Function: org-fold-core-region

org-fold-core-region is a byte-compiled function defined in org-fold-core.el.gz.

Signature

(org-fold-core-region FROM TO FLAG &optional SPEC-OR-ALIAS)

Documentation

Hide or show lines from FROM to TO, according to FLAG.

SPEC-OR-ALIAS is the folding spec or foldable element, as a symbol. If SPEC-OR-ALIAS is omitted and FLAG is nil, unfold everything in the region.

Aliases

org-fold-region org-flag-region (obsolete since 9.6)

Source Code

;; Defined in /usr/src/emacs/lisp/org/org-fold-core.el.gz
;;;; Changing visibility

;;;;; Region visibility

;; This is the core function performing actual folding/unfolding.  The
;; folding state is stored in text property (folding property)
;; returned by `org-fold-core--property-symbol-get-create'.  The value of the
;; folding property is folding spec symbol.
(defun org-fold-core-region (from to flag &optional spec-or-alias)
  "Hide or show lines from FROM to TO, according to FLAG.
SPEC-OR-ALIAS is the folding spec or foldable element, as a symbol.
If SPEC-OR-ALIAS is omitted and FLAG is nil, unfold everything in the region."
  (let ((spec (org-fold-core-get-folding-spec-from-alias spec-or-alias)))
    (when spec (org-fold-core--check-spec spec))
    (with-silent-modifications
      (org-with-wide-buffer
       (when (eq org-fold-core-style 'overlays) (remove-overlays from to 'invisible spec))
       (if flag
	   (if (not spec)
               (error "Calling `org-fold-core-region' with missing SPEC")
             (if (eq org-fold-core-style 'overlays)
                 ;; Use `front-advance' since text right before to the beginning of
                 ;; the overlay belongs to the visible line than to the contents.
                 (let ((o (make-overlay from to nil
                                        (org-fold-core-get-folding-spec-property spec :front-sticky)
                                        (org-fold-core-get-folding-spec-property spec :rear-sticky))))
                   (overlay-put o 'evaporate t)
                   (overlay-put o (org-fold-core--property-symbol-get-create spec) spec)
                   (overlay-put o 'invisible spec)
                   (overlay-put o 'isearch-open-invisible #'org-fold-core--isearch-show)
                   ;; FIXME: Disabling to work around Emacs bug#60399
                   ;; and https://orgmode.org/list/87zgb6tk6h.fsf@localhost.
                   ;; The proper fix will require making sure that
                   ;; `org-fold-core-isearch-open-function' does not
                   ;; delete the overlays used by isearch.
                   ;; (overlay-put o 'isearch-open-invisible-temporary #'org-fold-core--isearch-show-temporary)
                   )
	       (put-text-property from to (org-fold-core--property-symbol-get-create spec) spec)
	       (put-text-property from to 'isearch-open-invisible #'org-fold-core--isearch-show)
	       (put-text-property from to 'isearch-open-invisible-temporary #'org-fold-core--isearch-show-temporary)
               (when (memql 'grab-invisible org-fold-core--optimise-for-huge-buffers)
                 ;; If the SPEC has highest priority, assign it directly
                 ;; to 'invisible property as well.  This is done to speed
                 ;; up Emacs redisplay on huge (Mbs) folded regions where
                 ;; we don't even want Emacs to spend time cycling over
                 ;; `char-property-alias-alist'.
                 (when (eq spec (caar org-fold-core--specs)) (put-text-property from to 'invisible spec)))))
         (if (not spec)
             (mapc (lambda (spec) (org-fold-core-region from to nil spec)) (org-fold-core-folding-spec-list))
           (when (and (memql 'grab-invisible org-fold-core--optimise-for-huge-buffers)
                      (eq org-fold-core-style 'text-properties))
             (when (eq spec (caar org-fold-core--specs))
               (let ((pos from))
                 (while (< pos to)
                   (if (eq spec (get-text-property pos 'invisible))
                       (let ((next (org-fold-core-next-folding-state-change spec pos to)))
                         (remove-text-properties pos next '(invisible t))
                         (setq pos next))
                     (setq pos (next-single-char-property-change pos 'invisible nil to)))))))
           (when (eq org-fold-core-style 'text-properties)
	     (remove-text-properties from to (list (org-fold-core--property-symbol-get-create spec) nil)))))))))