October 2007 - Haskell

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

8 13

Haskell-mode 2.0
by Stefan Monnier 02 Feb '09

02 Feb '09

I have recently taken over maintainership of Haskell-mode, and after making a bunch of changes, I figured it would be a good idea to make a new release. You can find this new release at: http://www-perso.iro.umontreal.ca/~monnier/elisp/ If you think it should also be found at http://www.haskell.org/haskell-mode/, then please tell John Peterson to get back to me (my email to him seem to go straight to the bitbucket. John?). This release has several changes that have all been only lightly tested, especially w.r.t compatibility with various Emacsen. See appended the NEWS file that describes some of the notewirthy changes. Stefan Changes since 1.45: * keybindings C-c <char> have been replaced by C-c C-<char> so as not to collide with minor modes. * The following modules are now automatically activated without having to add anything to haskell-mode-hook: haskell-font-lock (just turn on global-font-lock-mode). haskell-decl-scan (just bind `imenu' to some key). * In recent Emacsen, haskell-doc hooks into eldoc-mode. * haskell-hugs and haskell-ghci are superceded by inf-haskell. * Indentation rules have been improved when using layout inside parens/braces. * Symbols like -> and \ can be displayed as actual arrows and lambdas. See haskell-font-lock-symbols. * Tweaks to the font-lock settings. Among other things paren-matching with things like \(x,y) should work correctly now. * New maintainer <monnier(a)gnu.org>.

3 6

The real Monad Transformer
by Henning Thielemann 13 Nov '08

13 Nov '08

It was argued that people avoid Haskell because of terms from Category theory like 'Monad'. This problem can now be solved by a wrapper which presents all the WWW without monads! Start e.g. at http://saxophone.jpberlin.de/MonadTransformer?source=http%3A%2F%2Fwww%2Ehas… Of course the tool is written in Haskell, that is, Haskell helps solving problems which only exist because of Haskell. Bug reports and feature requests can be tracked at https://sourceforge.net/projects/parallelweb

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ANN: MacOSX - A library some Haskell users on OS X might find useful.
by Corey O'Connor 27 Feb '08

27 Feb '08

I've been working on integrating haskell code with some Objective-C/C++ Cocoa Mac OS X applications. Nothing fancy like a Haskell/Cocoa bridge. Just trying to get the build process smooth. The default cabal build system was incomplete to do this effectively;* Extending XCode was no good either. With some effort I created some Cabal build hooks to fix up the behavior of build on OS X and add support for packaging an executable into a ".app" package. That's not much, but I packaged it up, plus some extras, into a library in case other projects would like to use it: http://tothepowerofdisco.com/repo/HaskellLibraries/ Of course, this is all hackish and very incomplete. EG: * No fat binary support. I only have a PPC Mac and the only fat-binary process usable with GHC I know of requires executing the x86 GHC. * The build hook in MacOSX.Build will only work on the Cabal distributed with GHC 6.6.1 and *completely* replaces the standard GHC build hook. * GHC compiled to use the framework version of GMP installed to /Library/Frameworks is required. * The name is vague... Still, I've used it to add haskell support and replace XCode for building for 3 exisitng Cocoa applications. Maybe somebody else will find it useful as well. -- -Corey O'Connor * I neglected to make a good list of why the default Cabal build hook doesn't work.

2 2

Image manipulation
by Björn Wikström 01 Nov '07

01 Nov '07

Hi! I have lots and lots of images (jpegs) that I would like to manipulate and shrink (in size). They are around 5 Mb big, so I thought this would be a good Haskell project since its a lazy evaluating language. The problem is that I cant find any libraries for image manipulation. Anyone who knows something that would interest me and maybe give me some advices? Best regards, Bjorn.

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HDBC & drivers 1.1.3 released
by John Goerzen 31 Oct '07

31 Oct '07

Today I have released HDBC 1.1.3 and the HDBC backend drivers 1.1.3. Changes follow: HDBC 1.1.3 http://software.complete.org/hdbc * [API] Added strict versions of fetchAll* and related functions. Specific new functions are: quickQuery', fetchAllRows', fetchAllRowsAL', fetchAllRowsMAP', sFetchAllRows'. This does not impact database drivers. No user impact. * [API] Changed spec to make the following functions strict in their result: describeResult, getTables, describeTable. No code change in HDBC. Potential code change in backends. No anticipated user impact. * Add SqlByteString constructor to SqlValue. Patch from Toby Allsopp. HDBC-sqlite3 1.1.3.0 http://software.complete.org/hdbc-sqlite3 * Updated for new strictness in HDBC 1.1.3 * Updated Cabal file * Efficint binding of ByteString arguments. (Path from Toby Allsopp) HDBC-postgresql 1.1.3.0 http://software.complete.org/hdbc-postgresql * Strictify a few functions for 1.1.3 API * Improve metadata handling. Patch from Steve Harris * Use better SqlValue constructors for column types. Patch from Steve Harris. HDBC-odbc 1.1.3.0 http://software.complete.org/hdbc-odbc * Stricify a few functions for 1.1.3 API

