July 2007 - Glasgow-haskell-users

using Haskell readline package on Cygwin
by Amir E. Aharoni 28 Jul '07

28 Jul '07

Hi, I'm trying to build pugs ( http://www.pugscode.org/ ) on Cygwin. I have GHC 6.6.1 (installed from MSI). Pugs build routine tries to look for the readline package and fails: $ ghc-pkg describe readline ghc-pkg.exe: cannot find package readline I have GNU readline installed as a Cygwin package, but it looks like the readline package, which appears to be standard on other GHC-supported platforms, is not installed with GHC on Windows. This problem is mentioned in the GHC FAQ ( http://tinyurl.com/2lyjno ) but there is no solution; maybe there was supposed to be a link, but it is not there now. Is it possible to install the readline package manually? Thanks in advance. (Please excuse my cluelessness - i'm a GHC newbie.) -- Amir Elisha Aharoni my band: http://www.myspace.com/tzabari/ my blog: http://aharoni.wordpress.com/

2 2

Is "-O currently also implies -fvia-C." still true?
by Thorkil Naur 27 Jul '07

27 Jul '07

Hello, The GHC User's Guide, Versio 6.6.1 (http://www.haskell.org/ghc/docs/latest/html/users_guide/options-optimise.ht…) says: -O currently also implies -fvia-C. I seem to remember some communication a while back that seemed to imply that this is no longer the case. So my question is: Is the quoted statement still true? Thanks and best regards Thorkil

3 2

OPTIONS_GHC -iMyDir
by Greg Fitzgerald 24 Jul '07

24 Jul '07

I notice that some of GHC's command-line parameters do not work from within the OPTIONS_GHC pragma (6.6.1 on Windows). I can see how that makes sense for some parameters like "--make", but what about "-i" and "-v"? Is this intentional or a bug? Can't specify the include path: {-# OPTIONS_GHC -iMyDir #-} Can't compile a single file in 'verbose' mode: {-# OPTIONS_GHC -v #-} Thanks, Greg

2 1

ForeignPtr and -threaded
by PHO 23 Jul '07

23 Jul '07

Hi, I have encountered a weird behavior of ForeignPtr. I want to know how to work around this. I am using GHC 6.6.1 on Darwin. [1] Foreign.Concurrent The following code prints "called" when it is linked with -threaded RTS, but it prints nothing when it isn't. import Foreign.Marshal.Alloc import qualified Foreign.Concurrent as Conc main = do mem <- mallocBytes 10 Conc.newForeignPtr mem $ print "called" [2] Foreign.ForeignPtr The following code prints nothing when it isn't linked with -threaded RTS, but when it is, it *sometimes* prints "called" but not always. import Foreign.Marshal.Alloc import Foreign.Ptr import Foreign.ForeignPtr foreign import ccall "wrapper" mkFinalizer :: (Ptr () -> IO ()) -> IO (FunPtr (Ptr () -> IO ())) main = do mem <- mallocBytes 10 fin <- mkFinalizer $ \ _ -> print "called" newForeignPtr fin mem _______________________________________________________ - PHO - http://ccm.sherry.jp/ OpenPGP public key: 1024D/1A86EF72 Fpr: 5F3E 5B5F 535C CE27 8254 4D1A 14E7 9CA7 1A86 EF72

3 4

ghc-pkg: can't unregister - not found - describe works?
by Marc Weber 22 Jul '07

22 Jul '07

marc@localhost /pr/source/wxh/wxhaskell-0.9.4 $ ghc-pkg-wrapper-6.6.1 unregister wx ghc-pkg: cannot find package wx marc@localhost /pr/source/wxh/wxhaskell-0.9.4 $ ghc-pkg-wrapper-6.6.1 describe wx name: wx version: 0.10.1 license: AllRightsReserved [...] What does happen here? ghc-pkg-wrapper is just a simple script defining GHC_PACKAGE_PATH marc@localhost /pr/source/wxh/wxhaskell-0.9.4 $ ghc-pkg-wrapper-6.6.1 list /nix/store/q74q9piy9fsk4k7w1p3r3xc8wsm1z87m-ghc-6.6.1/lib/ghc-6.6.1/package.conf: Cabal-1.1.6.2, HUnit-1.1.1, QuickCheck-1.0.1, base-2.1.1, [...] /nix/store/fbj85ijnbc69bh19zi1a14p9idknb5g9-wxHaskell-0.10.1-pre20070124/nix-support/package.conf: wx-0.10.1, wxcore-0.10.1 Marc

