X-Git-Url: https://code.delx.au/gnu-emacs/blobdiff_plain/0ba911156b93dbb1db9aaf5c58de7bbf0816165b..f4cb1d8caecffded4f2ef5187d096d9751c39d6e:/lisp/emacs-lisp/lisp.el

diff --git a/lisp/emacs-lisp/lisp.el b/lisp/emacs-lisp/lisp.el
index 9c4cbd1d78..a20b79335c 100644
--- a/lisp/emacs-lisp/lisp.el
+++ b/lisp/emacs-lisp/lisp.el
@@ -1,6 +1,7 @@
 ;;; lisp.el --- Lisp editing commands for Emacs
 
-;; Copyright (C) 1985, 1986 Free Software Foundation, Inc.
+;; Copyright (C) 1985, 1986, 1994, 2000, 2004, 2005
+;;   Free Software Foundation, Inc.
 
 ;; Maintainer: FSF
 ;; Keywords: lisp, languages
@@ -18,49 +19,83 @@
 ;; GNU General Public License for more details.
 
 ;; You should have received a copy of the GNU General Public License
-;; along with GNU Emacs; see the file COPYING.  If not, write to
-;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+;; along with GNU Emacs; see the file COPYING.  If not, write to the
+;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
 
 ;;; Commentary:
 
-;; Lisp ediing commands to go with Lisp major mode.
+;; Lisp editing commands to go with Lisp major mode.  More-or-less
+;; applicable in other modes too.
 
 ;;; Code:
 
-(defvar defun-prompt-regexp nil
-  "Non-nil => regexp to ignore, before the `(' that starts a defun.")
+;; Note that this variable is used by non-lisp modes too.
+(defcustom defun-prompt-regexp nil
+  "*If non-nil, a regexp to ignore before a defun.
+This is only necessary if the opening paren or brace is not in column 0.
+See function `beginning-of-defun'."
+  :type '(choice (const nil)
+		 regexp)
+  :group 'lisp)
+(make-variable-buffer-local 'defun-prompt-regexp)
+
+(defcustom parens-require-spaces t
+  "If non-nil, `insert-parentheses' inserts whitespace as needed."
+  :type 'boolean
+  :group 'lisp)
+
+(defvar forward-sexp-function nil
+  "If non-nil, `forward-sexp' delegates to this function.
+Should take the same arguments and behave similarly to `forward-sexp'.")
 
 (defun forward-sexp (&optional arg)
   "Move forward across one balanced expression (sexp).
-With argument, do it that many times.  Negative arg -N means
+With ARG, do it that many times.  Negative arg -N means
 move backward across N balanced expressions."
   (interactive "p")
   (or arg (setq arg 1))
-  (goto-char (or (scan-sexps (point) arg) (buffer-end arg)))
-  (if (< arg 0) (backward-prefix-chars)))
+  (if forward-sexp-function
+      (funcall forward-sexp-function arg)
+    (goto-char (or (scan-sexps (point) arg) (buffer-end arg)))
+    (if (< arg 0) (backward-prefix-chars))))
 
 (defun backward-sexp (&optional arg)
   "Move backward across one balanced expression (sexp).
-With argument, do it that many times.  Negative arg -N means
+With ARG, do it that many times.  Negative arg -N means
 move forward across N balanced expressions."
   (interactive "p")
   (or arg (setq arg 1))
   (forward-sexp (- arg)))
 
-(defun mark-sexp (arg)
+(defun mark-sexp (&optional arg allow-extend)
   "Set mark ARG sexps from point.
 The place mark goes is the same place \\[forward-sexp] would
-move to with the same argument."
-  (interactive "p")
-  (push-mark
-    (save-excursion
-      (forward-sexp arg)
-      (point))
-    nil t))
+move to with the same argument.
+Interactively, if this command is repeated
+or (in Transient Mark mode) if the mark is active,
+it marks the next ARG sexps after the ones already marked."
+  (interactive "P\np")
+  (cond ((and allow-extend
+	      (or (and (eq last-command this-command) (mark t))
+		  (and transient-mark-mode mark-active)))
+	 (setq arg (if arg (prefix-numeric-value arg)
+		     (if (< (mark) (point)) -1 1)))
+	 (set-mark
+	  (save-excursion
+	    (goto-char (mark))
+	    (forward-sexp arg)
+	    (point))))
+	(t
+	 (push-mark
+	  (save-excursion
+	    (forward-sexp (prefix-numeric-value arg))
+	    (point))
+	  nil t))))
 
 (defun forward-list (&optional arg)
   "Move forward across one balanced group of parentheses.
-With argument, do it that many times.
+With ARG, do it that many times.
 Negative arg -N means move backward across N groups of parentheses."
   (interactive "p")
   (or arg (setq arg 1))
@@ -68,146 +103,354 @@ Negative arg -N means move backward across N groups of parentheses."
 
