[Haskell-cafe] Continuation Workshop 2011: Call for participation
ACM SIGPLAN Continuation Workshop 2011 http://logic.cs.tsukuba.ac.jp/cw2011/ co-located with ICFP 2011, Tokyo, Japan Saturday, September 24, 2011 Call for Participation Early Registration deadline is August 15! Continuations have been discovered many times, which highlights their many applications in programming language semantics and program analysis, linguistics, logic, parallel processing, compilation and web programming. Recently, there has been a surge of interest specifically in delimited continuations: new implementations (in Scala, Ruby, OCaml, Haskell), new applications (to probabilistic programming, event-driven distributed processing), substructural and constructive logics, natural language semantics. The goal of the Continuation Workshop is to make continuations more accessible and useful -- to practitioners and to researchers in various areas of computer science and outside computer science. We wish to promote communication among the implementors and users in many fields. We would like to publicize the applications of continuations in academic (logic, linguistics) and practical fields and various programming languages (OCaml, Haskell, Scala, Ruby, Scheme, etc.). Invited talks - Mats Rooth, Cornell University http://conf.ling.cornell.edu/mr249/ >From Logic to Effects and Back Noam Zeilberger, Universite' Paris 7 http://www.pps.jussieu.fr/~noam/ Tutorials - In the evening before the workshop, there will be a tutorial session ``Introduction to Programming with Shift and Reset'' Tutorial date and time: Friday, September 23, 2011, 19:00-21:00 Tutorial place: IIJ (next to NII, the place of the ICFP conference) Tutorial speakers: Kenichi Asai and Oleg Kiselyov Presentations - Non-Deterministic Search Library Kenichi ASAI, Chihiro KANEKO `Focus movement' by delimited continuations Daisuke BEKKI Swarm: transparent scalability through portable continuations James DOUGLAS Correctness of Functions with Shift and Reset Noriko HIROTA, Kenichi ASAI Yield, the control operator: applications and a conjecture Roshan P. JAMES, Amr SABRY Demonstration of Continuation based C on GCC Shinji KONO Modular rollback through free monads Conor McBRIDE, Olin SHIVERS, Aaron TURON Using delimited continuations for distributed computing with the CIEL engine Derek G. MURRAY, Malte SCHWARZKOPF, Christopher SMOWTON, Steven SMITH, Anil MADHAVAPEDDY, Steven HAND The limit of the CPS hierarchy Josef SVENNINGSSON Visualizing continuations Naoki TAKASHIMA, Yukiyoshi KAMEYAMA ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Error in the asynchronous exception operational semantics
All you need to know about asynchronous exceptions is: *don't use them!* They're too difficult to reason about, in terms of failure modes and such. Use TVars or MVars instead. On Tue, Aug 9, 2011 at 1:40 PM, Edward Z. Yang wrote: > Hello all, > > I was recently reading "Asynchronous Exceptions as an Effect" by Harrison, > Allwein, Gill and Procter, and noticed at the end that they found an error > in the operational semantics described in "Asynchronous Exceptions in > Haskell" > by the Simons and Andrew Moran. Does anyone know what this error was, and > whether or not it was corrected in the December 12, 2006 version of the > paper > floating around on the net? > > Thanks, > Edward > > ___ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Problems building lambdabot on osx
On Aug 9, 2011, at 7:17 PM, John Lato wrote: >> From: Brandon Allbery >> >> Yes, because now it's finding the system readline, which isn't actually >> readline (Apple ships a "readline" which is actually BSD "editline", so you >> get missing symbols for things editline doesn't support such as completion). >> I think you'll need to temporarily deactivate MacPorts' iconv instead of >> using --extra-lib-dirs. >> >> This can't really be fixed by either GHC or MacPorts; there doesn't seem to >> be a good solution as yet, although the MacPorts folks may end up >> implementing a hacky solution because Apple has introduced *another* >> MacPorts-breaking library conflict in Lion (libnotify). > > Yep, this is Apple's problem and everyone else just has to put up with it. Thanks. That got lambdabot happy and installed. For the record (and for the lazyweb): $ sudo port deactivate -f libiconv $ cabal install lambdabot $ sudo port activate libiconv > If you want to mix macports and a non-macports ghc, I think the best > solution is to self-compile ghc against the macports libiconv. This > is easy, just configure ghc with > > ./configure --with-iconv-includes=/opt/local/include > --with-iconv-libraries=/opt/local/lib > > I haven't had a problem since I started building ghc this way (10.5 and 10.6). I may try that with a source install for the next release of the Haskell Platform. Thanks again everyone, -- Adam ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Problems building lambdabot on osx