2 1

Re: rpm for RHEL4
by chuckanut 19 Jul '07

19 Jul '07

Thanks very much! I am just replying to the list so that someone else can take advantage of your work. On 7/7/07, Ronald Cole <ronald.cole(a)gmail.com> wrote: > I posted that I had ported the Fedora Core RPMs to RHEL4 and RHEL5 for both > i386 and x86_64 and was making them available from my site. I also asked > for it to be announced on the "distribution packages" page of haskell.org, > but that request seems to have fallen on deaf ears. > > Help yourself to my RPM packages at > <http://forte-intl.com/~ronald/haskell/ghc/ >. > > > On 7/6/07, chuckanut <chuckanut(a)gmail.com> wrote: > > > > Hi, > > > > I am looking for an rpm for Red Hat enterprise linux 4 for x86_64. > > Can anyone point me to such an rpm? I don't think the FC5 binary will > > work on EL4. > > > > Thanks > > _______________________________________________ > > Glasgow-haskell-users mailing list > > Glasgow-haskell-users(a)haskell.org > > > http://www.haskell.org/mailman/listinfo/glasgow-haskell-users > > > >

3 3

Why hide Distribution.Compat.FilePath, or what to use instead?
by Dimitry Golubovsky 17 Jul '07

17 Jul '07

Hi, I'm trying to bring HSFFIG in order and make it work with GHC 6.6 and the modern package structure. I have found out that the Distribution.Compat.FilePath module (which used to be System.FilePath in its former life) is hidden: programs/ffipkg.hs:11:7: Could not find module `Distribution.Compat.FilePath': it is hidden (in package Cabal-1.1.6.2) I cannot use the new FilePath package because it does not have function like exeExtension. Other functions (splitFileExt, parseSearchPath, joinFileName, join FileExt) probably have their analogs in the new package. What else can I use for exeExtension? Thanks. -- Dimitry Golubovsky Anywhere on the Web

4 3

strange overlapping instance error
by Dave Herman 11 Jul '07

11 Jul '07

I'm a little mystified by an overlapping instance error I'm getting from GHC (I'm using v6.6.1 in Windows). Here's a simple test case that demonstrates the type error: ----- {-# OPTIONS_GHC -fglasgow-exts #-} module Overlap where class Needle a instance Needle String class Needle b => Haystack a b where find :: a -> [b] instance Needle a => Haystack a a where find a = [a] instance Haystack a b => Haystack [a] b where find xs = concatMap find xs data Tree = Leaf String | Node [Tree] instance Haystack Tree String where find (Leaf s) = find s find (Node ss) = concatMap find ss ----- The error is: overlap.hs:21:18: Overlapping instances for Haystack String String arising from use of `find' at overlap.hs:21:18-23 Matching instances: instance (Needle a) => Haystack a a -- Defined at overlap.hs:11:0 instance (Haystack a b) => Haystack [a] b -- Defined at overlap.hs:14:0 In the expression: find s In the definition of `find': find (Leaf s) = find s In the definition for method `find' Now, I understand that String is [Char], but since the proposition (Haystack Char String) is not true, I don't understand why the type checker is claiming that the second instance declaration matches. Thanks, Dave

2 1

ghc 6.6 Debian packages
by Christian Maeder 11 Jul '07

11 Jul '07

Hi, our developers that have a debian system (i.e Ubuntu) and want to compile our sources with ghc complain that they have to install many extra library packages one after another. Compiling fails at various stages due to missing packages. Is there no way to provide all the extra libs in one debian package for ghc? Cheers Christian ii libghc6-fgl-dev 5.3-3 Haskell graph library for GHC ii libghc6-haskell-src-dev 1.0-3 Haskell module for manipulating Haskell sour ii libghc6-html-dev 1.0-3 Haskell html library for GHC ii libghc6-hunit-dev 1.1-3 Haskell unit testing framework for GHC ii libghc6-mtl-dev 1.0-3 Haskell monad transformer library for GHC ii libghc6-network-dev 2.0-3 Haskell network library for GHC ii libghc6-quickcheck-dev 1.0-3 Haskell automatic testing library for GHC

6 9

problem compiling an older Haskell program with GHC 6.6.1
by Scott Stoller 10 Jul '07

10 Jul '07

hi, I really appreciate the amazingly fast and helpful feedback to my previous message. that problem (FiniteMap not found) is solved. but a new problem came up... I am trying to compile paradox 1.0, an older (GHC 5) Haskell program, with GHC 6.6.1 (the Solaris 10 / x86 binary distribution). now I get the error Data.hs:760:20: Not in scope: 'bounds' Data.hs is one of the files in the program. here is the nearby code: updateTable :: Hash a => a -> IO b -> Table a b -> IO b updateTable x my (MkTable ref) = do MkHTab n arr <- readIORef ref let (_,size) = bounds arr hashx = hash x i = hashx `mod` size ... in case it's helpful, the entire paradox source code is at http://www.cs.sunysb.edu/~stoller/out/paradox-1.0-casc.tar.gz just delete "-package lang" from the Makefile before running "make". any advice would be greatly appreciated. best regards, scott

3 5