Eliom development: Switch between server and client files

eliom-switch-client-server.el

(setq
 server-regexp  "\\`.*/eliom/src/\\(server\\)/"
 client-regexp  "\\`.*/eliom/src/\\(client\\)/")

(defun switch-client-server-file-name (file-name)
  (let* ((client-name (replace-regexp-in-string server-regexp "client" file-name nil nil 1))
         (server-name (replace-regexp-in-string client-regexp "server" file-name nil nil 1)))
    (cond
     ((not (equal client-name file-name)) (list client-name 'server))
     ((not (equal server-name file-name)) (list server-name 'client)))))

(defun rename-client-server-buffer ()
  (let ((switched (switch-client-server-file-name (buffer-file-name))))
    (when switched
      (let* ((switched-file-name (car switched))
             (target (cadr switched))
             (nondir-name (file-name-nondirectory switched-file-name)))
        (rename-buffer (format "%s (%s)" nondir-name target))))))

(defun switch-client-server ()
  (interactive)
  (let ((switched (switch-client-server-file-name (buffer-file-name))))
    (when switched
      (let* ((switched-file-name (car switched))
             (target (cadr switched)))
        (message (format "Switch to buffer %S" switched-file-name))
        (find-file switched-file-name)))))

(add-hook
 'tuareg-mode-hook
 '(lambda ()
    (add-hook 'find-file-hook 'rename-client-server-buffer)
    (define-key tuareg-mode-map (kbd "C-c a") 'switch-client-server)))