> From: Brandon Allbery > > On Mon, Aug 8, 2011 at 21:38, Adam Turoff wrote: > >> First, there's the issue with linking against libiconv, which is solved >> this >> way: >> >> cabal install --extra-lib-dirs=/usr/lib >> >> That leaves a whole mess of link errors against libHSreadline: >> > > Yes, because now it's finding the system readline, which isn't actually > readline (Apple ships a "readline" which is actually BSD "editline", so you > get missing symbols for things editline doesn't support such as completion). > I think you'll need to temporarily deactivate MacPorts' iconv instead of > using --extra-lib-dirs. > > This can't really be fixed by either GHC or MacPorts; there doesn't seem to > be a good solution as yet, although the MacPorts folks may end up > implementing a hacky solution because Apple has introduced *another* > MacPorts-breaking library conflict in Lion (libnotify). Yep, this is Apple's problem and everyone else just has to put up with it. If you want to mix macports and a non-macports ghc, I think the best solution is to self-compile ghc against the macports libiconv. This is easy, just configure ghc with ./configure --with-iconv-includes=/opt/local/include --with-iconv-libraries=/opt/local/lib I haven't had a problem since I started building ghc this way (10.5 and 10.6). John L. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Analyzing slow performance of a Haskell program
> > It's cheaper again to use quotInt# and remInt# as I did in my code. > Just want to point out that this is actually surprisingly less of an impact than I thought. As I did the step-by-step break down (you can see my blog post), this one (changing `quotRem` to `quotInt#` and `remInt#`) yielded almost negligible differences. Every other change had more impact than this, including turning the `Data.Array.Unboxed` into "lookup functions" (like `lenOnes 0 = 0; lenOnes 1 = 3; lenOnes 2 = 3; ...`) Chris On Wed, Aug 10, 2011 at 2:16 AM, Bryan O'Sullivan wrote: > On Tue, Aug 9, 2011 at 9:47 AM, Chris Yuen wrote: > >> >> - I was using GHC 32-bit. Int is 32-bit there, so I needed Int64. It turns >> out 64-bit operations in 32-bit programs are just darn slow. Maybe it's a >> Windows problem. > > > No, GHC calls out to C for 64-bit integer ops on all 32-bit platforms. > > >> On Linux 64 bit GHC Int is 64 bit so everything just works. Changing Int64 >> to Int liberates me from many `fromIntegral` which saved 20% >> > > Actually, fromIntegral is usually a no-op, so chances are you're seeing the > effect of something else. > > >> - Changing `divMod` to `quotRem` saved another 20% >> > > It's cheaper again to use quotInt# and remInt# as I did in my code. > > >> 1. Why are bangs needed on the length arrays? > > > GHC has to deconstruct the Vector in order to get at the real underlying > array, so that unsafeIndex can perform the actual index into the real > underlying array. > > Without bang patterns, the code performs at least one deconstruction on > every iteration through the loop. Each deconstruction has a cost. With the > bang patterns, they're all hoisted out and performed just once. > ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell syntax highlighting in a public blog
Thanks for your input. As stated by Ivan I was looking for a solution to use in a public blog like wordpress.com. I chose Chris Yuen solution with a minor revision because I use Posterous. Posterous does not use the embed script but it accepts Gists links. See: http://blog.posterous.com/posterous-now-supports-traileraddict-embeds-a On the other hand, Wordpress.com doesn't accept gists, see: http://en.forums.wordpress.com/topic/support-gists?replies=2 On Tue, Aug 9, 2011 at 12:52 PM, Chris Yuen wrote: > You can probably just post your code as Gists in GitHub. They provide an > "embed" button to give you a
[Haskell-cafe] Snap Riak Extension v0.1
Hi, I released this library a while ago but didn't tell anyone, thought I would let people know. Would be cool to get feedback, suggestions etc. https://github.com/et4te/snap-extension-riak/ PS: There are no recent commits since I'm going to be overhauling the architecture once Snap 6 comes out with 'Snaplets'. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] alex 3.0 broken with Data.ByteString.Lazy - w2c conversion missing (fix attached)
Hi Simon,
I found a bug in alex-3.0 and I'm attaching a fixed source file -
templates/wrappers.hs (modified against alex-3.0 from cabal unpack).