 (defun backward-list (&optional arg)
   "Move backward across one balanced group of parentheses.
-With argument, do it that many times.
+With ARG, do it that many times.
 Negative arg -N means move forward across N groups of parentheses."
   (interactive "p")
   (or arg (setq arg 1))
   (forward-list (- arg)))
 
-(defun down-list (arg)
+(defun down-list (&optional arg)
   "Move forward down one level of parentheses.
-With argument, do this that many times.
-A negative argument means move backward but still go down a level.
-In Lisp programs, an argument is required."
+With ARG, do this that many times.
+A negative argument means move backward but still go down a level."
   (interactive "p")
+  (or arg (setq arg 1))
   (let ((inc (if (> arg 0) 1 -1)))
     (while (/= arg 0)
       (goto-char (or (scan-lists (point) inc -1) (buffer-end arg)))
       (setq arg (- arg inc)))))
 
-(defun backward-up-list (arg)
+(defun backward-up-list (&optional arg)
   "Move backward out of one level of parentheses.
-With argument, do this that many times.
-A negative argument means move forward but still to a less deep spot.
-In Lisp programs, an argument is required."
+With ARG, do this that many times.
+A negative argument means move forward but still to a less deep spot."
   (interactive "p")
-  (up-list (- arg)))
+  (up-list (- (or arg 1))))
 
-(defun up-list (arg) 
+(defun up-list (&optional arg)
   "Move forward out of one level of parentheses.
-With argument, do this that many times.
-A negative argument means move backward but still to a less deep spot.
-In Lisp programs, an argument is required."
+With ARG, do this that many times.
+A negative argument means move backward but still to a less deep spot."
   (interactive "p")
+  (or arg (setq arg 1))
   (let ((inc (if (> arg 0) 1 -1)))
     (while (/= arg 0)
       (goto-char (or (scan-lists (point) inc 1) (buffer-end arg)))
       (setq arg (- arg inc)))))
 
-(defun kill-sexp (arg)
-  "Kill the sexp (balanced expression) following the cursor.
-With argument, kill that many sexps after the cursor.
-Negative arg -N means kill N sexps before the cursor."
+(defun kill-sexp (&optional arg)
+  "Kill the sexp (balanced expression) following point.
+With ARG, kill that many sexps after point.
+Negative arg -N means kill N sexps before point."
   (interactive "p")
   (let ((opoint (point)))
-    (forward-sexp arg)
+    (forward-sexp (or arg 1))
     (kill-region opoint (point))))
 
-(defun backward-kill-sexp (arg)
-  "Kill the sexp (balanced expression) preceding the cursor.
-With argument, kill that many sexps before the cursor.
-Negative arg -N means kill N sexps after the cursor."
+(defun backward-kill-sexp (&optional arg)
+  "Kill the sexp (balanced expression) preceding point.
+With ARG, kill that many sexps before point.
+Negative arg -N means kill N sexps after point."
   (interactive "p")
-  (kill-sexp (- arg)))
+  (kill-sexp (- (or arg 1))))
+
+;; After Zmacs:
+(defun kill-backward-up-list (&optional arg)
+  "Kill the form containing the current sexp, leaving the sexp itself.
+A prefix argument ARG causes the relevant number of surrounding
+forms to be removed."
+  (interactive "*p")
+  (let ((current-sexp (thing-at-point 'sexp)))
+    (if current-sexp
+        (save-excursion
+          (backward-up-list arg)
+          (kill-sexp)
+          (insert current-sexp))
+      (error "Not at a sexp"))))
 
+(defvar beginning-of-defun-function nil
+  "If non-nil, function for `beginning-of-defun-raw' to call.
+This is used to find the beginning of the defun instead of using the
+normal recipe (see `beginning-of-defun').  Major modes can define this
+if defining `defun-prompt-regexp' is not sufficient to handle the mode's
+needs.
+
+The function (of no args) should go to the line on which the current
+defun starts, and return non-nil, or should return nil if it can't
+find the beginning.")
+
 (defun beginning-of-defun (&optional arg)
   "Move backward to the beginning of a defun.
-With argument, do it that many times.  Negative arg -N
+With ARG, do it that many times.  Negative arg -N
 means move forward to Nth following beginning of defun.
 Returns t unless search stops due to beginning or end of buffer.
 
