enhanced-minibuffer.el

;; Enhanced minibuffer & find-file! 加強minibuffer和find-file！
;; 我一直無法忍受helm和ido-mode的find-file設計，但又覺得他們有部份功能
;; 實在很方便，例如能夠按DEL直接刪回上個目錄的路徑，或者整個路徑重新輸
;; 入等。這裡做了幾個符合自己需要的功能：

;;   1. 如果minibuffer中是個目錄的樣式，按M-[DEL]就可以往前刪到parent dir
;;   2. 按一次C-a只是一般的beginning-of-line，但按第二次C-a的話：
;;       (a) 如果是個路徑，會把~/或/以後的東西刪掉。
;;       (b) 如果不是路徑，則整行刪掉。
;;   3. 以上行為都不會把刪過的東西存到 kill-ring，所以可以放心用力刪，
;;      而不用擔心會影響到目前的 kill-ring~

(defun minibuffer-beginning-of-line ()
  "Pressing C-a once, this's just a normal `beginning-of-line'.
When pressing second time, and the string in minibuffer looks
like a file path, it will *delete* whole minibuffer except for ~/
or / in the beginning of minibuffer."
  (interactive)
  (defvar minibuffer-point-beginning-of-line nil)
  (if (eq minibuffer-point-beginning-of-line (point)) ;是否已經在 beginning-of-line
      (if (or (equal "~/" (substring-no-properties (buffer-string) (1- (point)) (+ 1 (point))))
              (equal "/" (substring-no-properties (buffer-string) (1- (point)) (point))))
          (progn
            (re-search-forward "/" nil :no-error)
            (delete-region (point) (point-max)))
        (delete-region (point) (point-max))) ;整個string看起來不是路徑就全部刪掉。
    (progn (move-beginning-of-line 1) ;不在 beginning-of-line的話
           (setq minibuffer-point-beginning-of-line (point)))))

(defun minibuffer-backward-delete-word (arg)
  "*Delete* word backward instead of kill it in minibuffer.
Besides, when the string in minibuffer looks like a file path, it will
delete backward until the parent directory."
  (interactive "p")
  (if (and (eq (point) (point-max)) ;如果在行尾，且整串看起來是個檔案路徑
           (string-match "~*/\\([^/\n]+/?\\)+$" (buffer-string)))
      (progn (re-search-backward "/." nil :no-error)
             (delete-region (1+ (point)) (point-max))
             (end-of-line))
    ;; 下面這個只是一般的backward delete word而已
    (delete-region (point) (progn (backward-word arg) (point)))))

(define-key minibuffer-local-completion-map (kbd "C-a") 'minibuffer-beginning-of-line)
(define-key minibuffer-local-completion-map (kbd "M-DEL") 'minibuffer-backward-delete-word)