Symposium welcomes contributions on the above themes as well as others which can be related to them. Such additional themes include, but are not limited to, relational semantics, relational algebra, healthiness conditions, normal forms, linkage of theories, algebraic descriptions, incorporation of probabilistic programming, timed calculi and object-based descriptions, as well as alternative programming paradigms such as functional, logical, data-flow, and beyond. In all cases, the UTP approach should be compared and advantages/disadvantages discussed. The proceedings of the first symposium was published by Springer as LNCS Volume 4010 and we are currently in negotiation with Springer for the second. Some of the best papers were revised and have been accepted for publication in a forthcoming special issue of Formal Aspects of Computing, and we are planning to have a special journal issue for the 2008 symposium as well. Papers may be up to 20 pages (single-column) in length and should ideally be prepared using LaTeX in LNCS format (http://www.springer.de/comp/lncs/authors.html) and submitted as pdf files no later than 14th April 2008. Paper submission and reviewing will be handled by EasyChair (http://www.easychair.org/conferences/?conf=UTP-08) This site will be open for submissions from April 7th. Invited Speakers ---------------- Jifeng He, East China Normal University, Shanghai, China Ralph-Johan Back, Abo Akademi University, Finland. Program Committee ----------------- Bernhard Aichernig, Graz University of Technology, Austria Andrew Butterfield (Chair), Trinity College Dublin, Ireland Ana Cavalcanti, University of York, UK Yifeng Chen, University of Durham, UK Steve Dunne, University of Teesside, UK Colin Fidge, Queensland University of Technology, Brisbane, Australia Jeremy Gibbons, University of Oxford, UK Lindsay Groves, Victoria University of Wellington, New Zealand Ian Hayes, University of Queensland, Australia Rick Hehner, University of Toronto, Canada Martin Henson, University of Essex, UK Arthur Hughes, Trinity College Dublin, Ireland Zhiming Liu, United Nations University, Macau David Naumann, Stevens Institute of Technology, New Jersey, US Shengchao Qin, University of Durham, UK Augusto Sampaio, Universidade Federal de Pernambuco, Brazil Jim Woodcock, University of York, UK Huibiao Zhu, East China Normal University, Shanghai, China Local Organisation ------------------ Andrew Butterfield, Arthur Hughes Pawel Gancarski -- -------------------------------------------------------------------- Andrew Butterfield Tel: +353-1-896-2517 Fax: +353-1-677-2204 Foundations and Methods Research Group Director. Course Director, B.A. (Mod.) in CS and ICT degrees, Year 4. Department of Computer Science, Room F.13, O'Reilly Institute, Trinity College, University of Dublin, Ireland. http://www.cs.tcd.ie/Andrew.Butterfield/ --------------------------------------------------------------------

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ANNOUNCE: multiset 0.1
by Twan van Laarhoven 12 Feb '08

12 Feb '08

Hello, I have just uploaded version 0.1 of the multiset library to hackage. This package provides Data.MultiSet and Data.IntMultiSet modules. A multiset or bag is like a set, but it can contain multiple copies of the same element. The library is already pretty much finished, maybe I should have called it 1.0. It implements the same interface as Data.Set, with some additional functions specific to multisets. Hackage: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/multiset-0.1 Haddock: http://twan.home.fmf.nl/multiset/doc/ Darcs: http://twan.home.fmf.nl/repos/multiset/ Twan

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Announce: Melbourne Functional Programming Union
by Bernie Pope 12 Feb '08

12 Feb '08

Hello Haskellers, After a few years hiatus, I'm pleased to announce that the Melbourne Functional Programming Union (FPU) is back. What is the FPU? It is a group of people who are interested in all things functional programming. We hold regular informal talks, and have friendly discussions afterwards. We are situated at the University of Melbourne (Australia), but the Union is open to all comers. Obviously it helps if you live near this part of the World. To give you an idea of the kinds of things we talk about, here is a list of our most recent topics: - the GHCi debugger - Arrows for parser combinators - a curious stack overflow in Haskell - a demonstration of Coq - deriving monads from vague ideas in several easy steps (this coming Friday) Here is our old outdated web page for historical reference: http://www.cs.mu.oz.au/fpu/ A new page is under construction. At the moment, talks are held on Fridays, 1-2pm, in the ICT Building at Melbourne Uni. Contact Bernie Pope if you are interested in participating in the FPU.

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Haskell Weekly News - February 10, 2008
by Don Stewart 11 Feb '08