Explanation:
I was installing bytestring-lexing 0.2.1 and it failed to install with
alex 3.0, which was released on Aug 4.
It succeeded, however, with the most recent earlier alex 2.3.5.
Turns out that the wrapper for lazy bytestrings (strict are ok) had
alexGetByte not doing w2c conversion:
alexGetByte (_, cs) | ByteString.null cs = Nothing
| otherwise = Just (ByteString.head cs,
(ByteString.head cs, ByteString.tail cs))
It should say ByteString.w2c $ ByteString.head cs here.
With this and an additional import of Data.ByteString.Internal (w2c),
the generated code compiles.
To reproduce, cabal unpack bytestring-lexing and try installing it.
Installation will fail, then manually alex the .x files in
Data/ByteString/Lex{,/Lazy} and try ghci'ing to them, doing the
modification I did and ghci'ing again.
--
Eugene Kirpichov
Principal Engineer, Mirantis Inc. http://www.mirantis.com/
Editor, http://fprog.ru/
wrappers.hs
Description: Binary data
___
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[Haskell-cafe] Error in the asynchronous exception operational semantics
Hello all, I was recently reading "Asynchronous Exceptions as an Effect" by Harrison, Allwein, Gill and Procter, and noticed at the end that they found an error in the operational semantics described in "Asynchronous Exceptions in Haskell" by the Simons and Andrew Moran. Does anyone know what this error was, and whether or not it was corrected in the December 12, 2006 version of the paper floating around on the net? Thanks, Edward ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Problems building lambdabot on osx
I didn't have any trouble building lambdabot when linking to readline built through Homebrew. Currently using Lion, Xcode 4.1, and GHC 7.0.4. On Aug 9, 2011, at 11:59 AM, Brandon Allbery wrote: > On Mon, Aug 8, 2011 at 21:38, Adam Turoff wrote: > First, there's the issue with linking against libiconv, which is solved this > way: > >cabal install --extra-lib-dirs=/usr/lib > > That leaves a whole mess of link errors against libHSreadline: > > Yes, because now it's finding the system readline, which isn't actually > readline (Apple ships a "readline" which is actually BSD "editline", so you > get missing symbols for things editline doesn't support such as completion). > I think you'll need to temporarily deactivate MacPorts' iconv instead of > using --extra-lib-dirs. > > This can't really be fixed by either GHC or MacPorts; there doesn't seem to > be a good solution as yet, although the MacPorts folks may end up > implementing a hacky solution because Apple has introduced *another* > MacPorts-breaking library conflict in Lion (libnotify). > > -- > brandon s allbery allber...@gmail.com > wandering unix systems administrator (available) (412) 475-9364 vm/sms > > ___ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe Jack Henahan jhena...@uvm.edu == Computer science is no more about computers than astronomy is about telescopes. -- Edsger Dijkstra == 398E692F.gpg Description: application/apple-msg-attachment ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Analyzing slow performance of a Haskell program
On Tue, Aug 9, 2011 at 9:47 AM, Chris Yuen wrote: > > - I was using GHC 32-bit. Int is 32-bit there, so I needed Int64. It turns > out 64-bit operations in 32-bit programs are just darn slow. Maybe it's a > Windows problem. No, GHC calls out to C for 64-bit integer ops on all 32-bit platforms. > On Linux 64 bit GHC Int is 64 bit so everything just works. Changing Int64 > to Int liberates me from many `fromIntegral` which saved 20% > Actually, fromIntegral is usually a no-op, so chances are you're seeing the effect of something else. > - Changing `divMod` to `quotRem` saved another 20% > It's cheaper again to use quotInt# and remInt# as I did in my code. > 1. Why are bangs needed on the length arrays? GHC has to deconstruct the Vector in order to get at the real underlying array, so that unsafeIndex can perform the actual index into the real underlying array. Without bang patterns, the code performs at least one deconstruction on every iteration through the loop. Each deconstruction has a cost. With the bang patterns, they're all hoisted out and performed just once. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Analyzing slow performance of a Haskell program
