[ ghc-Bugs-1285326 ] scavenge_one: strange object 47
Bugs item #1285326, was opened at 2005-09-08 20:18 Message generated for change (Comment added) made by simonmar You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=108032aid=1285326group_id=8032 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: None Group: None Status: Closed Resolution: Fixed Priority: 5 Submitted By: tuananhbirm (tuananhbirm) Assigned to: Nobody/Anonymous (nobody) Summary: scavenge_one: strange object 47 Initial Comment: Hi, i am running GHC 6.4, in Redhat 9, running sometimes with flag -threaded on. Please look at the file Mult.hs and function: startM1 (17-20) run this function for different inputs (orignially, multiply (1%7) with (0%2)) try to run with : (1%3) and (0%1) (2%3) and (0%1) (1%2) and (0%1) (1%5) and (0%1) Best regards TuanAnh -- Comment By: Simon Marlow (simonmar) Date: 2005-09-13 08:47 Message: Logged In: YES user_id=48280 After fixing the bug, I ran the test program for about 30mins and it still hadn't finished. Is there a way to run it for, say, 5 seconds? The fix will be in version 6.4.1. -- Comment By: tuananhbirm (tuananhbirm) Date: 2005-09-12 18:23 Message: Logged In: YES user_id=1341750 what do you mean by allow it to run for a shorter time ? btw, how do i use the fixed version of ghc ? (is there a patch for this bug or something similar ? ) Thanks a lot TuanAnh -- Comment By: Simon Marlow (simonmar) Date: 2005-09-12 15:56 Message: Logged In: YES user_id=48280 Fixed now, thanks for a good report. I'd like to use this as a test case - how can I provide inputs that allow it to run for a shorter time? -- You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=108032aid=1285326group_id=8032 ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
[ ghc-Bugs-1277825 ] segmentation fault when profiling large case
Bugs item #1277825, was opened at 2005-09-01 00:31 Message generated for change (Comment added) made by simonmar You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=108032aid=1277825group_id=8032 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Profiling Group: 6.4 Status: Open Resolution: None Priority: 5 Submitted By: Nobody/Anonymous (nobody) Assigned to: Nobody/Anonymous (nobody) Summary: segmentation fault when profiling large case Initial Comment: If the attached file is compiled with -prof -auto-all, the binary produced will segfault (even if RTS profiling options are not present). This seems to be caused by a combination of a case statement with a large number of branches and a relatively complex value at the end of each branch - reducing the number of branches by one or changing any of the data declarations to newtypes eliminates the segfault. -- Comment By: Simon Marlow (simonmar) Date: 2005-09-13 08:51 Message: Logged In: YES user_id=48280 Fergus - are you the original submitter? What was different about the environment in which the bug exhibits? -- Comment By: Fergus Henderson (fergus) Date: 2005-09-05 21:48 Message: Logged In: YES user_id=135331 I tried reproducing this using ghc 6.4 on Debian Linux, but I was unable to reproduce the bug. The program compiled fine with ghc -prof -auto-all bug.hs and I was able to get a profile by running ./a.out +RTS -p and looking at a.out.prof. -- You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=108032aid=1277825group_id=8032 ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
[ ghc-Bugs-1282571 ] +RTS -xc and SIGINT handler gives seg fault
Bugs item #1282571, was opened at 2005-09-05 22:33 Message generated for change (Comment added) made by simonmar You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=108032aid=1282571group_id=8032 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Profiling Group: None Status: Closed Resolution: Fixed Priority: 5 Submitted By: Fergus Henderson (fergus) Assigned to: Nobody/Anonymous (nobody) Summary: +RTS -xc and SIGINT handler gives seg fault Initial Comment: To reproduce this bug, save the attached file Bug.hs, run the following commands ghc -package posix -prof -auto-all Bug.hs ./a.out +RTS -xc and then hit control-C. The result is a SIGSEGV inside fprintCCS(). -- Comment By: Simon Marlow (simonmar) Date: 2005-09-13 08:57 Message: Logged In: YES user_id=48280 This one has been fixed in 6.4.1 (out soon). -- Comment By: Fergus Henderson (fergus) Date: 2005-09-05 22:44 Message: Logged In: YES user_id=135331 The crash is a null pointer dereference in fprintCCS(). Here's a gdb stack trace (gdb) where #0 0x08072cbf in fprintCCS () #1 0x in ?? () #2 0x08077fa1 in raiseAsyncWithLock () #3 0x402b60f0 in ?? () #4 0x0809f3e8 in MainCapability () #5 0x402c2014 in ?? () #6 0x0807b2d2 in raisezh_fast () #7 0x401a3440 in _IO_2_1_stdout_ () from /lib/libc.so.6 #8 0x0809f174 in hp_file () #9 0x402c2024 in ?? () #10 0x in ?? () #11 0x0001 in ?? () #12 0x402c2024 in ?? () #13 0x0002 in ?? () #14 0x in ?? () #15 0x001c in ?? () #16 0x08099314 in Main_CAFs_cc () #17 0x01db846e in ?? () #18 0x08099334 in Main_CAFs_cc_ccs () The crash occurs at fprintCCS+44: 0x08072c93 fprintCCS+0: push %esi 0x08072c94 fprintCCS+1: push %ebx 0x08072c95 fprintCCS+2: sub$0x14,%esp 0x08072c98 fprintCCS+5: mov0x20(%esp),%esi 0x08072c9c fprintCCS+9: mov0x24(%esp),%ebx 0x08072ca0 fprintCCS+13: mov%esi,0x4(%esp) 0x08072ca4 fprintCCS+17: movl $0x3c,(%esp) 0x08072cab fprintCCS+24: call 0x80492c8 _init+712 0x08072cb0 fprintCCS+29: test %ebx,%ebx 0x08072cb2 fprintCCS+31: je 0x8072d0e fprintCCS+123 0x08072cb4 fprintCCS+33: cmp$0x809d100,%ebx 0x08072cba fprintCCS+39: je 0x8072d0e fprintCCS+123 0x08072cbc fprintCCS+41: mov0x4(%ebx),%eax 0x08072cbf fprintCCS+44: mov0x4(%eax),%eax eax is zero. -- You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=108032aid=1282571group_id=8032 ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
RE: memory allocation failed
On 09 September 2005 15:40, David F. Place wrote: My program terminated with the following message: pal: internal error: memory allocation failed (requested 2097152 bytes) Please report this as a bug to glasgow-haskell-bugs@haskell.org, Forgive me for asking the obvious, but is it possible that you ran out of memory? If not, then yes we'd like to see your test case please. Cheers, Simon ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
RE: ghc-6.4.1.20050903 (and maybe newer versions?) doesn't support--exec-prefix different from --prefix
On 10 September 2005 01:33, Frederik Eaton wrote: It seems ghc-6.4.1.20050903 doesn't support having an --exec-prefix different from --prefix. When I tried this, ghci didn't work, it was looking for libraries in PREFIX/lib which had been installed under EXEC_PREFIX/lib. That's entirely possible. Cheers, Simon ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
RE: problems building ghc 6.4.1_pre using 6.4 with multiplecabalversions installed
Just glancing over the patch, I can't immediately see how it works. GHC 6.4 gives priority to package modules over modules on the local search path, so Distribution.