March 2010 - Haskell-Cafe

ANN: CPSA - Cryptographic Protocol Shapes Analyzer
by John D. Ramsdell 15 Mar '10

15 Mar '10

The Cryptographic Protocol Shapes Analyzer (CPSA) has been released on Hackage at <http://hackage.haskell.org/package/cpsa>. CPSA attempts to enumerate all essentially different executions possible for a cryptographic protocol. We call them the shapes of the protocol. Naturally occurring protocols have only finitely many, indeed very few shapes. Authentication and secrecy properties are easy to determine from them, as are attacks and anomalies. For each input problem, the CPSA program is given some initial behavior, and it descovers what shapes are compatible with it. Normally, the initial behavior is from the point of view of one participant. The analysis reveals what the other participants must have done, given the participant's view. We are working towards a version of CPSA with the property that whenever it successfully terminates, every possible execution is described by its output. However, the current implementation occasionally fails to find some executions. The package contains a set of programs used to perform and display the analysis. Program documentation is in the doc directory in the source distribution, and installed in the package's data directory. You can locate the package's data directory by searching for the file cpsauser.html. New users should study the documentation and the sample inputs in the data directory. The theory and algorithm used by CPSA was developed with the help of Joshua D. Guttman, John D. Ramsdell, Jon C. Herzog, Shaddin F. Doghmi, F. Javier Thayer, and Paul D. Rowe. John D. Ramsdell implemented the algorithm in Haskell.

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Using regexps to filter data
by michael rice 15 Mar '10

15 Mar '10

Not sure I'm even in the right neighborhood with this. Need to screen for integer data. Am I going about this correctly? Michael ====== [michael@localhost ~]$ ghci GHCi, version 6.10.4: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer ... linking ... done. Loading package base ... linking ... done. Prelude> :m + Text.Regex.Base.RegexLike Prelude Text.Regex.Base.RegexLike> let r = makeRegex "[+-]?[0-9]+" <interactive>:1:8: No instance for (RegexMaker regex compOpt execOpt [Char]) arising from a use of `makeRegex' at <interactive>:1:8-30 Possible fix: add an instance declaration for (RegexMaker regex compOpt execOpt [Char]) In the expression: makeRegex "[+-]?[0-9]+" In the definition of `r': r = makeRegex "[+-]?[0-9]+" Prelude Text.Regex.Base.RegexLike>

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Binaries using shared libraries with cabal-install
by Mathijs Kwik 15 Mar '10

15 Mar '10

Hi all, I'm using cabal-install 0.8.0 on ghc 6.12.1 on linux I switched on shared library support on cabal. Does this enable -dynamic and -fPIC during compilation and -dynamic -shared during linking? Or does it work a little differently? I noticed everything works for libraries. .so files get created, and using ldd on them shows they depend on other haskell shared libraries. But for binaries, it seems it still compiles them with everything included. ldd'ing them shows no haskell-library dependencies and their size is quite big as well. Is it possible to tell cabal-install I want binaries to use shared libs instead? And is there a way to specify which RTS to link binaries with? (debug, threaded, normal) Or a way to defer linking to an RTS so I can do this on execution using LD_PRELOAD ? Thanks for any help Mathijs

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#haskell-web, anyone ?
by Simon Michael 14 Mar '10

14 Mar '10

We just had a big old web dev discussion in #darcs, which made me want to hang out in #haskell-web and hear more of the same. I think it existed briefly and died, but maybe it's time to try again ? Normally I don't like removing interesting chat from the main channel, but #haskell is often pretty noisy/theoretical/general/random and I think there might be enough folks interested in having this more practical, topical channel. If you are one, put #haskell-web on auto-join in your irc client and let's see how it goes. The topic currently reads "friendly, practical discussion of haskell web app/framework/server development".

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how to user mergeIO
by Brock Peabody 14 Mar '10