Hi Chris, On Tue, Aug 9, 2011 at 12:47 PM, Chris Yuen wrote: > 1. Why are bangs needed on the length arrays? > > If I remove them from below, performance drops 10%. I thought `unsafeIndex` > is straight in both arguments, no? > > wordLength i = go i > where > go n > | n < 10 = lengthOnes !! n > | n < 20 = lengthTeens !! (n-10) > | n < 100 = (lengthTens !! (n // 10)) + (lengthOnes !! (n % 10)) > | n < 1000 = (lengthOnes !! (n // 100)) + 7 + go (n % 100) > | n < 100 = go (n // 1000) + 8 + go (n % 1000) > | otherwise = go (n // 100) + 7 + go (n % 100) > !lengthOnes = lengthVec ones > !lengthTens = lengthVec tens > !lengthTeens = lengthVec teens (It's "strict", not "straight".) The different lengths are not used in all branches and since Haskell is a lazy (or to be pendantic: non-strict) language we cannot compute them before knowing which branch will be evaluated. For example, given that we have ones = ... tens = error "Boom!" test = wordLength 0 evaluating 'test' should not cause an exception to be raised as the first (n < 10) branch is taken, but it would if lengthOnes was strict. Delaying the evaluation has some costs, namely allocating a thunk for e.g. `lengthVec ones` and later evaluate that thunk. By making the lengths strict we can evaluate them earlier and avoid some allocation and forcing of thunks. > 2. Why the single element worker wrapper pattern (`go` functions) increases > performance? > > If we change wordLength to > > wordLength n > | n < 10 = lengthOnes !! n > | n < 20 = lengthTeens !! (n-10) > | n < 100 = (lengthTens !! (n // 10)) + (lengthOnes !! (n % 10)) > | n < 1000 = (lengthOnes !! (n // 100)) + 7 + wordLength (n % 100) > | n < 100 = wordLength (n // 1000) + 8 + wordLength (n % 1000) > | otherwise = wordLength (n // 100) + 7 + wordLength (n % 100) > where > !lengthOnes = lengthVec ones > !lengthTens = lengthVec tens > !lengthTeens = lengthVec teens > > The performance drops by another 10%. This really surprised me. `go i` > seemed obvious to me and I don't understand how it could make any > difference. The full source code is available to GHC so it shouldn't be > related to call-by-pointer problem? If this is the case, shouldn't we always > wrap a "go" function for **any** recursive functions? Making wordLength non-recursive lets GHC inline it, which can sometimes help performance (e.g. if the inlining enables more optimizations). Inlining does increase code size (and sometimes allocation if a closure has to be allocated to capture free variables), so it's not always a good idea. Cheers, Johan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell syntax highlighting in a public blog
You can probably just post your code as Gists in GitHub. They provide an "embed" button to give you a
Re: [Haskell-cafe] Analyzing slow performance of a Haskell program
Hi all, Thanks Bryan, reading your clean code was good for my Haskell health :) I took your code and did some more research. I think I have found the answer. I have written an extensive analysis in my blog post http://cfc.kizzx2.com/index.php/in-search-of-performance-in-haskell/(comments are very much welcome, btw :) Here are summaries of key points: - I was using GHC 32-bit. Int is 32-bit there, so I needed Int64. It turns out 64-bit operations in 32-bit programs are just darn slow. Maybe it's a Windows problem. On Linux 64 bit GHC Int is 64 bit so everything just works. Changing Int64 to Int liberates me from many `fromIntegral` which saved 20% - Changing `divMod` to `quotRem` saved another 20% - Using `Data.Vector.Unboxed` and `unsafeIndex` saved another 15% or so - Moving the "length" arrays to `where` clause in `solve` with bang patterns on them save some more. This was a great learning experience! Now I have more questions :P 1. Why are bangs needed on the length arrays? If I remove them from below, performance drops 10%. I thought `unsafeIndex` is straight in both arguments, no? wordLength i = go i where go n | n < 10 = lengthOnes !! n | n < 20 = lengthTeens !! (n-10) | n < 100 = (lengthTens !! (n // 10)) + (lengthOnes !! (n % 10)) | n < 1000 = (lengthOnes !! (n // 100)) + 7 + go (n % 100) | n < 100 = go (n // 1000) + 8 + go (n % 1000) | otherwise = go (n // 100) + 7 + go (n % 100) !lengthOnes = lengthVec ones !lengthTens = lengthVec tens !lengthTeens = lengthVec teens 2. Why the single element worker wrapper pattern (`go` functions) increases performance? If we change wordLength to wordLength n | n < 10 = lengthOnes !! n | n < 20 = lengthTeens !! (n-10) | n < 100 = (lengthTens !! (n // 10)) + (lengthOnes !! (n % 10)) | n < 1000 = (lengthOnes !! (n // 100)) + 7 + wordLength (n % 100) | n < 100 = wordLength (n // 1000) + 8 + wordLength (n % 1000) | otherwise = wordLength (n // 100) + 7 + wordLength (n % 100) where !lengthOnes = lengthVec ones !lengthTens = lengthVec tens !lengthTeens = lengthVec teens The performance drops by another 10%. This really surprised me. `go i` seemed obvious to me and I don't understand how it could make any difference. The full source code is