11 Feb '08

--------------------------------------------------------------------------- Haskell Weekly News Issue 69 - February 10, 2008 --------------------------------------------------------------------------- Welcome to issue 69 of HWN, a newsletter covering developments in the [1]Haskell community. A quick update HWN this week, with a gazillion new libraries on Hackage. (> 150 new and updated libs!) 1. http://haskell.org/ Hackage New and updated libraries in [2]the Hackage library database. 2. http://hackage.haskell.org/ * WordNet 0.1.1. Uploaded by Max Rabkin. [3]WordNet: Haskell interface to the WordNet database. * lazysmallcheck 0.1. Uploaded by Gwern Branwen. [4]lazysmallcheck: A library for demand-driven testing of Haskell programs. * DrIFT 2.2.3. Uploaded by Gwern Branwen. [5]DrIFT: Program to derive type class instances. * highlighting-kate 0.2. Uploaded by John MacFarlane. [6]highlighting-kate: Syntax highlighting. * leksah 0.1. Uploaded by Juergen NicklischFranken. [7]leksah: Genuine Haskell Face. * frag 1.1. Uploaded by Gwern Branwen. [8]frag: 3-D First Person Shooter (FPS). * GoogleChart 0.2. Uploaded by Evan Martin. [9]GoogleChart: Generate web-based charts using the Google Chart API. * HFuse 0.1. Uploaded by Gwern Branwen. [10]HFuse: HFuse is a binding for the Linux FUSE library. * GoogleChart 0.1. Uploaded by Evan Martin. [11]GoogleChart: Generate web-based charts using the Google Chart API. * Finance-Quote-Yahoo 0.5.0. Uploaded by Brad Clawsie. [12]Finance-Quote-Yahoo: Obtain quote data from finance.yahoo.com. 3. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/WordNet-0.1.1 4. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/lazysmallcheck-0… 5. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/DrIFT-2.2.3 6. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/highlighting-kat… 7. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/leksah-0.1 8. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/frag-1.1 9. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/GoogleChart-0.2 10. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HFuse-0.1 11. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/GoogleChart-0.1 12. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Finance-Quote-Ya… * binary-strict 0.3.0. Uploaded by Adam Langley. [13]binary-strict: Binary deserialisation using strict ByteStrings. * Stream 0.2.3. Uploaded by Wouter Swierstra. [14]Stream: A library for manipulating infinite lists.. * Finance-Treasury 0.1.1. Uploaded by Stephen Lihn. [15]Finance-Treasury: Obtain Treasury yield curve data. * Hedi 0.1. Uploaded by Paolo Veronelli. [16]Hedi: Line oriented editor. * newports 1.1. Uploaded by Brad Clawsie. [17]newports: List ports newer than N days on a FreeBSD system. * Finance-Treasury 0.1. Uploaded by Stephen Lihn. [18]Finance-Treasury: Obtain Treasury yield curve data. * GPLib 0.0. Uploaded by Gwern Branwen. [19]GPLib: Generic library for genetic programming. * nano-hmac 0.1.1. Uploaded by Hitesh Jasani. [20]nano-hmac: Bindings to OpenSSL HMAC.. * multiset 0.1. Uploaded by Twan VanLaarhoven. [21]multiset: The Data.MultiSet container type. * hpodder 1.1.0. Uploaded by John Goerzen. [22]hpodder: Podcast Aggregator (downloader). 13. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/binary-strict-0.… 14. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Stream-0.2.3 15. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Finance-Treasury… 16. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Hedi-0.1 17. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/newports-1.1 18. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Finance-Treasury… 19. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/GPLib-0.0 20. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/nano-hmac-0.1.1 21. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/multiset-0.1 22. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hpodder-1.1.0 * bimap 0.2.1. Uploaded by Stuart Cook. [23]bimap: Bidirectional mapping between two key types. * monadLib 3.4.4. Uploaded by Iavor Diatchki. [24]monadLib: A collection of monad transformers.. * IOSpec 0.2. Uploaded by Wouter Swierstra. [25]IOSpec: A pure specification of the IO monad.. * bimap 0.2. Uploaded by Stuart Cook. [26]bimap: Bidirectional mapping between two key types. * strictify 0.1. Uploaded by Sterling Clover. [27]strictify: Find a local optimum of strictness annotations.. * heap 0.2.2. Uploaded by Stephan Friedrichs. [28]heap: Heaps in Haskell. * LDAP 0.6.4. Uploaded by John Goerzen. [29]LDAP: Haskell binding for C LDAP API. * HStringTemplate 0.2. Uploaded by Sterling Clover. [30]HStringTemplate: StringTemplate implementation in Haskell.. * RJson 0.3.2. Uploaded by Alex Drummond. [31]RJson: A reflective JSON serializer/parser.. * network-dns 0.1.1. Uploaded by Adam Langley. [32]network-dns: A pure Haskell, asyncronous DNS client library. 23. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/bimap-0.2.1 24. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/monadLib-3.4.4 25. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/IOSpec-0.2 26. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/bimap-0.2 27. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/strictify-0.1 28. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/heap-0.2.2 29. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/LDAP-0.6.4 30. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HStringTemplate-… 31. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/RJson-0.3.2 32. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/network-dns-0.1.1 * lcs 0.2. Uploaded by Ian Lynagh. [33]lcs: Find longest common sublist of two lists. * tracker 0.1. Uploaded by Will Thompson. [34]tracker: Client library for Tracker metadata database, indexer and search tool. * CC-delcont 0.2. Uploaded by Dan Doel. [35]CC-delcont: Delimited continuations and dynamically scoped variables. * control-timeout 0.1.2. Uploaded by Adam Langley. [36]control-timeout: Timeout handling. * network-dns 0.1. Uploaded by Adam Langley. [37]network-dns: A pure Haskell, asyncronous DNS client library. * binary-strict 0.2.4. Uploaded by Adam Langley. [38]binary-strict: Binary deserialisation using strict ByteStrings. * heap 0.1.1. Uploaded by Stephan Friedrichs. [39]heap: Heaps in Haskell. * HCL 1.3. Uploaded by Justin Bailey. [40]HCL: High-level library for building command line interfaces.. * yi 0.3. Uploaded by Jean PhilippeBernardy. [41]yi: The Haskell-Scriptable Editor. * binary-strict 0.2.3. Uploaded by Adam Langley. [42]binary-strict: Binary deserialisation using strict ByteStrings. 33. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/lcs-0.2 34. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/tracker-0.1 35. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/CC-delcont-0.2 36. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/control-timeout-… 37. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/network-dns-0.1 38. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/binary-strict-0.… 39. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/heap-0.1.1 40. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HCL-1.3 41. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/yi-0.3 42. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/binary-strict-0.… * heap 0.1. Uploaded by Stephan Friedrichs. [43]heap: Heaps in Haskell. * pureMD5 0.1.2. Uploaded by Thomas DuBuisson. [44]pureMD5: MD5 implementations that should become part of a ByteString Crypto package.. * RJson 0.3.1. Uploaded by Alex Drummond. [45]RJson: A reflective JSON serializer/parser.. * template 0.1.1.1. Uploaded by Johan Tibell. [46]template: Simple string substitution. * network-bytestring 0.1.1.1. Uploaded by Johan Tibell. [47]network-bytestring: Fast and memory efficient low-level networking. * ftphs 1.0.4. Uploaded by John Goerzen. [48]ftphs: FTP Client and Server Library. * mersenne-random-pure64 0.1.1. Uploaded by Donald Stewart. [49]mersenne-random-pure64: Generate high quality pseudorandom numbers purely using a Mersenne Twister. * Diff 0.1. Uploaded by Sterling Clover. [50]Diff: O(ND) diff algorithm in haskell.. * crack 0.1. Uploaded by Trevor Elliott. [51]crack: A haskell binding to cracklib. * miniplex 0.3.3. Uploaded by Lukas Mai. [52]miniplex: simple 1-to-N interprocess communication. 43. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/heap-0.1 44. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/pureMD5-0.1.2 45. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/RJson-0.3.1 46. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/template-0.1.1.1 47. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/network-bytestri… 48. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/ftphs-1.0.4 49. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/mersenne-random-… 50. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Diff-0.1 51. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/crack-0.1 52. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/miniplex-0.3.3 * colock 0.2.2. Uploaded by Lukas Mai. [53]colock: thread-friendly file locks that don't block the entire program. * mersenne-random-pure64 0.1. Uploaded by Donald Stewart. [54]mersenne-random-pure64: Generate high quality pseudorandom numbers purely using a Mersenne Twister. * network-rpca 0.0.1. Uploaded by Adam Langley. [55]network-rpca: A cross-platform RPC library. * xmonad-contrib 0.6. Uploaded by Spencer Janssen. [56]xmonad-contrib: Third party extensions for xmonad. * xmonad 0.6. Uploaded by Spencer Janssen. [57]xmonad: A tiling window manager. * codec-libevent 0.1.2. Uploaded by Adam Langley. [58]codec-libevent: Cross-platform structure serialisation. * bytestringparser 0.3. Uploaded by Bryan OSullivan. [59]bytestringparser: Combinator parsing with Data.ByteString.Lazy. * HStringTemplate 0.2. Uploaded by Sterling Clover. [60]HStringTemplate: StringTemplate implementation in Haskell.. * value-supply 0.1. Uploaded by Iavor Diatchki. [61]value-supply: A library for generating values without having to thread state.. * derive 0.1.1. Uploaded by Neil Mitchell. [62]derive: A program and library to derive instances for data types. 53. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/colock-0.2.2 54. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/mersenne-random-… 55. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/network-rpca-0.0… 56. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/xmonad-contrib-0… 57. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/xmonad-0.6 58. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/codec-libevent-0… 59. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/bytestringparser… 60. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HStringTemplate-… 61. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/value-supply-0.1 62. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/derive-0.1.1 * control-timeout 0.1.1. Uploaded by Adam Langley. [63]control-timeout: Timeout handling. * mkcabal 0.4.1. Uploaded by Donald Stewart. [64]mkcabal: Generate cabal files for a Haskell project. * regexpr 0.2.9. Uploaded by Yoshikuni Jujo. [65]regexpr: regular expression like Perl/Ruby in Haskell. * mtlparse 0.0.0.5. Uploaded by Yoshikuni Jujo. [66]mtlparse: parse library use mtl package. * cgi 3001.1.5.2. Uploaded by Bjorn Bringert. [67]cgi: A library for writing CGI programs. * xhtml 3000.0.2.2. Uploaded by Bjorn Bringert. [68]xhtml: An XHTML combinator library. * harpy 0.4. Uploaded by Martin Grabmueller. [69]harpy: Runtime code generation for x86 machine code. * editline 0.2. Uploaded by Judah Jacobson. [70]editline: Bindings to the editline library (libedit).. * hmatrix 0.2.0.0. Uploaded by Alberto Ruiz. [71]hmatrix: Linear algebra and numerical computations. * regexpr 0.2.8. Uploaded by Yoshikuni Jujo. [72]regexpr: regular expression like Perl/Ruby in Haskell. 63. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/control-timeout-… 64. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/mkcabal-0.4.1 65. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/regexpr-0.2.9 66. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/mtlparse-0.0.0.5 67. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/cgi-3001.1.5.2 68. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/xhtml-3000.0.2.2 69. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/harpy-0.4 70. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/editline-0.2 71. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hmatrix-0.2.0.0 72. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/regexpr-0.2.8 * pcre-light 0.3. Uploaded by Donald Stewart. [73]pcre-light: A small, efficient and portable regex library for Perl 5 compatible regular expressions. * mersenne-random 0.1. Uploaded by Donald Stewart. [74]mersenne-random: Generate high quality pseudorandom numbers using a SIMD Fast Mersenne Twister. * AvlTree 2.4. Uploaded by Adrian Hey. [75]AvlTree: Balanced binary trees using AVL algorithm.. * fec 0.1.1. Uploaded by Adam Langley. [76]fec: Forward error correction of ByteStrings. * COrdering 2.1. Uploaded by Adrian Hey. [77]COrdering: An algebraic data type similar to Prelude Ordering.. * i18n 0.3. Uploaded by Eugene Grigoriev. [78]i18n: Internationalization for Haskell. * binary-strict 0.2.2. Uploaded by Adam Langley. [79]binary-strict: Binary deserialisation using strict ByteStrings. * regexpr 0.2.6. Uploaded by Yoshikuni Jujo. [80]regexpr: regular expression like Perl/Ruby in Haskell. * RJson 0.2. Uploaded by Alex Drummond. [81]RJson: A reflective JSON serializer/parser.. * regexpr 0.2.5. Uploaded by Yoshikuni Jujo. [82]regexpr: regular expression like Perl/Ruby in Haskell. 73. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/pcre-light-0.3 74. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/mersenne-random-… 75. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/AvlTree-2.4 76. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/fec-0.1.1 77. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/COrdering-2.1 78. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/i18n-0.3 79. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/binary-strict-0.… 80. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/regexpr-0.2.6 81. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/RJson-0.2 82. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/regexpr-0.2.5 * fec 0.1. Uploaded by Adam Langley. [83]fec: Forward error correction of ByteStrings. * dataenc 0.10.2. Uploaded by Magnus Therning. [84]dataenc: Data encoding library. * regexpr 0.2.3. Uploaded by Yoshikuni Jujo. [85]regexpr: regular expression like Perl/Ruby in Haskell. * regexpr 0.2.2. Uploaded by Yoshikuni Jujo. [86]regexpr: regular expression like Perl/Ruby in Haskell. * reactive 0.3. Uploaded by Conal Elliott. [87]reactive: Simple foundation for functional reactive programming. * regexpr 0.2.1. Uploaded by Yoshikuni Jujo. [88]regexpr: regular expression like Perl/Ruby in Haskell. * djinn 2008.1.18. Uploaded by Lennart Augustsson. [89]djinn: Generate Haskell code from a type. * Etherbunny 0.3. Uploaded by Nicholas Burlett. [90]Etherbunny: A network analysis toolkit for Haskell. * regexpr 0.2.0. Uploaded by Yoshikuni Jujo. [91]regexpr: regular expression like Perl/Ruby in Haskell. * RJson 0.1. Uploaded by Alex Drummond. [92]RJson: A reflective JSON serializer/parser.. 83. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/fec-0.1 84. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/dataenc-0.10.2 85. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/regexpr-0.2.3 86. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/regexpr-0.2.2 87. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/reactive-0.3 88. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/regexpr-0.2.1 89. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/djinn-2008.1.18 90. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Etherbunny-0.3 91. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/regexpr-0.2.0 92. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/RJson-0.1 * regexpr 0.1.7. Uploaded by Yoshikuni Jujo. [94]regexpr: regular expression like Perl/Ruby in Haskell. * reactive 0.2. Uploaded by Conal Elliott. [95]reactive: Simple foundation for functional reactive programming. * srcinst 0.8.10. Uploaded by John Goerzen. [96]srcinst: Build and install Debian packages completely from source. * dfsbuild 1.0.2. Uploaded by John Goerzen. [97]dfsbuild: Build Debian From Scratch CD/DVD images. * darcs-buildpackage 0.5.12. Uploaded by John Goerzen. [98]darcs-buildpackage: Tools to help manage Debian packages with Darcs. * anydbm 1.0.5. Uploaded by John Goerzen. [99]anydbm: Interface for DBM-like database systems. * HDBC-sqlite3 1.1.4.0. Uploaded by John Goerzen. [100]HDBC-sqlite3: Sqlite v3 driver for HDBC. * HDBC-postgresql 1.1.4.0. Uploaded by John Goerzen. [101]HDBC-postgresql: PostgreSQL driver for HDBC. * HDBC-odbc 1.1.4.0. Uploaded by John Goerzen. [102]HDBC-odbc: ODBC driver for HDBC. 94. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/regexpr-0.1.7 95. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/reactive-0.2 96. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/srcinst-0.8.10 97. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/dfsbuild-1.0.2 98. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/darcs-buildpacka… 99. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/anydbm-1.0.5 100. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HDBC-sqlite3-1.1… 101. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HDBC-postgresql-… 102. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HDBC-odbc-1.1.4.0 * magic 1.0.7. Uploaded by John Goerzen. [103]magic: Interface to C file/magic library. * ListLike 1.0.1. Uploaded by John Goerzen. [104]ListLike: Generic support for list-like structures. * LDAP 0.6.3. Uploaded by John Goerzen. [105]LDAP: Haskell binding for C LDAP API. * hg-buildpackage 1.0.4. Uploaded by John Goerzen. [106]hg-buildpackage: Tools to help manage Debian packages with Mercurial. * HDBC 1.1.4. Uploaded by John Goerzen. [107]HDBC: Haskell Database Connectivity. * HSH 1.2.5. Uploaded by John Goerzen. [108]HSH: Library to mix shell scripting with Haskell programs. * editline 0.1. Uploaded by Judah Jacobson. [109]editline: Bindings to the editline library (libedit).. * pureMD5 0.1.1. Uploaded by Thomas DuBuisson. [110]pureMD5: MD5 implementations that should become part of a ByteString Crypto package.. * hmp3 1.4. Uploaded by Donald Stewart. [111]hmp3: An ncurses mp3 player written in Haskell. * binary-strict 0.2.1. Uploaded by Adam Langley. [112]binary-strict: Binary deserialisation using strict ByteStrings. 103. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/magic-1.0.7 104. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/ListLike-1.0.1 105. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/LDAP-0.6.3 106. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hg-buildpackage-… 107. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HDBC-1.1.4 108. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HSH-1.2.5 109. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/editline-0.1 110. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/pureMD5-0.1.1 111. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hmp3-1.4 112. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/binary-strict-0.… * GLFW 0.3. Uploaded by Paul Liu. [113]GLFW: A binding for GLFW, An OpenGL Framework. * hbeat 0.1.1. Uploaded by Tim Docker. [114]hbeat: A simple step sequencer GUI.. * hackage2hwn 0.2.1. Uploaded by Donald Stewart. [115]hackage2hwn: Convert hackage = Hackage RSS feeds to Haskell Weekly News format. * tagsoup 0.4. Uploaded by Neil Mitchell. [116]tagsoup: Parsing and extracting information from (possibly malformed) HTML documents. * HaXml 1.19.2. Uploaded by Malcolm Wallace. [117]HaXml: Utilities for manipulating XML documents. * Emping 0.3.1. Uploaded by Hans VanThiel. [118]Emping: derives heuristic rules from nominal data. * hbeat 0.1. Uploaded by Tim Docker. [119]hbeat: A simple step sequencer GUI.. * Imlib 0.1.1. Uploaded by Cale Gibbard. [120]Imlib: Added by CaleGibbard, Sun Jan 13 22:26:59 PST 2008.. * pcre-light 0.2. Uploaded by Donald Stewart. [121]pcre-light: A small, efficient and portable regex library for Perl 5 compatible regular expressions. * YamlReference 0.8. Uploaded by Oren BenKiki. [122]YamlReference: YAML reference implementation. 113. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/GLFW-0.3 114. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hbeat-0.1.1 115. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hackage2hwn-0.2.1 116. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/tagsoup-0.4 117. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HaXml-1.19.2 118. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Emping-0.3.1 119. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hbeat-0.1 120. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Imlib-0.1.1 121. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/pcre-light-0.2 122. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/YamlReference-0.8 * ContArrow 0.0.4. Uploaded by Evgeny Jukov. [123]ContArrow: Control.Arrow.Transformer.Cont. * ContArrow 0.0.3. Uploaded by Evgeny Jukov. [124]ContArrow: Control.Arrow.Transformer.Cont. * mkcabal 0.4. Uploaded by Donald Stewart. [125]mkcabal: Generate cabal files for a Haskell project. * pcre-light 0.1. Uploaded by Donald Stewart. [126]pcre-light: A lightweight binding to PCRE. * YamlReference 0.7. Uploaded by Oren BenKiki. [127]YamlReference: YAML reference implementation. * Crypto 4.1.0. Uploaded by Dominic Steinitz. [128]Crypto: DES, Blowfish, AES, TEA, SHA1, MD5, RSA, BubbleBabble, Hexdump, Support for Word128, Word192 and Word256 and Beyond, PKCS5 Padding, Various Encryption Modes e.g. Cipher Block Chaining all in one package.. * containers 0.1.0.1. Uploaded by Ross Paterson. [129]containers: Assorted concrete container types. * ConfigFile 1.0.4. Uploaded by John Goerzen. [130]ConfigFile: Configuration file reading & writing. * MissingH 1.0.0. Uploaded by John Goerzen. [131]MissingH: Large utility library. * hslogger 1.0.4. Uploaded by John Goerzen. [132]hslogger: Versatile logging framework. 123. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/ContArrow-0.0.4 124. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/ContArrow-0.0.3 125. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/mkcabal-0.4 126. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/pcre-light-0.1 127. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/YamlReference-0.7 128. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Crypto-4.1.0 129. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/containers-0.1.0… 130. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/ConfigFile-1.0.4 131. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/MissingH-1.0.0 132. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hslogger-1.0.4 * hslogger 1.0.2. Uploaded by John Goerzen. [133]hslogger: Versatile logging framework. * BerkeleyDB 0.3. Uploaded by John McCall. [134]BerkeleyDB: Bindings for Berkeley DB v1.x. * BitSyntax 0.3.2. Uploaded by Adam Langley. [135]BitSyntax: A module to aid in the (de)serialisation of binary data. * Hashell 0.15. Uploaded by Gwern Branwen. [136]Hashell: Simple shell written in Haskell. * binary-strict 0.2. Uploaded by Adam Langley. [137]binary-strict: Binary deserialisation using strict ByteStrings. * Shu-thing 1.1. Uploaded by Gwern Branwen. [138]Shu-thing: A vector shooter game. * zlib 0.4.0.2. Uploaded by Duncan Coutts. [139]zlib: Compression and decompression in the gzip and zlib formats. * i18n 0.2. Uploaded by Eugene Grigoriev. [140]i18n: Internationalization for Haskell. * pandoc 0.46. Uploaded by John MacFarlane. [141]pandoc: Conversion between markup formats. * hscolour 1.9. Uploaded by Malcolm Wallace. [142]hscolour: Colourise Haskell code.. 133. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hslogger-1.0.2 134. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/BerkeleyDB-0.3 135. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/BitSyntax-0.3.2 136. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Hashell-0.15 137. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/binary-strict-0.2 138. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Shu-thing-1.1 139. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/zlib-0.4.0.2 140. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/i18n-0.2 141. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/pandoc-0.46 142. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hscolour-1.9 * regex-pcre 0.94.1. Uploaded by ChrisKuklewicz. [143]regex-pcre: Replaces/Enhances Text.Regex. * regex-posix 0.93.1. Uploaded by Chris Kuklewicz. [144]regex-posix: Replaces/Enhances Text.Regex. * regex-base 0.93.1. Uploaded by Chris Kuklewicz. [145]regex-base: Replaces/Enhances Text.Regex. * regex-compat 0.91. Uploaded by Chris Kuklewicz. [146]regex-compat: Replaces/Enhances Text.Regex. * haddock 2.0.0.0. Uploaded by David Waern. [147]haddock: Added by DavidWaern 143. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/regex-pcre-0.94.1 144. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/regex-posix-0.93… 145. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/regex-base-0.93.1 146. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/regex-compat-0.91 147. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/haddock-2.0.0.0 Blog noise [148]Haskell news from the [149]blogosphere. 148. http://planet.haskell.org/ * [150]Scala Buzzzzings * [151]Taxicab Numbers * [152]Tuppence Tour of Haskell Concurrency Constructs * [153]Power of Functional Programming, its Features and its Future * [154]Monads in Python (with nice syntax!) * [155]Monads in Ruby (with nice syntax!) * [156]The Marvels of Monads (in C#) * [157]Pointfree programming in OCaml * [158]HSOE Chapter 3 * [159]Extra type safety using polymorphic types as first-level refinements * [160]Why you should use Haskell for your next domain specific language 149. http://haskell.org/haskellwiki/Blog_articles 150. http://patricklogan.blogspot.com/2008/01/scala-buzzzzings.html 151. http://python-tips-gw.blogspot.com/2008/01/taxicab-numbers.html 152. http://mult.ifario.us/p/tuppence-tour-of-haskell-concurrency-constructs 153. http://www.canerten.com/power-of-functional-programming-its-features-and-it… 154. http://www.valuedlessons.com/2008/01/monads-in-python-with-nice-syntax.html 155. http://www.valuedlessons.com/2008/01/monads-in-ruby-with-nice-syntax.html 156. http://blogs.msdn.com/wesdyer/archive/2008/01/11/the-marvels-of-monads.aspx? 157. http://alaska-kamtchatka.blogspot.com/2008/01/pointless-polymorphism.html 158. http://apocalisp.wordpress.com/2008/01/08/hsoe-chapter-3/ 159. http://blog.jbapple.com/2008/01/extra-type-safety-using-polymorphic.html 160. http://paulspontifications.blogspot.com/2008/01/why-haskell-is-good-for-emb… * [161]Record system headaches * [162]Programming Erlang * [163]Haskell syntax is not Java syntax; good or bad? * [164]Judging programming languages by the results * [165]One line binary reader in Haskell * [166]On the utility of functional programming * [167]The Rise Of Functional Programming: F#/Scala/Haskell and the failing of Lisp * [168]Seeqsuq: A Seeqpod URL Ripper (in Haskell) * [169]2008 predictions * [170]The Haskell Program Coverage Toolkit (part 1) 161. http://jpmoresmau.blogspot.com/2008/01/nested-records-headaches-in-haskell.… 162. http://www.oxtremists.co.uk/?p=68 163. http://jpmoresmau.blogspot.com/2008/01/haskell-syntax-is-not-java-syntax-go… 164. http://www.pvv.org/~alexanro/2008/01/11/judging-programming-languages-by-th… 165. http://tehgeekmeister.wordpress.com/2008/01/11/one-line-binary-reader-in-ha… 166. http://geekrant.wordpress.com/2008/01/12/on-the-utility-of-functional-progr… 167. http://www.brandonwerner.com/2008/01/13/the-rise-of-functional-programming-… 168. http://cmars232.blogspot.com/2008/01/seeqsuq-seeqpod-url-ripper-in-haskell.… 169. http://lambda-the-ultimate.org/node/2600#comment-39191 170. http://blog.unsafeperformio.com/?p=18 * [171]Haskell Code Coverage tool available * [172]A Little Lesson on Laziness and Unsafety * [173]Haskell's do syntax for python and ruby * [174]Error handling in Python: monads are too much for me * [175]Simple POSIX regular expression example * [176]Read the content of a file into a list of string * [177]How not to explain Haskell monads * [178]HStringTemplate: An Elegant, Functional, Nifty Templating Engine for Haskell. * [179]A (hopefully) painless introduction to monads * [180]Simple Type Inference in Haskell 171. http://leibnizdream.wordpress.com/2008/01/15/haskell-code-coverage-tool-ava… 172. http://mult.ifario.us/p/a-little-lesson-on-laziness-and-unsafety 173. http://www.valuedlessons.com/2008/01/recently-i-wrote-about-ways-to-add.html 174. http://ndanger.org/blog/2008/01/16/error-handling-in-python-monads-are-too-… 175. http://athashdollarpercent.blogspot.com/2008/01/simple-posix-regular-expres… 176. http://athashdollarpercent.blogspot.com/2008/01/read-content-of-file-into-l… 177. http://mvanier.livejournal.com/1205.html 178. http://fmapfixreturn.wordpress.com/2008/01/14/hstringtemplate-an-elegant-fu… 179. http://www.prairienet.org/~dsb/monads.htm 180. http://notvincenz.blogspot.com/2008/01/simple-type-inference-in-haskell.html * [181]Quality assurance for Haskell code via code coverage * [182]Getting started with Yi, the haskell editor * [183]Haskell Impressions, Part I * [184]Software Transactional Memory for F# * [185]One or so word summary of the programming languages I work with * [186]HStringTemplate: Turtles all the way * [187]Scraping my boilerplate: Generics instead of Records * [188]Functional Programming is Hard * [189]Erik Meijer: Evaluating Functional Programming Language Purity :: Video * [190]Solving XKCD's Ghost problem in Haskell: First player wins 181. http://blog.unsafeperformio.com/?p=18 182. http://nobugs.org/developer/yi/index.html 183. http://blog.safira.com/2008/01/haskell-impressions-part-i.html 184. http://cs.hubfs.net/blogs/hell_is_other_languages/archive/2008/01/16/4565.a… 185. http://berlinbrowndev.blogspot.com/2008/01/one-or-so-word-summary-of-progra… 186. http://fmapfixreturn.wordpress.com/2008/01/18/turtles-all-the-way/ 187. http://jpmoresmau.blogspot.com/2008/01/scraping-my-boilerplate-generics.html 188. http://blog.magenic.com/blogs/aarone/archive/2008/01/18/Functional-Programm… 189. http://channel9.msdn.com/ShowPost.aspx?PostID=374141 190. http://squing.blogspot.com/2008/01/first-player-wins-superghost.html * [191]Haskell Function calls and Parentheses * [192]an elementary proof of the undecidability of the halting problem * [193]Invasion of the multi-core machines * [194]Monads for Imperative Peeps * [195]Haskell Shuffling * [196]Notes on Haskell * [197]Functional Programming Languages * [198]Case Study: Using Haskell and HAppS for Openomy API v2.0 * [199]A Haskell Hackathon (in Japanese) * [200]Control.Parallel.Strategies introduction 191. http://berlinbrowndev.blogspot.com/2008/01/haskell-function-calls-and-paren… 192. http://www.bemuzed.com/lucasd/halting-poem.html 193. http://blog.susheelspace.com/?p=126 194. http://climbing-the-hill.blogspot.com/2008/01/haskell-monads-for-imperative… 195. http://brett-hall.blogspot.com/2008/01/haskell-shuffling.html 196. http://penberg.blogspot.com/2008/01/its-not-dead-yet.html 