- Haskell - Haskell.org

RE: Question About lists
by Jong Keun Na 31 Dec '02

31 Dec '02

> long = sum . map (const 1) How's this? /JongKeun -----Original Message----- From: William Lee Irwin III [mailto:wli@holomorphy.com] Sent: Tuesday, December 31, 2002 5:18 AM To: Artie Gold Cc: Cesar Augusto Acosta Minoli; haskell(a)haskell.org Subject: Re: Question About lists On Mon, Dec 30, 2002 at 01:47:37PM -0600, Artie Gold wrote: > One suggestion, though is that you're working too hard; there's really > no reason to define a locally defined function. The much simpler: > long [] = 0 > long (x:xs) = 1 + long xs > will do quite nicely. > HTH, > --ag There is already a length function in List and/or the Prelude. Bill _______________________________________________ Haskell mailing list Haskell(a)haskell.org http://www.haskell.org/mailman/listinfo/haskell

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Re: real-time heap profiling?
by Jan-Willem Maessen 29 Dec '02

29 Dec '02

John Meacham <john(a)repetae.net> writes: > I have been playing with the heap profiling graphs from ghc and find > them quite useful and was wondering if there was a tool to display them > in real-time? Oddly, I found myself looking at heap profiles in real time in the past week. It turns out to be pretty easy to generate a complete heap profile for a running program using a slightly tricky unix command line: head -`fgrep -n END_SAMPLE FOO.hp | tail -1 | cut -d : -f 1` FOO.hp \ | hp2ps > FOO.ps This takes the FOO.hp file of your running program and turns it into a heap profile FOO.ps which includes all the data from the running program. I create a little script which runs this program every few seconds or so. By running gv in "watch file" mode I can see the heap profile of my entire program to date. It's not hard to cook up similar scripts (for example, to display a sliding window of the last n profiling samples) if you load FOO.hp into your favorite editor and take a look at the format. For example, here's parts of the file phc.hp, generated by running the pH/EH compiler on a problematic program: JOB "phc -hC" DATE "Thu Dec 26 18:17 2002" SAMPLE_UNIT "seconds" VALUE_UNIT "bytes" BEGIN_SAMPLE 0.00 END_SAMPLE 0.00 BEGIN_SAMPLE 15.07 ... sample data ... END_SAMPLE 15.07 BEGIN_SAMPLE 30.23 ... sample data ... END_SAMPLE 30.23 ... etc. BEGIN_SAMPLE 11695.47 END_SAMPLE 11695.47 By gluing the header (JOB, DATE, SAMPLE_UNIT, VALUE_UNIT) onto a bunch of samples extracted from the .hp file, you can run hp2ps on arbitrary sample data. Indeed, I use an editor to select and extract interesting chunks of profile data and look at those chunks in greater detail. By using fgrep -n we find the line numbers of the end of each complete sample: % fgrep -n END_SAMPLE phc.hp ... lots of output ... 1004960:END_SAMPLE 11621.34 1006610:END_SAMPLE 11636.61 1008257:END_SAMPLE 11651.85 1009926:END_SAMPLE 11667.08 1011524:END_SAMPLE 11682.33 1011526:END_SAMPLE 11695.47 We select the line number of the last complete sample (the end of a .hp file will contain partially-written sample data while the program is running, causing hp2ps to choke): % fgrep -n END_SAMPLE phc.hp | tail -1 | cut -d : -f 1 1011526 This tells us that the first 1011526 lines of phc.hp will form a properly-formatted heap profile, which we can feed to hp2ps: head -1011526 phc.hp | hp2ps > phc.ps The "watch file" mode of gv is a godsend for this sort of application. It just wouldn't have been worth the effort to me to cook up a gui for the sole purpose of displaying an up-to-date profile. I suspect, by the way, that if .hp files were xml-formatted I would have had a far less pleasant time of things. There's such a thing as TOO much structure. A lesson for us tool-builders, perhaps? -Jan-Willem Maessen

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real-time heap profiling?
by John Meacham 28 Dec '02

28 Dec '02

I have been playing with the heap profiling graphs from ghc and find them quite useful and was wondering if there was a tool to display them in real-time? For interactive long-running applications written in haskell it would be nice to see how the heap profile reacts to user actions. I imagine a scrolling graph of the last minute or so of time. Does such a thing exist? would writing one be possible without modifying ghc? it seems you can poll the .hp file and update the graph, but i have not looked into the format of .hp files to see if this is plausable. any thoughts? John -- --------------------------------------------------------------------------- John Meacham - California Institute of Technology, Alum. - john(a)foo.net ---------------------------------------------------------------------------

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Question About Random Module
by Cesar Augusto Acosta Minoli 25 Dec '02

25 Dec '02

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Re: Question About Random Module
by Zdenek Dvorak 24 Dec '02

