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PhD position at Ghent University
by Tom Schrijvers 07 Dec '11

07 Dec '11

The Programming Languages Group of Ghent University invites applicants for a PhD position. This position centers around the modular treatment of side-effects in purely functional programs and models. It is part of the project "Modular handling of effects in purely functional programs and models" under the direction of Tom Schrijvers. The successful applicant has a master degree in Computer Science or equivalent. Ideally, she/he will also have a strong, documented interest in doing research. Strong problem-solving and programming skills are essential. Prior knowledge of purely functional programming (e.g., Haskell) and models of side-effects (e.g., monads) is an advantage. The PhD position is for 4 years. It starts between January and October 2012. The position is a fully-funded post. The salary is compatible with other Belgian PhD rates and among the better ones in Europe and abroad. For more information, see: http://users.ugent.be/~tschrijv/phdposition2.html -- prof. dr. ir. Tom Schrijvers Programming Languages Group Department of Applied Mathematics and Computer Science University of Ghent Krijgslaan 281 S9 9000 Gent Belgium Phone: +32 9 264 4805 http://users.ugent.be/~tschrijv/

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Neither of the sparks are converted into OS threads but parallelization happens surprisingly!!!
by Burak Ekici 07 Dec '11

07 Dec '11

Dear List, I have a point misunderstood! I am using second generation strategies of Haskell to parallelize some number of algorithms in Haskell. The missing point here is that: In some cases, neither of created sparks are converted into OS threads, but parallelization happens surprisingly, when I use threadscope to see what had happened during the evaluation. What happened to me was that 2 sparks were created one of which was pruned, none of which was converted into OS threads and the last one was missing, however, parallelism happened!!! I wonder what is the reason for this? Could someone aware, please shed light on the issue? Thanks in advance. Saluti, Burak.

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Haskell at University in Munich
by Bartosz Wójcik 06 Dec '11

06 Dec '11

Hello Haskell Cafe, I would be grateful for any information regarding Haskell (or at least Functional Programming) lectures at Universities near to Munich, Germany (Master or Bachelor). Unconfirmed information I've got regarding LMU and TUM are not promising. If Munich and 200 km circle do not provide with any offer, perhaps you may know what is available in Europe, limiting language of study to [German, English, Polish]? Best regards, Bartek

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Re: [Haskell-cafe] Haskell at University in Munich
by Janis Voigtländer 06 Dec '11

06 Dec '11

Am 05.12.2011 12:00, schrieb <bartek(a)sudety.it>: > Hello Haskell Cafe, > > I would be grateful for any information regarding Haskell (or at least > Functional Programming) lectures at Universities near to Munich, Germany > (Master or Bachelor). Unconfirmed information I've got regarding LMU and TUM > are not promising. Is Munich really that bad? FP'ers at LMU and TUM, please speak up. (I know that at least research-wise there are quite a few around there, though I don't know what they do in teaching.) > If Munich and 200 km circle do not provide with any offer, perhaps Less than 200 km from Munich: http://db.inf.uni-tuebingen.de/teaching/ws1112/afp Also, Germany extends farther than 200 km beyond Munich. :-) Say, Bonn: http://www.iai.uni-bonn.de/~jv/teaching/dp11/ http://www.iai.uni-bonn.de/~jv/teaching/ffp/ > you may know what is available in Europe, limiting language of study > to [German, English,Polish]? The thread Sean pointed to may provide information on that. Obvious candidates are Utrecht and Chalmers, both teaching in English I suppose, at least at Master level. Best, Janis. -- Jun.-Prof. Dr. Janis Voigtländer http://www.iai.uni-bonn.de/~jv/ mailto:jv@iai.uni-bonn.de

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Haddock and the qualified imports
by Yves Parès 06 Dec '11

06 Dec '11

Hi, I noticed some time ago the fact that qualified imports doesn't affect the generated documentation. It's kind of clumsy in case of libraries that define a lot of synonyms (vector and bytestring come in my mind first). For instance, in the package utf8-string: http://hackage.haskell.org/packages/archive/utf8-string/0.3.7/doc/html/Data… Here, the documentation doesn't say that the utf8-string/Data.ByteString.UTF8.ByteString datatype used all along comes in fact from Data.ByteString. If it were instead a new implementation of ByteString (as for bytestring/Data.ByteString.Char8.ByteString) the documentation would look exactly the same, so to disambiguate to reader has to crawl through the code to get to the initial definition. (clicking on a 'ByteString' doesn't even redirect you to the original bytestring/Data.ByteString page) It should be written that this 'ByteString' is not a newly defined type but instead a re-exportation. It's even worse when you see the doc of a module that uses in the meantime lazy and strict ByteStrings, or normal and unboxed/storable/<insert flavour here> vector: you have to hover the type name to see which haddock page it points to. In that case, a solution might be to indicate on top of the doc page that it uses another module as a qualified import, and to keep the prefixes in the function signatures.

