Hello Risto, I don't have a Windows system myself, and therefore no winhugs, but your problems seem unrelated to winhugs as such, so I will try to indicate how you might proceed, using my Linux Hugs for illustration. On Thursday 06 September 2007 14:13, Risto Rangel Kuoppa wrote:

Hello everyone,

I am having troubles to start using WinHugs. I downloaded it, installed, and run it. Yet I am unable to run something else than just evaluating expressions. For example, I am trying to define my first data type with:

Hugs> data Tipo = Cruz | Circulo deriving Eq

Quoting from the "The Hugs 98 User's Guide": "The Hugs prompt accepts expressions, but not Haskell definitions." (See http://cvs.haskell.org/Hugs/pages/users_guide/module-commands.html) So if you wish to work with definitions, you have to put them in a file and either list the file on the hugs command line (this is not winhugs) or load the file from the hugs promt. Here is what it would look like on a Linux system:

tn@linux:~/tn/tmp/hugs> cat Risto1.hs data Tipo = Cruz | Circulo deriving Eq

("cat" is the Linux "type" command.)

tn@linux:~/tn/tmp/hugs> hugs __ __ __ __ ____ ___ _________________________________________ || || || || || || ||__ Hugs 98: Based on the Haskell 98 standard ||___|| ||__|| ||__|| __|| Copyright (c) 1994-2003 ||---|| ___|| World Wide Web: http://haskell.org/hugs || || Report bugs to: hugs-bugs@haskell.org || || Version: November 2003 _________________________________________

Haskell 98 mode: Restart with command line option -98 to enable extensions

Type :? for help Prelude> :load Risto1 Main> Cruz ERROR - Cannot find "show" function for: *** Expression : Cruz *** Of type : Tipo

Main> :type Cruz Cruz :: Tipo Main>

From this, you can see that hugs has indeed "got" the data definition. (To enable values of type Tipo to be printed, you should derive Show in addition to Eq.)

But all I get is: ERROR - Syntax error in expression (unexpected keyword "data") Hugs>

I think that I must load some module or library but when I make:

Hugs> :load "C:\\Program Files\\WinHugs\\packages\\hugsbase\\Hugs\\Prelude.hs"

I get: ERROR file:.\Prelude.hs - Module "Hugs.Prelude" already loaded Hugs.Prelude>

Here, you are trying to load the standard prelude, but that is loaded already by default, so the error message tells you exactly that. As indicated, you should probably create your own file, containing your definitions, and then load that.

And I cannot find any Data.hs (Does it actually exist?) anywhere.

I am not sure what you are getting at here. Please give some additional information. I hope that you will be able to get past some of the initial hurdles. If not, or if you have additional questions, please feel free to ask again. Best regards Thorkil

Could someone help me with this please? I have already spent several hours trying to figure it out. All I want is to start testing the tutorials and learn Haskell but I am missing something to run them with WinHugs.

Thanks in advance,

Risto

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