-Normally a defun starts when there is an char with open-parenthesis
+Normally a defun starts when there is a char with open-parenthesis
 syntax at the beginning of a line.  If `defun-prompt-regexp' is
 non-nil, then a string which matches that regexp may precede the
-open-parenthesis."
+open-parenthesis, and point ends up at the beginning of the line.
+
+If variable `beginning-of-defun-function' is non-nil, its value
+is called as a function to find the defun's beginning."
   (interactive "p")
-  (and arg (< arg 0) (forward-char 1))
-  (and (re-search-backward (if defun-prompt-regexp
-			       (concat "^\\s(\\|"
-				       "\\(" defun-prompt-regexp "\\)\\s(")
-			     "^\\s(")
-			   nil 'move (or arg 1))
+  (or (not (eq this-command 'beginning-of-defun))
+      (eq last-command 'beginning-of-defun)
+      (and transient-mark-mode mark-active)
+      (push-mark))
+  (and (beginning-of-defun-raw arg)
        (progn (beginning-of-line) t)))
 
+(defun beginning-of-defun-raw (&optional arg)
+  "Move point to the character that starts a defun.
+This is identical to function `beginning-of-defun', except that point
+does not move to the beginning of the line when `defun-prompt-regexp'
+is non-nil.
+
+If variable `beginning-of-defun-function' is non-nil, its value
+is called as a function to find the defun's beginning."
+  (interactive "p")
+  (if beginning-of-defun-function
+      (if (> (setq arg (or arg 1)) 0)
+	  (dotimes (i arg)
+	    (funcall beginning-of-defun-function))
+	;; Better not call end-of-defun-function directly, in case
+	;; it's not defined.
+	(end-of-defun (- arg)))
+    (and arg (< arg 0) (not (eobp)) (forward-char 1))
+    (and (re-search-backward (if defun-prompt-regexp
+				 (concat (if open-paren-in-column-0-is-defun-start
+					     "^\\s(\\|" "")
+					 "\\(?:" defun-prompt-regexp "\\)\\s(")
+			       "^\\s(")
+			     nil 'move (or arg 1))
+	 (progn (goto-char (1- (match-end 0)))) t)))
+
+(defvar end-of-defun-function nil
+  "If non-nil, function for function `end-of-defun' to call.
+This is used to find the end of the defun instead of using the normal
+recipe (see `end-of-defun').  Major modes can define this if the
+normal method is not appropriate.")
+
 (defun buffer-end (arg)
+  "Return the \"far end\" position of the buffer, in direction ARG.
+If ARG is positive, that's the end of the buffer.
+Otherwise, that's the beginning of the buffer."
   (if (> arg 0) (point-max) (point-min)))
 
 (defun end-of-defun (&optional arg)
-  "Move forward to next end of defun.  With argument, do it that many times.
+  "Move forward to next end of defun.
+With argument, do it that many times.
 Negative argument -N means move back to Nth preceding end of defun.
 
