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Re: What is the current state of affairs with supercompilation?
by Peter A. Jonsson 25 Oct '09

25 Oct '09

Hi Eugene, here are some answers: > I'm mainly interested in the following: > - What supercompilers do exist, except for the ones mentioned above? We have prototype implementations of supercompilers for both GHC and the Timber compiler, but they are not yet in a suitable form for public inspection. Neil Mitchell has the source code to Supero available on his homepage [1], which I think uses yhc as frontend and ghc as backend. > - What academic organizations do research in the area? Looking at where the authors of some publications on supercompilation were at the time of the publication gives some hints: - University of York: Neil Mitchell, Colin Runciman - University of Copenhagen: Morten Heine Sørensen, Robert Glück, Jens Peter Secher, Neil Jones - University of Liverpool: Alexei Lisitsa - Russian Academy of Sciences: Sergei Romanenko, Ilya Klyuchnikov - Luleå University of Technology: myself and Johan Nordlander > - What papers should be read by someone eager to learn about > supercompilation and maybe to make research contributions? If you are interested in program optimization, here's two pointers: - A Positive Supercompiler [2] - An Algorithm of Generalization in Positive Supercompilation.[3] Combine these two and you have a positive supercompiler for a first- order functional language, using the notation that is familiar to the functional programming community. More recent work on program optimization: - Neil's thesis [4] - There's a number of tutorials available from the group at University of Copenhagen, all worth a read. Alexei Lisitsa, Sergei Romanenko, and Ilya Klyuchnikov have used supercompilation to do verification: - Verification as a parameterized testing (experiments with the SCP4 supercompiler). [5] - Proving the equivalence of higher-order terms by means of supercompilation. [6] > - What are some solved problems and some open problems in > supercompilation? The algorithms are quite well-studied with respect to correctness. There's less material available on actual implementations, and how to get them to perform well. I haven't seen anything discussing code explosion and similar practical issues. I don't think anyone has mechanically verified the correctness of supercompilation. This is by no means an exhaustive list of everything, but it's something to start with. I hope it helps. Kind Regards, Peter [1] http://community.haskell.org/~ndm/supero/ [2] ftp://ftp.diku.dk/pub/diku/semantics/papers/D-300.ps.gz [3] http://citeseerx.ist.psu.edu/viewdoc/download? doi=10.1.1.49.1869&rep=rep1&type=pdf [4] http://community.haskell.org/~ndm/thesis/ [5] http://www.springerlink.com/content/c8623847257w22j9/ [6] http://pat.keldysh.ru/~roman/doc/Klyuchnikov,Romanenko-2009-- Proving.the.Equivalence.of.Higher- Order.Terms.by.Means.of.Supercompilation.pdf

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unix pkg on cygwin
by Ben Fitzgerald 25 Oct '09

25 Oct '09

Hi just starting out on haskell so thought I'd try and install a few packages. from unix-2.3.2.0: $ runhaskell Setup.hs configure checking target system type... i686-pc-cygwin configure: creating ./config.status config.status: creating unix.buildinfo config.status: creating include/HsUnixConfig.h Setup.hs: Missing dependency on a foreign library: * Missing header file: HsUnix.h * Missing C library: dl This problem can usually be solved by installing the system package that provides this library (you may need the "-dev" version). If the library is already installed but in a non-standard location then you can use the flags --extra-include-dirs= and --extra-lib-dirs= to specify where it is. The file is part of the pkg I'm trying to build: $ find . -name HsUnix.h ./include/HsUnix.h I would not expect to have to include $CWD/include normally when building a pkg but even using --extra-include-dirs does not work. I've followed the setup guide here: http://hackage.haskell.org/trac/ghc/wiki/Building/Windows/Cygwin Any help appreciated! Regards, Ben

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bit of a noob question
by spot135 24 Oct '09

24 Oct '09

Ok maybe a noob question, but hopefully its an easy one. This is what I've got so far: test :: x->[a] -> (b,[b]) test x arrlist = let test1 = x a = filter (\n -> fst n == test1) arrlist test2 = map snd a in (test1, [test2]) so basically I have a list say [(a,1),(a,2),(a,3),(b,1),(b,2)] etc So I give the function a x value (a or b) in this case and it return (a,[1,2,3]) which is all gravy But, Is there a way that i dont have to supply the a or b ie i call the function and it gives me the list [(a,[1,2,3]),(b,[1,2])... I presume i need another layer of recursion but I cant figure out how to do it. Any help would be gratefully received :-) -- View this message in context: http://www.nabble.com/bit-of-a-noob-question-tp26043671p26043671.html Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.

