org-compat: Define proper-list-p

* lisp/org-compat.el (proper-list-p): New function for compatibility
with Emacsen before 27.1.

This is a follow-up to the backport of Emacs's 2fde6275b.
This commit is contained in:
Kyle Meyer 2018-08-26 15:36:49 -04:00
parent ede0d19feb
commit da31714c10
1 changed files with 9 additions and 0 deletions

View File

@ -598,6 +598,15 @@ attention to case differences."
(eq t (compare-strings suffix nil nil
string start-pos nil ignore-case))))))
(unless (fboundp 'proper-list-p)
;; `proper-list-p' was added in Emacs 27.1. The function below is
;; taken from Emacs subr.el 200195e824b^.
(defun proper-list-p (object)
"Return OBJECT's length if it is a proper list, nil otherwise.
A proper list is neither circular nor dotted (i.e., its last cdr
is nil)."
(and (listp object) (ignore-errors (length object)))))
;;; Integration with and fixes for other packages