November 2004 - Glasgow-haskell-users

ghc -e
by Benjamin Franksen 24 Nov '04

24 Nov '04

Hello, I want to use ghc as a script interpreter, using the '-e' option. The problem is that I can't give the script any command line arguments, because 'ghc -e' intepretes everything argument as the name of a module to compile. > cat Test.hs import System main = getArgs >>= print > ghc -e Main.main Test.hs [] > ghc -e Main.main Test.hs blabla Can't find module `blabla' (use -v to see a list of the files searched for) <interactive>:1: Failed to load interface for `Main': Bad interface file: Test.hi Test.hi: openBinaryFile: does not exist (No such file or directory) <interactive>:1: Variable not in scope: `Main.main' Is there a way to tell ghc that what follows are arguments to teh program ('main') and not to ghc itself? Ben

2 4

User-defined operators and compound expressions using Happy
by Frank-Andre Riess 24 Nov '04

24 Nov '04

Hi there folks, once again, I've got a question related to Happy (I've got version 1.13 at the moment). Maybe, it's even more a question on formal languages, but well... How can I write a grammar that can cope with user-defined operators (of different precedences/associativities) and compound expression like function calls, if-then-else- and case-statements and the like. I tried to write it down straight forwardly, but failed terribly (alas, I didn't keep it, so I can't show you - if someone of you is versed in this issue, I can try to explain the language's constructs). Thank you so much, Frank-Andre Riess

3 4

-fno-monomorphism-restriction
by Christian Maeder 24 Nov '04

24 Nov '04

Hi, I've a file ATC/Sml_cats.hs that does not compile (see below) with the flag -fno-monomorphism-restriction (ghc 6.2.2), whereas it compiles fine without that option. Since I want to use -fno-monomorphism-restriction for other files (from programatica) I've a problem, because there is no option -fmonomorphism-restriction that I could place inside of ATC/Sml_cats.hs. If someone wants to reproduce the error, do the following: 1) check out HetCATS repository with: cvs -d pserver:cvsread@cvs-agbkb.informatik.uni-bremen.de:/repository co HetCATS 2) comment out variable HC_PACKAGE in the Makefile (to avoid dependency from uni) 3) add the flag -fno-monomorphism-restriction to the variable HC_FLAGS 4) call (GNU) make Cheers Christian Compiling ATC.Sml_cats ( ./ATC/Sml_cats.hs, ./ATC/Sml_cats.o ) ./ATC/Sml_cats.hs:23: Ambiguous type variable `a' in the top-level constraint: `ATermConvertibleSML a' arising from use of `ad'' at ./ATC/Sml_cats.hs:2068 ./ATC/Sml_cats.hs:23: Ambiguous type variable `a1' in the top-level constraint: `ATermConvertibleSML a1' arising from use of `aa'' at ./ATC/Sml_cats.hs:1501 ./ATC/Sml_cats.hs:23: Ambiguous type variable `a2' in the top-level constraint: `ATermConvertibleSML a2' arising from use of `aa'' at ./ATC/Sml_cats.hs:1479 ./ATC/Sml_cats.hs:23: Ambiguous type variable `a3' in the top-level constraint: `ATermConvertibleSML a3' arising from use of `las' at ./ATC/Sml_cats.hs:421