197. http://blog.inquirylabs.com/2008/01/20/functional-programming-languages/ 198. http://blog.openomy.com/2008/01/case-study-using-haskell-and-happs-for.html 199. http://d.hatena.ne.jp/yukoba/20080121/p1 200. http://thoughtpolice.stringsandints.com/index.cgi/code/haskell#parallel_str… * [201]'I asked the manager if they were considering using such languages. He replied that they had actually considered using Haskell for some smaller projects' * [202]Solving IO Sequencing in Haskell with a Monad * [203]Haskell Music * [204]Matching checklists using Haskell * [205]State monads * [206]Haskell is a very expressive language * [207]Counting Infinity * [208]Haskell, del.icio.us, and JSON * [209]It's time for Haskell in the web browser * [210]OpenGL programming with Haskell 201. http://pinderkent.blogsavy.com/archives/150 202. http://wry-observer.blogspot.com/2008/01/solving-io-sequencing-in-haskell-w… 203. http://samdanielson.com/2008/1/23/haskell-music 204. http://porg.es/blog/matching-checklists-using-haskell 205. http://mvanier.livejournal.com/1901.html 206. http://berlinbrowndev.blogspot.com/2008/01/haskell-is-very-expressive-langu… 207. http://muaddibspace.blogspot.com/2008/01/counting-infinity.html 208. http://mult.ifario.us/p/haskell-del-icio-us-and-json 209. http://pinderkent.blogsavy.com/archives/151 210. http://metavar.blogspot.com/2008/01/opengl-programming-with-haskell.html * [211]unfolds in scala * [212]Haskell Snippet: looking at foldl (also a java version) * [213]MatLab: Why OCaml and Haskell are not ready for general scientists -- missing libraries * [214]Problems in Lisp: Historical relics, poor FFI, libraries, forks * [215]On blub * [216]Refining Pipelines * [217]Purely functional recursive types in Haskell and Python * [218]Counting matches in a list * [219]SPJ on .NET Rocks * [220]Hackage, cabal and the google charts api * [221]Haskell Rocks! * [222]How many functions are there from () to ()? 211. http://scala-blogs.org/2008/01/roman-numerals-in-scala.html 212. http://berlinbrowndev.blogspot.com/2008/01/haskell-snippet-looking-at-foldl… 213. http://alexandermikhalev.blogspot.com/2008/01/why-ocaml-and-haskell-is-not-… 214. http://nightschool.near-time.net/news/2008/1/31/some-improvements-are-distr… 215. http://etalog.blogspot.com/2008/01/on-blub.html 216. http://alaska-kamtchatka.blogspot.com/2008/02/refining-pipelines.html 217. http://sigfpe.blogspot.com/2008/02/purely-functional-recursive-types-in.html 218. http://haskell101.wordpress.com/2008/02/03/counting-matches-in-a-list/ 219. http://weblogs.asp.net/gbarnett/archive/2008/02/06/something-that-when-unno… 220. http://community.livejournal.com/evan_tech/241080.html 221. http://l33tminion.livejournal.com/189554.html 222. http://sigfpe.blogspot.com/2008/02/how-many-functions-are-there-from-to.html Quotes of the Week * Peter: I hardly know Haskell, but I can already write some code much faster and easier than I could do in C/C++ (and I've been programming 2 decades in that language) * Miguel Mitrofanov: Since NaN /= NaN, I think, we should decipher 'NaN' as 'Not a NaN' * Achim Schneider: The essence of non-strictness, though, is another kind of story. Like a golem plowing half of the country until you remember that you placed him a bit absent-mindedly into your backyard and said 'plow', that still won't plow mountains. The essence of strictness is easy, though: get stuck on a stone, fall over and continue moving until you break. * monochrom: OCaml tells you 'map f xs is bad because it takes O(n) space'. Haskell tells you 'map f xs' is good because it takes O(1) space * ddarius: It says *right on the box* that it it's intended for *both* research and applications. * Clifford Beshers: Why Haskell? Medical researchers announced today that MRI studies reveal that the structure of the human brain is significantly different in adolescence than adulthood. * Larry O'Brien: I really had a hard time refactoring my Ruby into a packrat parser. This was due, in no small part, because of the difficulty in understanding the types being built-up in the data structure. The paper, in explicitly-typed Haskell: clear as a bell. My code's behavior on unit tests: virtually indistinguishable from random. * SuperGrade: Haskell kind of herds you into functional programming. There are advantages to this manner of coding, and I'm getting to thinking you should attempt code this way almost all of the time, regardless of language. * Berlin Brown: Haskell is readable, fast, and expressive. I like it. * Yaakov Nemoy: Changing the type of a function in Python will lead to strange runtime errors that take some work to debug, whereas, when I tinker with a program in Haskell, I already know it will work once it compiles. * Michael Reid: Learning Haskell has completely reversed my feeling that static typing is an old outdated idea. The power of Haskell's type system makes it feel like you are programming in a dynamic language to some degree, yet all of it is type-checked, and that is just *really* cool. * weavejester: I've come across many parser generators that are a dream to work with in comparison to lex and yacc. The best one I've found so far is Haskell's Parsec. * David Roundy: What's the good of having a haskell-programming computational linguist on board if we can't get static compile-time guarantees of grammatical correctness? * Bulat Ziganshin: When FP just pass all the functions and data required for specialization of generic algorithm, OOP provides interfaces, virtual functions, anonymous classes, delegates and lots of other interesting ways to hide the fact of lack of first-class functions :) * [Douglas] Adams: was interested in computing --- I think his reaction to being told about functional programming was to wonder what non-functional programming might be. * ezekiel: I find Haskell to be like Lisp and APL and Python all put together in a way that leads me quickly to a solid result. Other languages work, but the road to the result is bumpier. * AlanYx: I've found that Haskell's uber-strong, static type system does help me be productive, because it increases the class of bugs that can be found at compile time, forces thinking at a higher level, and can help avoid edits to existing code breaking things elsewhere in the code * anonymous: Closures in today's world are a 'language geek' feature. Unless done extremely carefully and in a way that supports the various skill levels of developers, they end up being unusable and unsupportable by anything less than computer language savants. In their inherent obscurity and complexity, 'language geek' style closures are about as anti-Java as you can get. * anonymous: I work in a Smalltalk shop, where we extend and maintain an application that has been around over a decade. During the maintenance part of our job, it would be really nice to have type declarations on variables. For maintenance, the more dependable information we have, the better! The fewer things that can escape as runtime exceptions, the better! * consultant barbie: Languages are hard. Let's write web frameworks and go shopping! About the Haskell Weekly News New editions are posted to [223]the Haskell mailing list as well as to [224]the Haskell Sequence and [225]Planet Haskell. [226]RSS is also available, and headlines appear on [227]haskell.org. Headlines are available as [228]PDF. To help create new editions of this newsletter, please see the [229]contributing information. Send stories to dons at galois.com. The darcs repository is available at darcs get [230]http://code.haskell.org/~dons/code/hwn/ 223. http://www.haskell.org/mailman/listinfo/haskell 224. http://sequence.complete.org/ 225. http://planet.haskell.org/ 226. http://sequence.complete.org/node/feed 227. http://haskell.org/ 228. http://code.haskell.org/~dons/code/hwn/archives/20080210.pdf 229. http://haskell.org/haskellwiki/HWN 230. http://code.haskell.org/~dons/code/hwn/