* will be taken from the installed Cabal package. However, when linking GHC you are ommitting -package Cabal, so I'd expect a link error. Hmm, I guess I should try this and figure out what's happening. Cheers, Simon On 12 September 2005 15:53, Duncan Coutts wrote: On Mon, 2005-09-12 at 13:33 +0100, Simon Marlow wrote: Quite right this is a problem, and it looks like something we should fix before 6.4.1. I'll give it some thought. Hi Simon, glad to have you back! :-) Andres Loeh has looked into this a bit in the last few days. He's knocked up this patch which we're using in our Gentoo ebuilds for recent ghc-6.4.1 snapshots (2005/08/19 and 2005/09/09): http://haskell.org/~gentoo/gentoo-haskell/portage/dev-lang/ghc/files/ghc -6.4.1-nocabal.patch The patch is to make it build without using any existing installation of Cabal. So it'll work if there is no Cabal, 1 cabal or 2+ Cabal versions installed. Andres's disclamer is that it might make some gentoo-specific assumptions. Duncan On 24 August 2005 14:42, Duncan Coutts wrote: With our current 6.4.1 snapshot 20050819, we have problems building when we've got more than over version of cabal registered. That is we build it using ghc 6.4 and we have cabal-1.0 and cabal-1.1.2 installed. Then it complains that multiple packages match -package cabal. It also has problems when no version of cabal is registered. There is no problem building with ghc 6.2.2 with no cabal installed. I think it would be much more reliable if ghc did not rely on the version of cabal installed and registered with ghc 6.4. Since it has to work without cabal anyway (for the 6.2.2 case), wouldn't it be possible to make it ignore any installed version of cabal even when building with ghc 6.4? At the moment, it looks like we're going to have problems on gentoo upgrading users from ghc 6.4 to 6.4.1. Our current idea is to unregister the Cabal-1.0 package that ghc 6.4 comes with and use a later version (Cabal-1.1.2 at the moment) however it's not clear that ghc will cope with using the later version. We need to install the later version anyway for other reasons (version 1.0 has bugs and lacks some features we need for reasonable packaging) and ghc 6.4 does not cope very well with having multiple versions of a package installed (this is improved in 6.4.1), hence the rationale for unregistering the 1.0 version entirely. ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
RE: mysterious directory include error
On 13 September 2005 00:25, Frederik Eaton wrote: Works for me with a 6.4.1 snapshot. I've upgraded to 6.4.1.20050903 and it still doesn't work. Did you remember to create the empty directory 'foo'? Of course, I think there are two things wrong: (1) the fact that it doesn't work, (2) the fact that the error message is uninformative. Oh, I'm sorry, it's possible that I was using the wrong version. I think /usr/bin/runghc is version 6.4. However, it strangely reports being version 6.4.1: $ /usr/bin/runghc --version The Glorious Glasgow Haskell Compilation System, version 6.4.1.20050903 $ /usr/bin/ghc --version The Glorious Glasgow Haskell Compilation System, version 6.4 $ ghc --version The Glorious Glasgow Haskell Compilation System, version 6.4.1.20050903 $ runghc --version runghc: syntax: runghc [-f GHCPATH] [GHC-ARGS] FILE ARG...[1]$ When I use the newer version I am unable to reproduce the problem. (by the way, it would be nice if --version and --help were functional in the newer versions of runghc) This happens because runghc uses whatever ghc is on your path, and it passes any flags it doesn't understand to that ghc. Cheers, Simon ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
RE: runghc takes modules from current working directory
On 12 September 2005 16:34, Frederik Eaton wrote:
On Mon, Sep 12, 2005 at 12:41:32PM +0100, Simon Marlow wrote:
On 20 August 2005 22:38, Frederik Eaton wrote:
Hi,
It seems like it would be nice to have runghc not take modules from
the current working directory in many cases since it breaks
abstraction. It looks like it may be only a real problem for
debugging, when modules are supposed to be in a package somewhere,
but aren't, and the current directory happens to have files of the
same name, but in those cases it can be quite a pain to track down
the error. The problem comes up especially often when one writes
scripts in haskell to work with haskell packages or generate
haskell code. Do people frequently use the find modules in the
current directory feature, or could they be asked to do that with
{-# OPTIONS_GHC -i. #-}
? (I don't think this works yet) Otherwise maybe a special option
could be added to tell runghc not to look in the current directory?
Frederik
runghc -i foo.hs?
I'm talking about #! scripts, for which the interpreter is hidden
from the user. I tried putting #!/usr/bin/runghc -i at the top of a
script and it failed with Failed to load interface for `Main'...
I'm assuming this is fixed with a newer version of runghc?
Cheers,
Simon
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[ ghc-Bugs-1186741 ] stack overflow when loading a big
Bugs item #1186741, was opened at 2005-04-20 15:17 Message generated for change (Comment added) made by simonmar You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=108032aid=1186741group_id=8032 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Compiler Group: 6.2.2 Status: Closed Resolution: None Priority: 5 Submitted By: Peter (peter26) Assigned to: Nobody/Anonymous (nobody) Summary: stack overflow when loading a big Initial Comment: when loading a file with a very big list, ghci and ghc give a stack overflow error (also when stack is increase to 10M with the +RTS -Ksize option and stack size is set to unlimited using ulimit -s unlimited in linux). ghci also shows the error when loading the file. it would be at least better to report that the list is too big. -- Comment By: Simon Marlow (simonmar) Date: 2005-09-13 09:43 Message: Logged In: YES user_id=48280 We have fixed some performance problems that show up when you compile very long lists. We don't believe GHC is using non-linear stack, but it is reasonable for GHC to use linear stack space when compiling a long list - after all it is just syntactic sugar for a deeply nested expression. You should find that 6.4.1 is better than 6.4 in terms of performance, but it might not use less stack. -- You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=108032aid=1186741group_id=8032 ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
[ ghc-Bugs-1289569 ] hPutBuf doesn't respect LineBuffering
Bugs item #1289569, was opened at 2005-09-13 09:44 Message generated for change (Tracker Item Submitted) made by Item Submitter You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=108032aid=1289569group_id=8032 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: libraries/base Group: 6.4 Status: Open Resolution: None Priority: 3 Submitted By: Simon Marlow (simonmar) Assigned to: Simon Marlow (simonmar) Summary: hPutBuf doesn't respect LineBuffering Initial Comment: On 15 April 2005 02:39, Ian Lynagh wrote: If I run this program: -- import System.Cmd (system) import Foreign.C.String (castCharToCChar) import Foreign.Marshal.Array (newArray) import System.IO (hSetBinaryMode, hPutBuf, stdout, hSetBuffering, BufferMode(..)) main = do hSetBinaryMode stdout True hSetBuffering stdout LineBuffering p - newArray (map castCharToCChar foo\n) hPutBuf stdout p 4 system sleep 5 putStr bar\n -- compiled by GHC then it waits 5 seconds and then prints foo and bar together. With hugs, foo is printed and then 5 seconds later bar is printed, as I would expect. True, the implementation doesn't respect LineBuffering (though it does respect the other buffering modes, I believe). That's a bug. -- You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=108032aid=1289569group_id=8032 ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
[ ghc-Bugs-1285326 ] scavenge_one: strange object 47
Bugs item #1285326, was opened at 2005-09-08 20:18 Message generated for change (Comment added) made by tuananhbirm You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=108032aid=1285326group_id=8032 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: None Group: None Status: Closed Resolution: Fixed Priority: 5 Submitted By: tuananhbirm (tuananhbirm) Assigned to: Nobody/Anonymous (nobody) Summary: scavenge_one: strange object 47 Initial Comment: Hi, i am running GHC 6.4, in Redhat 9, running sometimes with flag -threaded on. Please look at the file Mult.hs and function: startM1 (17-20) run this function for different inputs (orignially, multiply (1%7) with (0%2)) try to run with : (1%3) and (0%1) (2%3) and (0%1) (1%2) and (0%1) (1%5) and (0%1) Best regards TuanAnh -- Comment By: tuananhbirm (tuananhbirm) Date: 2005-09-13 09:46 Message: Logged In: YES user_id=1341750 The program is supposed to compute an infinite list, so it would never finish (however i never see the error after 100-150 digits). If you always get the result of [1,0,0,0,0. , then try with inputs whose denominators are not power of 2 (like (1%3 and 1%3) or (1%3 and 3%5)) ... Best regards TuanAnh -- Comment By: Simon Marlow (simonmar) Date: 2005-09-13 08:47 Message: Logged In: YES user_id=48280 After fixing the bug, I ran the test program for about 30mins and it still hadn't finished. Is there a way to run it for, say, 5 seconds? The fix will be in version 6.4.1. -- Comment By: tuananhbirm (tuananhbirm) Date: 2005-09-12 18:23 Message: Logged In: YES user_id=1341750 what do you mean by allow it to run for a shorter time ? btw, how do i use the fixed version of ghc ? (is there a patch for this bug or something similar ? ) Thanks a lot TuanAnh -- Comment By: Simon Marlow (simonmar) Date: 2005-09-12 15:56 Message: Logged In: YES user_id=48280 Fixed now, thanks for a good report. I'd like to use this as a test case - how can I provide inputs that allow it to run for a shorter time? -- You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=108032aid=1285326group_id=8032 ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