1 0

RE: Bug in touchForeignPtr?
by Simon Marlow 23 Nov '04

23 Nov '04

On 22 November 2004 17:28, Benjamin Franksen wrote: > I understand that there are situations where finalizers cannot be > guaranteed to run: First because of an unconditional termination > signal (SIGKILL), second because of circular dependencies resulting > in a deadlock. > > I don't understand why it is necessary to "performGC" explicitly, in > order to run finalizers at *normal* program termination and without a > deadlock. It isn't necessary to performGC explicitly. However, you might be seeing a secondary effect due to Handles being finalised at program termination too - a common problem is writing a finaliser that tries to output something on a Handle, where the Handle gets finalised first. The original finaliser will then deadlock (or in 6.2.2 it'll get a more informative exception). This is because at program termination we just run all the outstanding finalisers without regard to ordering. Ordering is too hard to establish, and would at the least require a full GC before running each finaliser. > BTW, the sensible thing to do in this case would be to throw an > exception whenever a deadlock condition is detected. (That is, if it > can be detected.) Yes, GHC does cause exceptions to be raised on deadlock. > However, what I don't understand is why touchForeignPtr is not > honored in my example program: Note that the output text lines from > the finalizers appear *before* the last action in the program (which > is a second getChar). The finalizers *are* called by the GC, and > still the order is wrong. Note that the GC only starts the finaliser thread. The program can still terminate before this thread has run to completion (this is one reason why we say that finalisers don't always run before program termination). You have a point that the documentation is plain wrong. I'll try to fix it up for 6.4, and I think at the same time I'll remove the at-exit finalisation. Cheers, Simon

3 2

RE: optimized compilation fails with gcc 3.4.3 under solaris
by Simon Marlow 23 Nov '04

23 Nov '04

On 17 November 2004 14:01, Christian Maeder wrote: > maeder@leo -> uname -a > SunOS leo 5.8 Generic_117000-05 sun4u sparc SUNW,Sun-Fire-280R > maeder@leo -> ghc --version > The Glorious Glasgow Haskell Compilation System, version 6.2.1 > maeder@leo -> gcc -v > Reading specs from > /export/software/mirror/sparc-solaris/lang/bin/../lib/gcc/sparc-sun-sola ris2.8/3.4.3/specs > Configured with: ../gcc-3.4.3/configure --prefix=/usr/local/lang > -program-suffix=_3.4.3 --with-as=/usr/ccs/bin/as > --with-ld=/usr/ccs/bin/ld --enable-version-specific-runtime-libs > --enable-languages=c,c++,f77 --enable-shared=libstdc++ --disable-nls > Thread model: posix > gcc version 3.4.3 > maeder@leo -> ghc --make Main.hs -O > Chasing modules from: Main.hs > Compiling Main ( Main.hs, Main.o ) > /tmp/ghc14393.hc: In function `__stginit_Main': > /tmp/ghc14393.hc:5: note: if this code is reached, the program will > abort /tmp/ghc14393.hc: In function `__stginit_ZCMain': > /tmp/ghc14393.hc:12: note: if this code is reached, the program will > abort /tmp/ghc14393.hc: In function `Main_a_entry': > /tmp/ghc14393.hc:33: note: if this code is reached, the program will > abort /tmp/ghc14393.hc: In function `Main_main_slow': > /tmp/ghc14393.hc:49: note: if this code is reached, the program will > abort /tmp/ghc14393.hc: In function `Main_main_entry': > /tmp/ghc14393.hc:64: note: if this code is reached, the program will > abort /tmp/ghc14393.hc: In function `ZCMain_main_slow': > /tmp/ghc14393.hc:79: note: if this code is reached, the program will > abort Linking ... > maeder@leo -> ./a.out > Illegal Instruction Ah yes, I remember this. I think it was my bug report which caused the gcc folks to implement that warning message :-) GCC 3.4 is being terribly helpful by taking a rather extreme interpretation of the term "undefined behaviour" in the C99 spec to mean "abort". Unfortunately it looks like I haven't patched GHC to work around it. I patched my tree on the sourceforge Sparc machine I was using, but I can't access that right now (perhaps my account expired). IIRC, it was a simple change to the type cast in the definition of the JMP_ macro in ghc/includes/TailCall.h. Maybe change StgFunPtr to StgFun? You'll know when you get it right, because the warning will go away. Cheers, Simon