-An end of a defun occurs right after the close-parenthesis that matches
-the open-parenthesis that starts a defun; see `beginning-of-defun'."
+An end of a defun occurs right after the close-parenthesis that
+matches the open-parenthesis that starts a defun; see function
+`beginning-of-defun'.
+
+If variable `end-of-defun-function' is non-nil, its value
+is called as a function to find the defun's end."
   (interactive "p")
+  (or (not (eq this-command 'end-of-defun))
+      (eq last-command 'end-of-defun)
+      (and transient-mark-mode mark-active)
+      (push-mark))
   (if (or (null arg) (= arg 0)) (setq arg 1))
-  (let ((first t))
-    (while (and (> arg 0) (< (point) (point-max)))
-      (let ((pos (point)) npos)
-	(while (progn
-		(if (and first
-			 (progn
-			  (forward-char 1)
-			  (beginning-of-defun 1)))
-		    nil
-		  (or (bobp) (forward-char -1))
-		  (beginning-of-defun -1))
-		(setq first nil)
-		(forward-list 1)
-		(skip-chars-forward " \t")
-		(if (looking-at "\\s<\\|\n")
-		    (forward-line 1))
-		(<= (point) pos))))
-      (setq arg (1- arg)))
-    (while (< arg 0)
-      (let ((pos (point)))
-	(beginning-of-defun 1)
-	(forward-sexp 1)
-	(forward-line 1)
-	(if (>= (point) pos)
-	    (if (beginning-of-defun 2)
-		(progn
-		  (forward-list 1)
-		  (skip-chars-forward " \t")
-		  (if (looking-at "[;\n]")
-		      (forward-line 1)))
-	      (goto-char (point-min)))))
-      (setq arg (1+ arg)))))
-
-(defun mark-defun ()
+  (if end-of-defun-function
+      (if (> arg 0)
+	  (dotimes (i arg)
+	    (funcall end-of-defun-function))
+	;; Better not call beginning-of-defun-function
+	;; directly, in case it's not defined.
+	(beginning-of-defun (- arg)))
+    (let ((first t))
+      (while (and (> arg 0) (< (point) (point-max)))
+	(let ((pos (point)))
+	  (while (progn
+		   (if (and first
+			    (progn
+			      (end-of-line 1)
+			      (beginning-of-defun-raw 1)))
+		       nil
+		     (or (bobp) (forward-char -1))
+		     (beginning-of-defun-raw -1))
+		   (setq first nil)
+		   (forward-list 1)
+		   (skip-chars-forward " \t")
+		   (if (looking-at "\\s<\\|\n")
+		       (forward-line 1))
+		   (<= (point) pos))))
+	(setq arg (1- arg)))
+      (while (< arg 0)
+	(let ((pos (point)))
+	  (beginning-of-defun-raw 1)
+	  (forward-sexp 1)
+	  (forward-line 1)
+	  (if (>= (point) pos)
+	      (if (beginning-of-defun-raw 2)
+		  (progn
+		    (forward-list 1)
+		    (skip-chars-forward " \t")
+		    (if (looking-at "\\s<\\|\n")
+			(forward-line 1)))
+		(goto-char (point-min)))))
+	(setq arg (1+ arg))))))
+
+(defun mark-defun (&optional allow-extend)
   "Put mark at end of this defun, point at beginning.
-The defun marked is the one that contains point or follows point."
+The defun marked is the one that contains point or follows point.
+
+Interactively, if this command is repeated
+or (in Transient Mark mode) if the mark is active,
+it marks the next defun after the ones already marked."
+  (interactive "p")
+  (cond ((and allow-extend
+	      (or (and (eq last-command this-command) (mark t))
+		  (and transient-mark-mode mark-active)))
+	 (set-mark
+	  (save-excursion
+	    (goto-char (mark))
+	    (end-of-defun)
+	    (point))))
+	(t
+	 (let ((opoint (point))
+	       beg end)
+	   (push-mark opoint)
+	   ;; Try first in this order for the sake of languages with nested
+	   ;; functions where several can end at the same place as with
+	   ;; the offside rule, e.g. Python.
+	   (beginning-of-defun)
+	   (setq beg (point))
+	   (end-of-defun)
+	   (setq end (point))
+	   (while (looking-at "^\n")
+	     (forward-line 1))
+	   (if (> (point) opoint)
+	       (progn
+		 ;; We got the right defun.
+		 (push-mark beg nil t)
+		 (goto-char end)
+		 (exchange-point-and-mark))
+	     ;; beginning-of-defun moved back one defun
+	     ;; so we got the wrong one.
+	     (goto-char opoint)
+	     (end-of-defun)
+	     (push-mark (point) nil t)
+	     (beginning-of-defun))
+	   (re-search-backward "^\n" (- (point) 1) t)))))
+
+(defun narrow-to-defun (&optional arg)
+  "Make text outside current defun invisible.
+The defun visible is the one that contains point or follows point.
+Optional ARG is ignored."
   (interactive)
-  (push-mark (point))
-  (end-of-defun)
-  (push-mark (point) nil t)
-  (beginning-of-defun)
-  (re-search-backward "^\n" (- (point) 1) t))
-
-(defun insert-parentheses (arg)
-  "Put parentheses around next ARG sexps.  Leave point after open-paren.
-No argument is equivalent to zero: just insert () and leave point between."
-  (interactive "P")
-  (if arg (setq arg (prefix-numeric-value arg))
-    (setq arg 0))
-  (or (eq arg 0) (skip-chars-forward " \t"))
-  (and (memq (char-syntax (preceding-char)) '(?w ?_ ?\) ))
