sort-lines in HEAD is not compatible with current Emacs - with patch

[Ehud Karni]

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In GNU Emacs 21.3.50.3 (i686-redhat-linux-gnu)
 of 2003-03-26 on beta
configured using `configure '--host=i686-redhat-linux-gnu' '--with-pop' 
'--with-x-toolkit=gtk' '--with-xpm' '--with-jpeg' '--with-tiff' '--with-gif' 
'--with-png' 'CFLAGS=-O2 -DSITELOAD_PURESIZE_EXTRA=800000' 
'host_alias=i686-redhat-linux-gnu''


I found an incompatibility in `sort-lines' (and really any buffer sort)
between the HEAD version and the current version. The HEAD version
destroys markers at the _end_ of the sorted area. To demonstrate it
use the following function:

(defun test-sort-lines ()
  (interactive)
  (let ((cnt 17)
        (reverse nil)
        beg  end
        mrkb mrki mrke)

    (set-buffer (get-buffer-create "test-sort-buf"))
    (delete-region (point-min) (point-max))
    (while (> cnt 0)
       (insert (format " line == %3d ==\n" cnt))
       (setq cnt (1- cnt)))
    (goto-char (point-min))
    (forward-line 5)
    (setq mrkb (point-marker))
    (setq beg (point))
    (forward-line 3)
    (setq mrki (point-marker))
    (forward-line 3)
    (setq end (point))
    (setq mrke (point-marker))
    (message "Before: beg=%d, end=%d, Markers: beg=%S, in=%S, end=%S" beg end 
mrkb mrki mrke)
    (sort-lines reverse beg end)
    (message "After:  beg=%d, end=%d, Markers: beg=%S, in=%S, end=%S" beg end 
mrkb mrki mrke)
  ))

The results are:
"21.1.3" (Branch, just released)
Before: beg=81, end=177,
Markers: beg=#<marker at 81 in test-sort-buf>,
         in=#<marker at 129 in test-sort-buf>,
         end=#<marker at 177 in test-sort-buf>
After:  beg=81, end=177,
Markers: beg=#<marker at 81 in test-sort-buf>,
         in=#<marker at 81 in test-sort-buf>,
         end=#<marker at 177 in test-sort-buf>

"21.3.50.3" (HEAD)
Before: beg=81, end=177,
Markers: beg=#<marker at 81 in test-sort-buf>,
         in=#<marker at 129 in test-sort-buf>,
         end=#<marker at 177 in test-sort-buf>
After:  beg=81, end=177,
Markers: beg=#<marker at 81 in test-sort-buf>,
         in=#<marker at 81 in test-sort-buf>,
         end=#<marker at 81 in test-sort-buf>

As you can see the "end" marker is destroyed in HEAD but not in
the current Emacs.

I found that this was caused by a change to `sort-reorder-buffer'
in sort.el that now uses a temp buffer. I hacked it a little:


diff -c /usr/local/share/emacs/21.3.50/lisp/sort-org.el 
/usr/local/share/emacs/21.3.50/lisp/sort.el
*** /usr/local/share/emacs/21.3.50/lisp/sort-org.el     Mon Feb 10 23:36:03 2003
- --- /usr/local/share/emacs/21.3.50/lisp/sort.el       Thu Mar 27 17:40:27 2003
***************
*** 164,170 ****
  
  (defun sort-reorder-buffer (sort-lists old)
    (let ((last (point-min))
!       (min (point-min)) (max (point-max))
        (old-buffer (current-buffer))
        temp-buffer)
      (with-temp-buffer
- --- 164,170 ----
  
  (defun sort-reorder-buffer (sort-lists old)
    (let ((last (point-min))
!       (rest (point-max))
        (old-buffer (current-buffer))
        temp-buffer)
      (with-temp-buffer
***************
*** 185,207 ****
              sort-lists (cdr sort-lists)
              old (cdr old)))
        (goto-char (point-max))
!       (insert-buffer-substring old-buffer last max)
  
        ;; Copy the reordered text from the temporary buffer
        ;; to the buffer we sorted (OLD-BUFFER).
        (set-buffer old-buffer)
        (let ((inhibit-quit t))
        ;; Make sure insertions done for reordering
!       ;; do not go after any markers at the end of the sorted region,
!       ;; by inserting a space to separate them.
!       (goto-char max)
!       (insert-before-markers " ")
!       ;; Delete the original copy of the text.
!       (delete-region min max)
!       ;; Now replace the separator " " with the sorted text.
!       (goto-char (point-max))
        (insert-buffer-substring temp-buffer)
!       (delete-region min (1+ min))))))
  
  ;;;###autoload
  (defun sort-lines (reverse beg end)
- --- 185,201 ----
              sort-lists (cdr sort-lists)
              old (cdr old)))
        (goto-char (point-max))
!       (insert-buffer-substring old-buffer last rest)
  
        ;; Copy the reordered text from the temporary buffer
        ;; to the buffer we sorted (OLD-BUFFER).
        (set-buffer old-buffer)
        (let ((inhibit-quit t))
        ;; Make sure insertions done for reordering
!       (goto-char (point-min))
        (insert-buffer-substring temp-buffer)
!       ;; Delete the original copy of the text.
!       (delete-region (point) (point-max))))))
  
  ;;;###autoload
  (defun sort-lines (reverse beg end)

Diff finished at Thu Mar 27 17:41:24



With my patch the results are:

Patched "21.3.50.3"
Before: beg=81, end=177,
Markers: beg=#<marker at 81 in test-sort-buf>,
         in=#<marker at 129 in test-sort-buf>,
         end=#<marker at 177 in test-sort-buf>
After:  beg=81, end=177,
Markers: beg=#<marker at 81 in test-sort-buf>,
         in=#<marker at 176 in test-sort-buf>,
         end=#<marker at 177 in test-sort-buf>

Which keeps the "beg" and "end" markers, and sets all the intermediate
markers to the end position (contrast with current version that sets
all these markers to beginning position).

Ehud.


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