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ByteString install issues with GHC 7.0.3 on Windows 7
by Ralph Hodgson 02 Oct '11

02 Oct '11

This morning I was successfully running BlazeHtml on Windows 7. Then I installed some libraries from other packages and BlazeHtml broke. I then decided to go from ghc 6.12.1 to ghc 7.0.3 and reinstall everything. BlazeHtml installed OK. But my program also needed ByteString. So I did the following: First I tried the stable version: >cabal install bytestring-0.9.1.4 Resolving dependencies... Configuring bytestring-0.9.1.4... Preprocessing library bytestring-0.9.1.4... Building bytestring-0.9.1.4... Data\ByteString.hs:3:24: Cannot parse LANGUAGE pragma Expecting comma-separated list of language options, each starting with a capital letter E.g. {-# LANGUAGE RecordPuns, Generics #-} cabal: Error: some packages failed to install: bytestring-0.9.1.4 failed during the building phase. The exception was: ExitFailure 1 I am not experienced enough to fix this, so I tried a previous ByteString version: >cabal install bytestring-0.9.1.3 Resolving dependencies... Configuring bytestring-0.9.1.3... Preprocessing library bytestring-0.9.1.3... Building bytestring-0.9.1.3... [1 of 8] Compiling Data.ByteString.Fusion ( Data\ByteString\Fusion.hs, dist\buil d\Data\ByteString\Fusion.o ) [2 of 8] Compiling Data.ByteString.Internal ( Data\ByteString\Internal.hs, dist\ build\Data\ByteString\Internal.o ) Data\ByteString\Internal.hs:79:42: Module `GHC.IOBase' does not export `RawBuffer' cabal: Error: some packages failed to install: bytestring-0.9.1.3 failed during the building phase. The exception was: ExitFailure 1 No joy. Help appreciated. May try all this on my MAC tomorrow. Ralph Hodgson, <http://twitter.com/ralphtq> @ralphtq Mobile Phone: +1 781-789-1664

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ANNOUNCE: GA-1.0, a library for working with genetic algorithms
by Kenneth Hoste 01 Oct '11

01 Oct '11

Hello, I'm proud to announce the v1.0 release of GA [1], my library for working with genetic algorithms in Haskell. Source repo is available on github. [2] This is a major version bump compared to the previous v0.2 release, because the library is pretty mature now in my view. Major features: * flexible user-friendly API for working with genetic algorithms * Entity type class to let user define entity definition, scoring, etc. * abstraction over monad, resulting in a powerful yet simple interface * support for scoring entire population at once * support for checkpointing each generation, and restoring from last checkpoint * convergence detection, as defined by user * also available: random searching, user-defined progress output * illustrative toy examples included I'm happy to take any questions or suggestions that you might have. [1] http://hackage.haskell.org/package/GA [2] https://github.com/boegel/GA

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Haskell Cloud and Closures
by Fred Smith 01 Oct '11

01 Oct '11

I've built a little program to compute the plus function remotely by using Cloud Haskell: http://pastebin.com/RK4AcWFM but i faced an unfortunate complication, what i would like to do is to send a function to another host, no matter if the function is locally declared or at the top level. In seems to me that in cloud haskell library the function's closures can be computed only with top-level ones, is it possible to compute the closure at runtime of any function and to send it to another host? here's the code that i would like to compile: http://pastebin.com/7F4hs1Kk thank you all in advance! Fred

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Build local-gc branch of GHC
by Andreas Voellmy 01 Oct '11

