January 2001 - Haskell

Too Strict?
by Steinitz, Dominic J 15 Jan '01

15 Jan '01

Can someone help? The program below works fine with small files but when I try to use it on the one I need to (about 3 million lines of data) it produces no output. The hard disk is hammered - I assume this is the run time system paging. My suspicion is that the program is trying to read in the whole file before processing it. Is this correct? If so, how do I make the program lazy so that it processes a line at time? By the way, the MD5 function which I use and is included as part of HSLIBS has the type String -> IO String. The MD5 algorithm really is a function and should have type String -> String. Do people agree and if so how do I get it changed? Dominic. -- Compile with ghc -o test test.hs -static -package util -- under Windows. module Main(main) where import IO(openFile, hPutStr, IOMode(ReadMode,WriteMode,AppendMode)) import MD5 import Char -- showHex and showHex' convert the hashed values to -- human-readable hexadecimal strings. showHex :: Integer -> String showHex = map hexDigit . map (fromInteger . (\x -> mod x 16)) . takeWhile (/=0) . iterate (\x -> div x 16) . toInteger hexDigit x | (0 <= x) && (x <= 9) = chr(ord '0' + x) | (10 <= x) && (x <=16) = chr(ord 'a' + (x-10)) | otherwise = error "Outside hexadecimal range" powersOf256 = 1 : map (*256) powersOf256 showHex' x = showHex $ sum (zipWith (*) (map ((\x -> (mod x 16)*16 + (div x 16)) . toInteger . ord) x) powersOf256) -- The type Anon and function anonymize hide the anonymisation -- process. In this case, it's a hash function -- digest :: String -> IO String which implements MD5. type Anon a = IO a class Anonymizable a where anonymize :: a -> Anon a -- MyString avoids overlapping instances of Strings -- with the [Char] data MyString = MyString String deriving Show instance Anonymizable MyString where anonymize (MyString x) = do s <- digest x return ((MyString . showHex') s) instance Anonymizable a => Anonymizable [a] where anonymize xs = mapM anonymize xs filename = "ldif1.txt" fileout = "ldif.out" readAndWriteAttrVals = do h <- openFile fileout WriteMode s <- readFile filename a <- anonymize((map MyString) (lines s)) hPutStr h (unlines (map (\(MyString x) -> x) a)) main = readAndWriteAttrVals ------------------------------------------------------------------------------------------------- 21st century air travel http://www.britishairways.com

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Are fundeps the right model at all?
by qrczak＠knm.org.pl 15 Jan '01

15 Jan '01

Could somebody show an example which requires fundeps and cannot be expressed using a simpler model explained below - a model that I can even understand? Is the model self-consistent at all? Each class is associated with a set of subsets of type variables in its head. Let's call it the set of keys. The intuitive meaning of a key is that types corresponding to these variables are sufficient to determine which instance to choose. They correspond to lhss of some fundeps. Plain classes without explicitly written keys correspond to having a single key consisting of all type variables. Keys influence the typechecking thus: - A type is unambiguous if for every class constraint in it there exists its key such that types in the constraint corresponding to type variables from the key contain no type variables which are absent in the type itself. - All class methods must have unambiguous types, i.e. for each method there must be a key whose all type variables are present in the method's type. - For each key, there must be no pair of instances whose heads projected to the class parameters from the key overlap. - For each class constraint of an unambiguous type an each its key there must be an instance found basing on this key, or the type is incorrect because of missing instances. Moreover, instances found basing on all keys must be identical. - Perhaps something must be said about class contexts and instance contexts. I'm not sure what yet. Examples: class Collection c e | c where empty :: c insert :: c -> e -> c class Monad m => MonadState s m | m where get :: m s put :: s -> m () newtype State s a = State {runState :: s -> (a,s)} instance Monad (State s) instance MonadState s (State s) test1:: Int -> Int test1 x = snd (runState get x) -- Not ambiguous. class IOvsST io st | io, st where -- Two single-element keys. ioToST :: io -> st stToIO :: st -> io instance IOvsST (IORef a) (STRef s a) where ioToST = unsafeCoerce# stToIO = unsafeCoerce# test2:: IORef a -> IORef a test2 = ioToST . stToIO -- Not ambiguous. class Foo a b | a instance Foo Int [a] -- This is rejected by Hugs (with fundep a->b) but I would definitely -- accept it. -- __("< Marcin Kowalczyk * qrczak(a)knm.org.pl http://qrczak.ids.net.pl/ \__/ ^^ SYGNATURA ZASTÊPCZA QRCZAK