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PPDP'08: Call for Papers
by ppdp08-cfp＠clip.dia.fi.upm.es 08 Feb '08

08 Feb '08

................................................................ ACM PPDP 2008 - Call For Papers 10th ACM-SIGPLAN* International Symposium on Principles and Practice of Declarative Programming Valencia, Spain, July 15-17, 2008 http://www.clip.dia.fi.upm.es/Conferences/PPDP08 ................................................................ IMPORTANT DATES Submission: April 10, 2008 Notification: May 15, 2008 Conference: July 15-17, 2008 SCOPE: PPDP 2008 is a forum for researchers and practitioners in the declarative programming communities. It solicits papers on all aspects of logic, constraint and functional programming, as well as on related paradigms such as visual programming, executable specification languages, database languages, AI and knowledge representation languages for the "semantic web". MAIN TOPICS: Logic, Constraint, and Functional Programming; Database, AI and Knowledge Representation Languages; Visual Programming; Executable Specification for Languages; Applications of Declarative Programming; Methodologies for Program Design and Development; Declarative Aspects of Object-Oriented Programming; Concurrent Extensions to Declarative Languages; Declarative Mobile Computing; Paradigm Integration; Proof Theoretic and Semantic Foundations; Type and Module Systems; Program Analysis and Verification; Program Transformation; Abstract Machines and Compilation; Programming Environments. PROCEEDINGS: The proceedings will be published by ACM Press* RELATED EVENTS: PPDP 2008 will be co-located with the 15th International Static Analysis Symposium (SAS 2008) and the 18th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2008). SYMPOSIUM CHAIR: Elvira Albert, Complutense University of Madrid PROGRAM CHAIR: Sergio Antoy, Portland State University PROGRAM COMMITTEE: Elvira Albert Complutense University of Madrid, Spain Sergio Antoy Portland State University, USA Maribel Fernandez King's College, UK Maurizio Gabbrielli University of Bologna, Italy Joxan Jaffar National University, Singapore Claude Kirchner INRIA Bordeaux, France Herbert Kuchen University of Muenster, Germany Kostis Sagonas Uppsala University, Sweden Carsten Schurmann IT University of Copenhagen, Denmark Peter Sestoft IT University of Copenhagen, Denmark *ACM-SIGPLAN approval is pending

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Two Lectureships in Nottingham
by Graham Hutton 07 Feb '08

07 Feb '08

Dear all, We are advertising two new Lectureships (Assistant Professorships) in Computer Science at the University of Nottingham in England. Applications in the area of functional programming are particularly welcome. Further details are available from: http://jobs.nottingham.ac.uk/vacancies.aspx?cat=160#j2797 The closing date for applications is 22nd Feburary 2008 Best wishes, Graham Hutton +-----------------------------------------------------------------+ | Dr Graham Hutton Email : gmh(a)cs.nott.ac.uk | | School of Computer Science | | University of Nottingham Web : www.cs.nott.ac.uk/~gmh | | Jubilee Campus, Wollaton Road | | Nottingham NG8 1BB, UK Phone : +44 (0)115 951 4220 | +-----------------------------------------------------------------+ 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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Re: Typing unification algorithm for parameterized types using GADTs?
by oleg＠okmij.org 07 Feb '08

07 Feb '08

Ki Yung Ahn posed a problem of first-order syntactic unification over GADTs. There posted code seem to exhibit two problems: one deals with kind equality, and the other with unification. Let's start with the latter. You have chosen to represent substitutions as functions from terms to terms. That's OK. However, the following lines seems weird: > unify (t1 :-> t2) (t1' :-> t2') = unify t1 t1' . unify t2 t2' We wish to unify two composite (constructed terms) whose head is :->. Unification of t1 t1' gives a substitution, and so does the unification of t2 and t2'. Now we should prove that the results are compatible, that is, if the domains of both substitutions overlap, the common variables are associated with unifyable values. But the composition is the wrong operation here: the composition is a total operation. So, if we unify (X :-> X) (term1 :-> term2) where X is a free variable and term1 is distinct from term2, we are successful? Indeed, unify X term1 succeeds, so is unify X term2. The composition is total. The result can't be right. The line has to be re-written as follows > unify (t1 :-> t2) (t1' :-> t2') = > let s = unify t1 t1' in s `compose` unify (s t2) (s t2') where > compose s1 s2 t = loop t > where > s = s1 . s2 > loop t = let t1 = s t in if t1 == t then t else loop t1 The fixpoint assures the substitution is idempotent, as behooves to the result of unify. Now, the type of unify is also a bit wrong: > unify :: (Show v,Ord v) => Ty v k -> Ty v k -> Ty v k -> Ty v k It should be > unify :: (Show v,Ord v) => Ty v k -> Ty v k -> Ty v k' -> Ty v k' Finally, we come to the issue of kind equality. In > data Ty v k where > TyA :: Ty v (k1 :~> k2) -> Ty v k1 -> Ty v k2 k1 is an existentially quantified type variable. When we wish to compare (TyA t1l t1r) with (TyA t2l t2r), we first have to prove that the kind of t1r is the same as t2r. Both kinds are existentially quantified, there is no reason they must always be equal. So, we have to use intensional equality. > data Star = Star deriving (Show,Eq) -- the kind * > data k1 :~> k2 = k1 :~> k2 deriving (Show,Eq) Well, deriving Eq is not useful here: we can't actually compare Star with (k1 :~> k2) because they have different types. So, we need an intensional representation of kinds, with a useful comparison function. We should also re-write > TyC :: v -> k -> Ty v k to use that representation. The final code follows. {-# OPTIONS -fglasgow-exts #-} import List infixr :~> -- kind arrow -- term algebra of kinds data Star data k1 :~> k2 -- A representation of kinds data K k where KStar :: K Star KArr :: K k1 -> K k2 -> K (k1 :~> k2) infixr :-> -- type arrow data Ty v k where TyV :: v -> Ty v Star -- all type vars are of kind *. (:->) :: Ty v Star -> Ty v Star -> Ty v Star TyC :: v -> K k -> Ty v k TyA :: Ty v (k1 :~> k2) -> Ty v k1 -> Ty v k2 -- Kind equality data EQ a b where Refl :: EQ a a -- compare two kinds. Return either Nothing or the witness of their -- equality keq:: K k1 -> K k2 -> Maybe (EQ k1 k2) keq KStar KStar = Just Refl keq (KArr k1l k1r) (KArr k2l k2r) = keq' (keq k1l k2l) (keq k1r k2r) keq _ _ = Nothing keq' :: Maybe (EQ k1l k2l) -> Maybe (EQ k1r k2r) -> Maybe (EQ (k1l :~> k1r) (k2l :~> k2r)) keq' (Just Refl) (Just Refl) = Just Refl keq' _ _ = Nothing -- inverse of the above keqa :: Maybe (EQ (k1l :~> k1r) (k2l :~> k2r)) -> Maybe (EQ k1r k2r) keqa (Just Refl) = Just Refl keqa _ = Nothing -- compare two types for their kinds. tykeq :: Ty v k1 -> Ty v k2 -> Maybe (EQ k1 k2) tykeq (TyV _) (TyV _) = Just Refl tykeq (_ :-> _) (_ :-> _) = Just Refl tykeq (TyC _ k1) (TyC _ k2) = keq k1 k2 tykeq (TyA t1 _) (TyA t1' _) = keqa (tykeq t1 t1') -- term equality instance Eq v => Eq (Ty v k) where TyV v1 == TyV v2 = v1 == v2 (t1l :-> t1r) == (t2l :-> t2r) = t1l == t2l && t1r == t2r TyC v1 _ == TyC v2 _ = v1 == v2 (TyA t1l t1r) == (TyA t2l t2r) = teq'' (tykeq t1r t2r) t1r t2r && teq'' (tykeq t1l t2l) t1l t2l _ == _ = False teq'' :: Eq v => Maybe (EQ k1 k2) -> Ty v k1 -> Ty v k2 -> Bool teq'' (Just Refl) t1 t2 = t1 == t2 teq'' _ _ _ = False list = TyC "List" (KArr KStar KStar) nil_t = TyA list (TyV "a") -- the `List a' type nil'_t = TyA list (TyV "b") -- the `List b' type cons_t = TyV "b" :-> TyA list (TyV "b") :-> TyA list (TyV "b") instance Show v => Show (Ty v k) where show (TyV v) = show v show (t1 :-> t2) = "("++show t1++"->"++show t2++")" show (TyC v _) = show v show (TyA t1 t2) = "("++show t1++" "++show t2++")" occurs :: Eq v => v -> Ty v k -> Bool occurs x (TyV y) = x == y occurs x (t1:->t2) = occurs x t1 || occurs x t2 occurs _ (TyC _ _) = False occurs x (TyA t1 t2) = occurs x t1 || occurs x t2 -- A substitution on types can be written as follows: type Subst v k = Ty v k -> Ty v k substt :: Eq v => (v,Ty v Star) -> Subst v k substt (x,t1) t@(TyV y) | x == y = t1 | otherwise = t substt p (t1 :-> t2) = substt p t1 :-> substt p t2 substt _ t@(TyC _ _) = t substt p (TyA t1 t2) = substt p t1`TyA`substt p t2 compose s1 s2 t = loop t where s = s1 . s2 loop t = let t1 = s t in if t1 == t then t else loop t1 unify_gen :: (Show v,Ord v) => Maybe (EQ k1 k2) -> Ty v k1 -> Ty v k2 -> Subst v k' unify_gen (Just Refl) t1 t2 = unify t1 t2 unify_gen _ _ _ = error "incompat kinds" unify :: (Show v,Ord v) => Ty v k -> Ty v k -> Subst v k' unify t1@(TyV x) t2@(TyV y) | x == y = id | x <= y = substt (x,t2) | otherwise = substt (y,t1) unify (TyV x) t | occurs x t = error(show x++" occurs in " ++show t) | otherwise = substt (x,t) unify t1 t@(TyV _) = unify t t1 unify (t1 :-> t2) (t1' :-> t2') = let s = unify t1 t1' in s `compose` unify (s t2) (s t2') unify (TyC a _) (TyC b _) | a == b = id | otherwise = error(show a++" is not " ++show b) unify (TyA t1 t2) (TyA t1' t2') = let s = unify_gen (tykeq t2 t2') t2 t2' tn1 = s t1 tn1' = s t1' in s `compose` unify_gen (tykeq tn1 tn1') tn1 tn1' unify t1 t2 = error(show t1++" is not " ++show t2) test1 = unify nil_t nil_t $ nil_t test2 = unify nil_t cons_t $ nil_t test3 = let s = unify nil_t nil'_t in (s nil_t, s nil'_t) test4 = let t1 = (TyV "a" :-> TyV "b") t2 = (TyV "b" :-> TyC "unit" KStar) s = unify t1 t2 in (s t1, s t2) -- (("unit"->"unit"),("unit"->"unit")) -- Indeed, both types are the same