01 Oct '11

Hi, I've been trying to get and build a branch of ghc that includes the new local GC algorithm ( http://www.haskell.org/pipermail/cvs-ghc/2011-June/062748.html) but I haven't been able to build it successfully. Here is what I've done: 1. Got the latest source tree using these commands: $ git clone http://darcs.haskell.org/ghc.git/ $ cd ghc $ ./sync-all --testsuite get 2. Use 'fingerprint' script to get the state of the repository for the branch mentioned in the web page I mentioned above. A fingerprint file based on the announcement above fails due to some problem with binary and haddock change sets not being found. So I modified the fingerprint to use the latest versions for binary and deleted the change for haddock entirely. I ran this command: ./utils/fingerprint/fingerprint.py restore -f local-gc.fp and my local-gc.fp fingerprint file contains this: .|ab5aad587de8e3d9dde539982ae728b33e5bca50 ghc-tarballs|e7b7b152083f7c3e3559e557a239757d41ac02a6 libraries/Cabal|6f01f56a2702b50e2da909566c4a01622cb2ca7f libraries/Win32|0cf603103e9ad3fccd862171ba5e689b87930622 libraries/array|e4b4e2e0a79f4138bdff4f10d263436b0155f449 libraries/base|be2750a0a11b919fb03cc070074e430f88bdfa90 libraries/binary|376797487651cf995bd52458ce1f7d7a283341b3 libraries/bytestring|cab9d8566fba8611598f14fb4f2ac7b8d4aae75b libraries/containers|592f6d9da9090e8d53432f22a01bb117fea2246c libraries/deepseq|91e8a93b15ed32af3941f81e927291a023feb369 libraries/directory|3a0f2e2cb94c3e4f346023acc7201409d2876ed8 libraries/extensible-exceptions|a667b48d0cb6469b6611cb516d16836aa002e782 libraries/filepath|92d211a2752fe8827582ae0d97efd18722ad3d87 libraries/ghc-prim|7fcfc880853fa399c9468049aeb14e6eadb9eae5 libraries/haskeline|125ee5bba59fa9ac2fd77aa3922c30dffc11b7b5 libraries/haskell2010|f90687bee55adfd693fe460f2ab4bc270a7f97e3 libraries/haskell98|eb655b0317665acb9670025480b4af4465bc8f55 libraries/hoopl|0febb7f04ff4326bd120fc75549845e5e9678d72 libraries/hpc|fce8babbc3f60fb195d84545753dc342422ab8e1 libraries/integer-gmp|2567c97aaa467cb676a6ecc2cf840c92ee1cb6ec libraries/integer-simple|c3e9c0268b4d59895829e429d1ac767e6041b06a libraries/mtl|a748dfa2770af1d348dfaa8ad6955b25b4935711 libraries/old-locale|7f09f55ea3011c17c526805f099394a05ec9c3fe libraries/old-time|6aae8dc2f13cef6ab48c5436c6c0e7c1b5ae3f51 libraries/parallel|f82611fac439236e22a057cd555bb9fe393597b0 libraries/pretty|e00aa7e0f82fc6f13ad85f1b3a27f53efe473e60 libraries/process|d1c2999473ba0d4ceafdc6da309debca83f91abe libraries/random|ba8cb1b9fdfddeb29fdfedd8612c8ce85a987af8 libraries/stm|ccc6d74872916e5de7747df4cc61f64de64be591 libraries/template-haskell|acd4c3292d0f7a222a1f4f426054e4732a809fc8 libraries/terminfo|f4476f1881085b74dbe65cf4a4561e8fb34017d4 libraries/unix|c9a0bf119ce343b291bef77828066339e94fb64d libraries/utf8-string|d28cd1fbd4ebaaa0608c070bd02ed72dc9b70399 libraries/xhtml|9a4d7d64d0491a1844d5b5759275b029ccd1e2cd nofib|6d3ea16e56bd99d060e778fab3583aa67a6b50d4 testsuite|6560613138d61afddd0d8d428254370f8dfdb4cd utils/hsc2hs|c46eed44ce96f1719334ffb190eddf63695bc553 3. I then run $perl boot $./configure This succeeds telling me that it will be building ghc version 7.1.20110606. 4. Run make and it fails with this output: + test -f mk/config.mk.old + cp -p mk/config.mk mk/config.mk.old touch -r mk/config.mk.old mk/config.mk + test -f mk/project.mk.old + cp -p mk/project.mk mk/project.mk.old touch -r mk/project.mk.old mk/project.mk + test -f compiler/ghc.cabal.old + cp -p compiler/ghc.cabal compiler/ghc.cabal.old touch -r compiler/ghc.cabal.old compiler/ghc.cabal ===--- building phase 0 make -r --no-print-directory -f ghc.mk phase=0 phase_0_builds libraries/dph/ghc.mk:116: *** dph_th_deps(v,seq): libraries/dph/dph-base_dist-install_GHCI_LIB not defined!. Stop. make: *** [all] Error 2 5. I don't know how to fix this, so I tried deleting libraries/dph. Then I run make again, and get a ways through the build, and then get this error: "inplace/bin/ghc-stage1" -M -dep-makefile libraries/vector/dist-install/build/.depend-v-p-dyn.haskell.tmp -dep-suffix p -dep-suffix dyn -include-pkg-deps -H32m -O -package-name vector-0.8 -hide-all-packages -i -ilibraries/vector/. -ilibraries/vector/dist-install/build -ilibraries/vector/dist-install/build/autogen -Ilibraries/vector/dist-install/build -Ilibraries/vector/dist-install/build/autogen -Ilibraries/vector/include -Ilibraries/vector/internal -optP-DVECTOR_BOUNDS_CHECKS -optP-include -optPlibraries/vector/dist-install/build/autogen/cabal_macros.h -package base-4.3.1.0 -package primitive-0.4.0.1 -O2 -XHaskell98 -XCPP -XDeriveDataTypeable -O2 -no-user-package-conf -rtsopts -odir libraries/vector/dist-install/build -hidir libraries/vector/dist-install/build -stubdir libraries/vector/dist-install/build -hisuf hi -osuf o -hcsuf hc libraries/vector/./Data/Vector/Internal/Check.hs libraries/vector/./Data/Vector/Fusion/Util.hs libraries/vector/./Data/Vector/Fusion/Stream/Size.hs libraries/vector/./Data/Vector/Fusion/Stream/Monadic.hs libraries/vector/./Data/Vector/Fusion/Stream/Monadic/Safe.hs libraries/vector/./Data/Vector/Fusion/Stream.hs libraries/vector/./Data/Vector/Fusion/Stream/Safe.hs libraries/vector/./Data/Vector/Generic/Mutable.hs libraries/vector/./Data/Vector/Generic/Mutable/Safe.hs libraries/vector/./Data/Vector/Generic/Base.hs libraries/vector/./Data/Vector/Generic/New.hs libraries/vector/./Data/Vector/Generic/New/Safe.hs libraries/vector/./Data/Vector/Generic.hs libraries/vector/./Data/Vector/Generic/Safe.hs libraries/vector/./Data/Vector/Primitive/Mutable.hs libraries/vector/./Data/Vector/Primitive/Mutable/Safe.hs libraries/vector/./Data/Vector/Primitive.hs libraries/vector/./Data/Vector/Primitive/Safe.hs libraries/vector/./Data/Vector/Storable/Internal.hs libraries/vector/./Data/Vector/Storable/Mutable.hs libraries/vector/./Data/Vector/Storable.hs libraries/vector/./Data/Vector/Unboxed/Base.hs libraries/vector/./Data/Vector/Unboxed/Mutable.hs libraries/vector/./Data/Vector/Unboxed/Mutable/Safe.hs libraries/vector/./Data/Vector/Unboxed.hs libraries/vector/./Data/Vector/Unboxed/Safe.hs libraries/vector/./Data/Vector/Mutable.hs libraries/vector/./Data/Vector/Mutable/Safe.hs libraries/vector/./Data/Vector.hs libraries/vector/./Data/Vector/Safe.hs libraries/vector/Data/Vector/Fusion/Util.hs:4:14: Unsupported extension: Trustworthy make[1]: *** [libraries/vector/dist-install/build/.depend-v-p-dyn.haskell] Error 1 make: *** [all] Error 2 I deleted this library too, but my build errors just continued. After resolving a bunch of build errors in Haskell libraries, I started getting errors in the C files in the rts directory. While I could go on fixing these problems, it seems likely that I went wrong somewhere early on. Does anyone see where I went wrong? Did I use the various tools (git, sync-all, fingerprint, boot, configure, make) in the right order and way? Regards, Andreas

