- Haskell-Cafe - Haskell.org

STM program
by Ketil Malde 27 Oct '11

27 Oct '11

Hi, Café, I'm playing with STM a bit, and did a small writeup. As I'm considering to submit it, uh, tomorrow, I was wondering if anybody would care to take a look? I'm especially nervous about the accuracy and clarity of my descriptions of monads and STM, which are terse and written in a hurry. Anyway: I'd be most grateful for any feedback you care to give. http://malde.org/~ketil/stmcluster.pdf -k -- If I haven't seen further, it is by standing in the footprints of giants

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Really impossible to reinstall `base' using cabal?
by Captain Freako 27 Oct '11

27 Oct '11

In response to this: dbanas@dbanas-eeepc:~$ cabal install arrows Resolving dependencies... Configuring lazysmallcheck-0.6... Preprocessing library lazysmallcheck-0.6... Building lazysmallcheck-0.6... [1 of 1] Compiling Test.LazySmallCheck ( Test/LazySmallCheck.hs, dist/build/Test/LazySmallCheck.o ) Implicit import declaration: Could not find module `Prelude': Perhaps you haven't installed the "dyn" libraries for package `base'? Use -v to see a list of the files searched for. cabal: Error: some packages failed to install: Stream-0.4.6 depends on lazysmallcheck-0.6 which failed to install. arrows-0.4.4.0 depends on lazysmallcheck-0.6 which failed to install. lazysmallcheck-0.6 failed during the building phase. The exception was: ExitFailure 1 I did this: dbanas@dbanas-eeepc:~$ cabal install base and got this: Resolving dependencies... cabal: internal error: impossible Is it really impossible to use cabal to reinstall `base'? Thanks, -db

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Haskell Weekly News: Issue 205
by Daniel Santa Cruz 26 Oct '11

