Function: hierarchy-descendant-p

hierarchy-descendant-p is a byte-compiled function defined in hierarchy.el.gz.

Signature

(hierarchy-descendant-p HIERARCHY ITEM1 ITEM2)

Documentation

In HIERARCHY, return non-nil if and only if ITEM1 is a descendant of ITEM2.

ITEM1 is a descendant of ITEM2 if and only if both are items of HIERARCHY and either:

- ITEM1 is child of ITEM2, or
- ITEM1's parent is a descendant of ITEM2.

Source Code

;; Defined in /usr/src/emacs/lisp/emacs-lisp/hierarchy.el.gz
(defun hierarchy-descendant-p (hierarchy item1 item2)
  "In HIERARCHY, return non-nil if and only if ITEM1 is a descendant of ITEM2.

ITEM1 is a descendant of ITEM2 if and only if both are items of HIERARCHY
and either:

- ITEM1 is child of ITEM2, or
- ITEM1's parent is a descendant of ITEM2."
  (and
   (hierarchy-has-item hierarchy item1)
   (hierarchy-has-item hierarchy item2)
   (or
    (hierarchy-child-p hierarchy item1 item2)
    (hierarchy-descendant-p
     hierarchy (hierarchy-parent hierarchy item1) item2))))