Function: bounds-of-thing-at-point

bounds-of-thing-at-point is an autoloaded and byte-compiled function defined in thingatpt.el.gz.

Signature

(bounds-of-thing-at-point THING)

Documentation

Determine the start and end buffer locations for the THING at point.

THING should be a symbol specifying a type of syntactic entity. Possibilities include symbol, list, sexp, defun, number, filename, url, email, uuid, word, sentence, whitespace, line, and page.

See the file thingatpt.el for documentation on how to define a valid THING.

Return a cons cell (START . END) giving the start and end positions of the thing found.

Source Code

;; Defined in /usr/src/emacs/lisp/thingatpt.el.gz
;; General routines

;;;###autoload
(defun bounds-of-thing-at-point (thing)
  "Determine the start and end buffer locations for the THING at point.
THING should be a symbol specifying a type of syntactic entity.
Possibilities include `symbol', `list', `sexp', `defun', `number',
`filename', `url', `email', `uuid', `word', `sentence', `whitespace',
`line', and `page'.

See the file `thingatpt.el' for documentation on how to define a
valid THING.

Return a cons cell (START . END) giving the start and end
positions of the thing found."
  (cond
   ((get thing 'bounds-of-thing-at-point)
    (funcall (get thing 'bounds-of-thing-at-point)))
   ;; If the buffer is totally empty, give up.
   ((and (not (eq thing 'whitespace))
         (save-excursion
           (goto-char (point-min))
           (not (re-search-forward "[^\t\n ]" nil t))))
    nil)
   ;; Find the thing.
   (t
    (let ((orig (point)))
      (ignore-errors
	(save-excursion
	  ;; Try moving forward, then back.
	  (funcall ;; First move to end.
	   (or (get thing 'end-op)
	       (lambda () (forward-thing thing 1))))
	  (funcall ;; Then move to beg.
	   (or (get thing 'beginning-op)
	       (lambda () (forward-thing thing -1))))
	  (let ((beg (point)))
	    (if (<= beg orig)
		;; If that brings us all the way back to ORIG,
		;; it worked.  But END may not be the real end.
		;; So find the real end that corresponds to BEG.
		;; FIXME: in which cases can `real-end' differ from `end'?
		(let ((real-end
		       (progn
			 (funcall
			  (or (get thing 'end-op)
			      (lambda () (forward-thing thing 1))))
			 (point))))
		  (when (and (<= orig real-end) (< beg real-end))
		    (cons beg real-end)))
	      (goto-char orig)
	      ;; Try a second time, moving backward first and then forward,
	      ;; so that we can find a thing that ends at ORIG.
	      (funcall ;; First, move to beg.
	       (or (get thing 'beginning-op)
		   (lambda () (forward-thing thing -1))))
	      (funcall ;; Then move to end.
	       (or (get thing 'end-op)
		   (lambda () (forward-thing thing 1))))
	      (let ((end (point))
		    (real-beg
		     (progn
		       (funcall
			(or (get thing 'beginning-op)
			    (lambda () (forward-thing thing -1))))
		       (point))))
		(if (and (<= real-beg orig) (<= orig end) (< real-beg end))
		    (cons real-beg end)))))))))))