available to GHC so it shouldn't be related to call-by-pointer problem? If this is the case, shouldn't we always wrap a "go" function for **any** recursive functions? Thanks! Chris On Tue, Aug 9, 2011 at 9:09 AM, Reiner Pope wrote: > On 9 August 2011 10:06, Bryan O'Sullivan wrote: > >> On Mon, Aug 8, 2011 at 9:24 AM, Chris Yuen wrote: >> >>> >>> For reference I have asked the same question on StackOverflow. One person >>> suggested that the reason might be that Int64 on Windows is broken ( >>> http://stackoverflow.com/questions/6970904/analyzing-slow-performance-of-a-haskell-program/6976448#6976448 >>> ). >>> >> >> No, they're barking up the wrong tree. >> >> I've put an idiomatic Haskell translation of your C++ algorithm at >> https://gist.github.com/1133048#file_wordy.hs >> >> (I've also included a copy of your original C++, with a bug fixed, in the >> same gist.) >> >> As you can see, the two are almost identical. Not surprisingly, each one >> spends the bulk of its time computing word lengths. >> >> GHC simply doesn't do a great job of compiling fairly tight code like >> this. gcc generates about 100 lines of assembly that's mostly easy to follow >> (except for some bit-twiddling tricks to avoid div instructions). Although >> the Core it generates looks fine, GHC spends quite a bit of time in its >> generated assembly on what looks to me like STG housekeeping (it spends only >> 0.3% of its time in the garbage collector, because it doesn't allocate >> memory). The overall result is that the Haskell code runs about 5x more >> slowly than the C++ code. >> >> > GHC generating bad assembly suggests trying the llvm codegen (see > http://donsbot.wordpress.com/2010/02/21/smoking-fast-haskell-code-using-ghcs-new-llvm-codegen/). > Compiling Bryan's code with > > $ ghc -O2 -fllvm Wordy.hs > > it now runs only 2x slower than the C++ code. > > Reiner > ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Problems building lambdabot on osx
On Mon, Aug 8, 2011 at 21:38, Adam Turoff wrote: > First, there's the issue with linking against libiconv, which is solved > this > way: > >cabal install --extra-lib-dirs=/usr/lib > > That leaves a whole mess of link errors against libHSreadline: > Yes, because now it's finding the system readline, which isn't actually readline (Apple ships a "readline" which is actually BSD "editline", so you get missing symbols for things editline doesn't support such as completion). I think you'll need to temporarily deactivate MacPorts' iconv instead of using --extra-lib-dirs. This can't really be fixed by either GHC or MacPorts; there doesn't seem to be a good solution as yet, although the MacPorts folks may end up implementing a hacky solution because Apple has introduced *another* MacPorts-breaking library conflict in Lion (libnotify). -- brandon s allbery allber...@gmail.com wandering unix systems administrator (available) (412) 475-9364 vm/sms ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Second CFP: PADL'12 - Practical Aspects of Declarative Languages 2012
[Apologies if you receive multiple copies.] Call for Papers === 14th International Symposium on Practical Aspects of Declarative Languages (PADL 2012) http://research.microsoft.com/~crusso/padl12 Philadelphia, Pennsylvania, USA, January 23-24, 2012 Co-located with ACM POPL'12 Abstract/Paper submission deadline: September 10th/17th, 2011 Conference Description == Declarative languages build on sound theoretical bases to provide attractive frameworks for application development. These languages have been successfully applied to many different real-world situations, ranging from data base management to active networks to software engineering to decision support systems. New developments in theory and implementation have opened up new application areas. At the same time, applications of declarative languages to novel problems raise numerous interesting research issues. Well-known questions include designing for scalability, language extensions for application deployment, and programming environments. Thus, applications drive the progress in the theory and implementation of declarative systems, and benefit from this progress as well. PADL is a forum for researchers and practitioners to present original work emphasizing novel applications and implementation techniques for all forms of declarative concepts, including, functional, logic, constraints, etc. Topics of interest include, but are not limited to: * Innovative applications of declarative languages * Declarative domain-specific languages and applications * Practical applications of theoretical results * New language developments and their impact on applications * Declarative