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Typing unification algorithm for parameterized types using GADTs?
by Ahn, Ki Yung 07 Feb '08

07 Feb '08

I was writing a type inference algorithm for let-polymorphic type system with parametrized types. (That is, the type system as type constructors such as `Maybe'.) Things work out nicely except for one equation in the unification function. I will illustrate my problem with the definitions and examples that you can actually run. You will need -XGADTs and -XTypeOperators to run this as a literate Haskell script in ghc 6.8.2. FYI, my problematic unification function appears at the end. This is not that long article (about 150 lines), anyway. > import List First, we define the kind as follows: > infixr :~> -- kind arrow > > data Star = Star deriving (Show,Eq) -- the kind * > data k1 :~> k2 = k1 :~> k2 deriving (Show,Eq) Next, we define the type as GADTs indexed with kinds, > infixr :-> -- type arrow > > data Ty v k where > TyV :: v -> Ty v Star -- all type vars are of kind *. > (:->) :: Ty v Star -> Ty v Star -> Ty v Star > TyC :: v -> k -> Ty v k > TyA :: Ty v (k1 :~> k2) -> Ty v k1 -> Ty v k2 Note that, we only allow type variables to be of kind * (abbr. for Star). For example, we define the parametrized type List as follows: > list = TyC "List" (Star :~> Star) So, we can give `nil' (empty list) the type TyA list (TyV "a") -- the `List a' type and `cons' the type TyV "a" :-> TyA list (TyV "a") :-> TyA list (TyV "a") We also define an instance for Show class, since deriving does not support GATDs. > instance Show v => Show (Ty v k) where > show (TyV v) = show v > show (t1 :-> t2) = "("++show t1++"->"++show t2++")" > show (TyC v _) = show v > show (TyA t1 t2) = "("++show t1++" "++show t2++")" Then, we can write some functions. An occurs check on types can be written as follows: > occurs :: Eq v => v -> Ty v k -> Bool > occurs x (TyV y) = x == y > occurs x (t1:->t2) = occurs x t1 || occurs x t2 > occurs _ (TyC _ _) = False > occurs x (TyA t1 t2) = occurs x t1 || occurs x t2 A substitution on types can be written as follows: > substt :: Eq v => (v,Ty v Star) -> Ty v k -> Ty v k > substt (x,t1) t@(TyV y) | x == y = t1 > | otherwise = t > substt p (t1 :-> t2) = substt p t1 :-> substt p t2 > substt _ t@(TyC _ _) = t > substt p (TyA t1 t2) = substt p t1`TyA`substt p t2 Recall that we only have type variables of kind *. So, we only need to substitute a variable to a type of kind *. Finally, we try writing a unification function as follows: > unify :: (Show v,Ord v) => Ty v k -> Ty v k -> Ty v k -> Ty v k > unify t1@(TyV x) t2@(TyV y) | x == y = id > | x <= y = substt (x,t2) > | otherwise = substt (y,t1) > unify (TyV x) t | occurs x t = error(show x++" occurs in " > ++show t) > | otherwise = substt (x,t) > unify t1 t@(TyV _) = unify t t1 > unify (t1 :-> t2) (t1' :-> t2') = unify t1 t1' . unify t2 t2' > unify (TyC a _) (TyC b _) | a == b = id > | otherwise = error(show a++" is not " > ++show b) > unify (TyA t1 t2) (TyA t1' t2') = unify t1 t1' . unify t2 t2' > unify t1 t2 = error(show t1++" is not " > ++show t2) I think I may be able to make it go through by changing the representation of unification to a data structure such as list of substitution pairs. But, just out of curiosity, what kind of an operator should I define to combine the result of two unifications (unify t1 t1') (unify t2 t2') properly in this setting? -- Ahn, Ki Yung <kya(a)pdx.edu>

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ANN: hpodder 1.1.0
by John Goerzen 06 Feb '08

06 Feb '08

I'm pleased to announce version 1.1.0 of hpodder, the podcast downloader. Get it from http://software.complete.org/hpodder The new features in hpodder 1.1.0 include: * New support for configurable renaming of incoming episodes to standard extensions. The previous feature was hard-coded for certain data types. * New support for using file -i (or a user-configurable program) to determine the actual type of a file to deal with servers that don't send correct MIME types in their feeds. Enable this support by default. * New support for user-configurable post-processing commands that do things such as tagging. * New support for conditional running of post-processing commands based on content type. * Documented --debug. * New support for GUID tags to reduce occurances of duplicate downloads. Thanks to Jason Creighton for the patch to support this. This version is compatible with GHC 6.8.x and MissingH 1.0.x. -- John

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