- Glasgow-haskell-users

ANNOUNCE: GHC version 6.6.1
by Ian Lynagh 04 May '07

04 May '07

============================================================= The (Interactive) Glasgow Haskell Compiler -- version 6.6.1 ============================================================= The GHC Team is pleased to announce a new patchlevel release of GHC. This release contains a significant number of bugfixes relative to 6.6, so we recommend upgrading. Release notes are here: http://haskell.org/ghc/docs/6.6.1/html/users_guide/release-6-6-1.html How to get it ~~~~~~~~~~~~~ The easy way is to go to the web page, which should be self-explanatory: http://www.haskell.org/ghc/ We supply binary builds in the native package format for many platforms, and the source distribution is available from the same place. Packages will appear as they are built - if the package for your system isn't available yet, please try again later. Background ~~~~~~~~~~ Haskell is a standard lazy functional programming language; the current language version is Haskell 98, agreed in December 1998 and revised December 2002. GHC is a state-of-the-art programming suite for Haskell. Included is an optimising compiler generating good code for a variety of platforms, together with an interactive system for convenient, quick development. The distribution includes space and time profiling facilities, a large collection of libraries, and support for various language extensions, including concurrency, exceptions, and foreign language interfaces (C, whatever). GHC is distributed under a BSD-style open source license. A wide variety of Haskell related resources (tutorials, libraries, specifications, documentation, compilers, interpreters, references, contact information, links to research groups) are available from the Haskell home page (see below). On-line GHC-related resources ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Relevant URLs on the World-Wide Web: GHC home page http://www.haskell.org/ghc/ GHC developers' home page http://hackage.haskell.org/trac/ghc/ Haskell home page http://www.haskell.org/ Supported Platforms ~~~~~~~~~~~~~~~~~~~ The list of platforms we support, and the people responsible for them, is here: http://hackage.haskell.org/trac/ghc/wiki/Contributors Ports to other platforms are possible with varying degrees of difficulty. The Building Guide describes how to go about porting to a new platform: http://hackage.haskell.org/trac/ghc/wiki/Building Developers ~~~~~~~~~~ We welcome new contributors. Instructions on accessing our source code repository, and getting started with hacking on GHC, are available from the GHC's developer's site run by Trac: http://hackage.haskell.org/trac/ghc/ Mailing lists ~~~~~~~~~~~~~ We run mailing lists for GHC users and bug reports; to subscribe, use the web interfaces at http://www.haskell.org/mailman/listinfo/glasgow-haskell-users http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs There are several other haskell and ghc-related mailing lists on www.haskell.org; for the full list, see http://www.haskell.org/mailman/listinfo/ Some GHC developers hang out on #haskell on IRC, too: http://www.haskell.org/haskellwiki/IRC_channel Please report bugs using our bug tracking system. Instructions on reporting bugs can be found here: http://www.haskell.org/ghc/reportabug

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Error compiling GHC/Num.lhs
by Bas van Dijk 03 May '07

03 May '07

Hello, I'm trying to build GHC from darcs. Unfortunately compilation fails with the following error: ... cpphs: #error Please define LEFTMOST_BIT to be 2^(SIZEOF_HSWORD*8-1) in GHC/Num.lhs at line 27 col 1 make[1]: *** [doc.library.base] Error 1 make[1]: Leaving directory `/home/bas/development/haskell/ghc/libraries' make: *** [stage1] Error 2 ... The following is the part where the error occurs in libraries/base/GHC/Num.lhs : ... #include "MachDeps.h" #if SIZEOF_HSWORD == 4 #define LEFTMOST_BIT 2147483648 #define DIGITS 9 #define BASE 1000000000 #elif SIZEOF_HSWORD == 8 #define LEFTMOST_BIT 9223372036854775808 #define DIGITS 18 #define BASE 1000000000000000000 #else #error Please define LEFTMOST_BIT to be 2^(SIZEOF_HSWORD*8-1) -- DIGITS should be the largest integer such that 10^DIGITS < LEFTMOST_BIT -- BASE should be 10^DIGITS. Note that ^ is not available yet. #endif ... Note that in build.mk I set BuildFlavour = quick and I also tried building it with the following options added: SRC_HC_OPTS += -optc-march=athlon64 -opta-march=athlon64 SRC_CC_OPTS += -march=athlon64 What can be the problem? Thanks, Bas van Dijk Some info on my system (please ask for more if you need it): $ uname -a Linux bassbox 2.6.20-gentoo-r6 #1 PREEMPT Thu Apr 19 10:53:57 CEST 2007 i686 AMD Athlon(tm) 64 Processor 3200+ AuthenticAMD GNU/Linux $ gcc --version gcc (GCC) 4.1.1 (Gentoo 4.1.1-r3)

