(require 'smalltalk-mode)
(setq auto-mode-alist
      (append  '(("\\.st\\'" . smalltalk-mode))
	       auto-mode-alist))

(defun smalltalk-narrow-to-object ()
  ;;(interactive)
  (let* ((from (save-excursion (or (search-backward "! !" (point-min) t) (point-min))))
	(to (save-excursion (or (progn (search-forward "! !" (point-max) t)) (point-max)))))
    (narrow-to-region from to)))

(defun go-to-next-class ()
  (interactive)
  (widen)
  (let ((to (save-excursion (or (search-forward "! !" (point-max) t) (point-max)))))
    (when (not (= to (point-max)))
      (search-forward "! !" (point-max) t)
      (re-search-forward "^\\w" (point-max) t))
    (smalltalk-narrow-to-object)))

(defun go-to-prev-class ()
  (interactive)
  (widen)
  (let ((to (save-excursion (or (search-backward "! !" (point-min) t) (point-min)))))
    (when (not (= to (point-min)))
      (search-backward "! !" (point-min) t)
      (re-search-backward "\\w" (point-min) t))
    (smalltalk-narrow-to-object)))

(add-hook 'smalltalk-mode-hook
  (lambda ()
    (local-set-key (kbd "C-c n") 'go-to-next-class)
    (local-set-key (kbd "C-c p") 'go-to-prev-class)
    (local-set-key (kbd "C-c a") 'widen)))