1 0

how to delete images on the wiki
by Wolfgang Jeltsch 31 Oct '07

31 Oct '07

Hello, does anyone know how to delete images on the Haskell Wiki which were errornously added under a wrong name? Best wishes, Wolfgang

2 1

placing modules in the module hierarchy
by Wolfgang Jeltsch 29 Oct '07

29 Oct '07

Hello, I’m developing the Grapefruit library, a library for writing graphical user interfaces and animated graphics using concepts of Functional Reactive Programming. At the moment, all modules of Grapefruit reside under Graphics.UI.Grapefruit but I’m not satisfied with this situation. The reason is that a certain part of Grapefruit just deals with graphics, not user interfaces, and another part deals with basic reactive programming things (several kinds of signals) which could be used in contexts totally different from user interfaces and graphics (for example, sound synthesis). So I thought about spreading Grapefruit’s modules over the module hierarchy. In particular, I thought about splitting the set of modules into the following parts: * Control.Grapefruit and submodules * Graphics.Rendering.Grapefruit and submodules * Graphics.UI.Grapefruit and submodules However, including the name of the library all the time doesn’t seem like a very good idea to me. First, it’s confusing to have three subtrees of the module tree named “Grapefruit” since this looks like if there were three libraries of this name. Second, it’s strange to have Control.Grapefruit beside Control.Monad and Control.Concurrent since “monad” and “concurrent” are concepts whereas “Grapefruit” is a library. Since the Control.Grapefruit subtree would probably only consist of Control.Grapefruit.Signal and submodules, I’d prefer to just use Control.Signal and Control.Signal.*. But this would pose the problem that no other FRP library could use Control.Signal without conflicting with Grapefruit. At the moment, I don’t know of any general rule which gives an answer to these questions. It seems like the current module hierarchy follows multiple guidelines. For example, there are Graphics.Win32 and Graphics.X11 beside Graphics.Rendering and Graphics.UI, the former two referring to existing APIs, the latter two referring to concepts. Below Graphics.Rendering and Graphics.UI there are modules whose names refer to existing APIs again (OpenGL, GLUT, Gtk2Hs). A further question would be if putting FRP signals under Control is sensible at all, or if they should be put under Data. Signals denote functions from time to some value space (but are usually not implemented as simple functions). I’d appreciate any helpful information concerning this topic. Best wishes, Wolfgang

1 0

PhD position at Chalmers
by John Hughes 26 Oct '07

26 Oct '07

The Functional Programming group at Chalmers is seeking to recruit a PhD student to work on domain-specific languages embedded in Haskell for hardware design, and for programming graphics processors. PhD positions in Sweden are real jobs, paying a respectable salary for up to five years. The official announcement follows. John Hughes PhD Position in Functional Programming at the department of Computer Science and Engineering The Department provides strongly international and dynamic research environments with 76 faculty and 55 PhD students from about 30 countries. For more information, see http://www.chalmers.se/cse/EN/ Knowledge of Swedish is not a prerequisite for application. English is our working language for research. Both Swedish and English are used in undergraduate courses. Half of our researchers and PhD students are native Swedes; the rest come from more than 20 different countries. Aim of work The PhD student will pursue research on applying techniques from functional programming to develop novel methods of hardware design and verification. The PhD student will join the research activities at our department in applications of functional programming. In particular, we have concentrated on the design and application of Domain Specific Embedded Languages in Haskell. Two examples of our work are QuickCheck for specification-guided random testing and Lava for hardware design and verification. We have also developed Wired, for designing high performance hardware at the layout level. This project continues the above theme, by considering higher levels of abstraction, but still aiming to take account of physical properties, to give good performance and power consumption. We will even extend our ideas about circuit design to data parallel programming, including GPU programming. Applicants must have a very good undergraduate degree in Computing Science or in a related subject with a strong Computing Science component. They must also have a strong, documented interest in doing research. The ideal student for the project will be an accomplished functional programmer with an interest in applied functional programming. You may even apply if you have not yet completed your degree, but expect to do so by 1 January 2008. In order to improve gender balance, Chalmers welcomes in particular applications from female candidates. How to apply ------------ The full application should contain 1. A letter of application, listing specific research interests 2. A curriculum vitae 3. Attested copies of degrees and other certificates 4. Copies of relevant work, for example dissertations or articles, that you have authored or co-authored 5. Letters of recommendation from your teachers or employers *** You MUST include or e-mail Letters of Recommendation: we typically get over 100 apps, and it is simply not feasible for us to request individual letters *** The job reference number is: 2007/161. The last date for your full application to arrive is November 27, 2007 Send your application electronically in PDF files or by paper-mail to Registrator, Chalmers University of Technology, Se-412 96 Göteborg, Sweden. Phone: +4631 772 1000, Fax: +4631 772 4922, E-mail: registrator(a)adm.chalmers.se Details about employment The appointee must also have been admitted to Chalmers Doctoral Program. PhD student positions are limited to five years and will then normally include 20% departmental work, mostly teaching duties. Admission and employment are regulated in Chalmers' "Rules of Procedure for Doctoral Programs", §4 and §5. Salary follows the agreement for PhD student positions. Further information Research level: Professor Mary Sheeran e-mail ms'at'chalmers.se Division level: Graduate studies director Philippas Tsigas, e-mail: tsigas'at'chalmers.se Union representatives: SACO Jan Lindér, ST-ATF Marie Wenander, SEKO Ralf Berndtsson All reachable via Chalmers exchange: +46 31 772 10 00

