Dowe Keller <dowe@krikkit.localdomain> wrote:
+---------------
| I'm no scheme wizard but it looks like your consing up a doted list.
| try:
| (define (only-numbers a-list)
|   (cond ((null? a-list) #nil) <- this should fix your problem
|         ((number? (car a-list))
|          (cons (car a-list) (only-numbers (cdr a-list))))
|         (else (only-numbers (cdr a-list)))))
+---------------

Close, but Scheme has no such "#nil" token. Use '() instead:

    (cond ((null? a-list) '()) ...)

Or the following equivalent oft-seen idiom:

    (cond ((null? a-list) a-list) ...)


-Rob

-----
Rob Warnock, 31-2-510		rpw3@sgi.com
Network Engineering		http://reality.sgi.com/rpw3/
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