;; This file goes along with cindexmode.el
;; The key bindings I use: (add to your .emacs after loading this file)
;;
;; (global-set-key [(alt ?x)] 'cxref)
;; (global-set-key [(alt ?f)] 'cfunc-lookup)
;;
;; note you have to generate an index using cfuncindex
;; before these functions will work!
;;
;; - Peter Amstutz (tetron@student.umass.edu)
;;
;; This ELisp code is licensed under the GNU General Public License,
;; just like the rest of Emacs.

(defvar cxref-version "1.0")

(defvar cxref-buffer-name "*cfuncindex*")

(defun read-string-back-to (func &optional str)
  (unless str (setq str ""))
  (let ((c (preceding-char)))
  (unless (funcall func c)
    (setq str (read-string-back-to func (prog1
					    (setq str (concat (char-to-string c) str))
					    (backward-char))))))
  str)

(defun cxref ()
  (interactive)
  (let* ((pointpos (point))
	 (funcname (concat (read-string-back-to (lambda (c) (or (char= c ?\ ) 
								(char= c ?,) 
								(char= c ?\()
								(char= c ?=)
								(char= c ?\t)
								(char= c ?\n))))
			   (progn (goto-char pointpos) 
				  (read-string-to (lambda (c) (char= c ?\())))))
	 (indexbuf (get-buffer cxref-buffer-name))
	 (filestart 0))
    (set-buffer indexbuf)
    (goto-char 0)
    (search-forward funcname)
    (cfuncindex-load)))

(defun extract-functions ()
  (beginning-of-line)
  (read-string-to (lambda (c) (not (char= c ?\ ))))
  (cond
   ((or (eolp) (eobp)) nil)
   ((and (char= (char-after (point)) ?#)
	 (char= (char-after (+ (point) 1)) ?#)
	 (char= (char-after (+ (point) 2)) ?\ ))
    (next-line 1)
    (extract-functions))
   ((numberp (read (char-to-string (following-char))))
    (read-string-to (lambda (c) (char= c ?\()))
    (cons (prog1 (cons (read-string-back-to (lambda (c) (char= c ?\ ))) nil)
	    (next-line 1))
	  (extract-functions)))))

(defun cfunc-lookup (function)
  (interactive (list (completing-read "Function name: "
				      (let* ((oldbuf (current-buffer))
					     (buf (get-buffer "*cfuncindex*"))
					     (pos (point buf))
					     (olddepth max-lisp-eval-depth))
					(setq max-lisp-eval-depth 500)
					(set-buffer buf)
					(goto-char 0)
					(prog1 (extract-functions)
					  (goto-char pos)
					  (set-buffer oldbuf)
					  (setq max-lisp-eval-depth olddepth))))))
  (set-buffer (get-buffer "*cfuncindex*"))
  (goto-char 0)
  (search-forward function)
  (cfuncindex-load))