elisp - How to dump plist to property value pairs

Question

Below example dump it as a list, but I wish to dump it in property value pairs:

#+BEGIN_SRC elisp :results output
(defun dump-plist(obj level)
  (if (listp obj)
      (dolist (item obj)
        (dump-plist item (1+ level)))
    (progn
      (while (> level 1)
        (princ "  ")
        (setq level (1- level)))
      (princ obj)
      (princ "\n"))))

(defun test()
  (let* ((my-plist (list :a 1 :b 2 :c 3 :more (list 4 5 6))))
    (print my-plist)
    (dump-plist my-plist 0)
    ))

(test)
#+END_SRC

#+RESULTS:
#+begin_example

(:a 1 :b 2 :c 3 :more (4 5 6))
:a
1
:b
2
:c
3
:more
  4
  5
  6
#+end_example

expected output is:

:a 1
:b 2
:c 3
:more (4 5 6)

Answer 1

Replace your code block with this:

#+BEGIN_SRC elisp :results output
(defun dump-plist(obj)
    (unless (null obj)
        (princ (format "%s %s\n" (car obj)  (cadr obj)))
        (dump-plist (cddr obj))))

(defun test()
    (let* ((my-plist (list :a 1 :b 2 :c 3 :more (list 4 5 6))))
        (print my-plist)
        (dump-plist my-plist)))

(test)
#+END_SRC

It goes recursively through your plist and prints two entries at once until the list is empty

This works because plist means paired list. This implicates that this list has always a equal number of entries.

Replacing princ with format saves some lines of code.
The second parameter level is not needed anymore and therefore omitted.