Emacs父模式列表

Question

在emacs中,是否可以获得派生模式的父模式列表？

我找到了derived-mode-p,但这只允许我测试一个模式是否来自另一个模式.

Answer 1

每个符号都有一个属性列表,对于派生模式,此列表包含derived-mode-parent指示从哪个模式派生的组件.它似乎只是一个符号.

(define-derived-mode nst-mode text-mode "Testing")
=> nst-mode

(get 'nst-mode 'derived-mode-parent)
=> text-mode

我不知道怎么会有多个父母.

这是一个父母传递链的演示.

(define-derived-mode rope nil "Victim of mouse")
(define-derived-mode mouse rope "Victim of cat")
(define-derived-mode cat mouse "Victim of dog")
(define-derived-mode dog cat "Enough already")

(let ((mode 'dog) parents)
  (while mode
    (setq parents (cons mode parents)
          mode (get mode 'derived-mode-parent)))
  (reverse parents))

=> (dog cat mouse rope)

...或者,只是为了好玩,一个递归版本:

(defun derived-mode-parents (mode)
  (and mode
    (cons mode (derived-mode-parents
          (get mode 'derived-mode-parent)))))

(derived-mode-parents 'dog)
=> (dog cat mouse rope)