24 Dec '02

Hello, >Hello! I just Wanna Know, What should I do, to build a List of random >Numbers, >without IO type, just Float or Int the answer for this is either "you can't, read something about IO and monads (good starting places are http://haskell.org/wiki/wiki?UsingIo and http://haskell.org/wiki/wiki?UsingMonads, and reading other FAQs there is a good idea, too)" or "you should not, but if you really have to, browse this mailing list archives, where you'll find the answer 1000x", depending on what you are asking for. Zdenek _________________________________________________________________ MSN 8 helps eliminate e-mail viruses. Get 3 months FREE*. http://join.msn.com/?page=features/virus&xAPID=42&PS=47575&PI=7324&DI=7474&… http://www.hotmail.msn.com/cgi-bin/getmsg&HL=1216hotmailtaglines_virusprote…

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Announce: Gtk2hs version 0.9.2
by Axel Simon 21 Dec '02

21 Dec '02

Gtk2hs - A Haskell binding for Gtk+ version 2 Note: This is not gtk+hs. New features in this release: - Tree/List widgets support new features like selections and editing - drawing primitives allow the creation of costom widgets - documentation in DocBook XML automatically created from source (preliminary) - builds with GHC 5.04 - number of smaller additions and fixes The binding is available at: http://gtk2hs.sourceforge.net/ Merry Christmas, Axel

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Re: Interpret haskell within haskell.
by Bill Harrison 20 Dec '02

20 Dec '02

Hi- The Programatica project at OGI is building a Haskell-in-Haskell specification, which is freely available. It isn't complete as yet, but large parts of it are: a front-end, an executable specification of the module system, and an interpreter for a large subset of Haskell98. Check out the Programatica website for further details: http://www.cse.ogi.edu/PacSoft/projects/programatica/default.htm The interpreter is available from my webpage (as is the paper "Fine Control of Demand in Haskell" describing it): http://www.cse.ogi.edu/~wlh/index.html Cheers, Bill >Message: 1 >Date: Thu, 19 Dec 2002 21:39:56 -0800 (PST) >From: David Sankel <camio(a)yahoo.com> >Subject: Interpret haskell within haskell. >To: haskell(a)haskell.org > >I was wondering if there is any project that aims to >interpret haskell within haskell. > >Is it feasable that a program can import a user's .hs >file that has something like: > >greeting :: String >greeting = "Something" > >port :: Int >port = 32 + 33 > >And the program can parse and execute the user's >function. > >I'm looking for something similar to the eval command >in Python. > >Thanks, > >David J. Sankel > >--__--__-- > >Message: 2 >Subject: RE: Interpret haskell within haskell. >Date: Fri, 20 Dec 2002 10:04:39 -0000 >From: "Simon Marlow" <simonmar(a)microsoft.com> >To: "David Sankel" <camio(a)yahoo.com>, <haskell(a)haskell.org> > > > I was wondering if there is any project that aims to > > interpret haskell within haskell. > >=20 > > Is it feasable that a program can import a user's .hs > > file that has something like: > >=20 > > greeting :: String > > greeting =3D "Something" > >=20 > > port :: Int > > port =3D 32 + 33 > >=20 > > And the program can parse and execute the user's > > function. > >=20 > > I'm looking for something similar to the eval command > > in Python. > >You could potentially do this with GHCi, but we haven't tried. The idea >is that you would need to expose parts of GHCi itself as a library which >can be used from the program. Linking is a bit tricky (you don't want >to load another copy of GHCi), but we know one way to get around that: >the --export-dynamic flag to ld. > >If you're interested in having a go, come on over to >glasgow-haskell-users(a)haskell.org and we'll help out with any problems >you run into. > >Cheers, > Simon > > >--__--__-- > >_______________________________________________ >Haskell mailing list >Haskell(a)haskell.org >http://www.haskell.org/mailman/listinfo/haskell > > >End of Haskell Digest

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CFP: AADEBUG 2003
by nilsson＠cs.yale.edu 20 Dec '02