26 Oct '11

Welcome to issue 205 of the HWN, a newsletter covering developments in the Haskell community. This release covers the week of October 16 to 22, 2011. You can find an HTML version of this issue at: http://contemplatecode.blogspot.com/2011/10/haskell-weekly-news-issue-205.h… Announcements Ian Lynah sent out a call for nominations for the haskell.org committee. See the link for details on how to submit a nomination. Nominations close on October 29. [1] http://goo.gl/J9J6H New and Updated Projects * netwire (Ertugrul Soeylemez; 1.2.7) [2] http://goo.gl/ULujm Quotes of the Week * kmc: i just used Hayoo to see if anyone implemented this function and it came back with one of my own libraries * JoeyA: LLVM: The easy-to-use compiler infrastructure nobody knows how to use. * kmc: Haskell isn't really designed by mathematicians. it's designed by people who programmers would consider to be mathematicians and mathematicians would consider to be programmers * Cale: foldr is the real fold; foldl is an imposter * @remember hey daniel kmc wants his uploads featured on HWN [edit note: oops, I guess that was meant for me :) +1 for new and inventive ways to communicate!] Top Reddit Stories * Tech-talk about Haskell at Google: Haskell Amuse-Bouche Domain: youtu.be, Score: 86, Comments: 5 On Reddit: [3] http://goo.gl/Pf0NZ Original: [4] http://goo.gl/NPZ17 * Deprecate Prelude.head and partial functions Domain: chrisdone.com, Score: 58, Comments: 60 On Reddit: [5] http://goo.gl/Yat8J Original: [6] http://goo.gl/NyiRO * What does your company use Haskell for? I'll go first. Domain: self.haskell, Score: 51, Comments: 38 On Reddit: [7] http://goo.gl/VOfrO Original: [8] http://goo.gl/VOfrO * I am working on a functional web-programming language as a senior thesis. What do you think so far? Domain: elm-lang.org, Score: 40, Comments: 58 On Reddit: [9] http://goo.gl/6PrQM Original: [10] http://goo.gl/l3odM * Dear Redditor Emac-loving Haskeller(s): what cool emacs Haskell Mode (or custom) features do you use? Domain: self.haskell, Score: 40, Comments: 7 On Reddit: [11] http://goo.gl/LKW0A Original: [12] http://goo.gl/LKW0A * Macros in Haskell Domain: playingwithpointers.com, Score: 38, Comments: 0 On Reddit: [13] http://goo.gl/pwfjt Original: [14] http://goo.gl/bSYN8 * Type-safe event-based programming Domain: jaspervdj.be, Score: 35, Comments: 0 On Reddit: [15] http://goo.gl/gyj9J Original: [16] http://goo.gl/ZBC55 * Yesod excellent ideas Domain: yannesposito.com, Score: 34, Comments: 5 On Reddit: [17] http://goo.gl/ikFJV Original: [18] http://goo.gl/UgBaC * AI Challenge: Ants. Haskell support is only for GHC 6.12. Shall we lobby for 7.0? Domain: aichallenge.org, Score: 28, Comments: 24 On Reddit: [19] http://goo.gl/ShqaM Original: [20] http://goo.gl/O2YOp * Why not Haskell? Domain: neugierig.org, Score: 27, Comments: 26 On Reddit: [21] http://goo.gl/INmRp Original: [22] http://goo.gl/wK3U3 Top StackOverflow Questions * What are some compelling use cases for dependent method types? votes: 44, answers: 2 Read on SO: [23] http://goo.gl/2Xmgu * Why monads? How does it resolve side-effects? votes: 14, answers: 7 Read on SO: [24] http://goo.gl/UJimh * How does Haskell printf work? votes: 13, answers: 1 Read on SO: [25] http://goo.gl/351dE * Why is my genetic algorithm seemingly behaving randomly? votes: 10, answers: 1 Read on SO: [26] http://goo.gl/a5FtH * What are the benefits of applicative parsing over monadic parsing? votes: 10, answers: 4 Read on SO: [27] http://goo.gl/UEkpx * Fixity of backtick operators? votes: 9, answers: 1 Read on SO: [28] http://goo.gl/nwji2 * Bit Size of GHC's Int Type votes: 8, answers: 2 Read on SO: [29] http://goo.gl/DDtFZ * Simple word count in haskell votes: 8, answers: 4 Read on SO: [30] http://goo.gl/ZAYyT * existential search and query without the fuss votes: 8, answers: 2 Read on SO: [31] http://goo.gl/Fnes6 * How to selectively link certain system libraries statically into Haskell program binary? votes: 8, answers: 2 Read on SO: [32] http://goo.gl/HjPTc Until next time, Daniel Santa Cruz References 1. http://permalink.gmane.org/gmane.comp.lang.haskell.general/18983 2. http://permalink.gmane.org/gmane.comp.lang.haskell.cafe/93163 3. http://youtu.be/b9FagOVqxmI 4. http://www.reddit.com/r/haskell/comments/lkiiw/techtalk_about_haskell_at_go… 5. http://chrisdone.com/posts/2011-10-17-boycott-head.html 6. http://www.reddit.com/r/haskell/comments/lf71l/deprecate_preludehead_and_pa… 7. http://www.reddit.com/r/haskell/comments/lfwlv/what_does_your_company_use_h… 8. http://www.reddit.com/r/haskell/comments/lfwlv/what_does_your_company_use_h… 9. http://elm-lang.org/ 10. http://www.reddit.com/r/haskell/comments/liqb4/i_am_working_on_a_functional… 11. http://www.reddit.com/r/haskell/comments/llt44/dear_redditor_emacloving_has… 12. http://www.reddit.com/r/haskell/comments/llt44/dear_redditor_emacloving_has… 13. http://playingwithpointers.com/archives/615 14. http://www.reddit.com/r/haskell/comments/lgeuk/macros_in_haskell/ 15. http://jaspervdj.be/posts/2011-10-16-type-safe-events.html 16. http://www.reddit.com/r/haskell/comments/le2dk/typesafe_eventbased_programm… 17. http://yannesposito.com/Scratch/en/blog/Yesod-excellent-ideas/ 18. http://www.reddit.com/r/haskell/comments/lj2br/yesod_excellent_ideas/ 19. http://aichallenge.org/starter_packages.php 20. http://www.reddit.com/r/haskell/comments/ljs9z/ai_challenge_ants_haskell_su… 21. http://neugierig.org/software/blog/2011/10/why-not-haskell.html 22. http://www.reddit.com/r/haskell/comments/lfv4b/why_not_haskell/ 23. http://stackoverflow.com/questions/7860163/what-are-some-compelling-use-cas… 24. http://stackoverflow.com/questions/7840126/why-monads-how-does-it-resolve-s… 25. http://stackoverflow.com/questions/7828072/how-does-haskell-printf-work 26. http://stackoverflow.com/questions/7792456/why-is-my-genetic-algorithm-seem… 27. http://stackoverflow.com/questions/7861903/what-are-the-benefits-of-applica… 28. http://stackoverflow.com/questions/7807994/fixity-of-backtick-operators 29. http://stackoverflow.com/questions/7786662/bit-size-of-ghcs-int-type 30. http://stackoverflow.com/questions/7803449/simple-word-count-in-haskell 31. http://stackoverflow.com/questions/7813691/existential-search-and-query-wit… 32. http://stackoverflow.com/questions/7832112/how-to-selectively-link-certain-…

