April 2005 - Haskell - Haskell.org

Undefined of Char.toUpper ?
by Luo Shuli 27 Apr '05

27 Apr '05

Dear Haskellers, I am a beginer of the haskell language and study it from <<Yet Another Haskell Tutarial>> of Hal Daume III. Example from the tutarial: Prelude> map Char.toUpper "Hello World" I try it on Hugs for windows32, compile error: ERROR - Undefined qualified variable "Char.toUpper" Could anybody tell me what's the matter with it? Thanks, Luo Shuli

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Re: ANNOUNCE: The jhc Haskell compiler.
by Antonio Regidor García 26 Apr '05

26 Apr '05

Very interesting! What license uses jhc? The COPYING file seems to be empty. Best regards, Antonio Regidor García ______________________________________________ Renovamos el Correo Yahoo!: ¡250 MB GRATIS! Nuevos servicios, más seguridad http://correo.yahoo.es

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Re: [Haskell] MPTCs and type inference
by Iavor Diatchki 26 Apr '05

26 Apr '05

Hello, On 4/25/05, Andrew Pimlott <andrew(a)pimlott.net> wrote: > I appreciated your explanation, but can you also address (to the list) > the last case given by the original poster? > > > On 4/25/05, Andreas Rossberg <rossberg(a)ps.uni-sb.de> wrote: > > > in particular, when I compare with the single parameter case: > > > > > > class C a where fc :: a -> a -> () > > > > > > c1 x = let p = fc x in () > > > c2 x = let p y = fc x y in () > > > > > > where > > > > > > c1 :: C a => a -> () > > > c2 :: C a => a -> () > > > > > > is inferred, as I would expect. The inference steps for this case are much the same except, that the inferred type for "p" now will be: "a -> ()", provided that we can solve the constraint "C a". Because we have assumptions about "a" in the environment (namely it is mentioned in the type of the varible "x") we cannot generalize the type of "p". It therefore remains monomorphic, and the constraint "C a" is propagated to the type of "c2". -Iavor

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Read and write file on Windows XP.
by Alexandre Weffort Thenorio 25 Apr '05

25 Apr '05

I have a small program which simply reads a text file, gets the second line and changes it and writes a clone file with the second line changed. Basically it looks like that: main :: IO() main =do -- Some code here hexFile <- catch (readFile "int.hex") (\_ -> do putStrLn "File int.hex not found" getLine exitWith ExitSuccess) --some code here newLine <- outputLine keyno key (lines(hexFile)) --finish code for main function here outputLine keyno key orgFile = do -- Some code that modifies second line here newHexFile <- openFile "newint.hex" WriteMode hPutStrLn newHexFile (orgFile!!0 ++ "\n" ++ final ++ unlines (drop 2 orgFile)) The final variable above is the string containing the second line. What happens is everything works fine on my PC (Windows 2000) but on another PC (Using Windows XP) it sometimes gives a file which is incomplete, a couple of lines missing in the end making the file smaller and wrong. So I was wondering could it be the computer itself or is there any issue with Windows XP when it comes to reading and writing files. I tried using openFileEx but to my surprise it says it is deprecated (Which function to se instead then?). Best Regards NooK

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MPTCs and type inference
by Andreas Rossberg 25 Apr '05

25 Apr '05

This may well be stupidity on my side, but some experiments with multi parameter type classes got me slightly confused. Can somebody explain the following behaviour to me? class D a b where fd :: a -> b -> () d1 x = let p = fd x in () d2 x = let p y = fd x y in () GHC derives the following types: d1 :: D a b => a -> () d2 :: a -> () Hugs rejects d1 on the grounds that the type is ambiguous, but agrees on the type of d2. I do not understand where the context disappears to in this example - in particular, when I compare with the single parameter case: class C a where fc :: a -> a -> () c1 x = let p = fc x in () c2 x = let p y = fc x y in () where c1 :: C a => a -> () c2 :: C a => a -> () is inferred, as I would expect. -- Andreas Rossberg, rossberg(a)ps.uni-sb.de Let's get rid of those possible thingies! -- TB

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SOEGraphics
by Peter Padawitz 25 Apr '05

25 Apr '05

The Mar2005 release of Hugs includes SOEGraphics, but does not recognize the type constructor Draw. Has it been changed? Peter

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ICLP 2005 Doctoral Consortium: Call for Applications
by ICLP 2005 25 Apr '05