14 Mar '10

Hi, I've been trying to use Control.Concurrent.mergeIO to parallelize computation, and can't make it work. In the sample program below, I expect the function 'parallelTest' to be almost twice as fast as 'sequentialTest', and to compute its results in two threads, as implied by the documentation for mergeIO. This is not what happens. If I link my program with the option '-threaded', the running process does have three threads. If I run with the option "+RTS -N2", the process will have 5 threads. In no case does the process appear to be using more than one CPU, and in fact it is slower with the threading options turned on. I'm sure I am doing something obviously (to someone else) wrong. Any ideas? I am running the latest version of Mac OSX on a core2 duo machine with 2 cores, using ghc version 6.10.4. Cheers, Brock My test program follows: {-# OPTIONS_GHC -fglasgow-exts #-} module Main where import Control.Concurrent import Random doSum :: RandomGen g => g -> Int -> Integer doSum g count = let runner curG sum numDone | numDone == count = sum | otherwise = let (newNum :: Integer, newG) = random curG newSum = sum + newNum newNumDone = numDone + 1 in ((runner $! newG) $! newSum) $! newNumDone in runner g 0 0 sequentialTest = do let gen = mkStdGen 0 (g0,g1) = split gen count = 10000000 sum0 = doSum g0 count sum1 = doSum g1 count total = sum0 + sum1 putStrLn $ "total: " ++ show total parallelTest = do let gen = mkStdGen 0 (g0,g1) = split gen count = 10000000 sum0 = doSum g0 count sum1 = doSum g1 count [res0, res1] <- mergeIO [sum0] [sum1] let total = res0 + res1 putStrLn $ "total: " ++ show total main = parallelTest

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Splitting list with predicate
by michael rice 14 Mar '10

14 Mar '10

Is there a library function that will create two lists from one based on a predicate, one list for all elements that satisfy the predicate and one for all that do not? Don't want to reinvent the wheel. Michael

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difficulty getting cabal and macports to play nice
by Carter Schonwald 14 Mar '10

14 Mar '10

Hello, I'm not sure if theres a more specialized list for which this might be appropriate, but cabal (up to date) on snow leopard can't seem to find libraries installed by macports even if i show it where they are (which i have in fact installed the most up to date version of with the macports +universal variant) the version info thats relevant is cabal-install version 0.6.4 using version 1.6.0.3 of the Cabal library here is an example transcript sudo cabal install --extra-lib-dirs=/opt/local/lib --extra-include-dirs=/opt/local/include hieroglyph chart Resolving dependencies... cabal: cannot configure Hieroglyph-3.89. It requires cairo -any, glib -any, gtk >=0.10.0 and gtkglext -any There is no available version of cairo that satisfies -any There is no available version of glib that satisfies -any There is no available version of gtk that satisfies >=0.10.0 There is no available version of gtkglext that satisfies -any is there something obvious that i'm overlooking or is this a funny unfixed corner of cabal?

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First time haskell - parse error!
by boblettoj 14 Mar '10

14 Mar '10

Hi, i am getting an error when trying to compile this part of my program, its my first time using haskell and as lovely as it is it didn't give me very much to go on in the error message! <code>score :: String -> String -> String score [s] [] = false score [s] [g] = if valid 4 g then (s1 ++ s2 ++ s3 ++ s4) where s1 = "Golds " s2 = show (gold s g) s3 = ", Silvers " s4 = show (silver s g) else "Bad Guess"</code> when i try to compile it says: test.hs 63:29: parse error on input 'where' (its the line beginning with 'then') Anybody got any ideas whats going on? thanks! -- View this message in context: http://old.nabble.com/First-time-haskell---parse-error%21-tp27839657p278396… Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.

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ANNOUNCE: Haddock 2.7.0
by David Waern 14 Mar '10

14 Mar '10

-------------------------------------------- -- Haddock 2.7.0 -------------------------------------------- A new version of Haddock, the Haskell documentation tool, is out! -------------------------------------------- -- Changes in version 2.7.0 -------------------------------------------- * Instances can be commented * The Haddock API now exposes more of the internals of Haddock * Bug fixes (most importantly #128) -------------------------------------------- -- Links -------------------------------------------- Homepage: http://www.haskell.org/haddock Hackage page: http://hackage.haskell.org/package/haddock-2.7.0 Bugtracker and wiki: http://trac.haskell.org/haddock Mailing list: haddock(a)projects.haskell.org Code repository: http://code.haskell.org/haddock -------------------------------------------- -- Contributors -------------------------------------------- The following people contributed patches to this release: Isaac Dupree Yitzchak Gale David Waern -------------------------------------------- -- Get Involved -------------------------------------------- We would be very happy to get more contributors. To get involved, start by grabbing the code: http://code.haskell.org/haddock Then take a look at the bug and feature tracker for things to work on: http://trac.haskell.org/haddock

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gtk2hs gtkbuilder
by Andrew U. Frank 14 Mar '10

14 Mar '10

i currently use gtk2hs with libglade (and glade). i understand that the gtkbuilder allows more constructs than libglade. how to use gtkbuilder in gtk2hs? i see that John Millikin has posted a patch for gtk2hs - but i cannot find it and no documentation for its use? can anyone point me to a patched version of gtk2hs and some examples? thank you! andrew

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