-       (insert " "))
-  (insert ?\()
   (save-excursion
-    (or (eq arg 0) (forward-sexp arg))
-    (insert ?\))
-    (and (memq (char-syntax (following-char)) '(?w ?_ ?\( ))
-	 (insert " "))))
+    (widen)
+    (let ((opoint (point))
+	  beg end)
+      ;; Try first in this order for the sake of languages with nested
+      ;; functions where several can end at the same place as with
+      ;; the offside rule, e.g. Python.
+      (beginning-of-defun)
+      (setq beg (point))
+      (end-of-defun)
+      (setq end (point))
+      (while (looking-at "^\n")
+	(forward-line 1))
+      (unless (> (point) opoint)
+	;; beginning-of-defun moved back one defun
+	;; so we got the wrong one.
+	(goto-char opoint)
+	(end-of-defun)
+	(setq end (point))
+	(beginning-of-defun)
+	(setq beg (point)))
+      (goto-char end)
+      (re-search-backward "^\n" (- (point) 1) t)
+      (narrow-to-region beg end))))
+
+(defvar insert-pair-alist
+  '((?\( ?\)) (?\[ ?\]) (?\{ ?\}) (?\< ?\>) (?\" ?\") (?\' ?\') (?\` ?\'))
+  "Alist of paired characters inserted by `insert-pair'.
+Each element looks like (OPEN-CHAR CLOSE-CHAR) or (COMMAND-CHAR
+OPEN-CHAR CLOSE-CHAR).  The characters OPEN-CHAR and CLOSE-CHAR
+of the pair whose key is equal to the last input character with
+or without modifiers, are inserted by `insert-pair'.")
+
+(defun insert-pair (&optional arg open close)
+  "Enclose following ARG sexps in a pair of OPEN and CLOSE characters.
+Leave point after the first character.
+A negative ARG encloses the preceding ARG sexps instead.
+No argument is equivalent to zero: just insert characters
+and leave point between.
+If `parens-require-spaces' is non-nil, this command also inserts a space
+before and after, depending on the surrounding characters.
+If region is active, insert enclosing characters at region boundaries.
+
+If arguments OPEN and CLOSE are nil, the character pair is found
+from the variable `insert-pair-alist' according to the last input
+character with or without modifiers.  If no character pair is
+found in the variable `insert-pair-alist', then the last input
+character is inserted ARG times."
+  (interactive "P")
+  (if (not (and open close))
+      (let ((pair (or (assq last-command-char insert-pair-alist)
+                      (assq (event-basic-type last-command-event)
+                            insert-pair-alist))))
+        (if pair
+            (if (nth 2 pair)
+                (setq open (nth 1 pair) close (nth 2 pair))
+              (setq open (nth 0 pair) close (nth 1 pair))))))
+  (if (and open close)
+      (if (and transient-mark-mode mark-active)
+          (progn
+            (save-excursion (goto-char (region-end))       (insert close))
+            (save-excursion (goto-char (region-beginning)) (insert open)))
+        (if arg (setq arg (prefix-numeric-value arg))
+          (setq arg 0))
+        (cond ((> arg 0) (skip-chars-forward " \t"))
+              ((< arg 0) (forward-sexp arg) (setq arg (- arg))))
+        (and parens-require-spaces
+             (not (bobp))
+             (memq (char-syntax (preceding-char)) (list ?w ?_ (char-syntax close)))
+             (insert " "))
+        (insert open)
+        (save-excursion
+          (or (eq arg 0) (forward-sexp arg))
+          (insert close)
+          (and parens-require-spaces
+               (not (eobp))
+               (memq (char-syntax (following-char)) (list ?w ?_ (char-syntax open)))
+               (insert " "))))
+    (insert-char (event-basic-type last-command-event)
+                 (prefix-numeric-value arg))))
+
+(defun insert-parentheses (&optional arg)
+  "Enclose following ARG sexps in parentheses.
+Leave point after open-paren.
+A negative ARG encloses the preceding ARG sexps instead.
+No argument is equivalent to zero: just insert `()' and leave point between.
+If `parens-require-spaces' is non-nil, this command also inserts a space
+before and after, depending on the surrounding characters.
+If region is active, insert enclosing characters at region boundaries."
+  (interactive "P")
+  (insert-pair arg ?\( ?\)))
+
+(defun delete-pair ()
+  "Delete a pair of characters enclosing the sexp that follows point."
+  (interactive)
+  (save-excursion (forward-sexp 1) (delete-char -1))
+  (delete-char 1))
+
+(defun raise-sexp (&optional arg)
+  "Raise ARG sexps higher up the tree."
+  (interactive "p")
+  (let ((s (if (and transient-mark-mode mark-active)
+               (buffer-substring (region-beginning) (region-end))
+             (buffer-substring
+              (point)
+              (save-excursion (forward-sexp arg) (point))))))
+    (backward-up-list 1)
+    (delete-region (point) (save-excursion (forward-sexp 1) (point)))
+    (save-excursion (insert s))))
 
