+2012-12-21 Chong Yidong <cyd@gnu.org>
+
+ * simple.el (transpose-subr-1): Preserve marker positions by
+ changing the insertion sequence (Bug#13122).
+
2012-12-21 Kelly Dean <kellydeanch@yahoo.com> (tiny change)
* simple.el (kill-region): Deactivate mark even for empty regions
(setq pos1 pos2 pos2 swap)))
(if (> (cdr pos1) (car pos2)) (error "Don't have two things to transpose"))
(atomic-change-group
- (let (word2)
- ;; FIXME: We first delete the two pieces of text, so markers that
- ;; used to point to after the text end up pointing to before it :-(
- (setq word2 (delete-and-extract-region (car pos2) (cdr pos2)))
- (goto-char (car pos2))
- (insert (delete-and-extract-region (car pos1) (cdr pos1)))
- (goto-char (car pos1))
- (insert word2))))
+ ;; This sequence of insertions attempts to preserve marker
+ ;; positions at the start and end of the transposed objects.
+ (let* ((word (buffer-substring (car pos2) (cdr pos2)))
+ (len1 (- (cdr pos1) (car pos1)))
+ (len2 (length word))
+ (boundary (make-marker)))
+ (set-marker boundary (car pos2))
+ (goto-char (cdr pos1))
+ (insert-before-markers word)
+ (setq word (delete-and-extract-region (car pos1) (+ (car pos1) len1)))
+ (goto-char boundary)
+ (insert word)
+ (goto-char (+ boundary len1))
+ (delete-region (point) (+ (point) len2))
+ (set-marker boundary nil))))
\f
(defun backward-word (&optional arg)
"Move backward until encountering the beginning of a word.