Emacs Selectors

One of the nicer things that comes with slime is the slime-selector: it's just a little buffer switching thing, that lets you press r to switch to the repl buffer, d to switch to the debugger buffer, s to switch to the scratch buffer and so forth. Bound to a function key, it's an extraordinarily convenient way of switching to a specific buffer.

Of course, it's geared to SLIME and Lisp, but when coding C++ on the day job I often find myself switching between code, the debugger, shell and compilation buffer, so without further ado, here is the C equivalent, which is easily hacked up to include other buffers, too: actually, I'm beginning to think something like this functionality should be in emacs by default, as it eliminates a lot of keyboard gymnastics.

;; slime selector clone for c  ----------------------------------

(defvar c-selector-methods nil)

(defun c-selector ()
  (interactive)
  (message "Select [%s]: "
           (apply #'string (mapcar #'car c-selector-methods)))
  (let* ((ch (save-window-excursion
               (select-window (minibuffer-window))
                              (read-char)))
         (method (find ch c-selector-methods :key #'car)))
    (cond ((null method)
           (message (format "No method for charachter: %s" ch))
           (ding)
           (sleep-for 1)
           (discard-input)
           (c-selector))
          (t 
           (funcall (third method))))))
          
         
(defmacro def-c-selector-method (key description &rest body)
  `(setq c-selector-methods
         (sort* (cons (list ,key ,description
                            (lambda () 
                              (let ((buffer (progn ,@body)))
                                (cond ((get-buffer buffer)
                                       (switch-to-buffer buffer))
                                      (t
                                       (message  "No such buffer")
                                       (ding))))))
                      (remove* ,key c-selector-methods :key #'car))
                #'< :key #'car)))
  
(def-c-selector-method ?d "GDB debugger buffer"
  gud-comint-buffer)

(def-c-selector-method ?g "Grep buffer"
  grep-last-buffer)

(def-c-selector-method ?l "Buffer List"
  (let ((result (get-buffer "*buffer-selection*")))
    (if result
        result
      ((bs-show)
       (get-buffer "*buffer-selection*")))))

(def-c-selector-method ?c "Compilation buffer"
  (let ((result (get-buffer "*compilation*")))
    (if result
        result
      (compilation-find-buffer))))

(def-c-selector-method ?s "Shell buffer"
  (get-buffer "*shell*"))