file-transitter.el

;; [2015-05-11]
;; C-M-.で進む、C-M-,で戻るが出来る便利関数
;; 移動中はミニバッファに状況を表示します
;; 感想きかせてくれると嬉しいです
 
(require 'cl)
 
(defmacro kset (key fn) `(global-set-key (kbd ,key) ,fn))
 
(defun substr (str start end)
  (if (> end (length str))
      str
    (subseq str start end)))
 
(defun set-equal (a b)
  (and (subsetp a b) (subsetp b a)))
 
(defun real-buffer-list ()
  (remove-if-not #'(lambda (buffer)
                     (let ((buffer (buffer-name buffer)))
                       (or (and (not (equal ?* (elt buffer 0)))
                                (not (equal ?  (elt buffer 0))))
                           (equal "*slime-repl" (substr buffer 0 11))
                           (equal "*scratch*" buffer)
                           (equal "*ruby*" buffer))))
                 (buffer-list)))
 
(defun print-buffers-to-minibuffer (buffers)
  (labels ((normalize (buffer-name)
			 (if (equal buffer-name (buffer-name))
				 (format "[%-10s]" (substr buffer-name 0 10))
			   (format " %-10s " (substr buffer-name 0 10)))))
	(message (mapconcat #'normalize (mapcar #'buffer-name buffers) ""))))
 
(defun file-transitter (next-fn)
  (let ((bufs (real-buffer-list)))
    (unless (set-equal *buffers* bufs)
      (let ((added (set-difference bufs *buffers*))
            (deleted (set-difference *buffers* bufs)))
        (setq *buffers*
              (append added (remove-if (lambda (x) (find x deleted)) *buffers*))))))
  (switch-to-buffer (elt *buffers* (mod (funcall next-fn (or (position (current-buffer) *buffers*) 0))
                                        (length *buffers*))))
  (print-buffers-to-minibuffer *buffers*))
 
(defun next-file ()
  (interactive)
  (file-transitter #'1+))
 
(defun prev-file ()
  (interactive)
  (file-transitter #'1-))
 
(defvar *buffers* (real-buffer-list))
(kset "C-M-." #'next-file)
(kset "C-M-," #'prev-file)