20 Dec '02

Please find enclosed the call for papers and demos for AADEBUG 2003: Fifth Int. Workshop on Automated and Algorithmic Debugging, Ghent, Belgium, September 8-10, 2003 Apologies for multiple copies. /Henrik -- Henrik Nilsson Yale University Department of Computer Science nilsson(a)cs.yale.edu AADEBUG'2003 Fifth Int. Workshop on Automated and Algorithmic Debugging Ghent, Belgium, September 8-10, 2003 Call for papers and demos Over the past decades automated debugging has seen major achieve- ments. However, as debugging is by necessity attached to particu- lar programming paradigms, the results are scattered. The aims of the workshop are to gather common themes and solutions across programming communities, and to cross-fertilize ideas. We seek papers describing original research as well as reports on practi- cal experience. We also welcome demonstrations of tools and re- search prototypes. Typical topics of the workshop include (but are not limited to): automated debugging declarative debugging type debugging knowledge-based debugging algorithmic debugging assertion-based debugging trace analysis software testing program slicing monitoring performance debugging parallel and distributed debugging debugging by simulation debugging using record/replay for any kind of programming paradigms (sequential, parallel, dis- tributed, real-time, logic programming, functional, object-ori- ented, imperative, visual languages). Accepted papers and demo descriptions will be included in the workshop proceedings, distributed locally on paper and CD, and will also be published on the CoRR (Computing Research Reposito- ry) website. Authors of the best papers will be invited to submit journal versions of their papers to a special issue of the Jour- nal of Automated Software Engineering on automated debugging. Demonstration of tools and research prototypes that implement new ideas in debugging automation will be part of the AADEBUG2003 technical program. Demos will be given in sessions together with technical paper presentations. Both demos and regular papers will receive a 30' time slot. Submission of Papers Contributors should be aware that the prospective audience will not necessarily be familiar with the addressed programming paradigms, which should, therefore, be briefly introduced. Papers should be no longer than 5000 words in length, including a 150 to 200 word abstract. Submit papers by uploading a PDF file to http://aadebug2003.elis.rug.ac.be/. Concurrently send an e-mail to aadebug2003(a)elis.rug.ac.be with the title of the paper, names of the authors, full address of the correspondent and a 150 to 200 word abstract of the paper. Submission of Demos Demo descriptions should be no longer than 2000 words including a 150 to 200 word abstract. Submit demos by uploading a PDF file to http://aadebug2003.elis.rug.ac.be/ Concurrently send an e-mail to aadebug2003(a)elis.rug.ac.be containing the title of the demo, names of the authors, full address of the correspondent and a 150 to 200 word abstract of the paper. Clearly mention the fact that you submit a demo and not a regular paper in your email. Authors having problems to submit using the web server can send the paper to aadebug2003(a)elis.rug.ac.be. Conference Information The website for AADEBUG2003 containing this Call for Papers and more info can be found at http://aadebug2003.elis.rug.ac.be/. If you encounter any kind of problem or need more information mail to aadebug2003(a)elis.rug.ac.be. Important Dates Paper and demo submission before March 15, 2003 Notification of acceptance by May 15, 2003 Final version of paper before June 30, 2003 (this applies to the local and the CoRR proceedings) Conference Information The website for AADEBUG2003 containing this Call for Papers and more information about the conference can be found at http://aadebug2003.elis.rug.ac.be/. If you encounter any kind of problem or need more information mail aadebug2003(a)elis.rug.ac.be. General Conference Chair Koen De Bosschere Ghent University, Belgium Email: kdb(a)elis.rug.ac.be Program Chair Michiel Ronsse Ghent University, Belgium Email: ronsse(a)elis.rug.ac.be Program Committee Members Mikhail Auguston New Mexico State University, USA Koen De Bosschere Ghent University, Belgium Jacques Chassin de Kergommeaux LSR/ENSIMAG, France Jong-Deok Choi IBM T.J. Watson Research Center, USA Mireille Ducassé IRISA/INSA, France Peter Fritzson Linköpings Universitet, Sweden Michael Gerndt Tech. Universität München, Germany Gerda Janssens Katholieke Universiteit Leuven, Belgium Clinton L. Jeffery New Mexico State University, USA Mariam Kamkar Linköpings Universitet, Sweden Dieter Kranzlmüller Joh. Kepler University Linz, Austria Raimondas Lencevicius Nokia Research Center, Boston Edu Metz Nokia Research Center, Boston Henrik Nilsson Yale University, USA Michiel Ronsse Ghent University, Belgium Gary Sevitsky IBM T.J. Watson Research Center, USA Markus Stumptner University of South Australia, Australia Kazunori Ueda Waseda University, Japan Roland Wismüller Technische Univ. München, Germany About Ghent Ghent is one of the oldest cities in Flanders, the Dutch speaking northern part of Belgium. Through the Middle Ages, it was among the most important economic centres of Western Europe and the historic city centre still reminds us of this period through its beautiful medieval towers. There are several trains an hour that connect Ghent to the closest international airport (Brus- sels, 60km). Other closeby airports are Schiphol (The Nether- lands, 200km) and Lille (France, 90km), both having easy train connections to Ghent.

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RE: Interpret haskell within haskell.
by Simon Marlow 20 Dec '02

20 Dec '02

> I was wondering if there is any project that aims to > interpret haskell within haskell. > > Is it feasable that a program can import a user's .hs > file that has something like: > > greeting :: String > greeting = "Something" > > port :: Int > port = 32 + 33 > > And the program can parse and execute the user's > function. > > I'm looking for something similar to the eval command > in Python. You could potentially do this with GHCi, but we haven't tried. The idea is that you would need to expose parts of GHCi itself as a library which can be used from the program. Linking is a bit tricky (you don't want to load another copy of GHCi), but we know one way to get around that: the --export-dynamic flag to ld. If you're interested in having a go, come on over to glasgow-haskell-users(a)haskell.org and we'll help out with any problems you run into. Cheers, Simon

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Interpret haskell within haskell.
by David Sankel 20 Dec '02

20 Dec '02

I was wondering if there is any project that aims to interpret haskell within haskell. Is it feasable that a program can import a user's .hs file that has something like: greeting :: String greeting = "Something" port :: Int port = 32 + 33 And the program can parse and execute the user's function. I'm looking for something similar to the eval command in Python. Thanks, David J. Sankel

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