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Pretty printing type annotations
by C.M.Brown 03 May '07

03 May '07

Hi, I was wondering if there was an easy way to pretty print the result of the type checker from GHC. I basically want the format that GHCi spits out, rather than a type annotation with qualified types. I know I can knock up a parser that removes the qualifiers, but I was wondering if there was a simple function that I could call that would just printy print it for me (and saving me the work). The type checker gives me something of the form: (GHC.Num.Num t1, GHC.Num.Num t) => t1 -> t -> t1 But GHCi gives me the same without any qualifying. Hope someone can help. Chris.

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GHC -O2 and unsafePerformIO
by Neil Mitchell 03 May '07

03 May '07

Hi I have a program (below) which when compiled with -O2 gives the result: H:\work\supero\charcount>type log.txt | diff.exe i am here 109 done The process tried to write to a nonexistent pipe. And when compiled with -O0 gives: H:\work\supero\charcount>type log.txt | diff i am here 109 i am here 111 done The process tried to write to a nonexistent pipe. It tries to read two characters, so I really do want two characters to appear. I have tried NOINLINE, but with no effect. Any suggestions? Thanks Neil --------------- -- The program import System.IO.Unsafe import System.IO import Data.Word import Debug.Trace main = p_System_IO_hGetChar 1 `seq` p_System_IO_hGetChar 2 `seq` putStrLn "done" {-# NOINLINE wrapIO #-} wrapIO x = unsafePerformIO (x >>= return) foreign import ccall "stdio.h getchar" getchar :: IO Word8 {-# NOINLINE p_System_IO_hGetChar #-} p_System_IO_hGetChar h = trace "i am here" $ wrapIO (getchar >>= \c -> print c >> return (if c == (-1) then 0 else chr_ c)) chr_ = fromEnum

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GHC on ia64
by Cristian Perfumo 30 Apr '07

30 Apr '07

Hello, We've been trying to compile GHC 6.6 on ia64, and although we have applied the patch on http://hackage.haskell.org/trac/ghc/ticket/1150 , we still get some mangler errors with "nop 0"s. We have gcc 4.1, and Linux SUSE. Specifically: == make all -r; in .../ghc-6.6/rts ------------------------------------------------------------------------ ../compiler/ghc-inplace -H16m -O -optc-O2 -optc-DNOSMP -static -I. -#include HCIncludes.h -fvia-C -dcmm-lint -c Apply.cmm -o Apply.o WARNING: Epilogue junk?: nop 0 nop 0 nop 0 Unmangled TAILCALL tokens remain after mangling at .../ghc-6.6/driver/mangler/ghc-asm line 1187, <INASM> line 1154. make[1]: *** [Apply.o] Error 255 make: *** [stage1] Error 1 Thank you very much in advance. Cheers, Cristian Perfumo

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ghci module load path
by Joel Reymont 30 Apr '07

30 Apr '07

Folks, Suppose I have a cabalized project where the source is under src/ and the generated code goes into dist/build/test/test-tmp/. How can I load modules from the generated code directory when I'm in the parent of both src and dist? If I do :set -idist/build/test/test-tmp then ghci tries to look for source files there but they are in src. If I :set -isrc then ghci doesn't look for the already compiled code and just interprets the source files. I'm looking to load the pre-compiled files. Thanks, Joel -- http://wagerlabs.com/

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Re: Release plans
by David Waern 30 Apr '07