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Operator precedence and associativity with Polyparse
by Tom Hawkins 26 Oct '11

26 Oct '11

Hi, Can someone provide guidance on how handle operator precedence and associativity with Polyparse? Thanks in advance. -Tom

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Re: [Haskell-cafe] Open CV or alternate image processing library for Haskell on windows?
by Ivan Perez 26 Oct '11

26 Oct '11

Hi, Sorry for reopening an old thread (May 2011), but I just want to report that I'm using HOpenCV and cv-combinators under windows and I just wanted to tell you that it works just fine. I downloaded the opencv2 libraries as stated on this thread, and I'm successfully building software that works both on Windows (XP and 7, both x86) and Linux (x86 & amd64). The software will be released in a few days, if everything goes well. You'll be able to find it at keera.es, but I'll let you know when I release it anyway. Cheers, Ivan Perez. PS. I just re-subscribed to this mailing list. I can't reply to the old messages (don't have them), and I can't set the old Message-ID with gmail, so I'm providing a link to the original message. [1] http://www.mail-archive.com/haskell-cafe@haskell.org/msg89834.html

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blanket license for Haskell Platform?
by Eric Y. Kow 25 Oct '11

25 Oct '11

So I'm combining Haskell software with some non-free/closed source work. I was wondering what sort of effort it would take to organise a blanket license for everything in the Haskell Platform, and whether it would be worthwhile to anybody. Here's my use case: - I am combining my Haskell [:-)] program with some non-free/closed source [:-(] software - My user is concerned that a large number of having a large number of individual licenses even though textually identical modulo author, date, etc would mean a big hassle getting their lawyers and their user's lawyers to sign off on each and every license I feel a bit embarrassed asking this as it's already great and also very convenient that I can just grab this closed source stuff, but suppose we were to decide that putting together some sort of blanket license for the Haskell Platform would be a good idea. How would we go about organising such an effort? I wonder if this is a sort of thing we could tie to the IHG... Thanks, -- Eric Kow <http://erickow.com>

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Re: [Haskell-cafe] ANNOUNCE: Hac Boston from January *20-22* at MIT
by Edward Kmett 25 Oct '11

25 Oct '11

Correction: January 20-22nd ;) On Tue, Oct 25, 2011 at 5:45 PM, Edward Kmett <ekmett(a)gmail.com> wrote: > I am very pleased to officially announce Hac Boston, a Haskell hackathon > to be held January 21-23, 2012 at MIT in Cambridge, MA. > > The hackathon will officially kick off at 2:30 Friday afternoon, and go > until 5pm on Sunday with the occasional break for sleep. > > Everyone is welcome -- you do not have to be a Haskell guru to attend! > Helping hack on someone else's project could be a great way to increase > your Haskell skills. > > If you plan on coming, please officially register<http://haskell.org/haskellwiki/Hac_Boston/Register>, > even if you already put your name on the wiki. Registration, travel, some > information about lodging and many other details can now be found on the Hac > Boston wiki <http://haskell.org/haskellwiki/Hac_Boston>. > > We have confirmed space for about 30 people, so please register early! > Beyond that we'll have to either seek additional space or close > registration. > > We're also looking for a few people interested in giving short (15-20 min.) > talks, probably on Saturday afternoon. Anything of interest to the > Haskell community is fair game---a project you've been working on, a > paper, a quick tutorial. If you'd like to give a talk, add it on <http://goog_145539007>the > wiki <http://haskell.org/haskellwiki/Hac_Boston/Talks>. > > We look forward to seeing you at MIT! > > -Edward Kmett >

