- Hugs-Bugs - Haskell.org

Line Break Handling Request
by Ashley Yakeley 19 Feb '01

19 Feb '01

Currently I'm using the MacOS version of Hugs. The Macintosh platform is undergoing a sort of evolution towards Unix, and text files may either have traditional MacOS linebreaks (CR) or Unix linebreaks (LF). MacOS Hugs only works with the former. I think all platform-versions of Hugs should accept all kinds of linebreaks: CR (as MacOS) LF (as Unix) CR LF (as Windows) ...as line breaks. If you ever get around to supporting Unicode, you should also handle \u2028 and \u2029, but that is a separate issue. -- Ashley Yakeley, Seattle WA

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Re: Purity of the stack execution model? (fwd)
by Koen Claessen 17 Feb '01

17 Feb '01

Hi! Somebody posted the following message on comp.lang.functional. It reports an error when having a main function which has type "IO [()]", together with using runhugs. This is a bug; the Haskell report says that main "must be a computation of type IO t for some type t". /Koen. ---------- Forwarded message ---------- Date: Wed, 14 Feb 2001 23:23:50 +0100 From: Tore Lund <tl001(a)online.no> Newsgroups: comp.lang.functional Subject: Re: Purity of the stack execution model? Markus Mottl wrote: > > actions = [putStr "foo", putStr "bar"] > nl = putStr "\n" > main = sequence actions >> nl >> mapM (>> nl) (reverse actions) Maybe some kindly soul could tell me what is the type of main here. Running the right-hand clause within a "do" construct works fine. However, if I try the following: module Main where actions = [putStr "foo", putStr "bar"] nl = putStr "\n" main = sequence actions >> nl >> mapM (>> nl) (reverse actions) I get this message from runhugs: Program error: fromDyn failed. Expecting <<IO() >> found <<IO[ Program error: {instShow_v1536_v1601 [instTypeable_v1537 (head (unsafePerformIO main))]}runhugs: Error occurred Trying to equip main with various IO types just leads to more errors. What am I missing please? * Moreover, this is admittedly a powerful example of what can be done with Haskell and monads. Is it possible to write such a program with comparable ease in, say, SML or OCaml? -- Tore

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Let in do-expressions
by Martin Erwig 16 Feb '01

16 Feb '01

Hi there, I am trying to use the "let"-notation within do-expressions, and it seems to me that it does not work correctly. (I am using Hugs, version February 2000, on Solaris.) E.g., do {x <- [1..9]; let i=1 in do {return ((+i) x)}} works as expected, but with do {x <- [1..9]; let i=1; return ((+i) x)} I get: ERROR: Syntax error in definition (unexpected symbol "i") According to the Report (Section 3.14) the latter expression should be a valid abbreviation of the former, or am I missing something here? If it is a bug, has it been corrected in the new version of Hugs? Thanks, Martin

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hugs98 Februar 2001 release and graphics
by Friedrich Dominicus 16 Feb '01

16 Feb '01

Sorry, I do not know whom to ask. But the new version Hugs as of Feb 2001 does not work with graphics any longer. It seems that IOResult has changed significantly and so this code here does not work any longer safeTry :: IO a -> IO (Either IOError a) -- safeTry m = m >>= return . Right safeTry (IO m) = IO $ \ f s -> case catchError (m Hugs_Error Hugs_Return) of Just (Hugs_Return a) -> s (Right a) r -> s (Left (mkErr r)) where mkErr :: Maybe IOResult -> IOError -- mkErr (Just Hugs_SuspendThread) = userError "suspended inside protected code" mkErr (Just (Hugs_ExitWith e)) = userError "exited inside protected code" mkErr (Just (Hugs_Error e)) = e mkErr Nothing = userError "pattern match failure inside protected code" It would be nice if someone could point out what to do, to make those examples run again. I tried to learn Haskell with the SOE book and I'm quite helpless if that does not work any longer. Regards Friedrich

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Hugs98 Feb.2001
by Phiho Hoang 16 Feb '01

