The thread and all replies were in 2018. Six years later, in 2024, Anyone opening the up-to-date online manual still sees the old bad code there! The manual is not adjusted even though previous emails had pointed the cause and solution out!
Today, the page has a valid link of          https://www.gnu.org/software/guile/manual/html_node/Alist-Example.html  and still contains

         6.6.20.6  Alist Example

Here is a longer example of how alists may be used in practice.
(define capitals '(("New York" . "Albany")                    ("Oregon"   . "Salem")                    ("Florida"  . "Miami"))) ;; What's the capital of Oregon? (assoc "Oregon" capitals)       ⇒ ("Oregon" . "Salem") (assoc-ref capitals "Oregon")   ⇒ "Salem" ;; We left out South Dakota. (set! capitals       (assoc-set! capitals "South Dakota" "Pierre")) capitals ⇒ (("South Dakota" . "Pierre")     ("New York" . "Albany")     ("Oregon" . "Salem")     ("Florida" . "Miami")) ;; And we got Florida wrong. (set! capitals       (assoc-set! capitals "Florida" "Tallahassee")) capitals ⇒ (("South Dakota" . "Pierre")     ("New York" . "Albany")     ("Oregon" . "Salem")     ("Florida" . "Tallahassee")) ;; After Oregon secedes, we can remove it. (set! capitals       (assoc-remove! capitals "Oregon")) capitals ⇒ (("South Dakota" . "Pierre")     ("New York" . "Albany")     ("Florida" . "Tallahassee"))



 

              
                                                深圳大学                                  
                                                                    陈有骏