[ ghc-Bugs-1289573 ] mkProtoBCO: stack use won't fit in 16 bits 79141
Bugs item #1289573, was opened at 2005-09-13 09:48 Message generated for change (Tracker Item Submitted) made by Item Submitter You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=108032aid=1289573group_id=8032 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Compiler Group: 6.4 Status: Open Resolution: None Priority: 5 Submitted By: Simon Marlow (simonmar) Assigned to: Nobody/Anonymous (nobody) Summary: mkProtoBCO: stack use won't fit in 16 bits 79141 Initial Comment: ERROR MESSAGE: Prelude :r Compiling BookData ( ./BookData.hs, interpreted ) ghc-6.2.2: panic! (the `impossible' happened, GHC version 6.2.2): mkProtoBCO: stack use won't fit in 16 bits 79141 Test case and rest of message here: http://www.haskell.org//pipermail/glasgow-haskell-bugs/2005-March/004871.html -- You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=108032aid=1289573group_id=8032 ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
[ ghc-Bugs-807249 ] Instance match failure on openTypeKind
Bugs item #807249, was opened at 2003-09-16 16:37 Message generated for change (Settings changed) made by simonmar You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=108032aid=807249group_id=8032 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Compiler (Type checker) Group: None Status: Open Resolution: None Priority: 5 Submitted By: Simon Peyton Jones (simonpj) Assigned to: Simon Peyton Jones (simonpj) Summary: Instance match failure on openTypeKind Initial Comment: Consider instance Show (a-gt;b) where ... foo x = show (\ _ -gt; True) This fails with: No instance for (Show (t -gt; Bool)) arising from use of `show' at Foo.hs:5 Reason: the type of (\_ -gt; True) is (t -gt; Bool) where t has an quot;openTypeKindquot;. It's possible that the function will be applied to say an Int#, and the openTypeKind records that this is OK. BUT, the instance decl Show (a-gt;b) has a::liftedTypeKind, and that doesn't match an openTypeKind type variable. This bug relates to GHC's unsatisfactory treatment of the variants of kind quot;typequot;, for which there are at least 2 other SourceForge bugs registered (753780 and 753777). It's very obscure, so I'm not going to fix it today. -- Comment By: Simon Marlow (simonmar) Date: 2005-07-11 10:36 Message: Logged In: YES user_id=48280 ghci015 now tests for this bug. -- Comment By: Simon Peyton Jones (simonpj) Date: 2005-05-23 12:57 Message: Logged In: YES user_id=50165 I'm bumping up the priority of this bug, because it also happens if, in GHCi, you say Prelude :m +Text.Show.Functions Text.Show.Functions print (\x - x) (this elicits a no-such-instance error) It's even more perplexing that this does not happen if you say print id becuase 'id' has kind-defaulted type variables in its type. Sigh. -- You can respond by visiting: https://sourceforge.net/tracker/?func=detailatid=108032aid=807249group_id=8032 ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: memory allocation failed
Yes, it does seem that it has just run out of memory. In that case, the bug is the error message that instructs me to make a bug report. On Sep 13, 2005, at 5:02 AM, Simon Marlow wrote: On 09 September 2005 15:40, David F. Place wrote: My program terminated with the following message: pal: internal error: memory allocation failed (requested 2097152 bytes) Please report this as a bug to glasgow-haskell-bugs@haskell.org, Forgive me for asking the obvious, but is it possible that you ran out of memory? If not, then yes we'd like to see your test case please. Cheers, Simon David F. Place mailto:[EMAIL PROTECTED] ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
RE: memory allocation failed
On 13 September 2005 11:47, David F. Place wrote: The non-Darwin version of that error message does indicate out of memory. Wolfgang: can we detect out of memory on Darwin too? Cheers, Simon Yes, it does seem that it has just run out of memory. In that case, the bug is the error message that instructs me to make a bug report. On Sep 13, 2005, at 5:02 AM, Simon Marlow wrote: On 09 September 2005 15:40, David F. Place wrote: My program terminated with the following message: pal: internal error: memory allocation failed (requested 2097152 bytes) Please report this as a bug to glasgow-haskell-bugs@haskell.org, Forgive me for asking the obvious, but is it possible that you ran out of memory? If not, then yes we'd like to see your test case please. Cheers, Simon David F. Place mailto:[EMAIL PROTECTED] ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: problems building ghc 6.4.1_pre using 6.4 with multiplecabalversions installed
Just glancing over the patch, I can't immediately see how it works. GHC 6.4 gives priority to package modules over modules on the local search path, so Distribution.* will be taken from the installed Cabal package. However, when linking GHC you are ommitting -package Cabal, so I'd expect a link error. Hmm, I guess I should try this and figure out what's happening. The idea is that no installed Cabal version will be used. I think the ghc distribution should just always build its own Cabal during stage1. That's what the patch tries to achieve, and afaics, it works. However, Duncan didn't give you the full story with the patch. We also do the following: echo GHC+=-ignore-package Cabal mk/build.mk echo HC+=-ignore-package Cabal mk/build.mk This was the only way I could find to make sure that a preinstalled Cabal is ignored whenever the preinstalled ghc is called, but not once the in-place ghc is available. Cheers, Andres ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
RE: problems building ghc 6.4.1_pre using 6.4 withmultiplecabalversions installed
On 13 September 2005 12:22, Andres Loeh wrote: Just glancing over the patch, I can't immediately see how it works. GHC 6.4 gives priority to package modules over modules on the local search path, so Distribution.* will be taken from the installed Cabal package. However, when linking GHC you are ommitting -package Cabal, so I'd expect a link error. Hmm, I guess I should try this and figure out what's happening. The idea is that no installed Cabal version will be used. I think the ghc distribution should just always build its own Cabal during stage1. I agree - I just couldn't see how your patch achieved that. That's what the patch tries to achieve, and afaics, it works. However, Duncan didn't give you the full story with the patch. We also do the following: echo GHC+=-ignore-package Cabal mk/build.mk echo HC+=-ignore-package Cabal mk/build.mk Aha, that's the missing bit. I'll try to construct a robust version of this. Cheers, Simon ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
RE: GADT: weird error message