30 Apr '07

> Here's a quick summary of the major developments that we already have in > the 6.8 codebase: > > - Associated data types, and the new FC intermediate language > - GHCi debugger (although there's an overhaul of the breakpoint support > almost > ready to go in) > - Coverage (HPC) > - GADTs + typeclasses > - more packages moved from core to extralibs > - GHC API changes, compile to object code inside GHCi > - performance improvements: simplifier rewrite, and SpecConstr improvements > - standalone deriving declarations > - left-to-right impredicative instantiation: runST $ foo It also has the Haddock comment support, so we could do a release of Haddock-GHC. /David, voting for 6.8

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GHC Manuals online
by Neil Mitchell 26 Apr '07

26 Apr '07

Hi, Recently I've been wanting to search for things in the GHC manual, unfortunately that isn't very easy with Google, beacuse lots of people have put up their own copies of the GHC manual - mostly out of date! Try googling for "The Glorious Glasgow Haskell Compilation System User's Guide", I was able to find easily: 6.4 http://web.mit.edu/ghc/www/users_guide/ 3.02 http://www.dcs.gla.ac.uk/fp/software/ghc/3.02/users_guide/users_guide-1.html 6.4.1 http://www.ugcs.caltech.edu/manuals/lang/ghc-6.4.1/users_guide/index.html 4.06 http://www.macs.hw.ac.uk/~dsg/gph/docs/4.06/users_guide/introduction-ghc.ht… The disadvantage of having lots of out of date manuals is that Google rarely finds the correct one, which means when I search for the "Language Pragma GHC" I run into loads of manuals from ages ago. Any chance some GHC person could politely request that some of these get removed? Having the manual easily searchable is a good thing. Thanks Neil

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noinline in where clauses again
by Duncan Coutts 26 Apr '07

26 Apr '07

I winged before about NOINLINE pragma on things defined locally in a where clause not doing what I expected: http://www.mail-archive.com/glasgow-haskell-users@haskell.org/msg10338.html Turns out that one was fixed in ghc HEAD. I've got another similar one which is not working as I expect in 6.6 or in head from 1st March. This example is from an experimental re-implementation of the Put monad in Data.Binary: write :: Int -> (Ptr Word8 -> IO ()) -> Put () write !n body = Put $ \c buf@(Buffer fp o u l) -> if n <= l then write' c fp o u l else write' (flushOld c n fp o u) (newBuffer c n) 0 0 0 where {-# NOINLINE write' #-} write' c !fp !o !u !l = -- warning: this is a tad hardcore B.inlinePerformIO (withForeignPtr fp (\p -> body $! (p `plusPtr` (o+u)))) `seq` c () (Buffer fp o (u+n) (l-n)) {-# INLINE [1] write #-} Then we use it with things like word8 :: Word8 -> Put () word8 !w = write 1 (pokeWord8 w) pokeWord8 :: Word8 -> Ptr Word8 -> IO () pokeWord8 w p = poke p w Then there's a rule so that things like: foo :: Word8 -> Put () foo !n = do word8 n word8 (n+1) word8 (n+17) get turned into a single call to write. Anyway, the point is that when we look at the stg/core we see that in write above, the write' has been inlined at the two call sites where as I want both branches of the if test to make calls to write'. The code is here: http://haskell.org/~duncan/binary/PutMonad.hs http://haskell.org/~duncan/binary/PutTest.hs the stg from ghc-6.6 is: http://haskell.org/~duncan/binary/PutTest.stg with ghc head from 1st March the result is different but still inlines write' in both branches. Duncan

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libgdk_pixbuf-2.0-0.dll Problem
by Mike Matthews 25 Apr '07

25 Apr '07

I wonder if anyone can help me. I have used glade and gtk2hs to create a GUI for my Connect 4 program, using .png images to depict the counters on the screen. Everything was working fine until I tried running my program on another computer. Predictably, there were a number of dll files required, so I copied these into the directory containing my executable (compiled with GHC 6.6). The program then runs correctly, but doesn't display anyof my images. Further investigation showed that the problem seems to be with the libgdk_pixbuf-2.0-0.dll file. Whenever this is in the same folder as my executable (even on my computer) the program displays no images. If anyone can shed any light on this that'd be great. It may be that I'm going about this completely the wrong way. In particular if there's a program out there for easily creating an msi package or something to neatly package the required files please let me know - I haven't been able to find it. Many thanks in advance. Mike

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