June 2002 - Nhc-bugs - Haskell.org

More on integer division
by Dylan Thurston 29 Jun '02

29 Jun '02

On Fri, Jun 28, 2002 at 03:54:50PM -0400, Dylan Thurston wrote: > On Fri, Jun 28, 2002 at 10:24:13AM +0100, Malcolm Wallace wrote: > > Yes, -5`div`2 == -(5`div`2) == -2 > > but (-5)`div`2 == -3 > > > > Ghc 5.02.2 has the infix priority wrong, and interprets the former as the latter. > > But more bizarrely, ghc 5.02.2 gets this very wrong: > > > > Prelude> (-1796254192) `div` 357566600 > > 5 > > Thanks for the clear summary. After a looking a little more, there seem to be other problems (including errors in my proposed solution). I don't know where the code for quotRem is, but it is also buggy. For instance, Prelude> 9 `quotRem` (-5) (-1,4) (The correct answer is (-1,-4).) I'm frankly astonished: has noone used these functions with negative arguments before? This happens with both ghci and compiled programs, both -fvia-C and -fasm. Hugs (see below) and nhc make the same error in this case. There seems to be too strong a reliance on C's operators '/' and '%', which give these results (with gcc on x86). This may be a bug in gcc. I'm using gcc 2.95.4; I'm not sure which version compiled the Debian packages I'm using. According to http://home.tiscalinet.ch/t_wolf/tw/c/c9x_changes.html#Semantics, the C9x standard specifies that division should truncate towards 0; I believe that earlier it was undefined. I'm shocked that non of the three Haskell implementations had a test suite that caught this problem. ----- __ __ __ __ ____ ___ _________________________________________ || || || || || || ||__ Hugs 98: Based on the Haskell 98 standard ||___|| ||__|| ||__|| __|| Copyright (c) 1994-2001 ||---|| ___|| World Wide Web: http://haskell.org/hugs || || Report bugs to: hugs-bugs(a)haskell.org || || Version: February 2001 _________________________________________ Haskell 98 mode: Restart with command line option -98 to enable extensions Reading file "/usr/share/hugs98/lib/Prelude.hs": Hugs session for: /usr/share/hugs98/lib/Prelude.hs Type :? for help Prelude> 9 `quotRem` (-5) (-1,4) -----

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Re: [nhc-bugs] Unzipping Problems
by D.J.Steinitz 27 Jun '02

27 Jun '02

Malcolm, Simple incompetence! Many thanks, Dominic.

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Unzipping Problems
by D.J.Steinitz 27 Jun '02

27 Jun '02

I'm getting errors when I try to unzip nhc 1.14. Is there really something wrong or am I just being incompetent? Dominic. djs25@compsci-lt2:~$ tar -xzvf nhc98-1.14-ix86-Linux.tar.gz nhc98-1.14/ nhc98-1.14/Makefile.inc nhc98-1.14/Makefile nhc98-1.14/README nhc98-1.14/INSTALL nhc98-1.14/COPYRIGHT nhc98-1.14/configure nhc98-1.14/lib/ nhc98-1.14/lib/ix86-Linux/ nhc98-1.14/lib/ix86-Linux/config nhc98-1.14/lib/ix86-Linux/hmake-PRAGMA tar: Skipping to next header tar: Archive contains obsolescent base-64 headers gzip: stdin: invalid compressed data--format violated tar: Child returned status 1 tar: Error exit delayed from previous errors djs25@compsci-lt2:~$ djs25@compsci-lt2:~$ tar -xzvf nhc98src-1.14.tar.gz nhc98-1.14/ nhc98-1.14/Makefile.inc nhc98-1.14/Makefile nhc98-1.14/README nhc98-1.14/INSTALL nhc98-1.14/COPYRIGHT nhc98-1.14/configure nhc98-1.14/src/ nhc98-1.14/src/compiler98/ nhc98-1.14/src/compiler98/Makefile nhc98-1.14/src/compiler98/Makefile.hat nhc98-1.14/src/compiler98/Makefile.inc nhc98-1.14/src/compiler98/AssocTree.hs nhc98-1.14/src/compiler98/AuxFile.hs nhc98-1.14/src/compiler98/AuxFixity.hs nhc98-1.14/src/compiler98/AuxLabelAST.hs tar: Skipping to next header tar: Archive contains obsolescent base-64 headers gzip: stdin: invalid compressed data--format violated tar: Child returned status 1 tar: Error exit delayed from previous errors djs25@compsci-lt2:~$

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Mystery error while compiling for tracing
by Anthony Travers 11 Jun '02

11 Jun '02

Has anyone ever seen a error message like the following while compiling with tracing activated? Fail: Can't find int for (Prelude.49,Constructor) The target module and its imports don't define a type or data constructor called Constructor - any ideas? (They all compile without any problems with tracing turned off.) I'm using nhc98 1.10-1 from the RH 7.2 package. Thanks in advance, Anthony Travers (amt-public(a)dodo.com.au)

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