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Haskell Weekly News: October 25, 2007
by Don Stewart 25 Oct '07

25 Oct '07

--------------------------------------------------------------------------- Haskell Weekly News http://sequence.complete.org/hwn/20071025 Issue 66 - October 25, 2007 --------------------------------------------------------------------------- Welcome to issue 66 of HWN, a newsletter covering developments in the [1]Haskell community. A huge month for the Haskell community, with the Haskell Workshop, ICFP and CUFP conferences, the second international Haskell Hackathon, and 63 libraries and tools uploaded to hackage! A round of applause to everyone involved! 1. http://haskell.org/ Hackage This week's new libraries in [2]the Hackage library database. 2. http://hackage.haskell.org/ * SDL 0.5.0. Uploaded by Lemmih. [3]SDL, a binding to libSDL. * Stream 0.2.1. Uploaded by Wouter Swierstra. [4]Stream, functions, analogous to those from Data.List, to create and manipulate infinite lists * bktrees 0.1.1. Uploaded by Josef Svenningsson. [5]bktrees, Burhard-Keller trees provide an implementation of sets which apart from the ordinary operations also has an approximate member search, allowing you to search for elements that are of a certain distance from the element you are searching for. * happy 1.17. Uploaded by Simon Marlow. [6]happy, a parser generator for Haskell. * HaXml 1.19. Uploaded by Malcolm Wallace. [7]HaXml, utilities for parsing, filtering, transforming and generating XML documents. 3. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/SDL-0.5.0 4. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Stream-0.2.1 5. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/bktrees-0.1.1 6. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/happy-1.17 7. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HaXml-1.19 * polyparse 1.1. Uploaded by Malcolm Wallace. [8]polyparse, A variety of alternative parser combinator libraries, including the original HuttonMeijer set. The Poly sets have features like good error reporting, arbitrary token type, running state, lazy parsing, and so on. Finally, Text.Parse is a proposed replacement for the standard Read class, for better deserialisation of Haskell values from Strings. * bzlib 0.4.0.1 . Uploaded by Duncan Coutts. [9]bzlib, compression and decompression in the bzip2 format. * zlib 0.4.0.1. Uploaded by Duncan Coutts. [10]zlib, compression and decompression in the gzip and zlib formats * tar 0.1.1.1. Uploaded by Bjorn Bringert. [11]tar, a library for reading and writing TAR archives. * unix-compat 0.1.2.0. Uploaded by Bjorn Bringert. [12]unix-compat, provides portable implementations of parts of the unix package. This package re-exports the unix package when available. When it isn't available, portable implementations are used. 8. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/polyparse-1.1 9. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/bzlib-0.4.0.1 10. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/zlib-0.4.0.1 11. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/tar-0.1.1.1 12. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/unix-compat-0.1.… * oeis 0.1. Uploaded by Brent Yorgey. [13]oeis, Haskell interface to the Online Encyclopedia of Integer Sequences. * dataenc 0.9. Uploaded by Magnus Therning. [14]dataenc, Data encoding library currently providing Uuencode, Base64, Base64Url, Base32, Base32Hex, and Base16. * cabal-setup 1.2.1. Uploaded by Simon Marlow. [15]cabal-setup, cabal-setup is a user interface to Cabal. It provides the basic commands for configuring, building, and installing Cabal packages. * cabal-install 0.4.0. Uploaded by cabal-devel(a)haskell.org. [16]cabal-install, apt-get like tool for Haskell. The 'cabal' command-line program simplifies the process of managing Haskell software by automating the fetching, configuration, compilation and installation of Haskell libraries and programs. * HTTP 3001.0.0. Uploaded by Bjorn Bringert. [17]HTTP, A library for client-side HTTP. 13. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/oeis-0.1 14. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/dataenc-0.9 15. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/cabal-setup-1.2.1 16. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/cabal-install-0.… 17. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HTTP-3001.0.0 * iconv 0.4. Uploaded by Duncan Coutts. [18]iconv, provides an interface to the POSIX iconv library functions for string encoding conversion. * binary 0.4.1. Uploaded by the Binary Strike Team. [19]binary, efficient, pure binary serialisation using lazy ByteStrings. Haskell values may be encoded to and form binary formats, written to disk as binary, or sent over the network. Serialisation speeds of over 1 G/sec have been observed, so this library should be suitable for high performance scenarios. * Cabal 1.2.1. Uploaded by cabal-devel(a)haskell.org. [20]Cabal: the Haskell Common Architecture for Building Applications and libraries = Libraries: a framework defining a common interface for authors to more easily build their Haskell applications in a portable way. The Haskell Cabal is meant to be a part of a larger infrastructure for distributing, organizing, and cataloging Haskell libraries and tools. * bytestring 0.9. Uploaded by Don Stewart and Duncan Coutts. [21]bytestring. fast, packed, strict and lazy byte arrays with a list interface. * arrows 0.3. Uploaded by Ross Paterson. [22]arrows, Several classes that extend the Arrow class, and some transformers that implement or lift these classes. 18. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/iconv-0.4 19. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/binary-0.4.1 20. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Cabal-1.2.1 21. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/bytestring-0.9 22. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/arrows-0.3 * sat 1.0. Uploaded by Andrii Zvorygin. [23]sat, CNF(Clausal Normal Form) SATisfiability Solver and Generator. * pcap 0.4. Uploaded by Bryan O'Sullivan. [24]pcap, system-independent interface for user-level packet capture * hslogger4j 0.1.1. Uploaded by Bjorn Buckwalter. [25]hslogger4j, provides handlers for hslogger (John Goerzen's Haskell logging library) that are compatible with log4j's XMLLayout. In particular log messages created by the handlers can be published directly to the GUI-based log viewer Chainsaw v2. * IndentParser 0.2.1. Uploaded by Piyush P Kurur. [26]IndentParser, provides two modules, Text.ParserCombinators.Parsec.IndentParser and Text.ParserCombinators.Parsec.IndentToken, for constructing parser combinators for indentation based syntactic structures. The former exports the basic indentation parser combinators and the later together with Text.ParserCombinators.Parsec.Language and Text.ParserCombinators.Parsec.Token can be used to define tokenisers for programming languages. * lazysmallcheck 0.1. Uploaded by Matthew Naylor and Fredrik Lindblad. [27]lazysmallcheck, a library for exhaustive, demand-driven testing of Haskell programs. It is based on the idea that if a property holds for a partially-defined input then it must also hold for all fully-defined instantiations of the that input. Compared to `eager' input generation as in SmallCheck, Lazy SmallCheck may require significantly fewer test-cases to verify a property for all inputs up to a given depth. 23. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/sat-1.0 24. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/pcap-0.4 25. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hslogger4j-0.1.1 26. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/IndentParser-0.2… 27. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/lazysmallcheck-0… * HPDF 1.2. Uploaded by alpheccar. [28]HPDF, A PDF library with support for several pages, page transitions, outlines, annotations, compression, colors, shapes, patterns, jpegs, fonts, typesetting ... * xmonad. Uploaded by Spencer Janssen and Don Stewart. [29]xmonad, xmonad is a tiling window manager for X. Windows are arranged automatically to tile the screen without gaps or overlap, maximising screen use. All features of the window manager are accessible from the keyboard: a mouse is strictly optional. xmonad is written and extensible in Haskell. Custom layout algorithms, and other extensions, may be written by the user in config files. Layouts are applied dynamically, and different layouts may be used on each workspace. Xinerama is fully supported, allowing windows to be tiled on several screens. * HCL 1.2. Uploaded by Justin Bailey. [30]HCL, provides a set of functions for building simple command-line interfaces. It allows interfaces which collect values (such as Integers, Dates, or other structured values), build lists of values, and use simple menus. It is not intended to build complex interfaces with full cursor control. It is oriented towards line-based interfaces. * safecopy 0.2. Uploaded by David Himmelstrup. [31]safecopy, an extension to Data.Binary with built-in version control. * selenium 0.2.1. Uploaded by Aaron Tomb. [32]selenium, Haskell bindings to communicate with a Selenium Remote Control server. This package makes it possible to use Haskell to write test scripts that exercise web applications through a web browser. 28. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HPDF-1.2 29. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/xmonad-0.4 30. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HCL-1.2 31. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/safecopy-0.2 32. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/selenium-0.2.1 * HsOpenSSL 0.2. Uploaded by PHO. [33]HsOpenSSL, a (part of) OpenSSL binding for Haskell. It can generate RSA and DSA keys, read and write PEM files, generate message digests, sign and verify messages, encrypt and decrypt messages. * X11-extras 0.4. Uploaded by Spencer Janssen. [34]X11-extras, missing bindings to the X11 graphics library. * X11-1.2.3. Uploaded by Don Stewart. [35]X11, a Haskell binding to the X11 graphics library. * flow2dot-0.2. Uploaded by Dmitry Astapov. [36]flow2dot, generates sequence diagrams from textual descriptions with help of Graphviz graph drawing tool. * hsSqlite3-0.0.1. Uploaded by Evgeny Jukov. [37]hsSqlite, Bindings for Sqlite3 33. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HsOpenSSL-0.2 34. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/X11-extras-0.4 35. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/X11-1.2.3 36. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/flow2dot-0.2 37. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hsSqlite3-0.0.1 * X11-xft-0.1. Uploaded by Clemens Fruhwirth. [38]X11-xft, Bindings to the Xft, X Free Type interface library, and some Xrender parts. * metaplug-0.1.1. Uploaded by Austin Seipp. [39]metaplug, a ghc-api wrapper, designed to make the api more transparent across releases and offer eval and plugin esque facilities in the form of a simple, easy to modify library. * dimensional. Uploaded by Bjorn Buckwalter. [40]dimensional, a library providing data types for performing arithmetic with physical quantities and units. Information about the physical dimensions of the quantities and units is embedded in their types and the validity of operations is verified by the type checker at compile time. The boxing and unboxing of numerical values as quantities is done by multiplication and division with units. The library is designed to, as far as is practical, enforce/encourage best practices of unit usage. * ProbabilityMonads. Uploaded by Eric Kidd. [41]ProbabilityMonads, tools for random sampling, explicit enumeration of possible outcomes, and applying Bayes' rule. Highly experimental, and subject to change. In particular, the Data.Probability API is rather poor and could stand an overhaul. * MonadRandom. Uploaded by Eric Kidd . [42]MonadRandom, support for computations which consume random values. 38. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/X11-xft-0.1 39. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/metaplug-0.1.1 40. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/dimensional-0.7 41. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/ProbabilityMonad… 42. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/MonadRandom-0.1.0 * MaybeT. Uploaded by Eric Kidd. [43]MaybeT, Support for computations with failures. * network-bytestring. Uploaded by Johan Tibell. [44]network-bytestring, Faster and more memory efficient low-level socket functions using Data.ByteStrings instead of Strings. * irc. Uploaded by Trevor Elliott. [45]irc, a set of combinators and types for parsing IRC messages. * clevercss. Uploaded by Georg Brandl. [46]clevercss, a CSS preprocessing library that allows defining variables and nesting selectors so that you don't need to Repeat Yourself. * HsHyperEstraier. Uploaded by PHO. [47]HsHyperEstraier, a HyperEstraier binding for Haskell. HyperEstraier is an embeddable full text search engine which is supposed to be independent to any particular natural languages. 43. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/MaybeT-0.1.0 44. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/network-bytestri… 45. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/irc-0.2.3 46. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/clevercss-0.1 47. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/HsHyperEstraier-… * libmpd. Uploaded by Ben Sinclair. [48]libmpd, client library for MPD, the Music Player Daemon. * hS3. Uploaded by Greg Heartsfield. [49]hS3, provides an interface to Amazon's Simple Storage Service (S3), allowing Haskell developers to reliably store and retrieve arbitrary amounts of data from anywhere on the Internet. * infinity. Uploaded by Austin Seipp. [50]infinity, tiny IRC bot, extendable through plugins written in haskell * WURFL. Uploaded by alpheccar. [51]WURFL, support for the WURLF file format * hburg. Uploaded by Igor Boehm. [52]hburg, a program that generates tree parsers for cost-augmented tree grammars. It is useful for writing code generators for compilers. Given a mapping of a tree structured intermediate representation onto target machine instructions, HBURG generates a code generator that can be plugged into the instruction selection phase of a compiler. 48. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/libmpd-0.1.3 49. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hS3-0.2 50. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/infinity-0.1.1 51. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/WURFL-0.1 52. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hburg-1.1 * ipprint. Uploaded by Gleb Alexeyev. [53]ipprint, tiny helper for pretty-printing values in ghci console * numbers. Uploaded by Lennart Augustsson. [54]numbers, instances of the numerical classes for a variety of different numbers: (computable) real numbers, arbitrary precision fixed numbers, arbitrary precision floating point numbers, differentiable numbers, symbolic numbers, natural numbers, interval arithmetic. * numeric-quest. Uploaded by Henning Thielemann. [55]numeric-quest, List based linear algebra, similtaneous linear equations, eigenvalues and eigenvectors, roots of polynomials, transcendent functions with arbitrary precision implemented by continued fractions, quantum operations, tensors * shell-pipe. Uploaded by Henning Thielemann. [56]shell-pipe, shell scripting stuff. * hstats. Uploaded by Marshall Beddoe. [57]hstats, library of commonly used statistical functions. 53. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/ipprint-0.3 54. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/numbers-2007.9.25 55. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/numeric-quest-0.1 56. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/shell-pipe-0.1 57. http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hstats-0.2 Libraries This week's proposals and extensions to the [58]standard libraries. * [59]In base, for Data.Version, change the meaning of comparisons * [60]Add Compositor class as superclass of Arrow 58. http://haskell.org/haskellwiki/Library_submissions 59. http://article.gmane.org/gmane.comp.lang.haskell.libraries/7847 60. http://thread.gmane.org/gmane.comp.lang.haskell.libraries/7663 Conference roundup Haskell papers presented at the Haskell Workshp, ICFP and CUFP, in Freiburg, Germany. * [61]Andy Gill and Colin Runciman. Haskell Program Coverage (pdf) 61. http://www.unsafeperformio.com/papers/Hpc07.pdf * [62]Simon Marlow, José Iborra, Bernard Pope and Andy Gill. A Lightweight Interactive Debugger for Haskell (pdf) 62. http://www.haskell.org/~simonmar/papers/ghci-debug.pdf * [63]Wouter Swierstra and Thorsten Altenkirch. Beauty in the Beast: A Functional Semantics of the Awkward Squad (pdf) 63. http://www.cs.nott.ac.uk/~txa/publ/beast.pdf * [64]Matthew Naylor, Emil Axelsson and Colin Runciman. A Functional-Logic Library for Wired (acm.org) 64. http://tinyurl.com/2mw6jo * [65]Neil Mitchell and Colin Runciman. Uniform Boilerplate and List Processing; Or: Scrap Your Scary Types (pdf) 65. http://tinyurl.com/yulkt4 * [66]Philip Wadler and Simon Peyton Jones. Comprehensions with `Order by' and `Group by' 66. http://research.microsoft.com/~simonpj/papers/list-comp/index.htm * [67]Geoffrey Mainland. Why It's Nice to be Quoted: Quasiquoting for Haskell 67. http://www.eecs.harvard.edu/~mainland/ghc-quasiquoting/ * [68]Louis-Julien Guillemette and Stefan Monnier. A Type-Preserving Closure Conversion in Haskell (pdf) 68. http://www.iro.umontreal.ca/~monnier/tcm.pdf * [69]Demo 1: George Giorgidze and Henrik Nilsson. Programming Modular Synthesizer in Haskell (.mov) 69. http://www.ludd.ltu.se/~pj/hw2007/modular%20synthesis.mov * [70]Demo 2: Martin Grabmüller and Dirk Kleeblatt. Run-time Code Generation in Haskell (.mov) 70. http://www.ludd.ltu.se/~pj/hw2007/harpy.mov * [71]Joao Fernandes, Alberto Pardo and João Saraiva. A Shortcut Fusion Rule for Circular Program Calculation (pdf) 71. http://www.fing.edu.uy/~pardo/papers/hw07.pdf * [72]Peng Li, Andrew Tolmach, Simon Marlow and Simon Peyton Jones. Lightweight concurrency primitives for GHC (pdf) 72. http://web.cecs.pdx.edu/~apt/hw07.pdf * [73]Demo 3: Don Stewart XMonad (.mov) 73. http://www.ludd.ltu.se/~pj/hw2007/xmonad.mov * [74]Videos of all the Haskell Workshop talks 74. http://www.ludd.ltu.se/~pj/hw2007/HaskellWorkshop.html * [75]Selected videos from ICFP and IFL 75. http://www.ludd.ltu.se/~pj/icfp2007/ICFP2007.html Jobs Finance. An NYC finance company [76]requires an expert level Haskell user; must be comfortable with monads, monad transformers, type level programming (i.e. MPTC, overlapping and undecidable instances), and lazy evaluation (i.e. know how to find and eliminate space leaks). 