languages and Software Engineering * Evaluation of implementation techniques on practical applications * Practical experiences and industrial applications * Novel uses of declarative languages in the classroom * Practical extensions such as constraint-based, probabilistic, and reactive languages. PADL'12 welcomes new ideas and approaches pertaining to applications and implementation of declarative languages. In this occasion PADL is co-located, as traditionally, with ACM POPL, which will be held immediately following PADL, January 25-27. The symposium will be held in Philadelphia, Pennsylvania, USA. Important Dates and Submission Guidelines = Abstract Submission:September 10, 2011 Paper Submission: September 17, 2011 Notification: October 22, 2011 Camera-ready: November 5, 2011 Symposium: January 23-24, 2012 Authors should submit an electronic copy of the full paper in PDF using the Springer LNCS format. The submission will be done through EasyChair conference system. If electronic submission is impossible, please contact the program chairs for information on how to submit hard copies. All submissions must be original work written in English. Submissions must be unpublished and not submitted for publication elsewhere. Work that already appeared in unpublished or informally published workshops proceedings may be submitted. PADL'12 will accept both technical and application papers: * Technical papers must describe original, previously unpublished research results. Technical papers must not exceed 15 pages in Springer LNCS format. * Application papers are a mechanism to present important practical applications of declarative languages that occur in industry or in areas of research other than Computer Science. Application papers will be published in the Springer-Verlag conference proceedings, and will be presented in a separate session. Application papers are expected to describe complex and/or real-world applications that rely on an innovative use of declarative languages. Application descriptions, engineering solutions and real-world experiences (both positive and negative) are solicited. The limit for application papers is 6 pages in Springer LNCS format. Program Committee = Marcello Balduccini, Intelligent Systems Department, Kodak Research Labs Edwin Brady, University of St Andrews, Scotland Henning Christiansen, Roskilde University, Denmark Agostino Dovier, University of Udine, Italy Matthew Flatt, University of Utah, USA Gopal Gupta, University of Texas at Dallas, USA John Hughes, Chalmers University of Technology, Sweden; Quviq AB Gabriele Keller, University of New South Wales, Australia Lunjin Lu, Oakland University, USA Marc Pouzet, Éc
[Haskell-cafe] PhD Position available at Strathclyde
[My colleague, Patricia Johann, advertises the following...] PhD Position in Category Theory and Functional Programming Department of Computer and Information Sciences University of Strathclyde, Scotland Applications are invited for one PhD position within the Mathematically Structured Programming group at the University of Strathclyde. The group comprises Prof. Neil Ghani, Dr. Patricia Johann, Dr. Conor McBride, Dr. Peter Hancock, Dr. Robert Atkey, and six PhD students. The PhD project centres around applications of categorical methods to functional programming languages. The project is under the direction of Patricia Johann. The successful applicant will have either a first-class degree or an MSc in Mathematics or Computing Science or a related subject with a strong Mathematics or Computing Science component. Ideally, they will also have a strong, documented interest in doing research. Strong mathematical background and problem-solving skills are essential; good programming skills are a plus. Prior knowledge of category theory and/ or functional programming is an advantage, but is not required. The PhD position is for 3 years; it starts in January 2012. The position is a fully-funded post for a UK or EU student, and includes both coverage of fees and an EPSRC-level stipend for each of the three years. More information about the department is available at http://www.strath.ac.uk/cis The University of Strathclyde (http://www.strath.ac.uk) is located in the heart of Glasgow, which Lonely Planet Travel Guides hail as "one of Britain's largest, liveliest and most interesting cities" (seehttp://www.lonelyplanet.com/worldguide/scotland/glasgow/) . Southern Scotland provides a particularly stimulating environment for researchers in theoretical computer science, with active groups in this area at Heriot-Watt University, the University of Edinburgh, the University of Glasgow, the University of St. Andrews, and the University of Strathclyde. Requests for further information and other informal enquiries can be sent to: Patricia Johann patricia at cis.strath.ac.uk Those interested in the position are asked to send e-mail to the address given above in the next short while. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Question Formlets, file upload
