[plt-scheme] quasiquote?

I think if you consider `(foo , at x , at y) 
x must clearly be a proper list, so if you think that x and y should be of the same type, then they should be proper lists.

At 09:15 AM 1/13/2004 -0500, Joe Marshall wrote:
>  For list-related administrative tasks:
>  http://list.cs.brown.edu/mailman/listinfo/plt-scheme
>
>Doug Orleans <dougo at place.org> writes:
>
>>   For list-related administrative tasks:
>>   http://list.cs.brown.edu/mailman/listinfo/plt-scheme
>>
>> Ken Anderson writes:
>>  > I now see that args must be a list, which i assume means a proper list.
>>  > 
>>  > At 11:37 AM 1/7/2004 -0500, Ken Anderson wrote:
>>  > >> (define name 'sscanf)
>>  > >> (define args '(string format-string . args))
>>  > >> `(,name . ,args)
>>  > >(sscanf string format-string . args)
>>  > >> `(,name , at args)
>>  > >. append: expects argument of type <proper list>; given (string format-string . args)
>>  > >>
>>  > >
>>  > >>From my experience with Common Lisp i expected the two quasiquote expressions to print the same.   Am i doing somethine wrong in Scheme or is this a bug?
>>  > >I'm using  200alpha12 (iteration 0)
>>
>> Coincidentally, I just ran into the same limitation: unquote-splicing
>> only works on proper lists.  (Actually the one I ran into was
>> unsyntax-splicing.)  R5RS only says its argument "must evaluate to a
>> list", but it doesn't say proper list-- or is this always implied by
>> the spec?  Anyway, is there a good reason not to extend it to work on
>> improper lists as well?
>
>I'd call it a bug.