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Re: [Haskell] ANN: quickcheck-poly - Automating QuickCheck for polymorphic/overloaded properties in a small world of types
by Henning Thielemann 24 Oct '09

24 Oct '09

Ahn, Ki Yung schrieb: > Often times QuickCheck properties are polymophic/overloaded without > giving a monomorphic type signature. But there can be several types > that you are interested. You can write scripts that check all the types > you are interested annotating the generic property for each different > monotype, which is a tedious work to do. Here, I automated this via > hint (a Haskell Interpreter Library). How it works is it first asks a > type of a property to the Haskell interpreter and gets a type string, > identifies type variables that start with lowercase alphabet, generate > all possible substitution that may or may not be a correct type, stick > the type string to the property name as a signature and collect only the > meaningful types, and then finally run quickCheck over each meaningful > types. The example below clearly illustrates what it does. Maybe you could write a block of quickCheck tests, that shall be run on different types. tests :: a -> IO () tests x = do quickCheck (\y -> law1 (y `asTypeOf x)) ... allTests = tests (undefined :: Int) tests (undefined :: Double)

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A 3-line program that does not work
by Philippos Apolinarius 24 Oct '09

24 Oct '09

I have a friend who is an architect. I asked her why she does not use Haskell, since she is fond of functional programming. She writes her scripts in Clean, and needs to compile them before using them to generate postscript diagrams. In Haskell, I told her, she could use runghc, and skip the compilation step. She told me that she would consider switching to Haskell, and skipping the compilation step, if I could tell her how to write "façade" in Haskell. C:\ghc\hastex>runghc tudin.hs tudin.hs:10:19: lexical error in string/character literal (UTF-8 decoding error) After browsing the Internet, I noticed that a many of people are having the same problem. Could someone tell me what is wrong with my friend's program? import System.IO main= do outh <- openFile "garb.tsm" WriteMode hPutStrLn outh "A façade is the exterior of a building" hClose outh I would appreciate a "normal" solution, that is, I would like to type the text in any editor, or generate it with LaTeX macros, and compile it using ghc. __________________________________________________________________ Make your browsing faster, safer, and easier with the new Internet Explorer® 8. Optimized for Yahoo! Get it Now for Free! at http://downloads.yahoo.com/ca/internetexplorer/

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Re: [Haskell-beginners] using quickcheck for blackbox testing for 3rd party apps.
by Daniel Fischer 24 Oct '09

24 Oct '09

Am Dienstag 13 Oktober 2009 18:04:52 schrieb Brent Yorgey: > Brent > > * Some smart-alecks might pipe up with something about unsafePerformIO > here. But that's not a cure, it's more like performing an emergency > tracheotomy with a ballpoint pen. Quote of the month!

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STM semantics
by Paolino 24 Oct '09

24 Oct '09

I have a doubt that this code works like I want because actual STM implementation exposes its effects import Control.Concurrent import Control.Concurrent.STM main = do c <- atomically $ newTChan :: IO (TChan ()) r <- atomically $ newTVar False forkIO $ do atomically $ do r0 <- readTVar r case r0 of True -> return () False -> readTChan c myThreadId >>= killThread threadDelay 1000000 atomically (writeTVar r True) The thread stops on readTChan, but exits when I change the TVar, which happens before the readTChan. Should I trust this is the correct STM behaviour , and will not change in different implementations ? thanks paolino

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How do I uninstall GHC on a Mac running Snow Leopard?
by R J 24 Oct '09

24 Oct '09

What's the cleanest way to fully uninstall GHC on a Mac running Snow Leopard? Running Library/Frameworks/GHC.framework/Tools/Uninstaller from an account with admin privileges produced the following, surprising error message: > GHC.framework installer must be run with admin privileges> Prefix command by 'sudo'> logout > [Process completed] Thanks as always. _________________________________________________________________ Windows 7: Simplify your PC. Learn more. http://www.microsoft.com/Windows/windows-7/default.aspx?ocid=PID24727::T:WL…

