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Arch Haskell News: Nov 02 2008
by Don Stewart 03 Nov '08

03 Nov '08

News about the Haskell packages for Arch Linux. Highlights, * 672 Haskell packages now supported in Arch Linux, up 33 from two weeks ago. Noteworthy, * haskell-tcache-0.5.3: “A Transactional data cache with configurable persistence” * haskell-yampa-0.9.2.3: “Library for programming hybrid systems.” * haskell-network-bytestring-0.1.1.3: “Fast and memory efficient low-level networking” * haskell-checkers-0.1.1: “Check properties on standard classes and data structures.” * haskell-coreerlang-0.0.1: “Facilities for manipulating Core Erlang source code: an abstract syntax, parser and pretty-printer.” Full update list, http://archhaskell.wordpress.com/2008/11/03/arch-haskell-news-nov-02-2008/ -- Don How's your favourite distro doing? If its not up to scratch, talk to someone.

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HUnit in Hackage
by Jon Strait 01 Nov '08

01 Nov '08

Just some quick user feedback/questions. The current HUnit in Hackage depends on base (==4.*). I'm running GHC 6.8.3 with base 3.0.2.0. Is there an easier way to upgrade base without rebuilding GHC? Otherwise, the Cabal upgrade refuses to work unless I uninstall my older HUnit completely, do the Cabal upgrade, then re-install the older HUnit. I have other packages which depend on HUnit, so this must be done every time. Or is there a way to tell Cabal Install that I want to mask off HUnit for upgrading when I do a Cabal upgrade? Thanks, Jon

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configVerbose, writeHookedBuildInfo
by Johannes Waldmann 29 Oct '08

29 Oct '08

Hello. these things seem to have gone missing from Cabal-1.4 to 1.6: configVerbose writeHookedBuildInfo this is from a Setup.lhs posted here: http://article.gmane.org/gmane.comp.lang.haskell.libraries/7628 now what? I knew to insert build-depends: base==3.* but here I'm lost. J.W.

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Some QuickCheck Instances
by Dominic Steinitz 25 Oct '08

25 Oct '08

I often find I need to use QuickCheck & SmallCheck with e.g. Word8 but there don't seem to be standard instances. Would these be worth adding? If so, what would I need to do? Just send a patch to the maintainers? Thanks, Dominic. > > instance Serial Word8 where > series d = drawnFrom (map fromIntegral [0..d]) > instance Arbitrary Word8 where > arbitrary = > do n <- choose ((fromIntegral (minBound::Word8))::Int, > (fromIntegral (maxBound::Word8))::Int) > return (fromIntegral n) > > instance Arbitrary Word64 where > arbitrary = > do n <- choose ((fromIntegral (minBound::Word64))::Integer, > (fromIntegral (maxBound::Word64))::Integer) > return (fromIntegral n) > > instance Arbitrary Word128 where > arbitrary = > do n <- choose ((fromIntegral (minBound::Word128))::Integer, > (fromIntegral (maxBound::Word128))::Integer) > return (fromIntegral n) >

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fgl version missing on hackage
by Christian Maeder 23 Oct '08

23 Oct '08

Hi Ross, on http://hackage.haskell.org/cgi-bin/hackage-scripts/package/fgl there are fgl-versions 5.3, 5.4.1.1 However, ghc-6.8.3 was shipped with fgl-5.4.2.0 fgl-5.4.2.0 exports more functions (ie. xdfsWith) and I would like to use it with other ghc versions, too. Could you upload fgl-5.4.2.0? Cheers Christian

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Proposal #2717: Add nubWith, nubOrd
by Bart Massey 23 Oct '08

23 Oct '08

Ok, I've killed the overly ambitious proposal #2629, and replaced it with the more modest proposal #2717 http://hackage.haskell.org/trac/ghc/ticket/2717 which just adds Data.List.nubWith and Data.Set.nubOrd as previously discussed ad nauseam. I know at least one person thought that adding these was a bad idea, but some others thought it was a fine thing to do. Hence the discussion on this list. Bart Massey bart(a)cs.pdx.edu

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Repair to floating point enumerations?
by Malcolm Wallace 22 Oct '08

22 Oct '08

Dear Haskell-Primers (and libraries). Recently, Phil Wadler has pointed out a weird anomaly in the Haskell'98 Prelude, regarding numeric enumerations for Floats/Doubles: Prelude> [0, 0.3 .. 1.1] [0.0,0.3,0.6,0.899999,1.2] What is odd is that the last value of the list is much larger than the specified termination value. But this is exactly as specified by the Haskell'98 Report. http://haskell.org/onlinereport/basic.html#sect6.3.4 "For Float and Double, the semantics of the enumFrom family is given by the rules for Int above, except that the list terminates when the elements become greater than e3+i/2 for positive increment i, or when they become less than e3+i/2 for negative i. We have discussed this question (and related ones, such as whether Float and Double belong in the Enum class at all) several times before, and I do not wish to rehash all of those points again e.g.: http://www.cse.unsw.edu.au/~dons/haskell-1990-2000/msg07289.html http://www.haskell.org/pipermail/haskell/2001-October/008218.html http://www.haskell.org/pipermail/haskell/2002-October/010607.html Phil proposes that, although retaining the instances of Enum for Float and Double, we simplify the definitions of the numericEnumFrom family: numericEnumFromThenTo :: (Fractional a, Ord a) => a -> a -> a -> [a] numericEnumFrom = iterate (+1) numericEnumFromThen n m = iterate (+(m-n)) n numericEnumFromTo n m = takeWhile (<= m) (numericEnumFrom n) numericEnumFromThenTo n m p = takeWhile (<= p) (numericEnumFromThen n m) The particular feature of note is that the odd fudge factor of (1/2 * the increment) is removed. The inexact nature of floating point numbers would therefore cause a specification like [ 0.0, 0.1 .. 0.3 ] to yield the sequence [ 0.0, 0.1, 0.2 ] that is, to omit the upper bound, because (3 * 0.1) is actually represented as 0.30000000000004, strictly greater than 0.3. Phil argues that this behaviour is more desirable: "the simple fix is that the user must add a suitable epsilon to the upper bound. The key word here is *suitable*. The old definitions included completely bizarre and often highly unsuitable choices of epsilon." This proposal seems to me to improve the consistency of the enumeration syntax across both the integral and floating types. Some users may still be surprised, but the surprise will be easier to explain. I am bringing this question to the attention of all who are interested in Haskell Prime, because it seems like a sensible and well-reasoned change. Discussion on whether to adopt this proposal for H' is welcome. But as maintainer and bug-fixer of the Haskell'98 Report, I have also been asked whether we should make this change retrospectively to the Haskell'98 language (as a "typo"). Since it involves not merely an ordinary library function, but a Prelude function, and moreover a function that is used in the desugaring of syntax, it is less clear to me whether to alter Haskell'98. Thoughts? Regards, Malcolm

