From Newsgroup: comp.lang.lisp

Lieven Marchand wrote:

if we have this list:
(a <sold> b c d <sold> e f g <sold>)
that shows that article a, d and g are sold and the rest are not how
can we put all the sold articles in one list:
(a d g)

More homework?

(loop for (first next) on '(a <sold> b c d <sold> e f g <sold>)
when (eql next '<sold>)
collect first)

Scheme:

(define items '(a <sold> b c d <sold> e f g <sold> h i <sold>))

(filter-map
(lambda(x y) (and (eq? '<sold> y) x))
items
(cdr items))


(a d g i)
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