- Haskell-Cafe - Haskell.org

Haskell.org and Google Summer of Code 2006
by Paolo Martini 26 Apr '06

26 Apr '06

Hello, It is now official. Haskell.org is a mentoring organization for this year's Summer of Code programme. You can see it listed on the official site <http://code.google.com/soc/> clicking on `Haskell.org (ideas)' you'll be directed to the trac site we are setting up. (It's 4 AM and I've just finished adding the projects, and cleaning things up a bit.) I am _very_ happy about seeing this project working out for real. I fear that I wouldn't be able to reach everybody even mailing all the important mailing list; I hope many students will be able to take advantage of this great occasion. Help me spread the word, tell everybody about the project :-) You can find the new site here <http://hackage.haskell.org/trac/summer-of-code/>, the StartPage will be updated with details during the program. Projects ideas and volunteers for mentoring are still very much welcome! students' application period starts on May 1. Thanks very much for the support, hope to hear thoughts and proposals, Paolo. --

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Project proposal
by michael＠schmong.org 26 Apr '06

26 Apr '06

Hi, All this chatter about the Summer of Code has inspired me to throw caution to the wind and become more committed to an idea I had for a Haskell project. I first thought to apply this to Python, but well, Haskell stole my heart. I wanted to throw the idea out there and see if anyone was interested in mentoring me through the process. I want to build a MUD engine written in Haskell with Haskell as the MUD development language. This is a great way to introduce kids to Haskell as their first programming language. And when they get bored and grow out of mudding, they will have knowledge of a real-world language instead of just a toy language particular to whatever MUD they were playing with. Getting a mentor, and completing the project is more important to me than officially becoming a Summer of Code project. But if they both happen then all the better. Any takers? Michael Litchard of Mission College Santa Clara , CA

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Google Summer of Code 2006
by Paolo Martini 25 Apr '06

25 Apr '06

Hello, Haskell.org is going to partecipate as mentoring organization to the Google Summer of Code programme of this year. We have formed a group of volunteers taking care of the administrative work as well as the mentoring part. The group is listed here: <http://haskell.org/haskellwiki/Summer_of_Code:_People>. We are now looking for projects, and mentors. We've reached number 24 but we are happily going to add more, Haskell Open Source paid work for the summer! If you run some active open source program you might want to mentor some student who will be working on your code, for example. Either just add your ideas here: <http://haskell.org/haskellwiki/Summer_of_Code:_Project_suggestions> (as well as your informations on the People's page) or contact me for details. I am also looking for students, I'd like to ear from them if they are going to partecipate with Haskell projects, last year I was alone! (I did write the bindings to the Cairo vector graphics library and integrated them in Gtk2Hs.) Details about the programme itself can be found on the official webpage: http://code.google.com/summerofcode.html Hoping you like the idea as much as me, Paolo. --

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Re: [Haskell-cafe] Google Summer of Code 2006
by Paolo Martini 25 Apr '06

25 Apr '06

Evan Martin ha scritto: > (This is Evan from Google.) > Just wanted to say that it's rad to see you making all this happen. Hi Evan! Fabulous to see you around! Thank you very much, we have done great work last year. Google is doing so well making students able to work on what they like most, during the summer, I couldn't resist about sharing this opportunity and making it available for the bigger number of people I could. Cheers, Paolo. --

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Control.Exceptions and MonadIO
by oleg＠pobox.com 24 Apr '06

24 Apr '06

Robert Dockins wrote: > One additional (very unfortunate) point is that higher-order IO monad > combinators will not work on your monad, eg, the ones in > Control.Exception. Although that is true in general, for many useful and interesting cases (including ReaderT, the state transformer, and the newtype wrapping of IO) one _can_ use catch, bracket etc. constructs in MonadIO. Please see this message and the follow-up discussion: http://www.haskell.org/pipermail/haskell/2006-February/017547.html

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How to get Haddock to generate docs for a directory tree of modules
by Brian Hulley 24 Apr '06

24 Apr '06

Hi - I've been looking at the docs for Haddock at http://haskell.org/haddock/haddock-html-0.7/index.html but I can't seem to find any option to recursively traverse a directory generating hyperlinked docs for all modules anywhere in the directory or any sub directory etc. Is there a simple undocumented flag I'm missing? Thanks, Brian.

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Advice needed on best way to simulate an STL vector
by Brian Hulley 24 Apr '06

24 Apr '06

Hi - In C++, STL provides a vector class which behaves as an array except you can insert/delete elements from it. I'm wondering what is the best Haskell data structure to use to simulate this, either mutable or immutable. I've looked at the Array interface, but although there is the // operation to replace some elements, there does not appear to be a simple way to delete/insert elements. Ideally I'd like functions like: -- Insert new elements starting at the specified index, moving the others up to make room insert:: Array i e -> i -> [e] -> Array i e -- Delete a range of elements, moving later elements back down delete:: Array i e -> i -> i -> Array e -- Append a new element to the end of an array push_back :: Array i e -> e -> Array i e Is there an efficient way of implementing these operations in Haskell, based on arrays, or should I be using some other data structure altogether eg a list? Also, for large arrays, am I right in thinking that it is still more efficient to use immutable arrays rather than mutable arrays (because it is easier for gc to always just deal with immutable values)? Thanks, Brian.