Dear all, I am using the library Text.XHtml.Strict.Formlets to build a validating form. I use the function "file" to get a file upload widget. The encoding is set to multipart. I want to check, if the user entered something or left the widget empty. However, when entering nothing, instead of an empty string, I always get a string like "/tmp/12101" which corresponds to an empty file. It would be nice, if I could check for the empty string to see, weather the user entered something or not into the upload widget. I appreciate any hints to achive this and wish you a good day, Heinrich -- -- hoerde...@funktional.info www.funktional.info -- ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Problems building lambdabot on osx
Hi, there is a conflict between ghc' libiconv and Ports installed libiconv. make sure first sudo port deactivate -f libiconv then install again, it should work. however, it is very ugly since your other port installed libraries needs libiconv, like gnuplot, so when you need port installed libiconv, sudo port activate -f libiconv again. 于 11-8-8 下午9:38, Adam Turoff 写道: I've tried off and on the last couple of days to build Lambdabot on Mac OS X (before and after the upgrade from 10.6 to 10.7) and I keep running into linker errors with the 64-bit Haskell Platform (ghc 7.0.3). First, there's the issue with linking against libiconv, which is solved this way: cabal install --extra-lib-dirs=/usr/lib That leaves a whole mess of link errors against libHSreadline: Linking dist/build/lambdabot/lambdabot ... ld: warning: could not create compact unwind for _ffi_call_unix64: does not use RBP or RSP based frame Undefined symbols for architecture x86_64: "_rl_insert_completions", referenced from: _readlinezm1zi0zi1zi0_SystemziConsoleziReadline_zdwa5_info in libHSreadline-1.0.1.0.a(Readline.o) "_rl_possible_completions", referenced from: _readlinezm1zi0zi1zi0_SystemziConsoleziReadline_zdwa7_info in libHSreadlin (full error report at http://hpaste.org/50036 ) I did manage to install readline through macports: $ port installed readline The following ports are currently installed: readline @6.2.000_0 (active) $ file /opt/local/lib/libreadline.dylib /opt/local/lib/libreadline.dylib: Mach-O 64-bit dynamically linked shared library x86_64 and I did manage to get readline installed properly by specifying the include/lib dirs from macports: cabal install readline --configure-option=--with-readline-libraries=/opt/local/lib --configure-option=--with-readline-includes=/opt/local/include and readline does work in ghci: $ ghci GHCi, version 7.0.3: http://www.haskell.org/ghc/ :? for help Prelude> :m + System.Console.Readline Prelude System.Console.Readline> readline "testing> " testing> exit exit Just "exit" Prelude System.Console.Readline> The only issue, which has me stumped, is that lambdabot can't seem to find the readline dependency. Adding the --with-readline options when trying to build lambdabot has no effect. Neither does adding --extra-lib-dirs=/opt/local/lib to cabal install. Anyone have a clue where to start to work around this? Would switching to ghc HEAD help here? Thanks, -- Adam ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Haskell syntax highlighting in a public blog
Another alternative is to use the HsColour package: http://code.haskell.org/~malcolm/hscolour/ and choose html as output. (This works for me on blogspot.com) On 9 August 2011 05:16, Daniel Patterson wrote: > > On Aug 8, 2011, at 10:26 PM, Ivan Lazar Miljenovic wrote: > > On 9 August 2011 12:04, Arlen Cuss wrote: > > 9/08/2011 11:54 AM, Oscar Picasso kirjutas: > > Hi, > > > Is there a public blog that that allow syntax highlighting of Haskell code? > > > Are you talking about a plugin for a blog engine? CodeColourer on > > WordPress will do it. > > > I think he meant more along the lines of wordpress.com, which as far > as I know _doesn't_ support highlighting Haskell. > > > I haven't done this personally, but here is a javascript based solution > that should work with any blog that allows you to include custom stylesheets > / javascript: > http://nix-tips.blogspot.com/2010/09/javascript-highlighter-for-haskell-code.html > > ___ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > > -- http://adoseoflogic.blogspot.com/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