16 Feb '01

Environment ; Win2K Advanced Server SP1 on PII 233 MHz. Is the output of 'Calendar' correct ? __ __ __ __ ____ ___ _______________________________________________ || || || || || || ||__ 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 "F:\hugs98\lib\Prelude.hs": Hugs session for: F:\hugs98\lib\Prelude.hs Type :? for help Prelude> Prelude> :l "F:\\hugs98\\demos\\Calendar.hs" Reading file "F:\hugs98\demos\Calendar.hs": Reading file "F:\hugs98\demos\Gofer.hs": Reading file "F:\hugs98\lib\List.hs": Reading file "F:\hugs98\lib\Maybe.hs": Reading file "F:\hugs98\lib\List.hs": Reading file "F:\hugs98\lib\IO.hs": Reading file "F:\hugs98\lib\Ix.hs": Reading file "F:\hugs98\lib\IO.hs": Reading file "F:\hugs98\lib\System.hs": Reading file "F:\hugs98\demos\Calendar.hs": Hugs session for: F:\hugs98\lib\Prelude.hs F:\hugs98\demos\Gofer.hs F:\hugs98\lib\Maybe.hs F:\hugs98\lib\List.hs F:\hugs98\lib\Ix.hs F:\hugs98\lib\IO.hs F:\hugs98\lib\System.hs F:\hugs98\demos\Calendar.hs Calendar> cal 2000 " 2000 \n \n January February March \n Su Mo Tu We Th Fr Sa Su M o Tu We Th Fr Sa Su Mo Tu We Th Fr Sa \n 1 1 2 3 4 5 1 2 3 4 \n 2 3 4 5 6 7 8 6 7 8 9 10 11 12 5 6 7 8 9 10 11 \n 9 10 11 12 13 14 15 13 14 15 16 17 18 19 12 13 14 15 16 17 18 \n 16 17 18 19 20 21 22 20 21 22 23 24 25 26 19 20 21 22 23 24 25 \ n 23 24 25 26 27 28 29 27 28 29 26 27 28 29 30 31 \n 30 31 \n \n April May June \n Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa \n 1 1 2 3 4 5 6 1 2 3 \n 2 3 4 5 6 7 8 7 8 9 10 11 12 13 4 5 6 7 8 9 10 \n 9 10 11 12 13 14 15 14 15 16 17 18 19 20 11 12 13 14 15 16 17 \ n 16 17 18 19 20 21 22 21 22 23 24 25 26 27 18 19 20 21 22 23 24 \n 23 24 2 5 26 27 28 29 28 29 30 31 25 26 27 28 29 30 \n 30 \n \n July August September \n Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa S u Mo Tu We Th Fr Sa \n 1 1 2 3 4 5 1 2 \n 2 3 4 5 6 7 8 6 7 8 9 10 11 12 3 4 5 6 7 8 9 \ n 9 10 11 12 13 14 15 13 14 15 16 17 18 19 10 11 12 13 14 15 16 \n 16 17 1 8 19 20 21 22 20 21 22 23 24 25 26 17 18 19 20 21 22 23 \n 23 24 25 26 27 28 29 27 28 29 30 31 24 25 26 27 28 29 30 \n 30 31 \n \n October November December \n Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa \n 1 2 3 4 5 6 7 1 2 3 4 1 2 \ n 8 9 10 11 12 13 14 5 6 7 8 9 10 11 3 4 5 6 7 8 9 \n 15 16 1 7 18 19 20 21 12 13 14 15 16 17 18 10 11 12 13 14 15 16 \n 22 23 24 25 26 27 28 19 20 21 22 23 24 25 17 18 19 20 21 22 23 \n 29 30 31 26 2 7 28 29 30 24 25 26 27 28 29 30 \n 31 \n \n" Calendar>

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Re: Feb 2001 MSI available
by Sigbjorn Finne 15 Feb '01

15 Feb '01

I've updated the installer a bit based on quick feedback from Pepe Gallardo: * moved user's manual so that WinHugs will find it. * Haskell source files have been converted over to use Win32 line terminators, i.e., CRLF. * The installer will now also create a folder on the start menu (Programs->Hugs98.) The URL is the same as the one below. --sigbjorn ----- Original Message ----- From: "Sigbjorn Finne" <sigbjorn_finne(a)hotmail.com> To: "Hugs Bugs" <hugs-bugs(a)haskell.org> Cc: <hugs-users(a)haskell.org> Sent: Thursday, February 15, 2001 11:09 Subject: Feb 2001 MSI available > Hi, > > I've packaged up a Windows Installer (.msi) for people that > want to easily set up and use Hugs98 February 2001 on a > Win32 platform. The MSI can be downloaded from > > http://www.dcs.gla.ac.uk/~sof/hugs98.msi (1.4M) > > It contains executables (hugs,runhugs and winhugs), libs > (std + win32), docs (html, hlp and pdf) and the demos. The > only thing that's (intentionally) missing is the Hugs98 source > code. > > In the unlikely event that your machine doesn't already have > the Windows Installer engine/runtime installed, runtime > redistributables can be downloaded from > > http://www.microsoft.com/msdownload/platformsdk/instmsi.htm > > --sigbjorn > > >

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Feb 2001 MSI available
by Sigbjorn Finne 15 Feb '01

