[plt-scheme] List Manipulation

Hi All,

Thank you all for the help... Now I'm beginning to get a feeling about
Scheme and could finish my 'homework' without bothering you again ;-)

I hope that my next questions may be less elementary...

It's really a bliss to have people like you around the corner ;-)

[]

            ________________ _..----====~~~~====--,
=====  (______________I_)'- = ,~~----===*===----~~~~
===== / /__..---=='---./
----- `---'---._________.' Ricardo Massamitsu Nonomura
E-Mail: massamitsu_nonomura at hotmail.com
            nonomura at moimeichego.de 
Homepage: www.moimeichego.de
ICQ: 7234230
PGP: Oxo70F0B5C


> -----Original Message-----
> From: Dr. Peter Lane [mailto:P.C.Lane at herts.ac.uk] 
> Sent: Wednesday, January 07, 2004 11:09 AM
> To: 'Ricardo Massamitsu Nonomura'
> Cc: plt-scheme at list.cs.brown.edu
> Subject: RE: [plt-scheme] List Manipulation
> 
> 
> 
> Hi Ricardo,
> 
> The mistake is the set of brackets around aValue, which makes 
> Scheme think you want to call a function, whose name is the 
> value of aValue
> 
> > (define (wertVonBetrag aValue)
> >     (car (aValue)))
> 
> Instead, you want:
> 
> (define (wertVonBetrag aValue)
>     (car aValue))
> 
> The value of aValue is a list, and car is the function 
> operating on that list.
> 
> 	HTH,
> 
> 		Peter.
> 
> -----Original Message-----
> From: plt-scheme-admin at list.cs.brown.edu
> [mailto:plt-scheme-admin at list.cs.brown.edu] On Behalf Of 
> Ricardo Massamitsu Nonomura
> Sent: 07 January 2004 09:52
> To: plt-scheme at list.cs.brown.edu
> Subject: [plt-scheme] List Manipulation
> 
>   For list-related administrative tasks:
>   http://list.cs.brown.edu/mailman/listinfo/plt-scheme
> 
> Hi All,
> 
> I defined a procedure that will take 2 parameters and return 
> a list where value is a number and currency is the name of 
> the currency :
> 
> (define (neuerGeldbetrag value currency)
>   (list (* value 1.0) currency))
> 
> Therefore (neuerGeldbetrag 2 'Euro) => (2.0 euro)
> 
> Then I want a new procedure with 1 parameter that will give 
> me the value of the currency:
> 
> (define (wertVonBetrag aValue)
>     (car (aValue)))
> 
> Therefore I was expecting that
> 
>  (wertVonBetrag (neuerGeldbetrag 2 'Euro)) => 2.0
> 
> I tested the result from neuerGeldbetrag with length, which 
> returns 2, so the result is a list. Why car cannot take the 
> head of that list, but instead send me the following error msg:
> 
> procedure application: expected procedure, given: (2.0 euro) (no
> arguments)
> 
> 
> Is (2.0 euro) not a list that car can handle???
> 
> []
> 
>         ________________ _..----====~~~~====--,
> =====  (______________I_)'- = ,~~----===*===----~~~~
> ===== / /__..---=='---./
> ----- `---'---._________.' Ricardo Massamitsu Nonomura
> E-Mail: massamitsu_nonomura at hotmail.com
>             nonomura at moimeichego.de 
> Homepage: www.moimeichego.de
> ICQ: 7234230
> PGP: Oxo70F0B5C
> 
> 
> 
> 
>