 (defun move-past-close-and-reindent ()
   "Move past next `)', delete indentation before it, then indent after it."
@@ -217,58 +460,134 @@ No argument is equivalent to zero: just insert () and leave point between."
   (while (save-excursion		; this is my contribution
 	   (let ((before-paren (point)))
 	     (back-to-indentation)
-	     (= (point) before-paren)))
+	     (and (= (point) before-paren)
+		  (progn
+		    ;; Move to end of previous line.
+		    (beginning-of-line)
+		    (forward-char -1)
+		    ;; Verify it doesn't end within a string or comment.
+		    (let ((end (point))
+			  state)
+		      (beginning-of-line)
+		      ;; Get state at start of line.
+		      (setq state  (list 0 nil nil
+					 (null (calculate-lisp-indent))
+					 nil nil nil nil
+					 nil))
+		      ;; Parse state across the line to get state at end.
+		      (setq state (parse-partial-sexp (point) end nil nil
+						      state))
+		      ;; Check not in string or comment.
+		      (and (not (elt state 3)) (not (elt state 4))))))))
     (delete-indentation))
   (forward-char 1)
   (newline-and-indent))
+
+(defun check-parens ()			; lame name?
+  "Check for unbalanced parentheses in the current buffer.
+More accurately, check the narrowed part of the buffer for unbalanced
+expressions (\"sexps\") in general.  This is done according to the
+current syntax table and will find unbalanced brackets or quotes as
+appropriate.  (See Info node `(emacs)Parentheses'.)  If imbalance is
+found, an error is signaled and point is left at the first unbalanced
+character."
+  (interactive)
+  (condition-case data
+      ;; Buffer can't have more than (point-max) sexps.
+      (scan-sexps (point-min) (point-max))
+    (scan-error (goto-char (nth 2 data))
+		;; Could print (nth 1 data), which is either
+		;; "Containing expression ends prematurely" or
+		;; "Unbalanced parentheses", but those may not be so
+		;; accurate/helpful, e.g. quotes may actually be
+		;; mismatched.
+  		(error "Unmatched bracket or quote"))
+    (error (cond ((eq 'scan-error (car data))
+		  (goto-char (nth 2 data))
+		  (error "Unmatched bracket or quote"))
+		 (t (signal (car data) (cdr data)))))))
 
