- Hugs-Bugs - Haskell.org

recip bug?!
by Robert Reitmeier 24 Nov '03

24 Nov '03

HUGS says: > Main> :version > -- Hugs Version December 2001 > Main> (-1)%1 > -1 % 1 > Main> recip ((-1)%1) > 1 % -1 > Main> (recip ((-1)%1))+(1%1) > 0 % -1 > Main> ((recip ((-1)%1))+(1%1))==0 > False It's the same with HUGS Version November 2002, which is the newest I know of. Counterexample in GHCI: > ghci 5.04: > > *Main> (-1)%1 > -1 % 1 > *Main> recip ((-1)%1) > -1 % 1 > *Main> (recip ((-1)%1))+(1%1) > 0 % 1 > *Main> ((recip ((-1)%1))+(1%1))==0 > True Kind regards, Robert

2 1

No downloads work on your website!
by Nigel Banner 21 Nov '03

21 Nov '03

None of the downlads work on your website: http://cvs.haskell.org/Hugs/pages/downloading.htm: Files not found! Please check!

1 0

Patch to build Hugs Nov2002 release on Mac OS X 10.3 (Panther)
by Gregory Wright 07 Nov '03

07 Nov '03

Hi, Attached is a patch to build the last release of Hugs on Mac OS X 10.3 (Panther). The patch is required by a change to gcc (gcc-3.3 is now the default compiler). The patch fixes the behavior of the new preprocessor, which prefixes #pragma GCC set_debug_pwd <directory in which the file is found> to every file. Needless to say, if the output of the C preprocessor is used by a program other than gcc, problems occur. The convert_libraries script calls cpp. The patch filters the output through sed: sed -n '/^#pragma/!p' This should work on Apple's gcc-3.3 without affecting builds on other compilers. The patch applies in the top level hugs directory. Best Wishes, Greg Wright Gregory Wright Antiope Associates LLC gwright(a)antiope.com

1 0

Fwd: when is defaulting supposed to occur?
by Mark Tullsen 31 Oct '03

31 Oct '03

So, it looks like it is hugs which is not following the report (section 4.5.5 (rule 2) as Iavor noted), which seems to indicate that defaulting only occurs after an entire module is type-checked. - Mark Begin forwarded message: > From: "Iavor S. Diatchki" <diatchki(a)cse.ogi.edu> > Date: Thu Oct 23, 2003 3:07:45 PM US/Pacific > To: Mark Tullsen <tullsen(a)galois.com> > Cc: haskell(a)haskell.org > Subject: Re: when is defaulting supposed to occur? > > hello, > the problem has to do with the monomorphism restriction > see section 4.5.5 (rule 2) (or typing hashell in haskell section > 11.5.1 for details). > bye > iavor > > > Mark Tullsen wrote: > >> Note the following program >> x = 1 >> y = x :: Int >> >> This is accepted by ghc but it is rejected hugs (May 2003 cvs): >> ERROR "IntegerTest.hs":4 - Type error in type annotation >> *** Term : x >> *** Type : Integer >> *** Does not match : Int >> >> My guess is that hugs is doing defaulting after a "declaration group" >> is type-checked, but that ghci leaves 'x' with type 'Num a', then >> processes further declaration groups, and then does defaulting. >> >> I don't see that the report specifies this (did I miss it?). >> >> - Mark >> >> >> _______________________________________________ >> Haskell mailing list >> Haskell(a)haskell.org >> http://www.haskell.org/mailman/listinfo/haskell > > > > -- > ================================================== > | Iavor S. Diatchki, Ph.D. student | | Department of > Computer Science and Engineering | > | School of OGI at OHSU | > | http://www.cse.ogi.edu/~diatchki | > ================================================== >

2 1

type checking LazyST
by Iavor S. Diatchki 30 Oct '03

30 Oct '03

hello, hugs seems to have trouble type checking the following program. it seems to work if i import ST rather than LazyST. it also works with ghci. > module Test where > import LazyST > f :: ST RealWorld (STRef RealWorld ()) > f = newSTRef () the error i get is: ERROR "test.lhs":9 - Type error in explicitly typed binding *** Term : f *** Type : ST a (STRef a ()) *** Does not match : ST RealWorld (STRef RealWorld ()) bye iavor -- ================================================== | Iavor S. Diatchki, Ph.D. student | | Department of Computer Science and Engineering | | School of OGI at OHSU | | http://www.cse.ogi.edu/~diatchki | ==================================================

