返回父目录绝对路径的函数

    (parent-dir "/home/sk/parent/ab.el")

给

    "/home/sk/parent"

然后，

(parent-dir "/home/sk/parent")

给

"/home/sk"

任何elisp函数parent-dir都可以为文件路径和目录路径提供基本路径吗？

file-name-directory 完成您的要求。

但是，(file-name-directory "/home/sk/parent/")（带有斜杠）返回相同的目录，而不是其父目录。

这就是我想您真正想要的：

(file-name-directory (directory-file-name "/home/sk/parent/ab.el")) ; => "/home/sk/parent/"
(file-name-directory (directory-file-name "/home/sk/parent/")) ; => "/home/sk/"
(file-name-directory (directory-file-name "/home/sk/parent")) ; => "/home/sk/"

库Dired +使用此功能：

(defun diredp-parent-dir (file &optional relativep)
  "Return the parent directory of FILE, or nil if none.
Optional arg RELATIVEP non-nil means return a relative name, that is,
just the parent component."
  (let ((parent  (file-name-directory (directory-file-name (expand-file-name file))))
        relparent)
    (when relativep
      (setq relparent  (file-name-nondirectory (directory-file-name parent))))
    (and (not (equal parent file))  (or relparent  parent))))

(defun parent-directory (dir)
  (unless (equal "/" dir)
    (file-name-directory (directory-file-name dir))))

取自https://stackoverflow.com/a/14096693/5103881