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Where threadSleep is defined?
by dokondr 06 Dec '11

06 Dec '11

Hi, I need to make the current process (executing thread) go to sleep for a given amount of time. Can't find where threadSleep is defined. Thanks!

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List x ByteString x Lazy Bytestring
by John Sneer 06 Dec '11

06 Dec '11

Hello Café, I've used Haskell and GHC to solve particular real life application. 4 tools were developed and their function is almost the same - they modify textual input according to patterns found in the text. Thus, it is something like a compiler, the result is also a text and it is not parsed to tokens as patterns appear on a different level. The tools differ in tasks and number of modifications performed, otherwise, in principal, they are very much similar. I used lists (Prelude, Data.List) to develop the tools. After successfully completing the development, I've started to optimize the code to make the tools faster. After modification of some algorithms (which dropped the processing time notably), I started to change data structures. I swapped lists with lazy bytestrings. Nevertheless, what an unpleasant surprise, the processing speed dropped down, significantly / more then 30% time needed). So my questions follow: - What kind of application is lazy bytestring suitable for? - Would it be worth using strict bytestring even if input files may be large? (They would fit in memory, but may consume whole) - If bytestring is not suitable for text manipulation, is there something faster than lists? - It would be nice to have native sort for lazy bytestring - would it be slower than pack $ Data.List.sort $ unpack ? - If bytestring is suitable for text manipulation could we have some hGetTextualContents which translates Windows EOL (CR+LF) to LF? I'm sorry if the answers are obvious. Could anyone point me to some article/pages I could read about? Thanks and regards, John -- http://www.fastmail.fm - A fast, anti-spam email service.

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Complete package description list
by Shakthi Kannan 06 Dec '11

06 Dec '11

Hi, I would like to know: 1. The correct source to get the complete list of available Haskell package descriptions 2. Any feed or notification mechanism to get newer updates on packages How often does the 00-index.tar.gz file from: http://hackage.haskell.org/packages/archive/00-index.tar.gz get updated? Or if there is a newer version, where is it made available? Given 00-index.tar.gz, and using the following RSS feed: http://hackage.haskell.org/packages/archive/recent.rss give me the complete list of available packages? Appreciate any suggestions in this regard, Thanks! SK -- Shakthi Kannan http://www.shakthimaan.com

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ANNOUNCE: monad-control-0.3
by Bas van Dijk 06 Dec '11

06 Dec '11

Hello, I just released monad-control-0.3. The package for lifting control operations (like catch, bracket, mask, alloca, timeout, forkIO, modifyMVar, etc.) through monad transformers: http://hackage.haskell.org/package/monad-control-0.3 It has a new and improved API which is: * easier to understand by explicitly representing the monadic state using type families. * 60 times faster than the previous release! * more general because control operations can now, not only be lifted from IO, but from any base monad (ST, STM, etc.) I also released a new package: lifted-base: http://hackage.haskell.org/package/lifted-base-0.1 It provides lifted versions of functions from the base library. Currently it exports the following modules: * Control.Exception.Lifted * Control.Concurrent.Lifted * Control.Concurrent.MVar.Lifted * System.Timeout.Lifted These are just modules which people have needed in the past. If you need a lifted version of some function, just ask me to add it or send me a patch. Note that Peter Simons just discovered that these packages don't build with GHC-7.0.4 (https://github.com/basvandijk/monad-control/issues/3) I just committed some fixes which enable them to be build on GHC >= 6.12.3. Hopefully I can release these fixes this weekend. Regards, Bas

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Re: [Haskell-cafe] How to get a file path to the program invoked?
by Greg Weber 06 Dec '11

06 Dec '11

In addition to argv[0] http://hackage.haskell.org/packages/archive/system-argv0/0.1/doc/html/Syste… There is also this package: http://hackage.haskell.org/packages/archive/FindBin/0.0.5/doc/html/System-E… System-Argv0 has special cases for windows- FindBin may not work there.

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