Yes, GHC has a special rule to handle case-of-expression. (We call it smart-app in the paper.) But GHC's front end retains all syntax, including tuple syntax, and I failed to do the special rule for tuple syntax. Sorry! Perhaps you can file it as a Sourceforge bug. I'm going to do a raft of changes to GADTs in the autumn, and by filing it you'll ensure I don't forget. BTW, what are you using GADTs for? Any other unexpected surprises? Thanks Simon | -Original Message- | From: [EMAIL PROTECTED] [mailto:glasgow-haskell-bugs- | [EMAIL PROTECTED] On Behalf Of Arthur Baars | Sent: 06 September 2005 16:48 | To: glasgow-haskell-bugs@haskell.org | Subject: GADT: weird error message | | In the code below the function trans is accepted by GHC 6.4, but | trans1 is not. I would expect that (x,y) is just syntactic sugar | for (,) x y, but apparently it isn't. I guess this is a bug; can | anyone explain what is going on? | | Cheers, | | Arthur | | The Code: | data Equal a b where | Eq :: Equal a a | | trans :: forall a b c. Equal a b - Equal b c - Equal a c | trans = \x - \y - case (,) x y of | (Eq,Eq ) - Eq | | trans1 :: forall a b c. Equal a b - Equal b c - Equal a c | trans1 = \x - \y - case (x, y) of | (Eq,Eq ) - Eq | | The error message: | Test2.hs:9:0: | Quantified type variable `c' is unified with another quantified | type variable a | When trying to generalise the type inferred for `trans1' |Signature type: forall a b c. Equal a b - Equal b c - Equal | a c |Type to generalise: Equal a b - Equal b a - Equal a a | In the type signature for `trans1' | When generalising the type(s) for `trans1' | | ___ | Glasgow-haskell-bugs mailing list | Glasgow-haskell-bugs@haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: runghc takes modules from current working directory
On Tue, Sep 13, 2005 at 10:15:39AM +0100, Simon Marlow wrote:
On 12 September 2005 16:34, Frederik Eaton wrote:
On Mon, Sep 12, 2005 at 12:41:32PM +0100, Simon Marlow wrote:
On 20 August 2005 22:38, Frederik Eaton wrote:
Hi,
It seems like it would be nice to have runghc not take modules from
the current working directory in many cases since it breaks
abstraction. It looks like it may be only a real problem for
debugging, when modules are supposed to be in a package somewhere,
but aren't, and the current directory happens to have files of the
same name, but in those cases it can be quite a pain to track down
the error. The problem comes up especially often when one writes
scripts in haskell to work with haskell packages or generate
haskell code. Do people frequently use the find modules in the
current directory feature, or could they be asked to do that with
{-# OPTIONS_GHC -i. #-}
? (I don't think this works yet) Otherwise maybe a special option
could be added to tell runghc not to look in the current directory?
Frederik
runghc -i foo.hs?
I'm talking about #! scripts, for which the interpreter is hidden
from the user. I tried putting #!/usr/bin/runghc -i at the top of a
script and it failed with Failed to load interface for `Main'...
I'm assuming this is fixed with a newer version of runghc?
Yep, sorry.
Frederik
--
http://ofb.net/~frederik/
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Re: FFI: calling Haskell from C++?
we have tried long and hard to call Haskell functions from C++ usingthe FFI mechanism but without success. Don't forget to say which platform you're on - the solution might be slightly platform-dependent. $ ghc -fffi Foo.o Foo_stub.o main.cpp main.o(.text+0x22): In function `main': main.cpp: undefined reference to `__stginit_Foo()'#ifdef __GLASGOW_HASKELL__extern void __stginit_Foo ( void );#endifThis should be...extern "C" void __stginit_Foo ( void ); main.o(.eh_frame+0x11): undefined reference to `__gxx_personality_v0' collect2: ld returned 1 exit statusOn Mac OS X, all you need to do is add -lstdc++ to your ghc command line; it may or may not be that easy on other platforms.Cheers,Wolfgang___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: FFI: calling Haskell from C++?
On 9/13/05, Felix Breuer [EMAIL PROTECTED] wrote: $ ghc -fffi Foo.o Foo_stub.o main.cppmain.o(.text+0x22): In function `main':main.cpp: undefined reference to `__stginit_Foo()'main.o(.eh_frame+0x11): undefined reference to `__gxx_personality_v0'collect2: ld returned 1 exit status In main.cpp, you need to define __stginit_Foo(void) like this: extern C void __stginit_Foo(void); Specifying the C linkage with prevent the compiler from looking for a name-mangled version of the function. To fix the second problem, you need to shut off exception handling (specifying the -fno-exceptions option ought to do this. I don't know how to pass compiler option via ghc, though. -- RichAIM : rnezzyICQ : 174908475 ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
Re: FFI: calling Haskell from C++?
Hello everyone, the examples are working now! John, Wolfgang and Rich, thank you for your help! On Wed, 14 Sep 2005 02:07:52 +1000 skaller [EMAIL PROTECTED] wrote: On Tue, 2005-09-13 at 15:20 +, Felix Breuer wrote: main.o(.text+0x22): In function `main': main.cpp: undefined reference to `__stginit_Foo()' This was solved by extern C void __stginit_Foo(void); main.o(.eh_frame+0x11): undefined reference to `__gxx_personality_v0' collect2: ld returned 1 exit status and this by adding -lstdc++ to the ghc command line options. My platform is Linux 2.6.11 running GCC 3-4-4.. I will now try to apply this to my application. I will see if I run into trouble when I actually use C++ code (and not just rename a C source file). There is one more problem: you MUST NOT run gcc on files ending in *.cpp. You are REQUIRED to run g++. So you will have to somehow tell ghc to use g++ and NOT gcc. in particular C++ programs require different startup code to C, to initialise exception handling, etc etc. So the whole program MUST be linked by g++, not gcc, and the main() must be compiled with g++ not gcc. Is it possible to have ghc compile _and_ _link_ all the Haskell code, and then using g++ to compile the C++ code and link everything together? I tried using ghc to only compile the .hs files and have g++ do all the linking but I only got a bunch of undefined references due to the GHC libs not being linked into the executable. I always relied on ghc --make to figure out the dependencies here, and now I don't know which files to link against... Thanks again, Felix ___ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
[Haskell] OOHaskell -- major release of report and library
An extended technical report has been released at: TR software: http://homepages.cwi.nl/~ralf/OOHaskell/ TR: http://arxiv.org/abs/cs.PL/0509027 Haskell's overlooked object system 10 September 2005, 79 pages by O. Kiselyov (FNMOC, Monterey, CA, USA) and R. Laemmel (Microsoft Corp., WA, USA) Some recently added topics: - Many Haskell 98 encodings - Safe value recursion - Safe downcasts - Safe co-variant method arguments - Nominal subtyping - Iso-recursive object types - With and depth subtyping The report describes and classifies all principled, to our best knowledge, object encodings in Haskell98, with and without common extensions. On the one hand, this report covers many advanced topics, as to make it interesting for programming language researchers. On the other hand, the report is detailed and lightweight enough to be useful as an OO-FP tutorial. Regards, Oleg and Ralf ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
[Haskell] StringMaps available
Hello, I've put the first release of Data.StringMap here.. http://homepages.nildram.co.uk/~ahey/HLibs/Data.StringMap/ The implementation is a bit different than what was discussed earlier as I decided the first version would burn heap unecessarily. It's still based on Tries though. I'm afraid I won't be able to do much Haskelling for a few months so not much will be added in the near future. But if anybody would like to use this but finds the absence of some function or other a show stopping issue then let me know and I'll add it. Regards -- Adrian Hey ___ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
RE: [Haskell] reading call graphs
On 24 August 2005 11:10, Malcolm Wallace wrote:
Scherrer, Chad [EMAIL PROTECTED] writes:
individualinherited
COST CENTRE MODULE no.entries %time %alloc %time %alloc
MAIN MAIN 1 0 0.00.0 100.0 100.0
mainMain228 92329 0.20.999.8 99.8
step Main259 679 38.4 26.656.6 39.2
I'm trying to understand the entries column. I thought this was the
number of times a given function is called. But main is
nonrecursive, and only calls step (also nonrecursive) once. Where
are the 92329 and 679 coming from?
