January 2006 - Hugs-Users

No text output in WinHugs
by Kevin Lindsey 26 Feb '06

26 Feb '06

Hello, I suspect this is a total newbie question, so I wanted to check here before going over to the Hugs-Bugs list. I've just installed hugs_SOE-Jan2005.msi on a WinXP machine. When I enter an expression in WinHugs like following: putStr "Hello" I get a blank line instead of the expected "Hello". I do get output from commands like ":?", etc. I assume I need to change a setting somewhere, but I haven't seen anything obvious yet. Please note that everything works fine with Hugs (command prompt version) and WinHugs in hugs98-Nov2003-2.msi works fine too. However, I'm starting to work through SOE, so, as I understand it, I need to use the Jan2005 installer. Thanks for any help with this, Kevin P.S. Are there any archives of the Haskell lists?

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WinHugs error
by Paqui Lucio 26 Feb '06

26 Feb '06

Hi, > I have installed Hugs98 Nov2003 on Windows XP. > WinHugs opens with the message: > > __ __ __ __ ____ ___ > _______________________________________________ > || || || || || || ||__ Hugs 98: Based on the Haskell 98 standard > ||___|| ||__|| ||__|| __|| Copyright (c) 1994-2003 > ||---|| ___|| World Wide Web: http://haskell.org/hugs > || || Report bugs to: hugs-bugs(a)haskell.org > || || Version: Nov 2003 > _______________________________________________ > > Hugs mode: Restart with command line option +98 for Haskell 98 mode > > ERROR ".\Prelude.hs" - Module "Hugs.Prelude" already loaded > Hugs.Prelude> > > > > Is that normal ? > > Thanks in advance, > Paqui > > --------------------------------- > Paqui Lucio > Dpto de LSI > Facultad de Informática > Paseo Manuel de Lardizabal, 1 > 20080-San Sebastián > SPAIN > --------------------------------- > Tfn: (+34) (9)43 015049 > Fax: (+34) (9)43 015590 > --------------------------------- >

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WinHugs beta 3
by Neil Mitchell 30 Jan '06

30 Jan '06

Hi, I'm ready for a new beta of WinHugs, the 3rd beta since I started this. http://www-users.cs.york.ac.uk/~ndm/projects/winhugs.php Features: * Works on Windows 98 * A few corner cases of minimizing and exiting were fixed * Support for \0 in files and on the console * Faster and more accurate error printing * Failure to start is now more explicit * Some really minor tweaks I think its now in a release ready state, but I'm sure someone else will find something wrong with it. If no one runs into any problems, then I'm ready to suggest this for a full Hugs release. Thanks Neil

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bug with not using dependencies (Hugs03 and Hugs05)
by Bulat Ziganshin 30 Jan '06

30 Jan '06

Hello hugs-users, the attached program compiles under GHC, but not with Hugs. as far as i see, Hugs don't use dependencies in class headers to figure out that there is only one "vMkIOError" that can be called in the last definition (all Hugs extensions are enabled) -- Best regards, Bulat mailto:bulatz@HotPOP.com

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bug with reimporting class function (Hugs03 and Hugs05)
by Bulat Ziganshin 30 Jan '06

30 Jan '06

Hello hugs-users, i found a difference between GHC and Hugs behaviour, that seems like the small bug on the Hugs part. It needs at least 3 modules to reproduce :) and i included them all. try to execute c.hs by hugs and ghc and see the difference. the problem disappears when the whole class exported in a.hs -- Best regards, Bulat mailto:bulatz@HotPOP.com

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WinHugs: Implementation and user interface
by Neil Mitchell 20 Jan '06

