Re: Descending

HenHanna <HenHanna@devnull.tb> writes:

On 6/7/2024 3:57 AM, B. Pym wrote:

< > Ken Tilton wrote:
< >
< >>> I am having trouble coding a list traversal segment.
< >>>          eg list:
< >>>
< >>> (a (b) (c (e (h i)) (f (j))) (d (g)))
< >>>
< >>> I want to traverse this list in "preorder" and get the following
< >>> output:
< >>>
< >>>                  a b c e h i f j d g
< >>>
< >>> anyone have a code segment to this?
< >>>
< >>> thanks....
< >>>
< >>> Chris.

>
>

< >>
< >> Will this work?:
< >>
< >> (defun dump (list-or-atom)
< >>     (if (listp list-or-atom)
< >>        (dolist (loa list-or-atom)
< >>            (dump loa))
< >>        (format t "~s " list-or-atom)))
< > Gauche Scheme:
< > (define (dump list-or-atom)
< >    (cond ((null? list-or-atom) )
< >          ((list? list-or-atom)
< >            (begin
< >              (dump (car list-or-atom))
< >              (dump (cdr list-or-atom))))
< >          (#t (format #t ":~s " list-or-atom))))
< > (dump '(a (b) (c (e (h i)) (f (j))) (d (g))))
< >    ===>
< >           :a :b :c :e :h :i :f :j :d :g          #t
< >

>
(i've added some spaces)
>
the good ol'  Flatten ?

I actually found a reason to use flatten;  PDIS systems for rule names!

(defun flatten (l &optional res)
  (if (consp l)
      (flatten (car l)
               (flatten (cdr l) res))
      (cons l res)))

(defun generate-flattened-rule-name (pattern)
  "Transform <pattern> list into a readable name. Ex (on ?x ? ?y ?z) => ON-?X-?-?Y-?Z ."
  (mapconcat #'symbol-name (flatten pattern) "-"))



etc...