Perhaps these functions are split into smaller chunks by the
compiler/optimiser? Then the profiler would aggregate the data for
the individual chunks back up into the original cost centre.
That's a plausible hypothesis. Each time an expression of the form ({-#
SCC foo #-} e) is evaluated, the entries count for foo is
incremented. The effect of -auto-all is to wrap each top-level function
in an {-# SCC #-} expression, so you would normally get one entry per
call of the function. However, the optimiser can change the structure
of the code. Optimisations are supposed to retain the cost attribution
model, but they don't necessarily retain the same entry counts.
Basically I find the entries figure is a useful sanity check (i.e. is
this function called at all?), but not much more than that.
Cheers,
Simon
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Re: [Haskell-cafe] Template Haskell and Types
Tomasz Zielonka wrote: On Mon, Sep 12, 2005 at 12:08:14PM +0200, Gracjan Polak wrote: Probably very simple question about template haskell: How do I make a type for an argument to splice? Example: data MyData = MyData1 | MyData2 mysplice mytype = [| litE $ stringL $ show mytype |] main = do putStrLn $(mysplice MyData) Cale explained how you can quote types in general. In the special case when you simply want the Name of a type-constructor, you can use the '' quoting syntax: putStrLn $(mysplice ''MyData) Thanks for responses. Is there any up-to-date documentation avaliable? Best regards Tomasz ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Language Workbenches - the Haskell solution?
Correction - I wrote: If you want a GUI for configuration, you could, for example, write a fairly simple transformation of the master XML into a .NET dialog, or glade file for GTK, or whatever. We never did that, though. Actually, Yael Weinbach wrote a beautiful GUI for this configuration scheme. I apologize to Yael for the omission. Regards, Yitz ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
RE: [Haskell-cafe] Template Haskell and Types
| putStrLn $(mysplice ''MyData) | | | Thanks for responses. Is there any up-to-date documentation avaliable? Template Haskell is, alas, poorly documented. I would really welcome someone to volunteer to help write better documentation. Meanwhile, as the user manual says, the stuff about quoting names is described in a design note http://research.microsoft.com/~simonpj/tmp/notes2.ps Simon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Template Haskell and Types
On Tuesday 13 September 2005 09:16, Gracjan Polak wrote:
Tomasz Zielonka wrote:
On Mon, Sep 12, 2005 at 12:08:14PM +0200, Gracjan Polak wrote:
Probably very simple question about template haskell: How do I make
a type for an argument to splice? Example:
data MyData = MyData1 | MyData2
mysplice mytype =
[| litE $ stringL $ show mytype |]
main = do
putStrLn $(mysplice MyData)
Cale explained how you can quote types in general. In the special
case when you simply want the Name of a type-constructor, you can
use the '' quoting syntax:
putStrLn $(mysplice ''MyData)
Thanks for responses. Is there any up-to-date documentation
avaliable?
The only I know of is the TH 'update' paper, where e.g. the single ('a)
and double (''a) quote syntax is explained:
http://research.microsoft.com/~simonpj/tmp/notes2.ps
Ben
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[Haskell-cafe] Re: Language Workbenches - First attempt
source = #123456789012345678901234567890123456789012345678901234567890\n\ \SVCLFOWLER 10101MS0120050313.\n\ \SVCLHOHPE 10201DX0320050315\n\ \SVCLTWO x10301MRP220050329..\n\ \USGE10301TWO x50214..7050329... type ConfigLine = (String, [(String, (Int, Int))]) type Configuration = [ConfigLine] type KeyVal = (String, String) type Header = String type Entry = (Header, [KeyVal]) config :: Configuration config = [(SVCL, [(CustomerName, (4, 18)), (CustomerID, (19, 23)), (CallTypeCode, (24, 27)), (DateOfCallString, (28, 35))]), (USGE, [(CustomerID, (4, 8)), (CustomerName, (9, 22)), (Cycle, (30, 30)), (ReadDAte, (31, 36))])] getRange :: Int - Int - [a] - [a] getRange a b l = take (b-a+1) $ drop a l lineToFields :: String - [(Int,Int)] - [String] lineToFields line points = map (fieldFromTo line) points where fieldFromTo line (x,y) = getRange x y line lineType :: String - String lineType = getRange 0 3 applyConfig :: String - ConfigLine - [KeyVal] applyConfig line (ckey, cval) = if lineType line == ckey then zip names $ lineToFields line points else [] where part = unzip cval names = fst part points = snd part parseLine :: Configuration - String - Entry parseLine cnf line = (header, parsed) where rawData :: [[KeyVal]] rawData = map (applyConfig line) cnf parsed :: [KeyVal] parsed = head $ dropWhile null rawData header = lineType line parse :: Configuration - [String] - [Entry] parse cnf lines = map (parseLine cnf) lines run = parse config $ filter noComment $ lines source where noComment = \x - (head x) /= '#' == Output *Main run [(SVCL,[(CustomerName,FOWLER ),(CustomerID,10101),(CallTypeCode,MS01),(DateOfCallString,20050313)]),(SVCL,[(CustomerName,HOHPE ),(CustomerID,10201),(CallTypeCode,DX03),(DateOfCallString,20050315)]),(SVCL,[(CustomerName,TWO x),(CustomerID,10301),(CallTypeCode,MRP2),(DateOfCallString,20050329)]),(USGE,[(CustomerID,10301),(CustomerName,TWO x),(Cycle,7),(ReadDAte,050329)])] *Main Yoel Jacobsen wrote: It seems that Martin Fowler's article Language Workbenches: The killer-App for Domain Specific Languages? - http://www.martinfowler.com/articles/languageWorkbench.html - has generated some nice dynamic solution where a configuration file is written in the same language as the program. Notable examples are lisp - http://lispm.dyndns.org/news?ID=NEWS-2005-07-08-1 and python - http://billionairebusinessman.blogspot.com/2005/09/drop-that-schema-and-put-your-hands-in.html I'm trying to create an _elegant_ solution in Haskell. But I'm stuck. Since the native record-like access in Haskell syntax is using labelled fields in datatype decleration but the later are strictly compile-time. Therefore, if I compile my program and add a field in the configuration file (written in Haskell, using, for instance hs-plugins), I'll need to recompile the data declaration as well. Further, what is the type of the parser? Consider the following implementation: source = #123456789012345678901234567890123456789012345678901234567890\n\ \SVCLFOWLER 10101MS0120050313.\n\ \SVCLHOHPE 10201DX0320050315\n\ \SVCLTWO x10301MRP220050329..\n\ \USGE10301TWO x50214..7050329... data Configuration = Config String [(String, Int, Int)] config = [ Config SVCL [(CustomerName, 4, 18), (CustomerID, 19, 23), (CallTypeCode, 24, 27), (DateOfCallString, 28, 35)], Config USGE [(CustomerID, 4, 8), (CustomerName, 9, 22), (Cycle, 30, 30), (ReadDAte, 31, 36)]] -- parse takes the configuration, a line from the source string and generate a record parse :: Configuration - String - Record What is the type of Record? Anyway, any elegant solution or a hint towards one are most welcome. Thanks, Yoel ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] RE: [Haskell] ANNOUNCE: ghc-src version 0.2.0
On 30 August 2005 12:05, Arthur Baars wrote: Daan is right, I wrote a parser for GHC using Doaitse Swierstra's parsing combinator library (http://www.cs.uu.nl/groups/ST/Software/UU_Parsing/index.html). I needed a drop-in replacement for GHC's Happy parser, to make a prototype for syntax macros. Syntax Macros allow a programmer to extend a language with new syntax. Combinator based parsers parsers can be dynamically extended, making them suitable for implementing syntax macros. Unfortunately, I never had time to really finish the syntax macro implementation. But I did finish the combinator based parser for GHC. I tested it by having GHC( with combinator parser) compile itself and all the libraries. This took about 10% longer than with the original GHC, so in practice its speed is acceptable. With all due respect, a 10% increase in compile time isn't acceptable at all! And when you consider that parsing is less than 10% of compile time overall (probably much less), a 10% increase represents at least a factor of 2 in the parser. I'm not criticising the work at all - far from it, just the notion that we would consider adding 10% to GHC's compile times acceptable. I've recently been struggling to shave a few percent off GHC's compile times, BTW :-) Cheers, Simon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] RE: [Haskell] mailing list headaches