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Arch Haskell News: Oct 18 2008
by Don Stewart 18 Oct '08

18 Oct '08

= News about Haskell on Arch Linux = Arch Linux now has 639 Haskell packages in AUR. That’s an increase of 15 new Haskell packages in the last 7 days. Growth appears to be holding steady at just over 2 new packages a day on Hackage this month. Noteworthy * haskell-gnuplot-0.2: “2D and 3D plots using gnuplot” * alex-2.3: “Alex is a tool for generating lexical analysers in Haskell” * happy-1.18.1: “Happy is a parser generator for Haskell” * haskell-tfp-0.1: “Type-level programming library using type families” Full details on the site. http://archhaskell.wordpress.com/2008/10/18/arch-haskell-news-oct-18-2008/

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Re: [Haskell-cafe] ANNOUNCE: Glob 0.1, globbing library
by Krzysztof Skrzętnicki 18 Oct '08

18 Oct '08

On Fri, Oct 17, 2008 at 22:02, Matti Niemenmaa <matti.niemenmaa+news(a)iki.fi> wrote: > Greetings to all, > > I hereby announce the release of Glob 0.1, a small library for glob-matching > purposes based on a subset of zsh's syntax. > > Web page at: http://iki.fi/matti.niemenmaa/glob/index.html > Hackage: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Glob > > Simple example: match (compile "foo*baz") "foobarbaz" == True. > > It can also group the contents of a directory given a list of patterns to match: > globDir [compile "foo*baz"] "<a directory containing foobarbaz and joe>" gives > (["dir/foobarbaz"],["dir/joe"]). > > Comments, complaints, feature requests, bug reports are all welcome. It should > work on both GHC 6.8 and 6.10, but I've only tested the latter. > Hello I tried out your package, but it doesn't seem to work correctly on Windows. I checked the code and it has directory separator hard coded, which seem to be the source of problems. Please see: http://www.haskell.org/ghc/docs/latest/html/libraries/filepath/System-FileP… All best Christopher Skrzętnicki

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Re: Compiling regex-posix-0.93.2 on windows
by Chris Kuklewicz 17 Oct '08

17 Oct '08

I am not sure what is going wrong. I have not been using Haskell on windows. I am also copying this reply to haskell-cafe and libaries mailing lists. Does anyone know? Parnell Flynn wrote: > I am having a terrible time compiling the 0.93.2 version of the > regex-posix library on windows XP. > > I have Cygwin and MinGW installed and I have a version of the regex.h > header in C:/cygwin/usr/include what shared libraries do I need? > > Here is a copy of the error it finds the include but is unable to link. > > This links to the standard c library version of regular expressions. > > The corresponding c header file is regex.h and there is a chance you > > will need to edit the end of the regex-posix.cabal file to find the > > include directory and/or library. > > Preprocessing library regex-posix-0.93.2... > > dist/build/Text/Regex/Posix/Wrap_hsc_make.o(.text+0x85):Wrap_hsc_make.c: > undefined reference to `_impure_ptr' > > dist/build/Text/Regex/Posix/Wrap_hsc_make.o(.text+0xc9):Wrap_hsc_make.c: > undefined reference to `_impure_ptr' > > dist/build/Text/Regex/Posix/Wrap_hsc_make.o(.text+0xf1):Wrap_hsc_make.c: > undefined reference to `_impure_ptr' > > dist/build/Text/Regex/Posix/Wrap_hsc_make.o(.text+0x125):Wrap_hsc_make.c: > undefined reference to `_impure_ptr' > > dist/build/Text/Regex/Posix/Wrap_hsc_make.o(.text+0x159):Wrap_hsc_make.c: > undefined reference to `_impure_ptr' > > dist/build/Text/Regex/Posix/Wrap_hsc_make.o(.text+0x18d):Wrap_hsc_make.c: > more undefined references to `_impure_ptr' follow > > collect2: ld returned 1 exit status > > linking dist\build\Text\Regex\Posix\Wrap_hsc_make.o failed > > command was: y:\ghc\ghc-6.8.2\bin\ghc.exe -optl-LC:/cygwin/lib > dist\build\Text\Regex\Posix\Wrap_hsc_make.o -o > dist\build\Text\Regex\Posix\Wrap_hsc_make.exe > > bash-3.2$ > > Thanks, > > Parnell > > Parnell Flynn • 230 South Lasalle Street • Suite 400 • Chicago, IL 60604 > • 312.244.5317 (o) • parnell___.flynn(a)ronin-capital.com_ > <mailto:parnell.flynn@ronin-capital.com> >

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