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What is the current state of affairs with supercompilation?
by Eugene Kirpichov 24 Oct '09

24 Oct '09

Hi. I became intrigued with supercompilation; what is the current state of affairs with it? I know that there exist experimental supercompilers for Java and REFAL. I know of the existence of jhc and its follower lhc, although I don't know quite well what they can and what they can't. I know that ghc is probably going to have a supercompiler inside. I, again, don't know how broads the plans are. I'm mainly interested in the following: - What supercompilers do exist, except for the ones mentioned above? - What academic organizations do research in the area? - What papers should be read by someone eager to learn about supercompilation and maybe to make research contributions? - What are some solved problems and some open problems in supercompilation? -- Eugene Kirpichov Web IR developer, market.yandex.ru

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Haskell Weekly News: Issue 136 - October 24, 2009
by jfredett＠gmail.com 24 Oct '09

24 Oct '09

--------------------------------------------------------------------------- Haskell Weekly News http://sequence.complete.org/hwn/20091024 Issue 136 - October 24, 2009 --------------------------------------------------------------------------- Welcome to issue 136 of HWN, a newsletter covering developments in the [1]Haskell community. Short one this week, I have GREs today, so I've spent more time aggregating GRE knowledge rather than Haskell news. Till next week, Haskellers, The Haskell Weekly News! Announcements PastePipe -- a CLI for hpaste instances. Rogan Creswick [2]announced a new version of PastePipe, a library which reads from stdin and posts it to an hpaste instance (defaulting to hpaste.org) haskell-src-exts-1.2.0. Niklas Broberg [3]announced a major release of haskell-src-exts. Several breaking changes, a few (ideally) backwards compatable changes. See the post for all the details. mecha-0.0.0. Tom Hawkins [4]announced a very cool new DSL in Haskell for Constructive Solid Modelling. GPipe 1.02 and Vec-Transform 1.0.1. Tobias Bexelius [5]announced new versions of these packages, only a few API changes Data.Stream 0.4. Wouter Swierstra [6]announced a very delicate change to Data.Stream involving irrefutable patterns. Specifically added them in functions which produce new streams from old. strptime bindings. Eugene Kirpichov [7]announced bindings to strptime. cereal-0.2. Trevor Elliott [8]announced a new version of the cereal library, a variation on the `binary` package which provides strict parsing. quickcheck-poly. Ki Yung Ahn [9]announced a package for testing polymorphic functions automatically. 2nd CFP: JSC Special Issue on Automated Verification and Specification of Web Systems. demis [10]announced a special issue of the Journal of Symbolic Computation. The issue contains articles relating to Automated Specification and Verification of Web Systems. qtHaskell-1.1.3. David Harley [11]announced a new version of qtHaskell. Discussion Is there in Haskell the eval function? Waldemar Biernacki [12]asked about an `eval` function for Haskell. What's this pattern called? Martijn van Steenbergen [13]asked about a common pattern for an simple EDSL AST-like type. Problems with Haskell. Philippos Apolinarius [14]forwarded his response to a [15]Clean programmer who planned a move to Haskell upon fears of Clean being around for the long term. A very nice read. Statically checked binomail heaps? Maciej Kotowicz [16]talked about his implementation of Statically Checked Binomial Heaps in Haskell Blog noise [17]Haskell news from the [18]blogosphere. Blog posts from people new to the Haskell community are marked with >>>, be sure to welcome them! * Mikael Vejdemo Johansson (Syzygy-): [19][MATH198] Lecture 5 is up. * JP Moresmau: [20]Releasing my code on the unsuspecting public (EclipseFP). * Neil Brown: [21]Benchmarking STM with Criterion. * Galois, Inc: . * Brent Yorgey: [22]Typeclassopedia in Japanese!. * Neil Brown: [23]An early look at ThreadScope, a tool for profiling concurrent and parallel Haskell programs. * FP-Syd: [24]Sydney FP Group: FP-Syd #19.. * Michael Snoyman: [25]Monadic