On 08 September 2005 17:53, Glynn Clements wrote: Frederik Eaton wrote: However, threading by References, which RFC 2822 says SHOULD be possible, and which works on my other folders, doesn't work well on Haskell mailing lists. Presumably the issue is that there are a large number of Windows users with strange mail clients which don't insert References headers. It isn't so much that there are a large number of such users, but that two of the core developers are among them (and are both employed by Microsoft, so RFC-conformance probably isn't an option). Yes, this is partially our fault. When using Outlook through Exchange, the In-Reply-To header isn't generated at all. Outlook via SMTP works fine, though. I reported the bug several years ago, let's see if Office 12 fixes it :) Cheers, Simon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Functional vs Imperative
Hello, I'm quite interested in haskell, but there is something I don't understand(intuitively). I've been crawling the web for an answer, but nothing talks to me... So I was hoping I could find some help here: How is evaluating an _expression_ different from performing action? I'm puzzled... Doesn't it amount to the same thing? Maybe I have a wrong definition of evaluating(determine the value of an _expression_)? Examples would be appreciated. Also, just for kicks, may I had this: I read the code of some haskell-made programs and was astonished. Yes! It was clean and all, but there were dos everywhere... Why use a function language if you use it as an imperative one?(i.e. most of the apps in http://haskell.org/practice.html) Thanks in advance, ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Functional vs Imperative
On 13 Sep 2005, at 14:45, Dhaemon wrote:
Hello,
I'm quite interested in haskell, but there is something I don't
understand(intuitively). I've been crawling the web for an answer,
but nothing talks to me...
So I was hoping I could find some help here:
How is evaluating an expression different from performing action?
I'm puzzled... Doesn't it amount to the same thing? Maybe I have a
wrong definition of evaluating(determine the value of an
expression)?
Examples would be appreciated.
Also, just for kicks, may I had this: I read the code of some
haskell-made programs and was astonished. Yes! It was clean and
all, but there were dos everywhere... Why use a function language
if you use it as an imperative one?(i.e. most of the apps in http://
haskell.org/practice.html)
The difference is all about referential transparency -- in short, a
function given the same inputs will always give the same result.
This is not the same as in imperative languages, where functions/
methods/actions can have 'side-effects' that change the behavior of
the rest of the program.
Take this example:
C program:
#define square(x) ((x) * (x))
#define inc(x) ((x)++)
int myFunc (int *x)
{
return square(inc(*x));
}
the C preprocessor will re-write the return line to:
return x)++)) * (((x)++)));
this will be performed in sequence, so, x will be incremented
(changing the value of x), and that result will be multiplied by x
incremented again.
so if we run myFunc(y), where y is 5, what we get is 5 incremented
to 6, and them multiplied by 6 incremented to 7. So the result of
the function is 42 (when you might reasonably expect 36), and y is
incremented by 2, when you might reasonably expect it to be
incremented by 1.
Haskell program:
square x = x * x
inc = (+1)
myFunc = square . inc
and we now call myFunc 5, we get this evaluation:
myFunc 5 is reduced to (square . inc) 5
(square . inc) 5 is reduced to square (inc 5)
square (inc 5) is reduced to square ((+1) 5)
square ((+1) 5) is reduced to square 6
square 6 is reduced to 6 * 6
6 * 6 is reduced to 36
If you want to study these reductions on a few more examples, you
might want to download the Hat tracer, and use hat-anim to display
reductions step by step.
Bob
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[Haskell-cafe] Binary parser combinators and pretty printing
Hello I am trying to figure out the best interface to binary parser and pretty printing combinators for network protocols. I am trying to find the most natural syntax to express these parsers in Haskell and would like opinions and new ideas. As an example I will use a protocol with the following packet structure: 0 message-id 4 sender-id 8 receiver-id 12 number of parameters 16 parameters. Each parameter is prefixed by 32bit length followed by the data. We will use the following Haskell datatype: data Packet = Packet Word32 Word32 Word32 [FastString] 1) Simple monadic interface getPacket = do mid - getWord32BE sid - getWord32BE rid - getWord32BE nmsg- getWord32BE vars- replicateM (fromIntegral nmsg) (getWord32BE = getBytes) return $ Packet mid sid rid nmsg vars putPacket (Packet mid sid rid vars) = do mapM_ putWord32BE [mid, sid, rid, length vars] mapM_ (\fs - putWord32BE (length fs) putBytes fs) vars This works but writing the code gets tedious and dull. 2) Using better combinators packet = w32be w32be w32be lengthPrefixList w32be (lengthPrefixList w32be bytes) getPacket = let (mid,sid,rid,vars) = getter packet in Packet mid sid rid vars putPacket (Packet mid sid rid vars) = setter packet mid sid rid vars Maybe even the tuple could be eliminated by using a little of TH. Has anyone used combinators like this before and how did it work? 3) Using TH entirely $(getAndPut 'Packet w32 w32 w32 lengthPrefixList (w32 bytes)) Is this better than the combinators in 2)? Also what sort of syntax would be best for expressing nontrivial dependencies - e.g. a checksum calculated from other fields. 4) Using a syntax extension Erlang does this with the bit syntax (http://erlang.se/doc/doc-5.4.8/doc/programming_examples/bit_syntax.html) and it is very nifty for some purposes. getPacket = do mid:32, sid:32, rid:32, len:32 rest:len/binary ... The list of lists gets nontrivial here too... - Einar Karttunen ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Functional vs Imperative
Small point,
From: Thomas Davie [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
CC: Haskell-Cafe@haskell.org
Subject: Re: [Haskell-cafe] Functional vs Imperative
Date: Tue, 13 Sep 2005 14:55:14 +0100
On 13 Sep 2005, at 14:45, Dhaemon wrote:
Hello,
I'm quite interested in haskell, but there is something I don't
understand(intuitively). I've been crawling the web for an answer, but
nothing talks to me...
So I was hoping I could find some help here:
How is evaluating an expression different from performing action?
I'm puzzled... Doesn't it amount to the same thing? Maybe I have a wrong
definition of evaluating(determine the value of an expression)?
Examples would be appreciated.
Also, just for kicks, may I had this: I read the code of some
haskell-made programs and was astonished. Yes! It was clean and all, but
there were dos everywhere... Why use a function language if you use it
as an imperative one?(i.e. most of the apps in http://
haskell.org/practice.html)
The difference is all about referential transparency -- in short, a
function given the same inputs will always give the same result. This is
not the same as in imperative languages, where functions/ methods/actions
can have 'side-effects' that change the behavior of the rest of the
program.