76. http://article.gmane.org/gmane.comp.lang.haskell.cafe/30228 Web Developer. RedNucleus Ltd [77]requires a highly motivated programmer for a full or part-time posititon developing social web applications. Initially you will develop and maintain applications using RubyOnRails or a similar framework, but there will be opportunities to explore new web programming paradigms with declarative languages. The successful application will have exposure to functional programming methodologies, e.g. in Haskell, Lisp or Erlang 77. http://article.gmane.org/gmane.comp.lang.haskell.cafe/30685 Blog noise [78]Haskell news from the [79]blogosphere. 78. http://planet.haskell.org/ 79. http://haskell.org/haskellwiki/Blog_articles * [80]Strongly Specified Functions * [81]Amazon S3 binding * [82]Octane Mech, OpenGL Haskell based mech game; early code and some haskell notes * [83]Fast, parallel log file processing in Haskell * [84]Haskell in the Hallway: an interview with Simon Peyton Jones * [85]Agda Exercise: Sized Mergesort * [86]Agda Exercise: Proving that Mergesort Returns Ordered Lists * [87]Lazy functions in C# LlNQ * [88]Functional Javascript * [89]Seemingly impossible functional programs * [90]For most programmers learning Haskell will be no picnic : a tutorial 80. http://sequence.complete.org/node/363 81. http://scsibug.com/2007/09/23/haskell-s3-library/ 82. http://berlinbrowndev.blogspot.com/2007/09/octane-mech-opengl-haskell-based… 83. http://www.serpentine.com/blog/2007/09/25/what-the-heck-is-a-wide-finder-an… 84. http://port25.technet.com/archive/2007/09/26/haskell-in-the-hallway-sam-int… 85. http://www.iis.sinica.edu.tw/~scm/?p=36 86. http://www.iis.sinica.edu.tw/~scm/?p=37 87. http://www.aboutcode.net/2007/09/27/Lazy+Functions+In+LINQ.aspx 88. http://osteele.com/sources/javascript/functional/ 89. http://math.andrej.com/2007/09/28/seemingly-impossible-functional-programs/ 90. http://www.lisperati.com/haskell/ht5.html * [91]Haskell in industry: a surprising encounter! * [92]Exhaustive search over infinite binary trees * [93]How to Install HAppS * [94]Simple Haskell Web Programming with HAppS * [95]Haskell Web Spider, Part 1: HaXML * [96]Haskell Web Spider, Part 2: HXT, or I Was Promised There Would Be No Side Effects * [97]In praise of implementation-defined languages * [98]Arboreal Isomorphisms from Nuclear Pennies * [99]Higher-dimensional enumeration * [100]Haskell and my preception of programming languages 91. http://pinderkent.blogsavy.com/archives/133 92. http://conway.rutgers.edu/~ccshan/wiki/blog/posts/Exhaustive/ 93. http://bluebones.net/2007/09/how-to-install-happs/ 94. http://bluebones.net/2007/09/simple-haskell-web-programming-with-happs/ 95. http://kevin.scaldeferri.com/blog/2007/09/29/UrlSpider1HaXML.html 96. http://kevin.scaldeferri.com/blog/2007/09/30/UrlSpider2HXT.html 97. http://pozorvlak.livejournal.com/70452.html 98. http://sigfpe.blogspot.com/2007/09/arboreal-isomorphisms-from-nuclear.html 99. http://byorgey.wordpress.com/2007/10/01/higher-dimensional-enumeration/ 100. http://serishema.livejournal.com/28327.html * [101]Monads in Scala * [102]Total stream processors and quantification over infinite number of infinite streams * [103]The xmonad experience * [104]Wiring Haskell into a FastCGI Web Server * [105]A Link-Resolving Library * [106]Immutable data structures are the way of the future in C# * [107]What do you get when you curry partial application? * [108]Universal Architecture * [109]lambdacats * [110]A venture into functional programming (by a Python programmer) 101. http://james-iry.blogspot.com/2007/10/monads-are-elephants-part-2.html 102. http://conway.rutgers.edu/~ccshan/wiki/blog/posts/StreamPEval/ 103. http://braindump.dk/tech/2007/10/01/the-xmonad-experience/ 104. http://mult.ifario.us/articles/2007/10/03/wiring-haskell-into-a-fastcgi-web… 105. http://freeshells.ch/~revence/Link.lhs 106. http://blogs.msdn.com/ericlippert/archive/2007/10/04/path-finding-using-a-i… 107. http://tinyurl.com/2mdo93 108. http://luqui.org/blog/archives/2007/10/05/universal-architecture/ 109. http://arcanux.org/lambdacats.html 110. http://pyside.blogspot.com/2007/10/venture-into-functional-programming.html * [111]Is Java Dying? * [112]Tracing your code... the dirty way! * [113]Using Emacs to insert SCC annotations in Haskell code * [114]Erlang and Haskell Books: First Impressions * [115]Update on F# and Haskell, especially monads * [116]Back from ICFP * [117]A Simple RPN Calculator in Haskell * [118]Another simple RPN calculator in Haskell * [119]A simple regex engine in Haskell * [120]The square of the Catalan sequence 111. http://fiatdev.com/2007/10/09/is-java-dying 112. http://monadicheadaches.blogspot.com/2007/10/tracing-your-code-dirty-way.ht… 113. http://www.serpentine.com/blog/2007/10/09/using-emacs-to-insert-scc-annotat… 114. http://on-ruby.blogspot.com/2007/04/erlang-and-haskell-books-first.html 