How to select and replace the content of all specific org-headings?

Question

I am trying to select each content-heading extracted with org-noter and then remove all erroneous newlines.

---

This is my function.

(defun sanitize-noter-import ()
  "Sanitizes org-noter imports. This removes white-spaces from all '* Contents' headings."
  (interactive)
  (let (($headings nil)
        (nl "
") ; newline
        (nlb "-
") ; newline with hyphen-break
        heading)
    (org-map-entries
     (lambda ()
       (setq heading (org-entry-get (point) "ITEM"))
       (if (string= heading "Contents")
           (progn
             (message heading)
             (next-line)
             (mark-paragraph)
             (replace-string nlb "" nil (point) (mark)) ; reconnect hyphenated words
             (replace-string nl " " nil (point) (mark)) ; remove line breaks
             (message "point is %s" (point))
             (message "mark is %s" (mark))
             ))))
    ))

---

This is some example text.

** Skeleton

*** Highlight on page 2
:PROPERTIES:
:NOTER_PAGE: (2 . 0.18962766666666667)
:END:

**** Contents
Gamification is the application of game features, mainly video game elements, into non-game
context for the purpose of promoting motivation and engagement in learning. The application of
gamification in a pedagogical context provides some remedy for many students who find
themselves alienated by traditional methods of instruction. The use of gamifica-
tion could provide...

---

When I call the function nothing gets replaced and I get the output

Contents
point is 3983
mark is 4022
Mark set
Replaced 0 occurrences

Point and marker are here:

*** Highlight on page 2
:PROPERTIES:
:NOTER_PAGE: (2 . 0.18962766666666667)  // point
:END:                                   // marker

---

How do I select the headings "body" and perform a text-operation on it?

Answer 1

I solved it myself!

(defun sanitize-noter-import ()
  "Sanitizes org-noter imports. This operates on '* Contents' headings"
  (interactive)
  (let (heading cbeg cend)
    (org-map-entries
     (lambda ()
       (if (string= "Contents" (org-element-property :title (org-element-at-point)))
           (progn
             (message "Found 'Contents' heading")
             (message "%s" (org-element-context))
             (setq cbeg (org-element-property :contents-begin (org-element-at-point)))
             (setq cend (org-element-property :contents-end (org-element-at-point)))
             (sanitize-region cbeg cend)
             )
         )
       )
     )
    ))

(defun sanitize-region (cbeg cend)
  "Removes all line-breaks between CBEG and CEND"
  (let ((nl "
")
        (nlb "-
"))
    (message "contents-begin: %s contents-end: cend" cbeg)
    (message "Removing hyphen-breaks")
    (replace-string nlb "" nil cbeg cend)
    (message "Removing newlines")
    (replace-string nl " " nil cbeg cend)
    ))

---

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What I don't really understand is why the cend does not delimit the full end, but instead points to a space two chars before.

If I do (goto-char cend) (insert "END"), then it would insert it like last woENDrd.