1 0

RE: [Haskell] package with ghc and ghci
by Simon Marlow 23 Nov '04

23 Nov '04

I'm afraid that hasn't helped. GHC appears to be looking for a package '=DSP', but there's no indication why. Could you give us enough instructions to be able to reproduce the problem here, please? Including: - full source code, or where to get it - complete command lines - platform, GHC version Cheers, Simon On 17 November 2004 12:37, Fred Nicolier wrote: > Simon Marlow wrote: > >> >> Please send the output of command (2) with -v added to the command >> line. >> >> Cheers, >> Simon >> >> >> > I have isolated the dependancies of the packages : the work file is > now : \begin{code} > module Main where > import Data.Array > import DSP.Filter.FIR.FIR > import DSP.Filter.FIR.Sharpen > import DSP.Source.Basic > n :: Int > n = 1000 > h :: Array Int Double > h = listArray (0,16) [ -0.016674..] > y1 = fir h $ impulse > > main = do > putStrLn $ show (head y1) > \end{code} > > Here is the output of 'ghci -v -package DSP test.hs' : > ghci -v -package DSP test.hs > ___ ___ _ > / _ \ /\ /\/ __(_) > / /_\// /_/ / / | | GHC Interactive, version 6.2.1, for Haskell 98. > / /_\\/ __ / /___| | http://www.haskell.org/ghc/ > \____/\/ /_/\____/|_| Type :? for help. > > Glasgow Haskell Compiler, Version 6.2.1, for Haskell 98, compiled by > GHC version 6.2.1 > Using package config file: /usr/local/lib/ghc-6.2.1/package.conf > > ==================== Packages ==================== > Package > {name = "data", > auto = False, > import_dirs = ["/usr/local/lib/ghc-6.2.1/hslibs-imports/data"], > source_dirs = [], > library_dirs = ["/usr/local/lib/ghc-6.2.1"], > hs_libraries = ["HSdata"], > extra_libraries = [], > include_dirs = [], > c_includes = [], > package_deps = ["haskell98", "lang", "util"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "DSP", > auto = False, > import_dirs = ["/usr/local/lib/imports/HDsp"], > source_dirs = [], > library_dirs = ["/usr/local/lib"], > hs_libraries = ["HSDSP"], > extra_libraries = [], > include_dirs = [], > c_includes = [], > package_deps = ["data", "Polynomial", "Matrix", "Numeric"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "base", > auto = True, > import_dirs = ["/usr/local/lib/ghc-6.2.1/imports"], > source_dirs = [], > library_dirs = ["/usr/local/lib/ghc-6.2.1"], > hs_libraries = ["HSbase"], > extra_libraries = ["HSbase_cbits"], > include_dirs = [], > c_includes = ["HsBase.h"], > package_deps = ["rts"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "rts", > auto = False, > import_dirs = [], > source_dirs = [], > library_dirs = ["/usr/local/lib/ghc-6.2.1"], > hs_libraries = ["HSrts"], > extra_libraries = ["m", "gmp"], > include_dirs = ["/usr/local/lib/ghc-6.2.1/include"], > c_includes = ["Stg.h"], > package_deps = [], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = > ["-u", > "GHCziBase_Izh_static_info", > "-u", > "GHCziBase_Czh_static_info", > "-u", > "GHCziFloat_Fzh_static_info", > "-u", > "GHCziFloat_Dzh_static_info", > "-u", > "GHCziPtr_Ptr_static_info", > "-u", > "GHCziWord_Wzh_static_info", > "-u", > "GHCziInt_I8zh_static_info", > "-u", > "GHCziInt_I16zh_static_info", > "-u", > "GHCziInt_I32zh_static_info", > "-u", > "GHCziInt_I64zh_static_info", > "-u", > "GHCziWord_W8zh_static_info", > "-u", > "GHCziWord_W16zh_static_info", > "-u", > "GHCziWord_W32zh_static_info", > "-u", > "GHCziWord_W64zh_static_info", > "-u", > "GHCziStable_StablePtr_static_info", > "-u", > "GHCziBase_Izh_con_info", > "-u", > "GHCziBase_Czh_con_info", > "-u", > "GHCziFloat_Fzh_con_info", > "-u", > "GHCziFloat_Dzh_con_info", > "-u", > "GHCziPtr_Ptr_con_info", > "-u", > "GHCziPtr_FunPtr_con_info", > "-u", > "GHCziStable_StablePtr_con_info", > "-u", > "GHCziBase_False_closure", > "-u", > "GHCziBase_True_closure", > "-u", > "GHCziPack_unpackCString_closure", > "-u", > "GHCziIOBase_stackOverflow_closure", > "-u", > "GHCziIOBase_heapOverflow_closure", > "-u", > "GHCziIOBase_NonTermination_closure", > "-u", > "GHCziIOBase_BlockedOnDeadMVar_closure", > "-u", > "GHCziIOBase_Deadlock_closure", > "-u", > "GHCziWeak_runFinalizzerBatch_closure", > "-u", > "__stginit_Prelude", > "-L/usr/local/lib"], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "haskell98", > auto = True, > import_dirs = ["/usr/local/lib/ghc-6.2.1/imports"], > source_dirs = [], > library_dirs = ["/usr/local/lib/ghc-6.2.1"], > hs_libraries = ["HShaskell98"], > extra_libraries = [], > include_dirs = [], > c_includes = [], > package_deps = ["base"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "haskell-src", > auto = True, > import_dirs = ["/usr/local/lib/ghc-6.2.1/imports"], > source_dirs = [], > library_dirs = ["/usr/local/lib/ghc-6.2.1"], > hs_libraries = ["HShaskell-src"], > extra_libraries = [], > include_dirs = [], > c_includes = [], > package_deps = ["base", "haskell98"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "network", > auto = True, > import_dirs = ["/usr/local/lib/ghc-6.2.1/imports"], > source_dirs = [], > library_dirs = ["/usr/local/lib/ghc-6.2.1"], > hs_libraries = ["HSnetwork"], > extra_libraries = [], > include_dirs = [], > c_includes = ["HsNet.h"], > package_deps = ["base"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "parsec", > auto = True, > import_dirs = ["/usr/local/lib/ghc-6.2.1/imports"], > source_dirs = [], > library_dirs = ["/usr/local/lib/ghc-6.2.1"], > hs_libraries = ["HSparsec"], > extra_libraries = [], > include_dirs = [], > c_includes = [], > package_deps = ["base"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "QuickCheck", > auto = True, > import_dirs = ["/usr/local/lib/ghc-6.2.1/imports"], > source_dirs = [], > library_dirs = ["/usr/local/lib/ghc-6.2.1"], > hs_libraries = ["HSQuickCheck"], > extra_libraries = [], > include_dirs = [], > c_includes = [], > package_deps = ["base"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "readline", > auto = True, > import_dirs = ["/usr/local/lib/ghc-6.2.1/imports"], > source_dirs = [], > library_dirs = ["/usr/local/lib/ghc-6.2.1"], > hs_libraries = ["HSreadline"], > extra_libraries = ["readline", "ncurses"], > include_dirs = [], > c_includes = ["HsReadline.h"], > package_deps = ["base"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "unix", > auto = True, > import_dirs = ["/usr/local/lib/ghc-6.2.1/imports"], > source_dirs = [], > library_dirs = ["/usr/local/lib/ghc-6.2.1"], > hs_libraries = ["HSunix"], > extra_libraries = ["HSunix_cbits"], > include_dirs = [], > c_includes = ["HsUnix.h"], > package_deps = ["base"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "lang", > auto = False, > import_dirs = ["/usr/local/lib/ghc-6.2.1/hslibs-imports/lang"], > source_dirs = [], > library_dirs = ["/usr/local/lib/ghc-6.2.1"], > hs_libraries = ["HSlang"], > extra_libraries = ["HSlang_cbits"], > include_dirs = [], > c_includes = ["HsLang.h"], > package_deps = ["base"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "concurrent", > auto = False, > import_dirs = > ["/usr/local/lib/ghc-6.2.1/hslibs-imports/concurrent"], > source_dirs = [], > library_dirs = ["/usr/local/lib/ghc-6.2.1"], > hs_libraries = ["HSconcurrent"], > extra_libraries = [], > include_dirs = [], > c_includes = [], > package_deps = ["base"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "posix", > auto = False, > import_dirs = ["/usr/local/lib/ghc-6.2.1/hslibs-imports/posix"], > source_dirs = [], > library_dirs = ["/usr/local/lib/ghc-6.2.1"], > hs_libraries = ["HSposix"], > extra_libraries = ["HSposix_cbits"], > include_dirs = [], > c_includes = ["HsPosix.h"], > package_deps = ["lang", "unix"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "util", > auto = False, > import_dirs = ["/usr/local/lib/ghc-6.2.1/hslibs-imports/util"], > source_dirs = [], > library_dirs = ["/usr/local/lib/ghc-6.2.1"], > hs_libraries = ["HSutil"], > extra_libraries = ["HSutil_cbits"], > include_dirs = [], > c_includes = ["HsUtil.h"], > package_deps = > ["lang", "concurrent", "QuickCheck", "readline", "posix"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "text", > auto = False, > import_dirs = ["/usr/local/lib/ghc-6.2.1/hslibs-imports/text"], > source_dirs = [], > library_dirs = ["/usr/local/lib/ghc-6.2.1"], > hs_libraries = ["HStext"], > extra_libraries = [], > include_dirs = [], > c_includes = [], > package_deps = ["lang", "parsec"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "net", > auto = False, > import_dirs = ["/usr/local/lib/ghc-6.2.1/hslibs-imports/net"], > source_dirs = [], > library_dirs = ["/usr/local/lib/ghc-6.2.1"], > hs_libraries = ["HSnet"], > extra_libraries = [], > include_dirs = [], > c_includes = [], > package_deps = ["network"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "hssource", > auto = False, > import_dirs = ["/usr/local/lib/ghc-6.2.1/hslibs-imports/hssource"], > source_dirs = [], > library_dirs = ["/usr/local/lib/ghc-6.2.1"], > hs_libraries = ["HShssource"], > extra_libraries = [], > include_dirs = [], > c_includes = [], > package_deps = ["haskell-src"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "Matrix", > auto = False, > import_dirs = ["/usr/local/lib/imports/HDsp"], > source_dirs = [], > library_dirs = ["/usr/local/lib"], > hs_libraries = ["HSMatrix"], > extra_libraries = [], > include_dirs = [], > c_includes = [], > package_deps = ["data"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "Polynomial", > auto = False, > import_dirs = ["/usr/local/lib/imports/HDsp"], > source_dirs = [], > library_dirs = ["/usr/local/lib"], > hs_libraries = ["HSPolynomial"], > extra_libraries = [], > include_dirs = [], > c_includes = [], > package_deps = ["data"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "Numeric", > auto = False, > import_dirs = ["/usr/local/lib/imports/HDsp"], > source_dirs = [], > library_dirs = ["/usr/local/lib"], > hs_libraries = ["HSNumeric"], > extra_libraries = [], > include_dirs = [], > c_includes = [], > package_deps = ["data"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > Package > {name = "hips", > auto = False, > import_dirs = ["/usr/local/lib/imports/HShips"], > source_dirs = [], > library_dirs = ["/usr/local/lib"], > hs_libraries = ["HShips"], > extra_libraries = [], > include_dirs = [], > c_includes = [], > package_deps = > ["data", "network", "DSP", "Matrix", "Numeric", "Polynomial"], > extra_ghc_opts = [], > extra_cc_opts = [], > extra_ld_opts = [], > framework_dirs = [], > extra_frameworks = []} > > > Hsc static flags: -static > *** Parser: > *** Desugar: > *** Simplify: > *** CorePrep: > *** ByteCodeGen: > Loading package base ... linking ... done. > Loading package haskell98 ... linking ... done. > Loading package lang ... linking ... done. > Loading package concurrent ... linking ... done. > Loading package QuickCheck ... linking ... done. > Loading package readline ... linking ... done. > Loading package unix ... linking ... done. > Loading package posix ... linking ... done. > Loading package util ... linking ... done. > Loading package data ... linking ... done. > Loading package Polynomial ... linking ... done. > Loading package Matrix ... linking ... done. > Loading package Numeric ... linking ... done. > Loading package DSP ... linking ... done. > *** Parser: > *** Desugar: > *** Simplify: > *** CorePrep: > *** ByteCodeGen: > *** Chasing dependencies: > unload: retaining objs [] > unload: retaining bcos [] > Stable modules: > unload: retaining objs [] > unload: retaining bcos [] > *** Compiling Main: > compile: input file test.hs > *** Checking old interface for Main: > Skipping Main ( test.hs, test.o ) > *** Deleting temp files > Deleting: /tmp/ghc48419.hc > Warning: deleting non-existent /tmp/ghc48419.hc > Upsweep completely successful. > *** Deleting temp files > Deleting: > Ok, modules loaded: Main. > Prelude Main> main > main > *** Parser: > *** Desugar: > *** Simplify: > *** CorePrep: > *** ByteCodeGen: > unknown package name: =DSP > Prelude Main> > > is it giving more informations ? > > _______________________________________________ > Glasgow-haskell-users mailing list > Glasgow-haskell-users(a)haskell.org > http://www.haskell.org/mailman/listinfo/glasgow-haskell-users