115. http://jan.varwig.org/archiv/update-on-f-and-haskell-especially-monads 116. http://sneezy.cs.nott.ac.uk/fplunch/weblog/?p=75 117. http://jcreigh.blogspot.com/2006/11/simple-rpn-calculator-in-haskell.html 118. http://meta-meta.blogspot.com/2007/10/simple-infix-calculator-in-haskell.ht… 119. http://jcreigh.blogspot.com/2006/12/simple-regex-engine-in-haskell.html 120. http://blog.plover.com/2007/10/12/#catalan-squared * [121]Haskell changing your thinking * [122]How I started off with Haskell and wound up with Lisp * [123]Phantom type problems * [124]My first trip to the phantom zone * [125]Writing Your Last For-Loop * [126]The Curry-Howard Correspondence in Haskell * [127]Tuppence Tour of Haskell Concurrency Constructs * [128]Is Haskell really expressive? * [129]A Quickstart to Haskell * [130]Respect C Programmers 121. http://ephemient.livejournal.com/43696.html 122. http://blog.vagmim.com/2007/10/how-i-started-off-with-haskell-and.html 123. http://therning.org/magnus/archives/322 124. http://therning.org/magnus/archives/323 125. http://beautifulcode.oreillynet.com/2007/10/writing_your_last_forloop.php 126. http://www.thenewsh.com/~newsham/formal/curryhoward/ 127. http://mult.ifario.us/articles/2007/10/21/tuppence-tour-of-haskell-concurre… 128. http://monadicheadaches.blogspot.com/2007/10/is-haskell-reallt-expressive.h… 129. http://www.builderau.com.au/program/soa/A-Quickstart-to-Haskell/0,339024614… 130. http://kontsevoy.blogspot.com/2007/10/respect-c-programmers.html * [131]Building Functions from Functions, part 2: Function Composition * [132]On the Importance of Purity * [133]Functional programming - Back to the Roots * [134]Simpler, Easier! Or, how to write a simple dependent type checker * [135]Is Visual Basic 9 'Haskell for the Masses?' 131. http://diditwith.net/2007/10/23/BuildingFunctionsFromFunctionsPart2Function… 132. http://higherlogics.blogspot.com/2007/10/on-importance-of-purity.html 133. http://blog.codingnaked.com/?p=3 134. http://augustss.blogspot.com/2007/10/simpler-easier-in-recent-paper-simply.… 135. http://blogs.teamb.com/craigstuntz/2007/10/25/37762 Quotes of the Week * As someone who has written production code in functional languages (Ive written Haskell for the U.S. Navy) and in other languages (Perl and Ruby for several startups), I have to say that Haskell enabled me to be way more productive than the untyped scripting languages. Ruby is fun, but Haskell lets me get the work done faster and better. * Perhaps if C wants to be taken seriously it should provide portability, which has been present in Haskell since the beginning * However, since starting learning Haskell I?ve had aha-moments that manifest themselves in a single line of code. This has never happened before. Ever! * Cale: Inheritance? Inheritance is broken, anyway * DRMacIver: I dread to think what category theory would look like after the software engineering world had got their grubby paws on it. Enterprise variant functors. Commutative UML diagrams. * DukeDave: Haskell has the greatest unlearning curve * Jon Harrop: As Haskell has shown, laziness cannot be implemented efficient at all. * Logan Capaldo: All I want for christmas is monad comprehensions * Olathe: We can't be totally sure, though. There might be some value of 1 that wasn't checked. * Pseudonym: Smart programmers naturally write monadic code, even if they don't realise it. * augustss: Haskell already has enterprise monads; there is a fail method. * bitwize: The combinator known as compose; Makes me extremely morose; The full stop is better, than writing in letters; Which makes it extremely verbose * glguy: map became not overloaded in the great polymorphic scare of haskell 98 * mauke: haskell software should move from alpha to beta to eta, then lambda * pl0nk: I wonder what SPJ sees when he closes his eyes before answering a question. About the Haskell Weekly News New editions are posted to [136]the Haskell mailing list as well as to [137]the Haskell Sequence and [138]Planet Haskell. [139]RSS is also available, and headlines appear on [140]haskell.org. Headlines are available as [141]PDF. To help create new editions of this newsletter, please see the [142]contributing information. Send stories to dons at galois.com. The darcs repository is available at darcs get [143]http://www.cse.unsw.edu.au/~dons/code/hwn 136. http://www.haskell.org/mailman/listinfo/haskell 137. http://sequence.complete.org/ 138. http://planet.haskell.org/ 139. http://sequence.complete.org/node/feed 140. http://haskell.org/ 141. http://www.cse.unsw.edu.au/~dons/code/hwn/archives/20071025.pdf 142. http://haskell.org/haskellwiki/HWN 143. http://www.cse.unsw.edu.au/~dons/code/hwn

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