Allow storing buffer names in registers

* doc/emacs/regs.texi (File and Buffer Registers): Rename and add
doc for `buffer' version.
* lisp/register.el (register-val-jump-to, register-val-describe):
Add support for (buffer . ...) registers (bug#33033).

doc/emacs/emacs.texi

@@ -345,14 +345,14 @@ Cut and Paste Operations on Graphical Displays
 
 Registers
 
-* Position Registers::       Saving positions in registers.
-* Text Registers::           Saving text in registers.
-* Rectangle Registers::      Saving rectangles in registers.
-* Configuration Registers::  Saving window configurations in registers.
-* Number Registers::         Numbers in registers.
-* File Registers::           File names in registers.
-* Keyboard Macro Registers:: Keyboard macros in registers.
-* Bookmarks::                Bookmarks are like registers, but persistent.
+* Position Registers::        Saving positions in registers.
+* Text Registers::            Saving text in registers.
+* Rectangle Registers::       Saving rectangles in registers.
+* Configuration Registers::   Saving window configurations in registers.
+* Number Registers::          Numbers in registers.
+* File and Buffer Registers:: File and buffer names in registers.
+* Keyboard Macro Registers::  Keyboard macros in registers.
+* Bookmarks::                 Bookmarks are like registers, but persistent.
 
 Controlling the Display
 

doc/emacs/regs.texi

@@ -47,14 +47,14 @@ are similar in spirit to registers, so they are also documented in
 this chapter.
 
 @menu
-* Position Registers::       Saving positions in registers.
-* Text Registers::           Saving text in registers.
-* Rectangle Registers::      Saving rectangles in registers.
-* Configuration Registers::  Saving window configurations in registers.
-* Number Registers::         Numbers in registers.
-* File Registers::           File names in registers.
-* Keyboard Macro Registers:: Keyboard macros in registers.
-* Bookmarks::                Bookmarks are like registers, but persistent.
+* Position Registers::        Saving positions in registers.
+* Text Registers::            Saving text in registers.
+* Rectangle Registers::       Saving rectangles in registers.
+* Configuration Registers::   Saving window configurations in registers.
+* Number Registers::          Numbers in registers.
+* File and Buffer Registers:: File and buffer names in registers.
+* Keyboard Macro Registers::  Keyboard macros in registers.
+* Bookmarks::                 Bookmarks are like registers, but persistent.
 @end menu
 
 @node Position Registers
@@ -238,9 +238,10 @@ register contents into the buffer.  @kbd{C-x r +} with no numeric
 argument increments the register value by 1; @kbd{C-x r n} with no
 numeric argument stores zero in the register.
 
-@node File Registers
-@section Keeping File Names in Registers
+@node File and Buffer Registers
+@section Keeping File and Buffer Names in Registers
 @cindex saving file name in a register
+@cindex saving buffer name in a register
 
   If you visit certain file names frequently, you can visit them more
 conveniently if you put their names in registers.  Here's the Lisp code
@@ -265,6 +266,15 @@ puts the file name shown in register @samp{z}.
 @var{r}}.  (This is the same command used to jump to a position or
 restore a frame configuration.)
 
+  Similarly, if there's certain buffers you visit frequently, you
+can put their names in registers.  For instance, if you visit the
+@samp{*Messages*} buffer often, you can use the following snippet to
+put that buffer into the @samp{m} register:
+
+@smallexample
+(set-register ?m '(buffer . "*Messages*"))
+@end smallexample
+
 @node Keyboard Macro Registers
 @section Keyboard Macro Registers
 @cindex saving keyboard macro in a register

etc/NEWS

@@ -295,6 +295,15 @@ received.
 
 * Changes in Specialized Modes and Packages in Emacs 29.1
 
+** Registers
+
++++
+*** Buffer names can now be stored in registers.
+For instance, to enable jumping to the *Messages* buffer with
+`C-x r j m':
+
+    (set-register ?m '(buffer . "*Messages*"))
+
 ** pixel-fill
 
 *** This is a new package that deals with filling variable-pitch text.

lisp/register.el

@@ -279,6 +279,8 @@ ARG is the value of the prefix argument or nil."
     (goto-char (cadr val)))
    ((eq (car val) 'file)
     (find-file (cdr val)))
+   ((eq (car val) 'buffer)
+    (switch-to-buffer (cdr val)))
    ((eq (car val) 'file-query)
     (or (find-buffer-visiting (nth 1 val))
 	(y-or-n-p (format "Visit file %s again? " (nth 1 val)))
@@ -417,6 +419,11 @@ Interactively, reads the register using `register-read-with-preview'."
     (prin1 (cdr val))
     (princ "."))
 
+   ((eq (car val) 'buffer)
+    (princ "the buffer ")
+    (prin1 (cdr val))
+    (princ "."))
+
    ((eq (car val) 'file-query)
     (princ "a file-query reference:\n    file ")
     (prin1 (car (cdr val)))