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Independent component analysis and RDF
by Joel Reymont 24 Apr '06

24 Apr '06

Howdy folks! Does anyone have sample code for independent component analysis (ICA), singular value decomposition (SVD) aka spectral graph partitioning, or semidiscrete decomposition (SDD)? I'm trying to learn this rocket science and apply it to RDF graph analysis. Thanks, Joel -- http://wagerlabs.com/

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Re: Predicates in HaXml
by luby liao 23 Apr '06

23 Apr '06

For this purpose, try h1 [keep /> dfilter (parseXtract "/greetings/greeting[1]/-")] cheers, Luby Liao > I am just trying out a few things with the Xtract tool. I have a > simple XML document: > > <greetings> > <greeting>hello</greeting> > <greeting>world</greeting> > </greetings> > > I am using the Xtract query /greetings/greeting[1]/- hoping to get the > text "world" > e.g. > mkElem "h1" [applypred (keep) (parseXtract "/greetings/greeting[1]/-")] > > but this just returns the entire xml document. Have i got something > fundamentally wrong here? > > Thanks > Tom Spencer > >

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Re: [Haskell] Haskell.org and Google Summer of Code 2006
by Creighton Hogg 22 Apr '06

22 Apr '06

Well, now that we've started this discussion I presume it's okay if I ask a few things. I don't know if these are good ideas, but I thought I'd throw them out. Basically, I am a student and would be eligible for the SoC. I'd like to work on something related to numerics support or performance in Haskell. Either building on existing gsl bindings, making something out of whole cloth, or spending some intensive work on compiler optimizations. My dream would be to build up enough monte carlo support in haskell that things like high energy physics event simulators could be coded in the language without sacrificing too much performance and having a hundred times the flexibility and *maintainability*. Creighton Hogg On 4/22/06, Paolo Martini <paolo(a)nemail.it> wrote: > Hello everybody, nice to meet you all. > > Last year I did work on an Haskell project during the first year of > the Google Summer of Code programme[1]. I wrote the bindings to the > Cairo Vector Graphics library and integrated them in Gtk2Hs. You can > see last year's announcement on the website[2]. > > I had to take Google itself as my mentoring organization, in absence > of a better-suited one, no wonder I was the only one with an Haskell > project, eventually I got one of its 13 slots available -- Chris > DiBona[3], the project leader, seem to like Haskell very much! > > They recently announced they would be running the programme again > this year, and I thought we could surely do better! My idea is that > the best way we are going to get more Haskell projects done is having > Haskell.org as a mentoring organization this year. > > Let me briefly summarize how the project works; it starts with a > number of mentoring organizations that support active open source > projects. They are required to publish a list of projects for > students to apply for, and some mentors which will take care of the > pupils during their work. Part of the fun is of course that the > students can propose their own projects too. Each successful > applicant gets an initial $500, three months of coding time, a mid- > term $2,000 of are doing well and a final $2,000 on successful > completion of the project (The site[4] does explain it all.) > > I contacted many of the people who usually reside in the #haskell IRC > channel asking for collaboration, and they promptly accepted, forming > a quite big number of well organized people -- as now, those three > people are in charge for the administrative work: > > - Isaac Jones <http://www.syntaxpolice.org/>, > - Donald Bruce Steward <http://www.cse.unsw.edu.au/~dons/>, > - David Himmelstrup <http://darcs.haskell.org/~lemmih/aboutMe.html>. > > Not surprisingly, since the people of the channel are known to be > very kind and helpful, answering questions at every time of the day, > I've got a good number of volunteers for mentoring too (which I'm > very happy about): > > - David Himmelstrup, > - John Goerzen <http://www.complete.org/>, > - Cale Gibbard <http://www.haskell.org/hawiki/CaleGibbard>, > - Einar Karttunen <http://www.cs.helsinki.fi/u/ekarttun/>, > - Shae Matijs Erisson <http://www.ScannedInAvian.com/>, > - Duncan Coutts <http://haskell.org/gtk2hs/development/>. > - Andres L\¨oh <http://www.iai.uni-bonn.de/~loeh>, > - Ian Lynagh <http://web.comlab.ox.ac.uk/oucl/work/ian.lynagh/>, > > And the list is getting bigger and bigger! > > Unsure about where to get an "authoritative answer" about things like > this I have mailed Simon Peyton-Jones, he likes the idea (Thanks very > much!) He explained to me that since the Haskell community is very > decentralized I would better send a message to the Haskell mailing > list to propose this project. > > I hope you will be as enthusisatic as I am. Hacking Haskell code > during the summer, funded enough to keep up with the other things > (and getting some pretty cool hardware lately), was a *great* > experience. > > I sincerely hope that many students will apply for Haskell works. We > need projects done! I'll be mailing you the url of the wikipage > collecting projects and details. > > Thank you very much, > Paolo. > -- > > [1] <http://code.google.com/summerofcode.html> > [2] <http://haskell.org/gtk2hs/?p=30> > [3] <http://dibona.com> > > _______________________________________________ > Haskell mailing list > Haskell(a)haskell.org > http://www.haskell.org/mailman/listinfo/haskell >

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