-(defun lisp-complete-symbol ()
-  "Perform completion on Lisp symbol preceding point.  That symbol is
-compared against the symbols that exist and any additional characters
-determined by what is there are inserted.
-   If the symbol starts just after an open-parenthesis, only symbols
-with function definitions are considered.  Otherwise, all symbols with
-function definitions, values or properties are considered."
+(defun lisp-complete-symbol (&optional predicate)
+  "Perform completion on Lisp symbol preceding point.
+Compare that symbol against the known Lisp symbols.
+If no characters can be completed, display a list of possible completions.
+Repeating the command at that point scrolls the list.
+
+When called from a program, optional arg PREDICATE is a predicate
+determining which symbols are considered, e.g. `commandp'.
+If PREDICATE is nil, the context determines which symbols are
+considered.  If the symbol starts just after an open-parenthesis, only
+symbols with function definitions are considered.  Otherwise, all
+symbols with function definitions, values or properties are
+considered."
   (interactive)
-  (let* ((end (point))
-	 (buffer-syntax (syntax-table))
-	 (beg (unwind-protect
+
+  (let ((window (get-buffer-window "*Completions*")))
+    (if (and (eq last-command this-command)
+	     window (window-live-p window) (window-buffer window)
+	     (buffer-name (window-buffer window)))
+	;; If this command was repeated, and
+	;; there's a fresh completion window with a live buffer,
+	;; and this command is repeated, scroll that window.
+	(with-current-buffer (window-buffer window)
+	  (if (pos-visible-in-window-p (point-max) window)
+	      (set-window-start window (point-min))
+	    (save-selected-window
+	      (select-window window)
+	      (scroll-up))))
+
+      ;; Do completion.
+      (let* ((end (point))
+	     (beg (with-syntax-table emacs-lisp-mode-syntax-table
+		    (save-excursion
+		      (backward-sexp 1)
+		      (while (= (char-syntax (following-char)) ?\')
+			(forward-char 1))
+		      (point))))
+	     (pattern (buffer-substring-no-properties beg end))
+	     (predicate
+	      (or predicate
 		  (save-excursion
-		    (set-syntax-table emacs-lisp-mode-syntax-table)
-		    (backward-sexp 1)
-		    (while (= (char-syntax (following-char)) ?\')
-		      (forward-char 1))
-		    (point))
-		(set-syntax-table buffer-syntax)))
-	 (pattern (buffer-substring beg end))
-	 (predicate
-	  (if (eq (char-after (1- beg)) ?\()
-	      'fboundp
-	    (function (lambda (sym)
-			(or (boundp sym) (fboundp sym)
-			    (symbol-plist sym))))))
-	 (completion (try-completion pattern obarray predicate)))
-    (cond ((eq completion t))
-	  ((null completion)
-	   (message "Can't find completion for \"%s\"" pattern)
-	   (ding))
-	  ((not (string= pattern completion))
-	   (delete-region beg end)
-	   (insert completion))
-	  (t
-	   (message "Making completion list...")
-	   (let ((list (all-completions pattern obarray predicate)))
-	     (or (eq predicate 'fboundp)
-		 (let (new)
-		   (while list
-		     (setq new (cons (if (fboundp (intern (car list)))
-					 (list (car list) " <f>")
-				       (car list))
-				     new))
-		     (setq list (cdr list)))
-		   (setq list (nreverse new))))
-	     (with-output-to-temp-buffer " *Completions*"
-	       (display-completion-list list)))
-	   (message "Making completion list...%s" "done")))))
+		    (goto-char beg)
+		    (if (not (eq (char-before) ?\())
+			(lambda (sym)	;why not just nil ?   -sm
+			  (or (boundp sym) (fboundp sym)
+			      (symbol-plist sym)))
+		      ;; Looks like a funcall position.  Let's double check.
+		      (if (condition-case nil
+			      (progn (up-list -2) (forward-char 1)
+				     (eq (char-after) ?\())
+			    (error nil))
+			  ;; If the first element of the parent list is an open
+			  ;; parenthesis we are probably not in a funcall position.
+			  ;; Maybe a `let' varlist or something.
+			  nil
+			;; Else, we assume that a function name is expected.
+			'fboundp)))))
+	     (completion (try-completion pattern obarray predicate)))
+	(cond ((eq completion t))
+	      ((null completion)
+	       (message "Can't find completion for \"%s\"" pattern)
+	       (ding))
+	      ((not (string= pattern completion))
+	       (delete-region beg end)
+	       (insert completion))
+	      (t
+	       (message "Making completion list...")
+	       (let ((list (all-completions pattern obarray predicate)))
+		 (setq list (sort list 'string<))
+		 (or (eq predicate 'fboundp)
+		     (let (new)
+		       (while list
+			 (setq new (cons (if (fboundp (intern (car list)))
+					     (list (car list) " <f>")
+					   (car list))
+					 new))
+			 (setq list (cdr list)))
+		       (setq list (nreverse new))))
+		 (with-output-to-temp-buffer "*Completions*"
+		   (display-completion-list list)))
+	       (message "Making completion list...%s" "done")))))))
 
+;;; arch-tag: aa7fa8a4-2e6f-4e9b-9cd9-fef06340e67e
 ;;; lisp.el ends here