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{-# LINE 100 "Foo.hs #-} vs. # 100 "Foo.hs"
by qrczak＠knm.org.pl 13 Jan '01

13 Jan '01

What should be the preferred way of marking correspondence to source positions after some preprocessing? Here is what is currently supported: | {-# LINE 100 "Foo.hs #-} | # 100 "Foo.hs" ------------------------+------------------------------+---------------- Released ghc, no -cpp | understand | error Released ghc, with -cpp | understand | understand Developed ghc | understand | understand hbc | understand (ignore filename) | understand (warning) Hugs | ignore | error Released nhc98 | error | understand Developed nhc98 | ignore | understand I would choose LINE pragma. In this case nhc98 should be taught about it. -- __("< Marcin Kowalczyk * qrczak(a)knm.org.pl http://qrczak.ids.net.pl/ \__/ ^^ SYGNATURA ZASTÊPCZA QRCZAK

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IEEE Conference Software Maint. Italy,Florence, ICSM2001
by icsm2001 13 Jan '01

13 Jan '01

Dear Colleague I would like to invite you to propose papers, experiences, tutorials, tool expositions, dissertations at the IEEE International Conference on Software Maintenance, 2001, and workshops: SCAM, WESS, WSE and TABOO, etc., November 2001, Florence, Italy. ICSM is the major international conference in the field of software and systems maintenance, evolution, management, software metrics and quality, etc. Outstanding Keynotes such as: >->->Prof. David Lorge Parnas, Prof. Dieter Rombach, Prof. Ivar Jacobson<-<-<- Awards, workshops, panels, and other exciting activities have been planned. Please note in the following the new deadline that has been moved to satisfy the several requests recevied, next deadline >->->->-29 January 2001<-<-<-<-<-<- Please forward this remind to anybody who you think may be interested. Apologies if you have already seen this. If you would like to be removed from our list please send an email to icsm2001(a)dsi.unifi.it with REMOVE in the subject. ICSM2001 Paolo Nesi (General Chair) _=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_= >->->CALL---FOR---PAPERs<-<-< IEEE International Conference on Software Maintenance 2001 FLORENCE, ITALY, 6-10 November 2001 http://www.dsi.unifi.it/icsm2001 Theme: Systems and Software Evolution in the era of the Internet IMPORTANT DATES, DEADLINES Research Paper submission 29 January 2001 Dissertation submission 29 January 2001 Industrial Application submission 12 March 2001 Tools request and submission 12 March 2001 Tutorial submission 12 February 2001 _=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=_=

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gui building in haskell
by Matthew Liberty 12 Jan '01

12 Jan '01

Greetings, I've been looking at http://www.haskell.org/libraries/#guis and trying to figure out which package is "best" for building a gui. Can anyone give a comparison of the strengths/weaknesses of these packages (or any others)? thanks -Matt

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FORMAL GRAMMAR/MATHEMATICS OF LANGUAGE'01
by Ahti Pietarinen 12 Jan '01