15 Feb '01

Hi, I've packaged up a Windows Installer (.msi) for people that want to easily set up and use Hugs98 February 2001 on a Win32 platform. The MSI can be downloaded from http://www.dcs.gla.ac.uk/~sof/hugs98.msi (1.4M) It contains executables (hugs,runhugs and winhugs), libs (std + win32), docs (html, hlp and pdf) and the demos. The only thing that's (intentionally) missing is the Hugs98 source code. In the unlikely event that your machine doesn't already have the Windows Installer engine/runtime installed, runtime redistributables can be downloaded from http://www.microsoft.com/msdownload/platformsdk/instmsi.htm --sigbjorn

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ANNOUNCE: Hugs98 Feb 2001
by Johan Nordlander 15 Feb '01

15 Feb '01

====================================================================== __ __ __ __ ____ ___ || || || || || || ||__ ||___|| ||__|| ||__|| __|| ||---|| ___|| || || || || Version: Feb 2001 ====================================================================== Dear all, I'm pleased to announce the availability of a new release of Hugs98. This is a major release that incorporates bug fixes as well as several new features and enhancements that have been developed for Hugs over the last year. It is announced with the intentions that it will remain a stable and lightweight implementation of Haskell 98 + extensions for some considerable time. A list of the most important new features looks as follows: - A Foreign Function Interface closely modelled after the one provided by GHC. - Built-in, Hood-like debugging support. - Parallel list comprehensions, a.k.a. zip-comprehensions. - A new syntax for recursive monad bindings. - A new GUI under Windows that doesn't consume all CPU time. - Support for the MacOS platform integrated into the main distriution. - Corrections of all bugs reported for the January 2001 beta release. See the release notes in the "docs" directory of the distribution for more information on the new language features. Send email to hugs-users-request(a)haskell.org to join the hugs-users mailing list. Bug reports should be sent to hugs-bugs(a)haskell.org. Send email to hugs-bugs-request(a)haskell.org to subscribe to the hugs-bugs list. The home page and download site for Hugs is at http://www.haskell.org/hugs/ Enjoy, Johan Nordlander [Hugs maintainer]

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re-exporting imported modules
by Peter Thiemann 14 Feb '01

14 Feb '01

I have the following problem: I would like to define a non-standard prelude that redefines only a few names of the standard prelude. The Haskell report suggests that the following combination should do the job (BUG2A defines the non-standard prelude and BUG2B tries to use it): ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ module BUG2A (module BUG2A, module Prelude) where import Prelude hiding (head) head = "HEAD" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ module BUG2B where import qualified Prelude import BUG2A ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Unfortunately, loading BUG2B into the Jan2001 beta release gives the following error message: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ERROR BUG2B.hs - Entity "head" imported from module "BUG2A" already defined in module "Prelude" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >From my understanding of the report, the following BUG2C user module should also do the job, but it gives the same error message: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ module BUG2C where import Prelude () import BUG2A ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Is this a known problem? Cheers -Peter

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Re: AW: What does "Compiled code too complex" error message of Hugs mean?
by Jan Kort 12 Feb '01

12 Feb '01

Laaser Christian wrote: > > I never built Hugs on Windows before :-( ... > and a trial to do so with cygwin/gcc was unsuccessful. > Have you got a precompiled binary for Win (hugs.exe) with these settings, > which you could send me / I could download from somewhere? > > Christian > > > -----Urspr> üngliche Nachricht----- > > Von: Jan Kort [SMTP:kort@wins.uva.nl] > > Gesendet am: Mittwoch, 31. Januar 2001 13:34 > > An: Laaser Christian > > Cc: 'haskell(a)haskell.org' > > Betreff: Re: What does "Compiled code too complex" error message of Hugs mean? > > > > Laaser Christian wrote: > > > > > > When loading some Haskell files with Hugs, I get the error message "Compiled code too complex". However, the compilation with GHC 4.08.1 succeeds. > > > What does this message mean? What can I do about it? > > > > > > > You can grep for that sentence in "hugs98/src", it will point to the > > file "machine.c". There you will see it says "if (nextLab>=NUM_FIXUPS) ...". > > So grep for "NUM_FIXUPS" it will point to the file "prelude.h". I > > think the default value is 400, you should increase it to 1000 or so. > > I have it at 10000, but that's probably not necesary in your case > > and if you increase constants too much starting up Hugs will become > > slower. > > > > Jan You need one of: msc: Microsoft Visual C++ bcc32: 32 bit Borland C win32: 32 bit Borland C, Hugs for Windows djgpp2: DJGPP2 according to hugs98/Install, but I don't have any of them. I use Windows for playing games mostly. Maybe NUM_FIXUPS can be increased a little to say 1000 in the normal distribution, I don't know how much this would slow Hugs down ? Jan

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