emacs shell：用ido更改目录

(require 'ido)
(require 'cl-lib)
(require 'shell)

(defvar my-dir-selected nil "Flag to indicate that user has selected the directory")

(defun my-filter-cd-input (current-input)
  "Takes current user input for `cd' the a list
    whose car is the 'maximum possible directory path'
    and cdr is remaining string.

    Examples:
    '~/.emacs.d/in => ('~./emacs.d/' 'in')
    '/home/gue' => ('/home/' 'gue')
    '~/../' => ('~/../' '')"
  (let* ((unquoted-input (shell-unquote-argument current-input))
     (components (split-string unquoted-input "/"))
         (directory-parts (butlast components))
         (possible-prefix (car (last components))))
    (list (if (string= possible-prefix "")
              unquoted-input
            (concat (mapconcat 'identity directory-parts "/")
                    (when directory-parts "/")))
          possible-prefix)))

(defun my-complete-directory-name (directory current-input)
  "Prompts user for directories in `directory',`current-input'
    is the string entered by the user till now"
  (let* ((filtered-input (my-filter-cd-input current-input))
         (directory-path (car filtered-input))
         (partial-input (cadr filtered-input))
         (directory-choices (mapcar 'file-name-nondirectory
                                    (condition-case nil
                                        (cl-remove-if-not 'file-directory-p
                                                          (directory-files (concat directory directory-path) t))
                                      ('file-error (list)))))
         (selected-name (ido-completing-read "Directory: "
                                             directory-choices
                                             nil nil partial-input)))
    (comint-delete-input)
    (insert (concat "cd " 
            (shell-quote-argument (concat directory-path selected-name "/"))))))

(defun my-prompt-for-dir-or-fallback ()
  "If current shell command is `cd' prompt for directory
    using ido otherwise fallback to normal completion"
  (interactive)
  (let* ((user-input (buffer-substring-no-properties (comint-line-beginning-position)
                                                     (point-max))))
    (if (and (>= (length user-input) 3)
             (string= (substring user-input 0 3) "cd "))
        (progn 
          (setq my-dir-selected nil)
          (while (not my-dir-selected)
            (my-complete-directory-name default-directory 
                    (buffer-substring-no-properties (+ (comint-line-beginning-position) 3) 
                                    (point-max))))
          (comint-send-input))
      (call-interactively 'completion-at-point))))

(define-key shell-mode-map (kbd "<tab>") 'my-prompt-for-dir-or-fallback)

(add-hook 'ido-setup-hook 'ido-my-keys)

(defun ido-my-keys ()
  "Add my keybindings for ido."
  (define-key ido-completion-map (kbd "<C-return>") (lambda ()
                                                        (interactive)
                                                        (setq my-dir-selected t)
                                                        (ido-exit-minibuffer))))

点击< tab>如果当前输入的命令是cd,shell中将提示使用ido可用的目录,否则它将回退到默认完成,退出按C-RET