Re: C-r and C-s in minibuffer should search completion

[Juri Linkov <juri@jurta.org>]

> Yes, that's an acceptable solution, but really if there are only
> 2 buffers, C-x b TAB should select the only other buffer, so the better
> solution is to fix the completion table.

On a par with your efforts to move minibuffer stuff to minibuffer.el,
I've ported the existing function `internal-complete-buffer' to Lisp
and created a new function `internal-complete-buffer-sans-current' to
remove the current buffer from the completion table for `C-x b' family
of commands.  I also considered using `complete-with-action' internally
in `internal-complete-buffer' since it uses the same code pattern, but
`complete-with-action' doesn't call `all-completions' with the non-nil
arg `hide-spaces'.  Below is a complete patch that causes `C-x b TAB'
to omit the current buffer from the completion table:

Index: src/minibuf.c
===================================================================
RCS file: /sources/emacs/emacs/src/minibuf.c,v
retrieving revision 1.345
diff -c -r1.345 minibuf.c
*** src/minibuf.c	9 Apr 2008 19:33:51 -0000	1.345
--- src/minibuf.c	15 Apr 2008 22:27:45 -0000
***************
*** 1944,1967 ****
      return Qt;
  }
  
- DEFUN ("internal-complete-buffer", Finternal_complete_buffer, Sinternal_complete_buffer, 3, 3, 0,
-        doc: /* Perform completion on buffer names.
- If the argument FLAG is nil, invoke `try-completion', if it's t, invoke
- `all-completions', otherwise invoke `test-completion'.
- 
- The arguments STRING and PREDICATE are as in `try-completion',
- `all-completions', and `test-completion'. */)
-      (string, predicate, flag)
-      Lisp_Object string, predicate, flag;
- {
-   if (NILP (flag))
-     return Ftry_completion (string, Vbuffer_alist, predicate);
-   else if (EQ (flag, Qt))
-     return Fall_completions (string, Vbuffer_alist, predicate, Qt);
-   else				/* assume `lambda' */
-     return Ftest_completion (string, Vbuffer_alist, predicate);
- }
- 
  /* Like assoc but assumes KEY is a string, and ignores case if appropriate.  */
  
  DEFUN ("assoc-string", Fassoc_string, Sassoc_string, 2, 3, 0,
--- 1944,1949 ----
***************
*** 2220,2226 ****
    defsubr (&Sread_string);
    defsubr (&Sread_command);
    defsubr (&Sread_variable);
-   defsubr (&Sinternal_complete_buffer);
    defsubr (&Sread_buffer);
    defsubr (&Sread_no_blanks_input);
    defsubr (&Sminibuffer_depth);
--- 2202,2207 ----

Index: lisp/minibuffer.el
===================================================================
RCS file: /sources/emacs/emacs/lisp/minibuffer.el,v
retrieving revision 1.13
diff -c -r1.13 minibuffer.el
*** lisp/minibuffer.el	14 Apr 2008 22:04:38 -0000	1.13
--- lisp/minibuffer.el	15 Apr 2008 22:27:03 -0000
***************
*** 730,734 ****
--- 730,758 ----
                              'completion--file-name-table)
    "Internal subroutine for `read-file-name'.  Do not call this.")
  
+ (defun internal-complete-buffer (string predicate flag)
+   "Perform completion on buffer names.
+ If the argument FLAG is nil, invoke `try-completion', if it's t, invoke
+ `all-completions', otherwise invoke `test-completion'.
+ 
+ The arguments STRING and PREDICATE are as in `try-completion',
+ `all-completions', and `test-completion'."
+   (let ((table (mapcar 'buffer-name (buffer-list))))
+     (cond
+      ((null flag) (try-completion string table predicate))
+      ((eq flag t) (all-completions string table predicate t))
+      (t (test-completion string table predicate)))))
+ 
+ (defun internal-complete-buffer-sans-current (string predicate flag)
+   "Perform completion on buffer names excluding the current buffer.
+ Like `internal-complete-buffer', but removes the current buffer from
+ the completion list."
+   (let ((table (mapcar 'buffer-name (delq (other-buffer (current-buffer) t)
+ 					  (buffer-list)))))
+     (cond
+      ((null flag) (try-completion string table predicate))
+      ((eq flag t) (all-completions string table predicate t))
+      (t (test-completion string table predicate)))))
+ 
  (provide 'minibuffer)
  ;;; minibuffer.el ends here