12 Jan '01

[apologies if you receive this more than once] FGMOL'01 FGMOL'01 FGMOL'01 FGMOL'01 FGMOL'01 FGMOL'01 FGMOL'01 FGMOL'01 FORMAL GRAMMAR/MATHEMATICS OF LANGUAGE CONFERENCE August 10--12, 2001 Helsinki, Finland FIRST CALL FOR PAPERS We are pleased to announce the joint meeting of two conferences: the sixth conferene on Formal Grammar and the seventh on the Mathematics of Language. The joint meeting will be held just prior to the European Summer School in Logic, Language, and Information. AIMS and SCOPE especially with regard to the application of formal methods to natural language analysis. Themes of interest include, but are not limited to, * formal and computational syntax, semantics, pragmatics, and phonology; * model-theoretic and proof-theoretic methods in linguistics; * constraint-based and resource-sensitive approaches to grammar; * foundational, methodological and architectural issues in grammar. * mathematical properties of linguistic frameworks * theories and models of natural language processing and generation * parsing theory * statistical and quantitative models of language INVITED SPEAKERS will be announced with the circulation of the second call for papers in early February SUBMISSION DETAILS We invite E-MAIL submissions of abstracts for 30-minute papers (including questions, comments, and discussion). A submission should consist of two parts: - an information sheet (in ascii), containing the name of the author(s), affiliation(s), e-mail and postal address(es) and a title; - an abstract, consisting of a description of not more than 5 pages (including figures and references). Abstracts may be either in plain ASCII or in (unix-compatible encoded) postscript, PDF, or DVI. Abstracts can be sent to fgmol(a)cs.indiana.edu ABSTRACT SUBMISSION DEADLINE April 1, 2001 NOTIFICATION OF ACCEPTANCE May 15, 2001 PROCEEDINGS A full version of each accepted paper will be included in the conference proceedings, to be distributed at the conference. Full papers are due June 30, 2001. PROGRAMME COMMITTEE Anne Abeill'e (Paris) Patrick Blackburn (INRIA) Gosse Bouma (Groningen) Mary Dalrymple (Xerox Parc) Nissim Francez (Haifa) Thilo Goetz (IBM) David Johnson (IBM) Mark Johnson (Brown) Aravind Joshi (UPenn) Gerhard J"ager (Utrecht) Ruth Kempson (London) Alain Lecomte (LORIA) Uwe Moennich (T"ubingen) Glyn Morrill (U.P. Catalunya) Michael Moortgat (Utrecht) Owen Rambow (Cogentex) James Rogers (Earlham) Giorgio Satta (Padova) Mark Steedman (Edinburgh) FURTHER INFORMATION Web site for ESSLLI XIII: http://www.helsinki.fi/esslli/ Web site for FGMOL'01 :http://www.cis.upenn.edu/~ircs/mol/mol7.html The organizers: Geert-Jan Kruijff gj(a)cogsci.ed.ac.uk Larry Moss lsm(a)cs.indiana.edu Dick Oehrle oehrle(a)linc.cis.upenn.edu %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%[LaTeX2E Source File]%%%%%%%%%%%%%%%%%%%%%%%%%%%% \documentclass{article} \usepackage{tabularx} \setlength{\textwidth}{7in} \setlength{\oddsidemargin}{-.5in} \setlength{\topmargin}{-36pt} \pagestyle{empty} \begin{document} \begin{center} {\em Please Post}\\[.1cm] {\large{\bf Formal Grammar / Mathematics of Language Conference --- FGMOL'01\\ CALL FOR PAPERS}}\\ {August 10--12, 2001}\qquad Helsinki\\ \end{center} \begin{center} \begin{tabular}{@{}p{.27\textwidth}|p{.70\textwidth}@{}} %\small\ixpt\setlength{\baselineskip}{9pt} \footnotesize \begin{flushleft} {\bf Programme Committee} \end{flushleft} \begin{tabular}{l@{}} Anne Abeill\'{e} (Paris) \\ Patrick Blackburn (INRIA) \\ Gosse Bouma (Groningen) \\ Mary Dalrymple (Xerox Parc) \\ Nissim Francez (Haifa)\\ Thilo Goetz (IBM)\\ David Johnson (IBM) \\ Mark Johnson (Brown)\\ Aravind Joshi (UPenn)\\ Gerhard J\"{a}ger (Utrecht)\\ Ruth Kempson (London)\\ Alain Lecomte (LORIA)\\ Uwe M\"{o}nnich (T\"{u}bingen)\\ Glyn Morrill (U.P. Catalunya) \\ Michael Moortgat (Utrecht) \\ Owen Rambow (Cogentex)\\ James Rogers (Earlham) \\ Giorgio Satta (Padova) \\ Mark Steedman (Edinburgh)\\ [12pt] {\bf Organizing Committee}\\ Geert-Jan Kruijff (Prague)\\ Larry Moss (Indiana)\\ Richard Oehrle (Ashford) \end{tabular} \medskip {\bf Important Dates} \smallskip \begin{tabular}{l@{}} Abstracts Due: March 31, 2001\\ Notification: May 15, 2001\\ Final Versions: June 30, 2001\\ Conference: August 10-12, 2001\\ \end{tabular} \medskip {\bf Addresses:\quad} \smallskip \begin{tabular}{l@{}} ESSLLI XIII: \\ \texttt{http://www.helsinki.fi/esslli}\\ FGMOL'01:\\ \texttt{http://www.cis.upenn.edu/\ldots}\\ $\quad$ \texttt{\ldots $^{\sim}$ircs/mol/mol7.html} \end{tabular} & \setlength{\parskip}{2pt} We are pleased to announce the joint meeting of two conferences: the sixth conferene on Formal Grammar and the seventh on the Mathematics of Language. The joint meeting will be held just prior to the European Summer School in Logic, Language, and Information. \medskip {\it Aims And Scope} FGMOL'01 provides a forum for the presentation of new and original research on formal grammar and mathematical aspects of language, especially with regard to the application of formal methods to natural language analysis. Themes of interest include, but are not limited to, \begin{itemize} \setlength{\itemsep}{0pt}\setlength{\parskip}{0pt} \item formal and computational syntax, semantics, pragmatics, and phonology; \item model-theoretic and proof-theoretic methods in linguistics; \item constraint-based and resource-sensitive approaches to grammar; \item foundational, methodological and architectural issues in grammar. \item mathematical properties of linguistic frameworks \item theories and models of natural language processing and generation \item parsing theory \item statistical and quantitative models of language \end{itemize} \noindent We welcome papers from a wide variety of frameworks. \medskip {\it Invited Speakers} will be announced with the circulation of the second call for papers in early February. \medskip {\it Submission Details} We invite E-MAIL submissions of abstracts for 30-minute papers (including questions, comments, and discussion). A submission should consist of two parts: \begin{itemize} \setlength{\itemsep}{0pt}\setlength{\parskip}{0pt} \item an information sheet (in ascii), containing the name of the author(s), affiliation(s), e-mail and postal address(es) and a title; \item an abstract, consisting of a description of not more than 5 pages (including figures and references). Abstracts may be either in plain ASCII or in (unix-compatible encoded) postscript, PDF, or DVI. \end{itemize} \noindent Abstracts can be sent to {\tt fgmol@cs.indiana.edu} (Larry Moss). \medskip {\it Abstract Submission Deadline} March 31, 2001 {\it Notification of Acceptance} May 15, 2001 {\it Proceedings} A full version of each accepted paper will be included in the conference proceedings, to be distributed at the conference. Full papers are due June 30, 2001. \end{tabular} \end{center} \end{document}

