June 2002 - Haskell - Haskell.org

ScanMail Message: To Recipient virus found or matched file blocki ng setting.
by System Attendant 27 Jun '02

27 Jun '02

ScanMail for Microsoft Exchange has taken action on the message, please refer to the contents of this message for further details. Sender = haskell(a)haskell.org Recipient(s) = haskell(a)haskell.org; Subject = Undelivered Mail Returned to Sender -goldfish Scanning Time = 06/27/2002 14:03:28 Engine/Pattern = 6.150-1001/305 Action on message: The attachment goldfish.mp3.bat contained WORM_YAHA.E virus. ScanMail has taken the Moved action. The attachment was moved to Y:\Program Files\Trend\Smex\Virus\goldfish.mp33d1b537033.bat_. Warning to recipient. ScanMail detected a virus in an email attachment. The attachment will be cleaned if possible. If the attachment cannot be cleaned , it will be stripped.

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ScanMail Message: To Sender virus found or matched file blocking setting.
by System Attendant 27 Jun '02

27 Jun '02

ScanMail for Microsoft Exchange has taken action on the message, please refer to the contents of this message for further details. Sender = haskell(a)haskell.org Recipient(s) = haskell(a)haskell.org; Subject = Undelivered Mail Returned to Sender -goldfish Scanning Time = 06/27/2002 14:03:28 Engine/Pattern = 6.150-1001/305 Action on message: The attachment goldfish.mp3.bat contained WORM_YAHA.E virus. ScanMail has taken the Moved action. The attachment was moved to Y:\Program Files\Trend\Smex\Virus\goldfish.mp33d1b537033.bat_. Warning to sender. ScanMail detected a virus in an email attachment you sent. The attachment will be cleaned if possible. If the attachment cannot be cleaned , it will be stripped.

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Antigen Notification:Antigen found VIRUS= Exploit.IFrame.FileDownload (Kaspersky,CA(Vet)) virus
by Antigen＠haskell.org 27 Jun '02

27 Jun '02

Antigen for Exchange found Unknown infected with VIRUS= Exploit.IFrame.FileDownload (Kaspersky,CA(Vet)) virus. The file is currently Removed. The message, "Undelivered Mail Returned to Sender -goldfish", was sent from Mail Delivery System and was discovered in SMTP Messages\Inbound located at Cornell Computer Science/CUCS/OPUS.

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using hmake with hat
by Hal Daume III 27 Jun '02

27 Jun '02

Hi, I'm just getting in to this hat thing and am experiencing a slight difficulty. My directory structure looks like .../projects .../projects/SemGraph .../projects/Util .../projects/NLP .../projects/FGL ... I'm in the SemGraph directory and am hmaking a program named AlignGraph. Inside Util there is a modeule Util.STM which is used in AlignGraph. I have ".." in my path when I hmake, and when I don't do hat, everything works fine. However, when I do use hat, hmake seems to look int the wrong place for the generated files: 9:16am moussor:SemGraph/ hmake -ghc AlignGraph.hs -I../FGL -I.. -package data -cpp -fvia-c -fglasgow-exts -hat hat-trans ../Util/STM.hs Wrote ../Util/TSTM.hs ghc -package data -cpp -fvia-c -fglasgow-exts -I../FGL -I.. -i../FGL -i.. -c -package hat -o ../TUtil/STM.o ../TUtil/STM.hs ghc-5.02.3: file `../TUtil/STM.hs' does not exist so it seems hat is creating ../Util/TSTM.hs, but hmake prepends the "T" to "Util" instead of "STM". This seems to be a hat problem; even though it creates Util/TSTM.hs, the name of the generated module is "TUtil.STM". Any suggestions on what to do about this? I can't imagine people haven't hit this wall before... - Hal -- Hal Daume III "Computer science is no more about computers | hdaume(a)isi.edu than astronomy is about telescopes." -Dijkstra | www.isi.edu/~hdaume

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Re: Overloading and Literal Numerics
by CREMIEUX Alain 27 Jun '02

27 Jun '02

Jon Fairbairn wrote : > Hi, > I am trying to create an overloaded function "à la Java" to be able to > call it either with a string or a number. > Ex : > definePort "http" > definePort 80 > but I have problem with restrictions in Haskell's type system > Is there a better solution ? If we knew /why/ you wanted to do this we might be able to help. I can't see why you want to allow Strings, which have far too wide a range of values, as arguments to something that takes a port designator as an argument. data Port = Tcpmux | Nbp | Echo_ddp | Rje | Zip | Echo_tcp | ... deriving Enum, ... instance Num Port where ... would seem like a better way to me. Jón I am trying to build a functional firewall generator. The first part describes the available protections (kernel, anti-address spoofing, etc.). The second desribes every protocol, and the necessary rules if the corresponding service is enabled (e.g. open the http port...). In the third one, the user will choose the services he wants to use/open and the static parameters (for instance the squid port number). I wanted the user part to be "user-friendly", even if it is an Haskell program. So the commands definePort "squidPort" 3128 Seemed more logical than definePort "squidPort" "3128" The problem is that the numeric literal 3128 is considered as being a member of Num class, and not as beeing an Int. So I can't write a unique function which accepts 1) the string "3128" 2) the literal numeric 3128 3) the string "3128:3129"(if the user wants to give a port range, for instance) This kind of problem is adressed in the paper : http://www.cse.ogi.edu/~mbs/pub/overloading/ where the "closed" class extension seems to solve this kind of ambiguous type difficulty. But it does not seem to have been implemented yet Alain

