* lisp/register.el (increment-register): Route it to `append-to-register',

if register contains text so that `C-x r +' can now be
used for appending to a text register.
(register): New group.
(register-separator): New user option.
(append-to-register, prepend-to-register): Add separator based on
`register-separator.
* doc/emacs/regs.texi (Text Registers): `C-x r +' can now be used instead of
M-x append-to-register.  New option `register-separator'.
(Number Registers): Mention that `C-x r +' is polymorphic.

Fixes: debbugs:12217

2 files changed, 33 insertions, 5 deletions

diff --git a/doc/emacs/ChangeLog b/doc/emacs/ChangeLog
index 49c472ca793..508dbbf8021 100644
--- a/doc/emacs/ChangeLog
+++ b/doc/emacs/ChangeLog
@@ -1,3 +1,9 @@
+2012-09-08  Jambunathan K  <kjambunathan@gmail.com>
+
+        * regs.texi (Text Registers): `C-x r +' can now be used instead of
+        M-x append-to-register.  New option `register-separator'.
+        (Number Registers): Mention that `C-x r +' is polymorphic.
+
 2012-09-07  Chong Yidong  <cyd@gnu.org>
 
         * windows.texi (Window Choice): Don't mention obsolete
@@ -10,9 +16,9 @@
 
 2012-08-24  Michael Albinus  <michael.albinus@gmx.de>
 
-        * cmdargs.texi (General Variables): Setting
-        $DBUS_SESSION_BUS_ADDRESS to a dummy value suppresses connections
-        to the D-Bus session bus.  (Bug#12112)
+        * cmdargs.texi (General Variables):
+        Setting $DBUS_SESSION_BUS_ADDRESS to a dummy value suppresses
+        connections to the D-Bus session bus.  (Bug#12112)
 
 2012-08-14  Eli Zaretskii  <eliz@gnu.org>
 
diff --git a/doc/emacs/regs.texi b/doc/emacs/regs.texi
index 72fd6458dde..0a83c0bdddd 100644
--- a/doc/emacs/regs.texi
+++ b/doc/emacs/regs.texi
@@ -92,6 +92,13 @@ Copy region into register @var{r} (@code{copy-to-register}).
 Insert text from register @var{r} (@code{insert-register}).
 @item M-x append-to-register @key{RET} @var{r}
 Append region to text in register @var{r}.
+
+@kindex C-x r +
+When register @var{r} contains text, you can use @kbd{C-x r +}
+(@code{increment-register}) to append to that register.  Note that
+command @kbd{C-x r +} behaves differently if @var{r} contains a
+number.  @xref{Number Registers}.
+
 @item M-x prepend-to-register @key{RET} @var{r}
 Prepend region to text in register @var{r}.
 @end table
@@ -116,6 +123,19 @@ region after appending it to the register.  The command
 the region text to the text in the register instead of
 @emph{appending} it.
 
+@vindex register-separator
+  When you are collecting text using @code{append-to-register} and
+@code{prepend-to-register}, you may want to separate individual
+collected pieces using a separator.  In that case, configure a
+@code{register-separator} and store the separator text in to that
+register.  For example, to get double newlines as text separator
+during the collection process, you can use the following setting.
+
+@example
+(setq register-separator ?+)
+(set-register register-separator "\n\n")
+@end example
+
 @kindex C-x r i
 @findex insert-register
   @kbd{C-x r i @var{r}} inserts in the buffer the text from register
@@ -191,8 +211,10 @@ Store @var{number} into register @var{r} (@code{number-to-register}).
 @item C-u @var{number} C-x r + @var{r}
 @kindex C-x r +
 @findex increment-register
-Increment the number in register @var{r} by @var{number}
-(@code{increment-register}).
+If @var{r} contains a number, increment the number in that register by
+@var{number}.  Note that command @kbd{C-x r +}
+(@code{increment-register}) behaves differently if @var{r} contains
+text.  @xref{Text Registers}.
 @item C-x r i @var{r}
 Insert the number from register @var{r} into the buffer.
 @end table