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Re: [Haskell-cafe] [Haskell] mapM with Traversables
by Marc Ziegert 30 Sep '11

30 Sep '11

Hi Thomas, this should be on the haskell-cafe or haskell-beginners mailing list. Haskell@... is mainly for announcements. You have: > f :: Monad m => > a -> m b > Data.Traversable.mapM :: (Monad m, Traversable t) => > (a -> m b) -> t a -> m (t b) So, if you define g with > g a = do Data.Traversable.mapM f a or in short > g = Data.Traversable.mapM f , then the type will be > g :: (Monad m, Traversable t) => > t a -> m (t b) instead of > g :: [a] -> m (Seq b) . Try using ghci to find these things out. It helps to get not confused with the types. Besides the missing "Monad" context, g misses a generic way to convert between different Traversables, which does not exist. You can only convert from any Traversable (imagine a Tree) "toList"; not all Traversables have a "fromList" function. For conversion, you might want to use Foldable and Monoid, fold to untangle and mappend to recombine; but any specific "fromList" function will surely be more efficient. Regards - Marc -------- Original-Nachricht -------- > Datum: Wed, 28 Sep 2011 17:27:58 -0600 > Von: thomas burt <thedwards(a)gmail.com> > An: haskell(a)haskell.org > Betreff: [Haskell] mapM with Traversables > Hi - > > I have a function, "f :: Monad m => a -> m b", as well as a list of a's. > I'd > like to produce a sequence (Data.Sequence) of b's, given the a's: > > g :: [a] -> m (Seq b) > g a = do Data.Traversable.mapM f a -- type error! > > I see that "Data.Traversable.mapM f a" doesn't work... is this like asking > the compiler to infer the cons/append operation from the type signature of > g? > > Do I need to write my own function that explicitly calls the "append" > functions from Data.Sequence or can I do something else that would work > for > any "g :: Traversable t, Traversable u => t a -> m (u b)" given "f :: a -> > m > b"? > > Thanks for any comments! > Thomas

