[plt-scheme] Problem with define-syntax. It is still not clear.

Hello

If you try the following code, it seems that the macro sees the list (1 3)
in both case but fails to match. In both case x should be the list (1 3) and
not (quote (1 3)). I don't understand why. I guess the answer is simple but
I can't find it after a few hours. 

Thank you

(define-syntax testListe
  (syntax-rules ()
    [(_ (1 3)) #t]
    [(_ xxx)
     (begin
       (display xxx)
       (newline)
       #f)]))


(let ((x (list 1 3)))
  (testListe  x))

=> (1 3)
=> #f


(define x '(1 3))
(testListe x)

=> (1 3)
=> #f

-----Message d'origine-----
De : plt-scheme-bounces at list.cs.brown.edu [
<mailto:plt-scheme-bounces at list.cs.brown.edu>
mailto:plt-scheme-bounces at list.cs.brown.edu] De la part de Chongkai Zhu
Envoyé : 19 janvier, 2006 00:30
À : plt-scheme
Objet : Re: [plt-scheme] Problem with define-syntax

======= At 2006-01-18, 19:57:10 Andre Mayers wrote: =======

>Good day
>
>I miss something which is surely basic.
>How can I define a macro that will match a list ?
>Why the following is not working ?
>
>(define-syntax testListe
>  (syntax-rules ()
>    [(_ (1 3)) #t]
>    [(_ xxx) #f]))
>
>
>(define x '(1 3))
>(testListe  x)
>
>Thank you
>
>Andre Mayers, Ph.D., professeur  |  tel: 819-821-8000x2041
>Departement d'informatique       |  fax: 819-821-8200
>Universite de Sherbrooke         |  andre.mayers at usherbrooke.ca
>Sherbrooke (Quebec)              |   <http://www.dmi.usherb.ca/~amayers>
http://www.dmi.usherb.ca/~amayers
>Canada J1K 2R1
>

You are trying to match (quote (1 3)) with (1 3).

> (testListe (1 3))
#t

-
Chongkai

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