pairs and Kleisli arrows. * Martijn van Steenbergen: [26]Transforming polymorphic values. * Manuel M T Chakravarty: [27]Multicore Haskell Now!. * Don Stewart (dons): [28]Multicore Haskell Now! ACM Reflections | Projections 2009. * Dan Piponi (sigfpe): [29]What Category do Haskell Types and Functions Live In?. * Manuel M T Chakravarty: [30]Don Stewart's talk on Domain Specific Languages and Haskell. Quotes of the Week * Veinor: I program in austere haskell. I name all my variables a, a', a'', a''', etc * ddarius: releases network version 127.0.0.1 * Berengal: 'Bobby Boolean felt horrible. What did he ever do to the other values? He was just a simple bit, a simple answer to a simple question! Suddenly he felt his insides churn; he felt an exception coming on! Oh no! What should he do, now that he was outside of IO?' * Berengal: '"Go away! You're not like us!" the other values yelled. "You're impure! Impure! Impure! Impure!" they started chanting.' * dpratt71: <dpratt71> so I read somewhere that the unofficial motto of Haskell was "avoid success at all costs"... <Baughn> dpratt71: Yeah. We failed. * Warrigal: Note to self: don't do maximum [1..]. * mauke: the first and foremost task of a haskell compiler is to break haskell programs * ksf: ...premature generalisation is the root of all procrastination. * jimi_hendrix: that took longer than it should have, but it feels so pure * ddarius: Unfortunately, the logic programming community has this unhealthy death grip on Prolog. About the Haskell Weekly News New editions are posted to [31]the Haskell mailing list as well as to [32]the Haskell Sequence and [33]Planet Haskell. [34]RSS is also available, and headlines appear on [35]haskell.org. To help create new editions of this newsletter, please see the information on [36]how to contribute. Send stories to jfredett . at . gmail . dot . com. The darcs repository is available at darcs get [37]http://patch-tag.com/r/jfredett/HWN2/pullrepo HWN2 . References Visible links 1. http://haskell.org/ 2. http://article.gmane.org/gmane.comp.lang.haskell.cafe/65222 3. http://article.gmane.org/gmane.comp.lang.haskell.cafe/65219 4. http://article.gmane.org/gmane.comp.lang.haskell.cafe/65134 5. http://article.gmane.org/gmane.comp.lang.haskell.cafe/65119 6. http://article.gmane.org/gmane.comp.lang.haskell.cafe/65116 7. http://article.gmane.org/gmane.comp.lang.haskell.cafe/65061 8. http://article.gmane.org/gmane.comp.lang.haskell.cafe/65043 9. http://article.gmane.org/gmane.comp.lang.haskell.general/17586 10. http://article.gmane.org/gmane.comp.lang.haskell.general/17585 11. http://article.gmane.org/gmane.comp.lang.haskell.general/17583 12. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/65153 13. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/65148 14. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/65014 15. http://clean.cs.ru.nl/ 16. http://thread.gmane.org/gmane.comp.lang.haskell.cafe/64998 17. http://planet.haskell.org/ 18. http://haskell.org/haskellwiki/Blog_articles 19. http://blog.mikael.johanssons.org/archive/2009/10/math198-lecture-5-is-up/ 20. http://jpmoresmau.blogspot.com/2009/10/releasing-my-code-on-unsuspecting.ht… 21. http://chplib.wordpress.com/2009/10/21/benchmarking-stm-with-criterion/ 22. http://byorgey.wordpress.com/2009/10/20/typeclassopedia-in-japanese/ 23. http://chplib.wordpress.com/2009/10/19/an-early-look-at-threadscope/ 24. http://www.mega-nerd.com/erikd/Blog/FP-Syd/fp-syd-19.html 25. http://blog.snoyman.com/2009/10/19/monadic-pairs-and-kleisli-arrows/ 26. http://martijn.van.steenbergen.nl/journal/2009/10/18/transforming-polymorph… 27. http://justtesting.org/post/216085196 28. http://donsbot.wordpress.com/2009/10/17/multicore-haskell-now-acm-reflectio… 29. http://blog.sigfpe.com/2009/10/what-category-do-haskell-types-and.html 30. http://justtesting.org/post/215438784 31. http://www.haskell.org/mailman/listinfo/haskell 32. http://sequence.complete.org/ 33. http://planet.haskell.org/ 34. http://sequence.complete.org/node/feed 35. http://haskell.org/ 36. http://haskell.org/haskellwiki/HWN 37. http://patch-tag.com/r/jfredett/HWN2/pullrepo%20HWN2 Hidden links: 38. http://www.galois.com/blog/2009/10/20/crenshaw-simplex/

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