20 Jan '06

Hi, WinHugs is now looking pretty good I think, a few things outstanding, but overall its quite good to use. Unfortunately the way its designed means that its quite hard to do some enhancements that I would very much like to make, which would be very cool. However, changing the way its designed in this case will also change its user interface quite substantially, so I thought i'd check with people first. == The Proposed Change == Move from looking and acting like a console, to looking and acting like IRC. In the current behaviour you type on the console, in IRC you type in a window at the bottom, when you press enter your changes are reflected on the content area. For an example of the kind of design I mean see http://www-users.cs.york.ac.uk/~miked/images/gyhe_sceengrab2.jpg (although obviously mine would be prettier :) ) == The advantages for the user == You can type a multiline input (maybe), some really cool features become possible (bracket matching, type information, syntax hilighting, perhaps even auto-complete) == The advantages for me == Currently the RTF window code is 20% of WinHugs, and its by far the most brittle bit (occasionally the text flies around teh window, and I have _no idea_ why). With this change, I can make it more like 3%, and all really simple stuff. It will also be faster. == The Question == Do users want to change their model of how to use WinHugs? I have used Gyhe a bit, and its perfectly useable, just less console like. I think I prefer the Console style by a small margin, but guess thats because of habit rather than anything else. And the improvements I could make, in my opinion, far outweight the change. What do other people think? Once I change, there is probably no going back... Thanks Neil

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bug with the "hPutChar h (chr 0)"
by Bulat Ziganshin 19 Jan '06

19 Jan '06

Hello , the following programs shows the bug in the WinHugs20051031 - it doesn't write the '\0' chars to the files. this error shows only in winhugs.exe, but not in hugs.exe nor in runhugs.exe import Data.Char import System.IO main = do h <- openBinaryFile "test" WriteMode hPutChar h (chr 0) hClose h ps: btw, Neil, there is one more small suggestion about WinHugs - in the window showing the class hierarchy the scroller bar at the right is not working properly. you know, it's the same bug, that was in the WinHugs2003 with the scroller in main window -- Best regards, Bulat mailto:bulatz@HotPOP.com

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Comparing TRex records
by Lajos Nagy 19 Jan '06

19 Jan '06

Hi, I tried to create a set of records using Data.Set but it turns out that Rec doesn't implement Ord. Is there a nice solution or you need a new builtin function to do the trick? Sample code: Main> Data.Set.mkSet [(a="apple"), (a="peach")] ERROR - Unresolved overloading *** Type : Ord (Rec (a :: [Char])) => Set (Rec (a :: [Char])) *** Expression : mkSet [(a = "apple"),(a = "peach")] If a new builtin is needed, any pointers where to start? Thanks and Regards, Lajos Nagy Computer Science Ph.D. Student Florida Institute of Technology

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ifdef
by Doug McIlroy 07 Jan '06

07 Jan '06

A recent posting that expressed a desire for #ifdef struck me as perverse. A prime reason for using Haskell is its elegance and clarity. To adopt the most inelegant and turgid feature from C would be like encouraging graffiti in a museum. Most #ifdef's and #if's memorialize failures of imagination or care, often in the name of "portability". Code is NOT portable if it has to be rewritten according to the conventions of each environment. Ifdef expresses just such rewriting, and in an egregious style: it inverts the logical structure of a program, bringing the tweaks to the top while fragmenting the real architecture. To make code portable, one should first get rid of system dependencies to the greatest extent possible. Then treat the recalcitrant residue with the same sense of style as any other programming task. Some standard methods that apply everywhere in programming are equally helpful for portability: Modularization (sweeping systemisms into a corner) Generalization (rising above the systemisms) For dealing with the recalcitrant residue, a method that Haskellites should find specially sympathetic is Specialization (freezing certain parameter values) Ifdef, if course, is a specialization technique, but from another era. If there really is a need for specialization, it would be far better to employ a Ershovian specializer that creates Haskell from Haskell rather than from stone-age idioms. Is one available? Doug McIlroy

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Re[2]: [Hugs-users] __HUGS__
by Bulat Ziganshin 07 Jan '06

07 Jan '06

Hello Ross, Friday, January 06, 2006, 7:02:21 PM, you wrote: >> how can i test in preprocessor version of Hugs? RP> You can't, sorry. i think the same :) but how i need to write libs which is compatible with at least 2003 and 2005 versions? or this problem never arised before?? -- Best regards, Bulat mailto:bulatz@HotPOP.com

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