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RE: Haskell 98 (Library) Report: contradiction about fail :: Stri ng -> IO a
by Simon Peyton-Jones 12 Jan '01

12 Jan '01

Marcin writes: | The Haskell 98 Report says that fail in instance Monad IO invokes error. | The Library Report says that fail in instance Monad IO raises a user error. | | I would let it raise a user error, to be able to use fail in exception | monads where strings suffice as the error type. He's right. The instance declaration in the Prelude (p101) should say instance Monad IO where ... fail s = ioError (userError s) This was always intended (see Library report p55, 11.1). Other clarifications should be * Index the reference to userError in Sec 7.3 of the Report and give a type signature for userError * In that same section, specify that fail s = ioError (userError s) I'll do these as part of the (long-postponed) H98 report revision. Any objections? I don't think this is controversial. Implementors take note, though. Simon

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Re: Hash Functions
by Jan Skibinski 12 Jan '01

12 Jan '01

On 12 Jan 2001, Steinitz, Dominic J wrote: > I was thinking of using MD5 or SHA-1 for an application. > Is there a Haskell library that contains these or other hash algorithms > that have a very low probability of giving clashes? > > Dominic. http://www.numeric-quest.com/haskell/bridge/index.html contains interface to MD5 code in C via Greencard. There is a support for one function only (the only function I really needed for a certain CGI application) digest :: String -> String. It uses 'unsafePerformIO' but you could redesign it changing its signature to digest :: String -> String IO or extend it to supply other functions you need. Jan

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Hash Functions
by Steinitz, Dominic J 12 Jan '01

12 Jan '01

I was thinking of using MD5 or SHA-1 for an application. Is there a Haskell library that contains these or other hash algorithms that have a very low probability of giving clashes? Dominic. ------------------------------------------------------------------------------------------------- 21st century air travel http://www.britishairways.com

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Hugs
by Krprtn＠aol.com 11 Jan '01

11 Jan '01

I tried sending this message to the hugs email address but it kept being sent back! I have installed Hugs on my PC, could you please tell me how I can configure Hugs to use winedt (editor). I have alreadly tried using the hugs user manual (section 4). Also is it a problem if I use the latest version of winedt with hugs 98. thankyou

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