emacs中搜索值包含特定字符串的所有变量

在emacs中，有的扩展会自作主张的给你创建文件（夹），而你一时又不知道该用哪个变量控制，那么下面这个脚本可以帮上你的忙：

;;search variables by value
(defun my-search-variables-by-value (r)
 (interactive "MSearch variable match this regex :")
 (with-output-to-temp-buffer "*Help*"
 (with-current-buffer (get-buffer "*Help*")
 (princ "Variables value matches ")
 (let ((p (point)))
 (princ (format "%s :\n\n" r))
 (add-text-properties
 p (point)
 (list
 'face 'bold)))
 (mapatoms
 (lambda (s)
 (if (and (boundp s)
 (stringp (symbol-value s))
 (string-match r (symbol-value s)))
 (progn
 (let ((p (point))
 (map (make-sparse-keymap)))
 (define-key map [mouse-1]
 (lambda (event)
 (interactive "e")
 (save-excursion
 (mouse-set-point event)
 (describe-variable 
 (intern (get-text-property (point) 'symname))))))
 (princ (symbol-name s))
 (add-text-properties
 p (point)
 (list
 'symname (symbol-name s)
 'face 'button
 'mouse-face 'highlight
 'keymap map))
 (princ "\n")
 (princ (concat (symbol-value s) "\n\n"))
 ))))))
 (help-setup-xref (list #'my-search-variables-by-value r)
 (interactive-p))
 (print-help-return-message)))

使用方法：
将上面的代码拷贝到你的dotEmacs
需要的时候输入M-x my-search-variables-by-value，然后按照提示输入一个regex即可在一个*Help* buffer中列出所有包含该regex的变量了。点击查看运行效果。