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RE: [Haskell] writeFile for a looong string
by Simon Marlow 14 Jul '05

14 Jul '05

On 14 July 2005 10:08, Johannes Waldmann wrote: > I am writing a long string (several MByte) to a file, > with writeFile fname ( render d ) > where d :: Text.PrettyPrint.HughesPJ.Doc > > I wonder what happens internally > (when compiled with ghc -O, if that matters) > Will the string be in memory completely > before it is actually written? No, it should be streamed to the output in constant space, as long as the String can be evaluated lazilly. Cheers, Simon

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line-based interactive program
by mt 14 Jul '05

14 Jul '05

hi, i'd like to know how to write simply a line-based interactive program, that is one with which you have a 'talk'. a simple filter-like line-based program ca be written as: -- a filter program process an entire input to yield some output type FilterProgram = [Line] -> [Line] but i don't knwo how to handle input/output such that the output can be printed before all the input exists (the user enter some lines, the program writes a response based on those lines, and so on) what's the simplest/most elegant approach ? thanks, minh thu

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writeFile for a looong string
by Johannes Waldmann 14 Jul '05

14 Jul '05

Dear all, I am writing a long string (several MByte) to a file, with writeFile fname ( render d ) where d :: Text.PrettyPrint.HughesPJ.Doc I wonder what happens internally (when compiled with ghc -O, if that matters) Will the string be in memory completely before it is actually written? My d is in fact vcat xs, for a list xs that is generated item by item. Is there a way to get more efficient behaviour without too much rewriting the program? -- -- Johannes Waldmann -- Tel/Fax (0341) 3076 6479/80 -- ---- http://www.imn.htwk-leipzig.de/~waldmann/ -------

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Template id function
by Mads Lindstrøm 13 Jul '05

13 Jul '05

Hi I am trying to learn Meta Haskell. One thing I want to do is create an identity function. It should get a type constructor as input and return the same type constructor as output. It should be possible to do: $(idDecl data Foo = Foo Int) and it should "return": data Foo = Foo Int Is this possible? if yes, how does one do it? -- Mads Lindstrøm <mads_lindstroem(a)yahoo.dk>

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PADL'06 Call for Papers
by Logic Programming Rsrch Association 12 Jul '05

12 Jul '05

----------------------------------------------------------------------------- CALL FOR PAPERS!!! Eighth International Symposium on Practical Aspects of Declarative Languages 2006 (PADL '06) http://www.cs.brown.edu/people/pvh/PADL06.html Charleston Place Hotel Charleston, South Carolina January 9-10 Co-located with ACM POPL'06 Declarative languages build on sound theoretical bases to provide attractive frameworks for application development. These languages have been successfully applied to vastly different real-world situations, ranging from data base management to active networks to software engineering to decision support systems. New developments in theory and implementation have opened up new application areas. At the same time, applications of declarative languages to novel problems raises numerous interesting research issues. Well-known questions include designing for scalability, language extensions for application deployment, and programming environments. Thus, applications drive the progress in the theory and implementation of declarative systems, and benefit from this progress as well. PADL is a forum for researchers and practioners to present original work emphasizing novel applications and implementation techniques for all forms of declarative concepts, including, functional, logic, constraints, etc. Topics of interest include: * innovative applications of declarative languages; * declarative domain-specific languages and applications; * practical applications of theoretical results; * new language developments & their impact on applications; * evaluation of implementation techniques on practical applications; * novel uses of declarative languages in the classroom; and * practical experiences PADL 06 welcomes new ideas and approaches pertaining to applications and implementation of declarative languages, and is not limited to the scope of the past five PADL symposia. PADL 06 will be co-located with the ACM POPL. IMPORTANT DATES AND SUBMISSION GUIDELINES Paper Submission: August 20, 2005 Notification: September 30, 2005 Final Manuscript: October 20, 2005 Symposium: January 9-10, 2005 Authors should submit an electronic copy of the full paper (written in English) in Postscript (Level 2) or PDF. Papers must be no longer than 15 pages, written in 11-point font and with single spacing. Since the final proceedings will be published as Lecture Notes in Computer Science by Springer Verlag, authors are strongly encouraged to use the LNCS paper formatting guidelines for their submission. Each submission must include on its first page the paper title; authors and their affiliations; contact author's email and postal addresses, telephone and fax numbers, abstract, and three to four keywords. The keywords will be used to assist us in selecting appropriate reviewers for the paper. If electronic submission is impossible, please contact the program chair for information on how to submit hard copies. MOST PRACTICAL PAPER AWARD The Most Practical Paper award will be given to the submission that is judged by the programm committee to be the best in terms of practicality, originality, and clarity of presentation. The program committee may choose not to make an award; or may make multiple awards. PROGRAM COMMITTEE: Kenichi Asai Ochanomizu University, Japan Daniel Damien BRICS, Denmark Mireille Ducasse IRISA/INSA of Rennes, France Matthew Flatt University of Utah, US Gopal Gupta University at Texas at Dallas, US Manuel Hermenegildo UP Madrid, Spain Paul Hudak Yale University, US Narendra Jusien Ecole des Mines de Nantes, France Laurent Michel University of Connecticut, US Enrico Pontelli New Mexico State University Gopalan Nadathur U. of Minnesota, US Vitor Santos-Costa U. Federal do Rio de Janeiro, Brazil Christian Schulte Royal Institute of Technology, Sweden Peter Stuckey U. of Melbourne, Australia Pascal Van Hentenryck Brown University, US Peter van Roy U. of Louvain, Belgium David S. Warren SUNY at Stony Brook, US Roland Yap National U. of Singapore, Singapore Contacts: For information about papers and submissions, please contact the Program Chair: Pascal van Hentenryck PC Chair - PADL 2006 Department of Computer Science Brown University Providence, RI, U.S.A. Email: pvh(a)cs.brown.edu For other information about the conference and the summer school, please contact: Gopal Gupta Department of Computer Science University at Texas at Dallas Dallas, TX, U.S.A. Email: gupta(a)utdallas.edu Sponsored by COMPULOG Americas (http://www.cs.nmsu.edu/~complog)

