[plt-scheme] List Manipulation

From: John Clements (clements at brinckerhoff.org)
Date: Wed Jan 7 14:13:38 EST 2004

On Jan 7, 2004, at 5:05 AM, Felix Klock's PLT scheme proxy wrote:

>  For list-related administrative tasks:
>  http://list.cs.brown.edu/mailman/listinfo/plt-scheme
> Ricardo-
> You want to write instead:
>> (define (wertVonBetrag aValue)
>>     (car aValue))
> (note that I have removed a pair of parentheses that were wrapped 
> around aValue).
> In what you had written, you were trying to apply aValue  **as a 
> procedure** to zero arguments.  That is why the error message says it 
> expected a procedure but was given a list -- specifically, (list 2.0 
> euro)
> If you are using DrScheme, I recommend that you change your language 
> level to Beginning Student.  That way, you will get error messages 
> that are more informative for bugs like this.

You should also notice, in all language levels, that the application 
(aValue) is highlighted. If the problem had been with the application 
of 'car', the expression (car (aValue)) would have been highlighted.


Posted on the users mailing list.