1 0

instances for bottom?
by Keean Schupke 23 Nov '04

23 Nov '04

I was wondering whether the method by which default types are chosen for unresolved overloading could be made available to the programmer. It seems that if we consider the overlapping instances: class x instance Int instance Float instance x x overlaps with Int and Float... I was wondering if it were possible to determine that type inferance had failed... like with: show (read x :: y) Here y (the type of read x) has no type... and does not match _any_ instance apart from 'x'... so would it not be possible to have an instance for "no type"? perhaps: instance _|_ ... Keean.

1 0

RE: Bug in touchForeignPtr?
by Simon Marlow 23 Nov '04

23 Nov '04

On 20 November 2004 23:02, Benjamin Franksen wrote: > I am using Foreign.Concurrent.newForeignPtr and touchForeignPtr > inside the finalizers to express liveness dependencies as hinted to > by the documentation. This doesn't seem to work, though, or at least > I can't see what I've done wrong. I attached a test module; compiled > with ghc -fglasgow-exts --make TestForeignTouchBug.hs, ghc version > 6.2.2, this gives > > .../foreigntouchbug > ./a.out > <hit enter here> > before finalizing A > after finalizing A > before finalizing B > after finalizing B > <hit enter here> > > I expected the order of the finalizer calls be be the other way > around, since the finalizer for the Bs explicitly touches the A value. The problem is that the runtime is running all outstanding finalizers at the end of execution, without regard for GC dependencies like the ones introduced by touchForeignPtr. I've been planning to remove this automatic running of finalizers for other reasons. However, then you will get absolutely no guarantee that your finalizer will ever run at all (indeed, the property isn't always true right now, but it is usually true). Let me share with you something that I've come to appreciate over the last few years: Finalizers are almost always not the right thing. Finalizers look terribly attractive, but often lead to a huge can of worms - best avoided if at all possible. Cheers, Simon

7 14

RE: proposal for ghc-pkg to use a directory of .conf files
by Simon Marlow 22 Nov '04

22 Nov '04

On 21 November 2004 00:56, Isaac Jones wrote: > The systems that would want to do this kind of thing, such as Debian, > have other mechanisms for deciding whether packages conflict, etc. IIRC, this is the argument I just used against adding support for multiple libraries in Cabal, so I guess I agree :-D > Over-all I'm kinda neutral about whether HC-pkg needs to be an opaque > interface to the packaging system. What are the advantages to this? Well, for one thing it allows us flexibility in how we store the package database. In GHC, I'm using the show/read form of [InstalledPackageInfo] to store the database, but it'd be nice if I could use binary serialisation in the future. To support a directory of config files, we don't have to expose the complete format, though. As long as hc-pkg can process the InstalledPackageInfo to produce the native format into a file, then we just ship that file with the distribution. So I'm fine with this, as long as we're not specifying the contents of the *.conf file. Cheers, Simon

1 0

RE: unlit/ghci does not work on DOS file
by Simon Marlow 22 Nov '04

22 Nov '04

On 18 November 2004 20:31, Christian Maeder wrote: > calling unlit on a DOS file fails, whereas hugs is able to process the > same file (under unix). > > Christian > > Prelude> readFile "Test.lhs" >>= putStrLn . show > "\r\n> module Test where\r\n>\r\n" > Prelude> :l Test.lhs > Test.lhs line 2: unlit: Program line next to comment > phase `Literate pre-processor' failed (exitcode = 1) Thanks, fixed. Cheers, Simon

1 0