Re: Function to find outer parenthesis

[Lou Vanek]

This is what I use. It aint elegant, but it gets the job done.
Works in xemacs, but probably dies an agonizing death in gnu-emacs.
Argument 'tgtchar' can be specified to make it search for any character,
and the scan can go either forwards or backwards (see 'direc').


;;__________________________________________________________________________
;;;;    Move point quickly past a certain character (and, if grouped together,
;;;;    move point past entire group composed of this character.
;;;;    Typically this function is used to scan for the next group of open
;;;;    parentheses ( ?\( ) and move one character past them. This is a way of
;;;;    quickly moving 'point' either 'up' or 'down' through s-expressions.
;;;;    lv 5/5/2006
;;;;
;;;; ARGUMENTS
;;;;   direc:  1, if move forward (default)
;;;;          -1, if move backward
;;;;
;;;; tgtchar:  character that is being scanned for.
;;;;           Once this character is found, scanning continues until
;;;;           all continuous occurrances of the character have been scanned by.
;;;;           Default character: '(', which is represented in elisp as ?\(
;;;;
;;;;   start:  location in buffer where scan is to start.
;;;;           Default: current point location.
(defun scan-and-move-past (&optional direc tgtchar start)
  ;(interactive
  ; (let ((s (read-string "Direction: " nil)))
  ;   (list (string-to-number s))))

  (if (null start)
        (setf start (point)))
  (if (null direc)
        (setf direc 1))
  (if (null tgtchar)
      (setf tgtchar ?\( ))
  (let (( p (+ start direc)))
    (and
     (do ((tgt (char-after p) (char-after (incf p direc))))
                 ((or (null tgt) (char-equal tgtchar tgt )) (cond ((null tgt) 
nil)
                                                 ((< p 1) nil)
                                                 (t p))))
     (incf p direc)
     (do ((tgt (char-after p) (char-after (incf p direc))))
                 ((or (null tgt) (not (char-equal tgtchar tgt )))
                  (cond ((null tgt) nil)
                        ((< p 1) nil)
                        (t p))
                  )
       )
     (goto-char p))))


(defun samp1 ()
  (interactive)
  (scan-and-move-past  1))
(defun samp-1 ()
  (interactive)
  (scan-and-move-past -1))


(define-key slime-mode-map (kbd "C-.") 'samp1)
(define-key slime-mode-map (kbd "C-,") 'samp-1)






Leo Liou wrote:

> In analyzing programs in the edit buffer, I sometimes wish I can do this 
> - from where the cursor is, find the first outer "{" backward.
>
> I wonder if there is an existing function or way to do this.
> Thanks :-)
>
>
> Leo Liou
> Not a shred of evidence exists in favor of the notion that life is 
> serious ...
>
>
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