Take this example:
C program:
#define square(x) ((x) * (x))
#define inc(x) ((x)++)
int myFunc (int *x)
{
return square(inc(*x));
}
the C preprocessor will re-write the return line to:
return x)++)) * (((x)++)));
Shouldn't that be:
return *x)++)) * (((*x)++)));
this will be performed in sequence, so, x will be incremented (changing
the value of x), and that result will be multiplied by x incremented
again.
so if we run myFunc(y), where y is 5, what we get is 5 incremented to 6,
and them multiplied by 6 incremented to 7. So the result of the function
is 42 (when you might reasonably expect 36), and y is incremented by 2,
when you might reasonably expect it to be incremented by 1.
Haskell program:
square x = x * x
inc = (+1)
myFunc = square . inc
and we now call myFunc 5, we get this evaluation:
myFunc 5 is reduced to (square . inc) 5
(square . inc) 5 is reduced to square (inc 5)
square (inc 5) is reduced to square ((+1) 5)
square ((+1) 5) is reduced to square 6
square 6 is reduced to 6 * 6
6 * 6 is reduced to 36
If you want to study these reductions on a few more examples, you might
want to download the Hat tracer, and use hat-anim to display reductions
step by step.
Bob
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Re: [Haskell-cafe] Functional vs Imperative
On Tue, Sep 13, 2005 at 01:45:52PM +, Dhaemon wrote: Also, just for kicks, may I had this: I read the code of some haskell-made programs and was astonished. Yes! It was clean and all, but there were dos everywhere... Why use a function language if you use it as an imperative one?(i.e. most of the apps in http://haskell.org/practice.html) Monadic code isn't synonymous with imperative code, and do only indicates that you're looking at monadic code. The Maybe monad is an example of a very useful, very non-imperative monad that can be used to cleanly write functional code. On the other hand, IO is always monadic, so perhaps you're looking at IO code. But I'd assert that even monadic IO code isn't quite the same as true imperative code. I'd probably say that the difference has to do with whether you create modifiable variables. When you start doing that, whether you're in the ST monad or the IO monad, I think you're writing imperative-style code. But I think that that sort of usage is actually pretty uncommon. -- David Roundy ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Binary parser combinators and pretty printing
Einar Karttunen ekarttun@cs.helsinki.fi writes: I am trying to figure out the best interface to binary parser and pretty printing combinators for network protocols. 2) Using better combinators packet = w32be w32be w32be lengthPrefixList w32be (lengthPrefixList w32be bytes) Has anyone used combinators like this before and how did it work? Yes, the nhc98 Binary library has a combinator, in very much the style you outline. It is only used in pure code, but it permits some very concise descriptions of the binary layout. The library is described here: ftp://ftp.cs.york.ac.uk/pub/malcolm/ismm98.html but unfortunately that paper has only the tiniest examples of the usage of . However, in my experience the style worked well and was pleasant to use. Regards, Malcolm ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
RE: [Haskell-cafe] Weak hashtable memoization code?
On 28 August 2005 16:39, Bulat Ziganshin wrote: Hello David, Sunday, August 28, 2005, 4:19:07 PM, you wrote: Hi all, Does anyone have a nice bit of example code to implement memoization using weak pointers and hash tables? It would be nice to have a pre-packaged module that I could just use, which has already been tested. The contents of Data.WeakPtr seem a bit lower-level than I'd rather work with. http://www.haskell.org/~simonmar/papers/weak.pdf There's the memo table implementation in the util package: hslibs/util/Memo.lhs. Note that this is scheduled for demolition in GHC 6.6. Cheers, Simon ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Functional vs Imperative
On 13 Sep 2005, at 16:22, David Roundy wrote: On Tue, Sep 13, 2005 at 01:45:52PM +, Dhaemon wrote: Also, just for kicks, may I had this: I read the code of some haskell-made programs and was astonished. Yes! It was clean and all, but there were dos everywhere... Why use a function language if you use it as an imperative one?(i.e. most of the apps in http://haskell.org/practice.html) Monadic code isn't synonymous with imperative code, and do only indicates that you're looking at monadic code. The Maybe monad is an example of a very useful, very non-imperative monad that can be used to cleanly write functional code. On the other hand, IO is always monadic, so perhaps you're looking at IO code. But I'd assert that even monadic IO code isn't quite the same as true imperative code. I'd probably say that the difference has to do with whether you create modifiable variables. When you start doing that, whether you're in the ST monad or the IO monad, I think you're writing imperative-style code. But I think that that sort of usage is actually pretty uncommon. I would tend to argue that even in those monads you aren't really writing imperative style code -- you still can't have side effects. The point of the monad is that it preserves referential transparency while doing something ordered. Bob ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
RE: [Haskell-cafe] Haskell poker server
On 28 August 2005 20:00, Joel Reymont wrote:
I get a message from Erlang once data arrives over TCP and the
message is a {tcp, Socket, Bin} tuple where Bin is binary data. I can
easily extract what I need using Erlang binary pattern matching:
read(24, GID:32, Seq:16) -
{24, GID, Seq}.
I didn't see anyone mention this (apologies if I missed it), but the
House project does parsing of network packets and has some useful
combinators for parsing binary data:
http://www.cse.ogi.edu/~hallgren/House/
Cheers,
Simon
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Re: [Haskell-cafe] Functional vs Imperative
Am Dienstag, 13. September 2005 15:45 schrieb Dhaemon: [...] Also, just for kicks, may I had this: I read the code of some haskell-made programs and was astonished. Yes! It was clean and all, but there were dos everywhere... Why use a function language if you use it as an imperative one?(i.e. most of the apps in http://haskell.org/practice.html) Note that do expressions are not expressions whose evaluation has side-effects. The evaluation of a do expression doesn't yield the result of the action it describes, causing side-effects, but it yields the action itself. Evaluation of this action is done seperately. Thanks in advance, Best wishes, Wolfgang ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Template Haskell and Types
Simon Peyton-Jones wrote: | putStrLn $(mysplice ''MyData) | | | Thanks for responses. Is there any up-to-date documentation avaliable? Template Haskell is, alas, poorly documented. I would really welcome someone to volunteer to help write better documentation. Meanwhile, as the user manual says, the stuff about quoting names is described in a design note http://research.microsoft.com/~simonpj/tmp/notes2.ps Thanks. With haddoc documentation it is quite easy to translate old names to new names and guess the meanning of others. Next quiestion is: how do I debug my macros? When I make some error in my program, I get coredump (or the windows equivalent)? -- Gracjan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Functional vs Imperative
On 9/13/05, Dhaemon [EMAIL PROTECTED] wrote: Hello, I'm quite interested in haskell, but there is something I don't understand(intuitively). I've been crawling the web for an answer, but nothing talks to me... So I was hoping I could find some help here: How is evaluating an expression different from performing action? I'm puzzled... Doesn't it amount to the same thing? Maybe I have a wrong definition of evaluating(determine the value of an expression)? Examples would be appreciated. Also, just for kicks, may I had this: I read the code of some haskell-made programs and was astonished. Yes! It was clean and all, but there were dos everywhere... Why use a function language if you use it as an imperative one?(i.e. most of the apps in http://haskell.org/practice.html) Well, most of the code is still functional in nature, only some of it is imperative. And even if you're writing a very IO heavy program writing IO in Haskell is still much nicer than in traditional imperative languages since all actions are first class citizens etc. It's better to have a nice clean way of doing IO that's completely separated away from pure code than to have everything be done in a less clean imperative style always. In Haskell you have it both ways. When a functional approach is cleaner, use it, when stuff should be evaluated in sequence (not just IO, but other monads like Maybe and State as well) you do that. It all works out in a sane and clean way. /S -- Sebastian Sylvan +46(0)736-818655 UIN: 44640862 ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Functional vs Imperative
