bug#21885: 24.5; Transposing things with a negative argument

[Eli Barzilay <eli@barzilay.org>]

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In the past (IIRC, up to around v24.3) transposing things (chars,
words, sexprs, lines) would always leave the point after the
transposed thing.  This means that I could always use a `C--' prefix
to "drag" the current thing backwards in the same way that the default
action drags it forwards.  This is no longer happenning.

After a few trials the thing that seems to fix it is adding this line
at the end of the `transpose-subr' definition:

    (goto-char (+ (car pos2) (- (cdr pos1) (car pos1))))

To be clear, this is not a backward incompatible change -- it fixes
the *current* incompatible change.

Patch file attached.


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From 84a951fa309ff45c033428c7cb8c32290ab13168 Mon Sep 17 00:00:00 2001
From: Eli Barzilay <eli@barzilay.org>
Date: Thu, 12 Nov 2015 03:00:33 -0500
Subject: [PATCH] Fix `transpose-subr' with a negative argument

Make the cursor go to the end of the transposed text, in the same way it
does with a positive argument.
---
 lisp/simple.el | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lisp/simple.el b/lisp/simple.el
index 1f2f4fe..86fa16d 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -6497,7 +6497,8 @@ current object."
       (setq pos1 (funcall aux -1))
       (goto-char (car pos1))
       (setq pos2 (funcall aux arg))
-      (transpose-subr-1 pos1 pos2)))))
+      (transpose-subr-1 pos1 pos2)
+      (goto-char (+ (car pos2) (- (cdr pos1) (car pos1))))))))
 
 (defun transpose-subr-1 (pos1 pos2)
   (when (> (car pos1) (cdr pos1)) (setq pos1 (cons (cdr pos1) (car pos1))))
-- 
2.6.3


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