2 1

INTERNAL ERROR: parseInput
by Henk-Jan.van.Tuyl 26 Oct '03

26 Oct '03

L.S., The attached program leads to the message: INTERNAL ERROR: parseInput at load time. I am running Hugs Version Nov 2002 on a Windows 98 system. Best regards, Henk-Jan van Tuyl --

2 1

Re: Calling an external command from a Haskell program
by C.Reinke 21 Oct '03

21 Oct '03

> The function system works fine in Hugs except on windows where DOS limitations > cause the function to always return ExitSuccess. (ghc suffers from the same > problem on Windows.) Actually, that is not quite correct: ghc seems to suffer from this problem only on older Windows versions (such as Windows 98), whereas Hugs seems to have the bug also on newer Windows versions (such as XP), at least in its current binary release.. I reported the ghc/win98 problem earlier, below is what happens on Windows XP. So the bug seems even worse in Hugs than in GHC? Claus PS. why the differences in default access to standard modules? should GHC be more restrictive there? --------------------------------------------------- ___ ___ _ / _ \ /\ /\/ __(_) / /_\// /_/ / / | | GHC Interactive, version 6.0.1, for Haskell 98. / /_\\/ __ / /___| | http://www.haskell.org/ghc/ \____/\/ /_/\____/|_| Type :? for help. Loading package base ... linking ... done. Prelude> System.system "fail" >>= print 'fail' is not recognized as an internal or external command, operable program or batch file. ExitFailure 1 Prelude> --------------------------------------------------- || || || || || || ||__ Hugs 98: Based on the Haskell 98 standard ||___|| ||__|| ||__|| __|| Copyright (c) 1994-2002 ||---|| ___|| World Wide Web: http://haskell.org/hugs || || Report bugs to: hugs-bugs(a)haskell.org || || Version: Nov 2002 _________________________________________ Haskell 98 mode: Restart with command line option -98 to enable extensions Reading file "C:\Program Files\Hugs98\lib\Prelude.hs": Hugs session for: C:\Program Files\Hugs98\lib\Prelude.hs Type :? for help Prelude> :a System Reading file "C:\Program Files\Hugs98\lib\System.hs": Hugs session for: C:\Program Files\Hugs98\lib\Prelude.hs C:\Program Files\Hugs98\lib\System.hs System> system "fail" >>= print 'fail' is not recognized as an internal or external command, operable program or batch file. ExitSuccess

3 2

None
by Doug McIlroy 16 Oct '03

16 Oct '03

In Hugs 1.4, ++ was an operator of class Monad; in Hugs 98 it is an operator on lists. I've looked in the Hugs documentation and haven't found anything about the change (probably a failing of mine, not the documentation). Anyway, that breaks some code in an article that's been accepted for JFP, wherein I overloaded ++ by placing the operand type in class Monad. This doesn't work any more. I don't want to publish code that doesn't work, and I don't want to give up that overloading, which is completely natural. Can you shed any light on what happened between the two versions? Or offer an idea about how to rescue the overloading? Many thanks, Doug McIlroy

4 3

Type error for function main
by Josef Svenningsson 16 Oct '03

16 Oct '03

Hi! I was just trying to write the smallest valid Haskell program. One try was the following: > main = return 0 But I get the following error message: ERROR "foo.hs":1 - Unresolved top-level overloading *** Binding : main *** Outstanding context : Monad c Why do I get this? According to the Haskell report a module where one doesn't specify the name should implicitly be called Main. And a Main module have a function main of type IO t for some t. So Hugs should be able to figure out that the monad should be IO in this case, at least according the Haskell report. Cheers, /Josef

2 2

crash at infinite recursion
by Felix Hummel 14 Oct '03

14 Oct '03

Hugs98 Version: Nov 2002 crashes when evaluating the following line let x = x+1 in x Of course this line is quite stupid, but none the less the interpreter should not crash... Cheers, Felix "Bumblebee" Hummel

2 1