On 13/09/05, Dhaemon [EMAIL PROTECTED] wrote: Hello, I'm quite interested in haskell, but there is something I don't understand(intuitively). I've been crawling the web for an answer, but nothing talks to me... So I was hoping I could find some help here: How is evaluating an expression different from performing action? I'm puzzled... Doesn't it amount to the same thing? Maybe I have a wrong definition of evaluating(determine the value of an expression)? Examples would be appreciated. Also, just for kicks, may I had this: I read the code of some haskell-made programs and was astonished. Yes! It was clean and all, but there were dos everywhere... Why use a function language if you use it as an imperative one?(i.e. most of the apps in http://haskell.org/practice.html) Thanks in advance It should be made clear that the only IO action which is ever actually performed in a Haskell program is main (short of loading the code up in an interactive environment and getting it to run other actions separately). IO actions themselves are described in a pure functional, referentially transparent way. Evaluation of an expression is different from performing an IO action in the various things which can occur as a result. Essentially the only thing which should be able to occur (without some major cheating) as the result of evaluating a Haskell expression, is the production of a value, and this value will always be the same for a given expression. It should not print things to the screen, fire packets over the network, read from the random number generator or read or write to files. (There are instances where IO is lazily delayed until a result is demanded, so that evaluation of what looks like a pure list results in reading from a file, but one can only construct these situations so that they occur inside the execution of an IO action anyway. The lists aren't really pure.) The upshot of this is that if one has a Haskell expression, within time and memory constraints, one can evaluate it on any computer, under any ordinary circumstances, and get the same result. One can't make that claim about performing an IO action. IO actions when performed may read from the keyboard or network or filesystem (as well as write to the screen, etc.). However, evaluation of an expression which represents an IO action always yields the same action (even if that action may not do the same thing when it is actually performed in the end). That's the distinction that's being made. As it has been pointed out in other posts, do notation is pure, in the sense that do blocks are expressions which evaluate to the same thing every time. This thing may be an IO action, but it may also be a list, a Maybe value, a binary tree, a function of type s - (a, s) (called a state computation), a graph, or any number of other monadic types. Most monads m are not one-way in that one can extract results from the monadic containers - there usually exist functions (m a - a) -- IO is a major example of a case where this doesn't hold, but it's by far not the only example of a monad. - Cale ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Functional vs Imperative
On 13/09/05, Dhaemon [EMAIL PROTECTED] wrote: Hello, I'm quite interested in haskell, but there is something I don't understand(intuitively). I've been crawling the web for an answer, but nothing talks to me... So I was hoping I could find some help here: How is evaluating an expression different from performing action? I'm puzzled... Doesn't it amount to the same thing? Maybe I have a wrong definition of evaluating(determine the value of an expression)? Examples would be appreciated. Also, just for kicks, may I had this: I read the code of some haskell-made programs and was astonished. Yes! It was clean and all, but there were dos everywhere... Why use a function language if you use it as an imperative one?(i.e. most of the apps in http://haskell.org/practice.html) Thanks in advance It should be made clear that the only IO action which is ever actually performed in a Haskell program is main (short of loading the code up in an interactive environment and getting it to run other actions separately). IO actions themselves are described in a pure functional, referentially transparent way. Evaluation of an expression is different from performing an IO action in the various things which can occur as a result. Essentially the only thing which should be able to occur (without some major cheating) as the result of evaluating a Haskell expression, is the production of a value, and this value will always be the same for a given expression. It should not print things to the screen, fire packets over the network, read from the random number generator or read or write to files. (There are instances where IO is lazily delayed until a result is demanded, so that evaluation of what looks like a pure list results in reading from a file, but one can only construct these situations so that they occur inside the execution of an IO action anyway. The lists aren't really pure.) The upshot of this is that if one has a Haskell expression, within time and memory constraints, one can evaluate it on any computer, under any ordinary circumstances, and get the same result. One can't make that claim about performing an IO action. IO actions when performed may read from the keyboard or network or filesystem (as well as write to the screen, etc.). However, evaluation of an expression which represents an IO action always yields the same action (even if that action may not do the same thing when it is actually performed in the end). That's the distinction that's being made. As it has been pointed out in other posts, do notation is pure, in the sense that do blocks are expressions which evaluate to the same thing every time. This thing may be an IO action, but it may also be a list, a Maybe value, a binary tree, a function of type s - (a, s) (called a state computation), a graph, or any number of other monadic types. Most monads m are not one-way in that one can extract results from the monadic containers - there usually exist functions (m a - a) -- IO is a major example of a case where this doesn't hold, but it's by far not the only example of a monad. - Cale ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] some algorithm help with jhc
I have started working on jhc more recently and have come across some places where I think my algorithms could be improved but was not sure exactly where to start so thought I would ask the list since perhaps someone here has some insight. After a long time of trying various methods of speeding up the fixpoint iteration of my points-to analysis (the current main bottleneck) I decided to step back and look at the basic problem again. It turns out I can express the problem as one of constraint satisfaction resulting in much smaller code (600 lines vs 2000) and 10fold speedups with my unoptimized first draft solver. It is much faster but still not as fast as I'd like. I don't know a lot about constraint problems, but my intuiton says this particular problem is of a type that should be particularly easy to solve but am uncertain where to start in my searching to find a fast algorithm. My constraints come in two types of rules. the rules are of the form (where a and b are variables to be solved for and x and y are values in my domain) * a = f(b) where x = y implies f(x) = f(y) * enforce g(a) as a new set of rules where if x = y then g(x) subsumes g(y) f and g are typed thusly. f :: domain - domain g :: domain - set of rules the following useful derived rules can be expressed by the above. a = b a == b if z(a) then b = c now, the reason my intuiton says there should be a fast solution is that there is no way for the variables to decrease. every added rule can only add to the least solution and not shrink any set. so, my basic question is, is this a known form of constraint satisfaction problem? does it admit a particulary fast solution as my intuition tells me? does it have a name I can search for on scholar.google.com? my current first draft implementation represents each rule as an IO action taking a difference set that propegates said difference set and then adds it to the current set for each var. The second problem I am facing is one of debugging. my code dealing with jhc core and all the optimizations that are performed on it has gone through a lot of evolution. over time, bugs have been introduced that are very hard to track down, the symptom would be suddenly having core that doesn't typecheck or has an unknown identifier or worse a segfault in the generated program. backtracking to find the error is quite tedious, mainly involving commenting out transformations until I find the offending one, then rederiving the correct code and comparing it to what I have written. I have decided to remedy the situation and start using QuickCheck to verify all my transformations are meaning and type preserving. however, the problem arrises in how to come up with a meaningful instance of Arbitrary for expressions in jhc core. It is not clear at all how to come up with code that generates random yet interesting, well typed, convergent, terms in the extended lambda calculus with things like recursive definitons and primitives. even if I solved that, the problem of deciding whether two expressions (which might be functions) do the 'same thing' is undecidable, so how do I even test if the transformations are meaning preserving? Ideally, someone would have written a paper on this. I have seen several papers on generating suitable random graphs for testing graph algorithms, but have not come across one on creating typed lambda calculus terms. perhaps someone else has come across this same problem and has some insights? I am interested in ideas, brainstorming and pointers to papers or terms to search for as much as ready made solutions. In any case, I think they are interesting problems to begin with... hopefully someone out there thinks so too :) John -- John Meacham - ⑆repetae.net⑆john⑈ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Functional vs Imperative
I apologise for the duplicate messages -- GMail was having issues, and told me that the message couldn't be sent the first time I'd attempted it. - Cale ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