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Using hs-plugins
by Thomas Davie 12 Jul '05

12 Jul '05

I've been trying to get hs-plugins working on a box, to use the Eval module, but the register script seems not to register the eval package, or the printf module, which judging by the readme: --- And to unregister (maybe as root). Note that the unistall order matters: $ ghc-pkg -r printf $ ghc-pkg -r eval $ ghc-pkg -r plugins $ ghc-pkg -r hi $ ghc-pkg -r altdata --- it should have registered. Have I missed something really obvious? Bob

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Re: ST Monad and all that
by Srinivas Nedunuri 11 Jul '05

11 Jul '05

OK, thanks for the references. I think I've got a better handle on what's what. The library documentation mentions the ability to convert the ST monad into an IO monad. What are the reasons/pluses/minuses of doing this? (I can see one reason being that you won't have to use monad transformers to try and thread two different monads through your code). Also, I didn't see any mention of a mutable List - I suppose you have to use Data.Array.ST? cheers

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Project to add cairo support to Gtk2Hs wins Google Summer of Code grant
by Duncan Coutts 10 Jul '05

10 Jul '05

All, We are very pleased to announce that Paolo Martini's project proposal to add support for the new cairo[1] vector graphics library to Gtk2Hs[2] has been selected to receive a grant in Google's Summer of Code[3] programme. This will make it possible to create GUIs in Haskell that take advantage of cairo's sophisticated vector graphics capabilities and its high quality display and print output. Paolo now has until the beginning of September to complete the project and receive the full $4500 grant. I know everyone will join me in wishing him the best of luck! Paolo will be maintaining a blog about his project on the Gtk2Hs website. We would also like to thank Google for recognising the importance of supporting projects like Gtk2Hs and hscairo[4] that aim to make Haskell an even more versatile programming system. See the Gtk2Hs website for Paolo's full project proposal[5] [1] http://www.cairographics.org/ [2] http://haskell.org/gtk2hs/ [3] http://code.google.com/summerofcode.html [4] http://www.cairographics.org/hscairo [5] http://haskell.org/gtk2hs/archives/2005/07/10/gtk2hs-cairo-project/ Duncan

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ST Monad and all that
by Srinivas Nedunuri 08 Jul '05

08 Jul '05

Hello, in trying to understand how to use the ST Monad I've come across references to a bewildering variety of related types such as STRefs, STArrays, MutVar, ArrayRef, IORef, IOArray, ArrRef, etc. the list goes on. Is there a place where I can get a comprehensive explanation of what's what? Its a bit fustrating trying to figure out how these concepts relate to each other by reading snippets of information on different web sites and papers (e.g. "State in Haskell"). Thanks for your help

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FACS'05: Deadline Extended 29 July
by Luis Barbosa 07 Jul '05

07 Jul '05

[apologies for cross-posting] ------------------------------------------------------------------------ -------------------- FACS'05 II International Workshop on Formal Aspects of Component Software Macao October 24-25, 2005 www.iist.unu.edu/facs05/ ------------------------------------------------------------------------ -------------------- NEWS: * On-line submissions are now OPEN at www.iist.unu.edu/facs05/ * Submission deadline has been EXTENDED to 29 July ------------------------------------------------------------------------ --------------------

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