- Glasgow-haskell-users

Generalized phase control for GHC
by Max Bolingbroke 07 Jul '08

07 Jul '08

Hi, As some of you may know, I'm working on adding support for dynamically loaded plugins to GHC this summer. As part of this we need a way to specify ordering on the compiler phases installed, so e.g. you can say that a phase you install should run after strictness analysis does. This problem begs for a more modular and principled solution than just reusing the current system where we use the natural numbers to impose an ordering on INLINE/RULE activations. I have proposed a system at http://hackage.haskell.org/trac/ghc/wiki/Plugins/Phases that replaces this with one of named compiler phases not only for plugins but for all activation control in the compiler. The proposal mostly remains backwards compatible with the most common uses of the numeric format, with an exception noted on the page and below. I would be interested in feedback on the design before the implementation is complete and in the wild. I'm especially interested in hearing if you believe that loss of support for numeric phase numbers > 2 is a problem, as this is the only breaking change that I'm proposing. Cheers, Max

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using ghc-paths and rlwrap with GHCi - two additions to the GHCi HaskellWiki
by Claus Reinke 06 Jul '08

06 Jul '08

1. If you ever find yourself inside a GHCi session, wondering what packages are installed for this very GHCi, whereever those OpenGL modules were located in the module hierarchy, what package that module belongs to, or where the library docs are, well, anything that means you need to find the *matching ghc-pkg*, or the *matching users_guide* for your GHCi session, you can exploit Simon's new ghc-paths package (also for GHC API clients who need to find that libdir for their session): http://hackage.haskell.org/cgi-bin/hackage-scripts/package/ghc-paths This wiki entry suggests some command :defs, using ghc-paths to call the right ghc-pkg, or open the right users_guide from within a GHCi session: http://www.haskell.org/haskellwiki/GHC/GHCi#Package_and_documentation_looku… 2. If you're using GHCi on windows, you're probably missing out on its commandline completion support - rlwrap can get you at least some of that (might also be interesting for other Haskell apps that can't or won't use readline/editline for user input). This wiki entry shows basic usage, and how to extract lists of GHC options and package modules, for completion purposes: http://www.haskell.org/haskellwiki/GHC/GHCi#rlwrap_-_what_to_try_when_your_… Enjoy (and don't forget to add your own tips&tricks to that wiki page!-), Claus

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ghc-6.8.1 on solaris-sparc
by Johannes Waldmann 03 Jul '08

03 Jul '08

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hello. I am assuming that 6.8.1 is the latest binary release for solaris-sparc? When I try to call ghc, it says ld.so.1: ghc-6.8.1: fatal: relocation error: file /usr/local/lib/libncurses.so.5: symbol main: referenced symbol not found my machine is: sparc-sun-solaris2.10 I think I have all the necessary packages: ldd /home/waldmann/built/lib/ghc-6.8.1/ghc-6.8.1 librt.so.1 => /lib/librt.so.1 libreadline.so.5 => /usr/local/lib/libreadline.so.5 libncurses.so.5 => /usr/local/lib/libncurses.so.5 libdl.so.1 => /lib/libdl.so.1 libm.so.2 => /lib/libm.so.2 libgmp.so.3 => /home/waldmann/built/lib/libgmp.so.3 libpthread.so.1 => /lib/libpthread.so.1 libc.so.1 => /lib/libc.so.1 libaio.so.1 => /lib/libaio.so.1 libmd.so.1 => /lib/libmd.so.1 libgcc_s.so.1 => /usr/local/lib/libgcc_s.so.1 /platform/SUNW,Sun-Fire-V445/lib/libc_psr.so.1 /platform/SUNW,Sun-Fire-V445/lib/libmd_psr.so.1 but this looks strange: nm /usr/local/lib/libncurses.so.5|grep main [1192] | 0| 0|NOTY |GLOB |0 |UNDEF |main Any hints appreciated - J.W. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4-svn0 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFIbJUjDqiTJ5Q4dm8RAqWvAKCAwkVKJgLnLL3Uz0rr3Yp3AzVQmACfVyEe n3LqWHh2zvaeGopm4t7xpSc= =nryk -----END PGP SIGNATURE-----

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Takusen build error
by Benjamin Franksen 02 Jul '08