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module -> package
by Roman Beslik 30 Sep '11

30 Sep '11

Hello. How can I find which installed package a specified module belongs to? ghci or cabal or ghc-pkg?

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Handy abbreviations for using SciTE with Haskell
by Amy de Buitléir 30 Sep '11

30 Sep '11

I often use SciTE for editing Haskell code. I wanted an easy way to type symbols such as "∀" (instead of "forall"), so I created a properties file that allows me to do that. I haven't seen anything similar online (I Googled first), so I made the code available online. You can find the file and instructions here: http://www.haskell.org/haskellwiki/Tips_for_using_SciTE_with_Haskell

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Re: [Haskell-cafe] Programming with arrows, exercises
by Sergey Mironov 30 Sep '11

30 Sep '11

2011/9/30 John Lask <jvlask(a)hotmail.com>: > On 30/09/2011 7:15 AM, Sergey Mironov wrote: >> >> Hello. I am reading "Programming with Arrows" by John Hughes (very >> helpful and interesting!), the book has an exercises requiring a >> module called Circuits for checking the answer. There should be things >> like class ArrowCircuit and various functions related to digital logic >> circuits simulation. Does anybody know where can I find one? >> >> Thanks, >> Sergey >> >> _______________________________________________ >> Haskell-Cafe mailing list >> Haskell-Cafe(a)haskell.org >> http://www.haskell.org/mailman/listinfo/haskell-cafe >> >> > > This was in the old arrows library I have attached a copy, it will probably > need modification to compile. > > You should be able to use the examples with the current arrows library with > a few mods. > Yes, looks quite old. Unfotinately, it doesn't match the book.. I found that module I was looking for is in Appendix! Should I be more attentive.. Anyway, thank you!

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Type family instances in Haddock?
by Sean Leather 30 Sep '11

30 Sep '11

Would it be useful/worthwhile to have type/data family instances show up in Haddock just as type class instances do? Regards, Sean

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Indentation problem using Happy
by Amy de Buitléir 30 Sep '11

30 Sep '11

I'm trying to use Happy for the first time, and I'm having trouble with this very simple example: ===== BEGIN: PolyParser.y ===== { module Main where import Char ( isAlpha, isDigit, isSpace ) } %name calc %tokentype { Token } %error { parseError } %token id { TokenId $$ } ',' { TokenCOMMA } wombat { TokenWombat $$ } %% Poly : id ',' wombat { parseError :: [Token] -> a parseError _ = error "Parse error" data Poly = Poly Int String deriving Show data Token = TokenId Int | TokenCOMMA | TokenWombat String deriving Show lexer :: String -> [Token] lexer [] = [] lexer (c:cs) | isSpace c = lexer cs | isAlpha c = lexVar (c:cs) | isDigit c = lexNum (c:cs) lexer (',':cs) = TokenCOMMA : lexer cs lexNum cs = TokenInt (read num) : lexer rest where (num,rest) = span isDigit cs lexVar cs = case span isAlpha cs of (wombat,rest) -> TokenWombat wombat : lexer rest (id,rest) -> TokenId id : lexer rest main = getContents >>= print . calc . lexer } ===== END: PolyParser.y ===== The resulting PolyParser.hs has an indentation problem (second-to-last line, below), so it won't compile. happyReduce_1 = happySpecReduce_3 4 happyReduction_1 happyReduction_1 _ _ _ = HappyAbsSyn4 (parseError :: [Token] -> a parseError _ = error "Parse error" Thank you in advance to anyone who can tell me where I've gone wrong.

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