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ANNOUNCE: Hac Boston from January 21-23rd at MIT
by Edward Kmett 25 Oct '11

25 Oct '11

I am very pleased to officially announce Hac Boston, a Haskell hackathon to be held January 21-23, 2012 at MIT in Cambridge, MA. The hackathon will officially kick off at 2:30 Friday afternoon, and go until 5pm on Sunday with the occasional break for sleep. Everyone is welcome -- you do not have to be a Haskell guru to attend! Helping hack on someone else's project could be a great way to increase your Haskell skills. If you plan on coming, please officially register<http://haskell.org/haskellwiki/Hac_Boston/Register>, even if you already put your name on the wiki. Registration, travel, some information about lodging and many other details can now be found on the Hac Boston wiki <http://haskell.org/haskellwiki/Hac_Boston>. We have confirmed space for about 30 people, so please register early! Beyond that we'll have to either seek additional space or close registration. We're also looking for a few people interested in giving short (15-20 min.) talks, probably on Saturday afternoon. Anything of interest to the Haskell community is fair game---a project you've been working on, a paper, a quick tutorial. If you'd like to give a talk, add it on <goog_145539007>the wiki<http://haskell.org/haskellwiki/Hac_Boston/Talks> . We look forward to seeing you at MIT! -Edward Kmett

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List archives searchable?
by Captain Freako 25 Oct '11

25 Oct '11

Are the archives of this list searchable?

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ANN: diagrams 0.4
by Brent Yorgey 25 Oct '11

25 Oct '11

I am pleased to announce the release of version 0.4 of diagrams, a full-featured framework and embedded domain-specific language for declarative drawing. The last announcement was of the 0.1 release; there have been quite a few changes and improvements since then, including: - A new website including a gallery of examples: http://projects.haskell.org/diagrams/gallery.html - A new comprehensive user manual with lots of illustrative examples: http://projects.haskell.org/manual/diagrams-manual.html - New primitive shapes: rounded rectangles, wedges, and a new flexible API for generating polygons - Cubic splines - Basic text support - Support for external image primitives - Lots more convenient combinators, bug fixes, and improvements Cool, how can I try it out? --------------------------- For the truly impatient: cabal install gtk2hs-buildtools cabal install diagrams For the slightly less impatient, read the quick tutorial, which has detailed information about how to install the necessary packages and will introduce you to the fundamentals of the framework: http://projects.haskell.org/diagrams/tutorial/DiagramsTutorial.html For those who are even less impatient but want to really dig in and use the power features, read the user manual: http://projects.haskell.org/manual/diagrams-manual.html Cool, how can I contribute? --------------------------- There are lots of ways you can contribute! First, you may want to subscribe to the project mailing list (http://groups.google.com/group/diagrams-discuss) and/or come hang out in the #diagrams IRC channel on freenode.org. - There are lots of easy bug fixes, improvements, and feature requests just waiting for people wanting to get involved: see the bug tracker for a list of open tickets: http://code.google.com/p/diagrams/issues/list - The source repositories are mirrored using both darcs (on patch-tag.com) and git (on github.com) and patches are accepted in either place, thanks to Owen Stephen's great work on darcs-bridge [1]. - Create a higher-level module built on top of the diagrams framework (e.g. tree or graph layout, generating Turing machine configuration diagrams, Penrose tilings ... your imagination is the only limit!) and submit it for inclusion in a special diagrams-contrib package which will be created for such higher-level user-contributed modules. - Use diagrams to create some cool graphics and submit them for inclusion in the gallery. - Start your own project built on top of diagrams and let us know how it goes! - Last but certainly not least, just try it out for your pet graphics generation needs and contribute your bug reports and feature requests. Happy diagramming! Brought to you by the diagrams team: - Brent Yorgey - Ryan Yates with contributions from: - Sam Griffin - Claude Heiland-Allen - John Lato - Vilhelm Sjöberg - Luite Stegeman - Kanchalai Suveepattananont - Scott Walck [1] http://wiki.darcs.net/DarcsBridgeUsage

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