02 Jul '08

I get a strange error building Takusen (more precisely: the module Foreign/C/UTF8.hs) with ghc-6.8.3. It says aragon: .../ghc-6.8.3/Takusen-0.8.1 > ./Setup build -v Reading parameters from /srv/projects/ctl/franksen/haskell/ghc-6.8.3/Takusen-0.8.1/takusen.buildinfo Creating dist/build (and its parents) Creating dist/build/autogen (and its parents) Preprocessing library Takusen-0.8.1... Building Takusen-0.8.1... Building library... Creating dist/build (and its parents) Creating dist/build (and its parents) /projects/ctl/franksen/usr/bin/ghc -package-name Takusen-0.8.1 --make -hide-all-packages -i -idist/build/autogen -idist/build -i. -Idist/build -I/opt/oracle/product/client/rdbms/demo -odir dist/build -hidir dist/build -stubdir dist/build -package base-3.0.2.0 -package mtl-1.1.0.1 -package time-1.1.2.1 -package old-time-1.0.0.0 -O -XCPP Database.Enumerator Database.Util Database.Oracle.Enumerator Database.Oracle.OCIConstants Database.Oracle.OCIFunctions Database.Stub.Enumerator Control.Exception.MonadIO Foreign.C.UTF8 Database.InternalEnumerator [1 of 9] Compiling Foreign.C.UTF8 ( Foreign/C/UTF8.hs, dist/build/Foreign/C/UTF8.o ) /tmp/ghc18936_0/ghc18936_0.s: Assembler messages: /tmp/ghc18936_0/ghc18936_0.s:1257:0: Error: symbol `base_GHCziBase_Z0T_closure' is already defined I compiled ghc-6.8.3 from source, using ghc-6.8.2 to bootstrap. Any ideas? Cheers Ben

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ANNOUNCE: GHC version 6.8.3
by Ian Lynagh 02 Jul '08

02 Jul '08

============================================================= The (Interactive) Glasgow Haskell Compiler -- version 6.8.3 ============================================================= The GHC Team is pleased to announce a new patchlevel release of GHC. This release contains a number of bugfixes relative to 6.8.2, so we recommend upgrading. Release notes are here: http://haskell.org/ghc/docs/6.8.3/html/users_guide/release-6-8-3.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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X11-1.4.2 on 64bit Fedora 8 fails to build
by Christian Höner zu Siederdissen 01 Jul '08

01 Jul '08

Hi, I'm trying to get X11-1.4.1 compiled on a 64 bit x86 Fedora 8 system. runhaskell Setup.hs configure --prefix $HOME/ghc has no problems but runhaskell Setup.hs build produces: Preprocessing library X11-1.4.2... /usr/bin/ld: skipping incompatible /usr/lib/libXinerama.so when searching for -lXinerama /usr/bin/ld: cannot find -lXinerama collect2: ld returned 1 exit status linking dist/build/Graphics/X11/Types_hsc_make.o failed command was: /scr/airline/choener/ghc-6.8.3/bin/ghc -optl-lXinerama \ -optl-lXext -optl-lX11 -optl-L/usr/lib64 \ dist/build/Graphics/X11/Types_hsc_make.o -o \ dist/build/Graphics/X11/Types_hsc_make Trying something like runhaskell Setup.hs configure --ld-options="-nostdlib -L/usr/lib64" runhaskell Setup.hs build --ld-options="-nostdlib -L/usr/lib64" does not change the fact that ld looks in the wrong place for libXinerama. It looks in /usr/lib, but should look in /usr/lib64. Btw. I don't have root on the machine. Thanks, Christian Höner zu Siederdissen

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Error building GHC 6.8.3 with MinGW 4.2.1-2 dw2
by leledumbo 30 Jun '08

30 Jun '08

I try to build a lite version (e.g. no extra libs) of GHC 6.8.3, I'm using MinGW GCC 4.2.1-2 with dwarf-2 exception and pre-compiled GHC 6.8.3. Here's my configure: sh configure --prefix=/c/ghc-new CFLAGS='-s -O2' LDFLAGS='-s -O2' --with-gmp-includes=/usr/local/gmp/include --with-gmp-libraries=/usr/local/gmp/lib And my make: make bootstrap3 But in the middle, I got this: Preprocessing library hpc-0.5.0.1... In file included from D:/Sources/ghc/ghc-6.8.3-lite/includes/Stg.h:183, from D:/Sources/ghc/ghc-6.8.3-lite/includes/Rts.h:19, from Trace\Hpc\Reflect.hsc:18: D:/Sources/ghc/ghc-6.8.3-lite/includes/Regs.h:28:17: error: gmp.h: No such file or directory In file included from D:/Sources/ghc/ghc-6.8.3-lite/includes/Stg.h:183, from D:/Sources/ghc/ghc-6.8.3-lite/includes/Rts.h:19, from Trace\Hpc\Reflect.hsc:18: D:/Sources/ghc/ghc-6.8.3-lite/includes/Regs.h:121: error: expected specifier-qua lifier-list before 'MP_INT' In file included from Trace\Hpc\Reflect.hsc:18: D:/Sources/ghc/ghc-6.8.3-lite/includes/Rts.h:203: error: expected ')' before '*' token D:/Sources/ghc/ghc-6.8.3-lite/includes/Rts.h:204: error: expected ')' before '*' token compiling dist\build\Trace\Hpc\Reflect_hsc_make.c failed command was: gcc -c -mno-cygwin -D__GLASGOW_HASKELL__=608 -ID:/Sources/ghc/ghc-6 .8.3-lite/includes -ID:/Sources/ghc/ghc-6.8.3-lite/gmp/gmpbuild -I/usr/local/gmp /include -D__GLASGOW_HASKELL__=608 dist\build\Trace\Hpc\Reflect_hsc_make.c -o di st\build\Trace\Hpc\Reflect_hsc_make.o make[2]: Entering directory `/d/Sources/ghc/ghc-6.8.3-lite/libraries/hpc' make[2]: *** No targets specified and no makefile found. Stop. make[2]: Leaving directory `/d/Sources/ghc/ghc-6.8.3-lite/libraries/hpc' make[1]: *** [make.library.hpc] Error 2 make[1]: Leaving directory `/d/Sources/ghc/ghc-6.8.3-lite/libraries' make: *** [stage1] Error 2 As you can see above, I have gmp installed under /usr/local/gmp. However, this is not the gmp that comes with GHC (version 4.2.1, mine is 4.2.2). PS: I must comment these two lines in IOManager.h: 12: extern void* GetCurrentFiber ( void ); 13: extern void* GetFiberData ( void ); or an error about "static declaration follows non-static declaration" will come up. -- View this message in context: http://www.nabble.com/Error-building-GHC-6.8.3-with-MinGW-4.2.1-2-dw2-tp181… Sent from the Haskell - Glasgow-haskell-users mailing list archive at Nabble.com.