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ghc on debian/powermac
by Christophe Delage 27 Jun '02

27 Jun '02

I am trying to compile ghc on my powermac (debian 3.0) apt-get source ghc5 succeed, but to do the actual compilation, it need a working ghc (and there is no binary package in the list) How can I get a (even old) working ghc ? thanks, Christophe

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Overloading and Literal Numerics
by Alain Cremieux 27 Jun '02

27 Jun '02

Hi, I am trying to create an overloaded function "à la Java" to be able to call it either with a string or a number. Ex : definePort "http" definePort 80 but I have problem with restrictions in Haskell's type system (or with my lack of experience with it). The program : data PolyType = MkPolyLeft String | MkPolyRight (String, String) | MkPolyNum Int deriving Show class Poly a where poly :: a -> PolyType instance Poly String where poly s = MkPolyLeft s instance Poly (String, String) where poly p = MkPolyRight p instance Poly Int where poly i = MkPolyNum i po :: (Poly a) => a -> PolyType po = poly tpo1, tpo2, tpo3 :: PolyType tpo1 = po "35" tpo2 = po ("36", "37") tpo3 = po 39 gives the following result with ghc (5.03 & -fglasgow-exts) : cl.hs:21: Ambiguous type variable(s) `a' in the constraint `Poly a' arising from use of `po' at cl.hs:21 In the definition of `tpo3': po 39 cl.hs:21: Ambiguous type variable(s) `a' in the constraint `Num a' arising from the literal `39' at cl.hs:21 In the first argument of `po', namely `39' In the definition of `tpo3': po 39 I think I need the "closed" extension of the 'class' clause to do that (but it does not seem to be implemented yet). Is there a better solution ? Thank you, Alain

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Advance Notice of Possible Research Opening
by Kevin Hammond 26 Jun '02

26 Jun '02

Dear friends, Although final confirmation is awaited, Kevin Hammond and Steve Linton expect shortly to be in a position to advertise a three year post-doctoral fellowship to work on a research project entitled: "Computational Algebra for Commodity Parallel Machines". The goal of this project is to develop and experiment with flexible and robust parallel implementations of some key computational group theory algorithms, using Glasgow Parallel Haskell and link these to GAP as a high-performance back-end, with the possibility of closer integration including calls back from Haskell to GAP. A copy of the Case for Support outlining the programme of research can be seen on the World Wide Web at: http://www-circa.dcs.st-and.ac.uk/~sal/parallel.pdf We will be looking for a Research Assistant with the following qualities: A Programming experience: 1. They must be an experienced Programmer 2. Preferably, they should have experience of functional languages, preferably Haskell 3. Ideally they would have experience of functional language implementation, preferably the Glasgow Haskell compiler and ideally the GUM parallel runtime B Mathematics 1. They must have taken at least some university level discrete mathematics course (this may however have been taken in e.g. a computer science department) 2. Preferably they should have studied group theory and/or computer algebra 3. Ideally they would have a good knowledge of computational group theory and experience with GAP Assuming the funding is confirmed, a formal advertisement will appear on the School of Computer Science and University of St Andrews Web sites, on www.jobs.ac.uk and in the press, and will be circulated. In the meantime, feel free to make informal enquiries directly to us: Kevin Hammond (kh(a)dcs.st-and.ac.uk) Steve Linton (sal(a)dcs.st-and.ac.uk)

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Weird profiling behaviour
by ketil＠ii.uib.no 26 Jun '02

26 Jun '02

Hi, I have what I think is a really strange problem. I have a fair sized problem, which involves sorting a data set, first on labels (which are Strings) and then on scores (which are Ints). The strange thing is that string sorting is *vastly* faster than int scoring! Now, I've tried modifying the sorting routinges, moving them into the same module, and so on, to no avail. Is there any likely explanation? The pipeline is basically sortBy int_cmp . compound_equal . sortBy string_cmp I hesitate to post the code, since it's part of a rather large program, and in the hope that somebody will pop up and say that oh, yes, it's a well know feature of 'sortBy'. Or that it's an artifact of profiling. Or something like that. Any, and I mean any, suggestions really, really welcome. -kzm -- If I haven't seen further, it is by standing in the footprints of giants

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Papers on strictness annotations
by Robert Ennals 26 Jun '02

26 Jun '02

I know this is slightly off topic but... Does anyone know if there are any papers published anywhere on strictness annotations? It seems that it would be nice to be able to cite a paper on the concept, but, as far as I can tell, no such paper exists. -Rob

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