Index: lisp/files.el
===================================================================
RCS file: /sources/emacs/emacs/lisp/files.el,v
retrieving revision 1.970
diff -c -r1.970 files.el
*** lisp/files.el	12 Apr 2008 03:14:56 -0000	1.970
--- lisp/files.el	15 Apr 2008 22:27:11 -0000
***************
*** 1033,1038 ****
--- 1033,1048 ----
      (rename-file encoded new-encoded ok-if-already-exists)
      newname))
  \f
+ (defun read-buffer-to-switch (prompt)
+   "Read the name of a buffer to switch to and return as a string.
+ It is intended for `switch-to-buffer' family of commands since they
+ need to omit the name of current buffer from the list of defaults."
+   (minibuffer-with-setup-hook
+       (lambda ()
+ 	(set (make-local-variable 'minibuffer-completion-table)
+ 	     'internal-complete-buffer-sans-current))
+     (read-buffer prompt (other-buffer (current-buffer)))))
+ 
  (defun switch-to-buffer-other-window (buffer &optional norecord)
    "Select buffer BUFFER in another window.
  If BUFFER does not identify an existing buffer, then this function
***************
*** 1047,1053 ****
  
  This uses the function `display-buffer' as a subroutine; see its
  documentation for additional customization information."
!   (interactive "BSwitch to buffer in other window: ")
    (let ((pop-up-windows t)
  	;; Don't let these interfere.
  	same-window-buffer-names same-window-regexps)
--- 1057,1064 ----
  
  This uses the function `display-buffer' as a subroutine; see its
  documentation for additional customization information."
!   (interactive
!    (list (read-buffer-to-switch "Switch to buffer in other window: ")))
    (let ((pop-up-windows t)
  	;; Don't let these interfere.
  	same-window-buffer-names same-window-regexps)
***************
*** 1061,1067 ****
  
  This uses the function `display-buffer' as a subroutine; see its
  documentation for additional customization information."
!   (interactive "BSwitch to buffer in other frame: ")
    (let ((pop-up-frames t)
  	same-window-buffer-names same-window-regexps)
      (prog1
--- 1072,1079 ----
  
  This uses the function `display-buffer' as a subroutine; see its
  documentation for additional customization information."
!   (interactive
!    (list (read-buffer-to-switch "Switch to buffer in other frame: ")))
    (let ((pop-up-frames t)
  	same-window-buffer-names same-window-regexps)
      (prog1

Index: src/buffer.c
===================================================================
RCS file: /sources/emacs/emacs/src/buffer.c,v
retrieving revision 1.557
diff -c -r1.557 buffer.c
*** src/buffer.c	2 Apr 2008 20:15:11 -0000	1.557
--- src/buffer.c	15 Apr 2008 22:27:01 -0000
***************
*** 1767,1773 ****
    return buf;
  }
  
! DEFUN ("switch-to-buffer", Fswitch_to_buffer, Sswitch_to_buffer, 1, 2, "BSwitch to buffer: ",
         doc: /* Select buffer BUFFER in the current window.
  If BUFFER does not identify an existing buffer,
  then this function creates a buffer with that name.
--- 1767,1774 ----
    return buf;
  }
  
! DEFUN ("switch-to-buffer", Fswitch_to_buffer, Sswitch_to_buffer, 1, 2,
!        "(list (read-buffer-to-switch \"Switch to buffer: \"))",
         doc: /* Select buffer BUFFER in the current window.
  If BUFFER does not identify an existing buffer,
  then this function creates a buffer with that name.



-- 
Juri Linkov
http://www.jurta.org/emacs/