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Implicit Function Arguments
by Tyson Whitehead 30 Jun '08

30 Jun '08

What do people think about implicit function argument? That is, named function arguments, possibly tagged with something special like a tilde, whereby scoped variables of the same name are automatically passed. The idea is to avoid the pain of a lots of pass through parameters while make it easy to modify one or two of them. For example, in f1 :: ~state::State -> Input -> Output f1 input = f2 input f2 :: ~state::State -> Input -> Output f2 input = <whatever> we don't have to specify ~state for f2 because it picks it up automatically from ~state being in scope from f1. To change it, however, we just do f1 :: ~state::State -> Input -> Output f1 input = f2 input where ~state = <whatever> The advantage over wrapping it in a monad being: 1) it is evident what is being passed around behind the scenes from the type signatures, and 2) we avoiding the lifting issue (to compose multiple implicit arguments we just specifying them -- assuming their are no name clashes). Cheers! -Tyson

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Illegal instruction with ghc-6.8.3 distribution (OS X Tiger)
by Judah Jacobson 27 Jun '08

27 Jun '08

Hi, I recently installed ghc-6.8.3 on an iBook running OS X 10.4.11 (PowerPC G4), using the following distribution: http://www.haskell.org/ghc/dist/6.8.3/maeder/ghc-6.8.3-powerpc-apple-darwin… Running the following program, compiled with -O, causes an illegal instruction error: =========== module Main where main = print foo foo :: Integer foo = gcd 400 85 ================== Running through gdb produced the following output: Program received signal EXC_BAD_INSTRUCTION, Illegal instruction/operand. 0x00046b50 in __gmpn_gcd_1 () (gdb) where #0 0x00046b50 in __gmpn_gcd_1 () #1 0x00028cb0 in gcdIntzh_fast () #2 0x0002be34 in scheduleWaitThread () #3 0x0001fdb8 in real_main () #4 0x0001fec0 in main () (gdb) quit Christian, did you compile this distribution on a G5 PowerPC? GMP is statically linked into this distribution, so if it's using any processor-specific instructions I could see that tripping up my G4. If you or someone else can confirm that this works on a G5, then we should probably just update the downloads page with that requirement. Thanks, -Judah

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possible OI extension
by Serge D. Mechveliani 27 Jun '08

27 Jun '08

Hello, people, This is about possible extension in treating of overlapping instances. Here is a simple example. ------------------------------------------ import qualified Data.Set as Set (empty, member, insert) import List (nub) class Nub a where myNub :: a -> a instance Eq a => Nub [a] where myNub = nub instance Ord a => Nub [a] where myNub xs = nub' Set.empty xs where nub' _ [] = [] nub' set (x: xs) = if Set.member x set then nub' set xs else x: (nub' (Set.insert x set) xs) ------------------------------------------ The idea is that it is good to replace nub of the Haskell-98 library with myNub. Because: for Eq a, myNub costs O(n^2), for Ord a, myNub costs O(n*(log n)), and it is good to denote this operation with the same name. Compiling this by GHC under -fglasgow-exts -fallow-overlapping-instances -fallow-undecidable-instances yields the error report: Duplicate instance declarations: instance [overlap ok] (Eq a) => Nub [a] -- Defined at IOverlap2.hs:8:0-43 instance [overlap ok] (Ord a) => Nub [a] -- Defined at IOverlap2.hs:(9,0)-(15,71) Probably, as the context of Ord a is stronger than Eq a, then on the instance overlap, the compiler could choose the instance with the stronger context. Can there be a reasonably implemented extension of this kind? Thank you in advance for your comments, ----------------- Serge Mechveliani mechvel(a)botik.ru

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