25 Apr '05

International Conference on Logic Programming Doctoral Consortium Sitges (Barcelona), Spain October 2-5, 2005 http://www.cs.nmsu.edu/~epontell/DC2005 ----------- The ICLP Doctoral Consortium (DC) is the first ever doctoral consortium to be offered as part of the International Conference on Logic Programming. The DC will take place during ICLP 2005 in Sitges (Barcelona), Spain. The Doctoral Consortium is designed for doctoral students working in areas related to logic programming, who are planning to pursue a career in academia. The Doctoral Consortium aims to provide students with an opportunity to present and discuss their research directions and to obtain feedbacks from peers as well as world-renown experts in the field. The Doctoral Consortium will also offer invited speakers and panels discussions. ------------ The Doctoral Consortium is held the during the regular activities of the ICLP 2005 Conference. The aims of the Doctoral Consortium are: * To provide doctoral students working in the field of logic programming with a friendly and open forum to present their research ideas, listen to ongoing work from peer students, and receive constructive feedback * To provide students with relevant information about important issues for doctoral candidates and future academics * To develop a supportive community of scholars and a spirit of collaborative research. * To support a new generation of researchers with information and advice on academic, research, industrial, and non- traditional career paths. The Consortium is designed for students currently enrolled in a Ph.D. program, though we are also open to exceptions (e.g., students currently in a Masters program and interested in doctoral studies). The Consortium is for students at any stage of their doctoral studies are welcome to apply. Applicants are expected to be conducting research in the field of Logic Programming; topics of interest include (but are not limited to): * Theoretical Foundations of Logic and Constraint Logic Programming * Sequential and Parallel Implementation Technology * Static and Dynamic Analysis, Abstract Interpretation, Compilation Technology, Verification * Logic-based Paradigms (e.g., Answer Set Programming, Concurrent Logic Programming, Inductive Logic Programming) * Innovative Applications of Logic Programming The Consortium allows participants to interact with established researchers and with other students, through presentations, question- answer sessions, panel discussions, and invited presentations. The Doctoral Consortium will provide the possibility to reflect - through short activities, information sessions, and discussions - on the process and lessons of research and life in academia. Each participant will give a short, critiqued, research presentation. The Doctoral Consortium will be held on a date to be determined, in parallel with the regular activities of the ICLP 2005 conference; the ICLP conference will run from October 2nd to October 5th, 2005. Doctoral Consortium participants will be offered the opportunity to have their abstracts published in the ICLP 2005 conference proceedings. Discussants: Several renown faculty members and researchers in the field of Logic Programming will join in evaluating the submission packets and will participate in the Doctoral Consortium, providing feedback to the presenters. The list of the discussants will be published at a later date. -------- Detailed submission instructions can be found in the ICLP 2005 Doctoral Consortium web site, at: http://www.cs.nmsu.edu/~epontell/DC2005 -------- Important Dates Submission Deadline: June 1st, 2005 Acceptance Notification: July, 1st 2005 Last Date to Update Research Summary: July 15th, 2005 Doctoral Consortium: October 2-5, 2005 ICLP 2005 Conference: October 2-5, 2005 ------------ Doctoral Consortium Chair: Enrico Pontelli Department of Computer Science New Mexico State University MSC CS, Box 30001 Las Cruces, NM 88003, USA epontell _a_t_ cs.nmsu.edu

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Are there libraries for finite words and computable functions?
by Frank Rosemeier 25 Apr '05

25 Apr '05

Dear Haskellers, I would like to know if there are Haskell libraries for finite words and recursive functions. With "finite words" I refer to a datatype similar to data Word a = Nil | Cons a !(Word a) . With "computable functions" I mean recursive functions, Turing machines, register machines or something like that. Thank you very much! Frank Rosemeier

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Announce: Haskell Cryptographic Library 2.0.1
by Dominic Steinitz 24 Apr '05

24 Apr '05

I would like to announce the release of a new version of the Haskell Cryptographic Library. It now uses darcs and cabal and provides the modules listed below. The most significant change is in the way ASN.1 is handled. This has been made generic enough to handle PKCS#8 private keys and X.509 certificates. For further information see http://www.haskell.org/crypto. Dominic. Codec.ASN1 Codec.ASN1.BER Codec.ASN1.PKCS8 Codec.ASN1.TLV Codec.ASN1.X509 Codec.Binary.Base64 Codec.Encryption.AES Codec.Encryption.Blowfish Codec.Encryption.DES Codec.Encryption.Modes Codec.Encryption.Padding Codec.Encryption.RSA Codec.Encryption.RSA.EMEOAEP Codec.Encryption.RSA.MGF Codec.Encryption.RSA.NumberTheory Codec.Utils Data.Digest.MD5 Data.Digest.SHA1 Data.LargeWord

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HTML version of the H98 FFI Addendum
by Manuel M T Chakravarty 23 Apr '05

23 Apr '05

Finally! The Haskell 98 addendum for the Foreign Function Interface 1.0 in HTML format. Browse online or download at http://www.cse.unsw.edu.au/~chak/haskell/ffi/ I apologise for the slowness in producing this format. Manuel PS: XHTML 1.0 with CSS 2.1 produced by tex4ht <http://www.cse.ohio-state.edu/~gurari/TeX4ht/> PPS: Shouldn't this be hosted at haskell.org?

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