4 files changed, 149 insertions, 55 deletions

diff --git a/doc/lispref/ChangeLog b/doc/lispref/ChangeLog
index 89b456f5c22..062692ee9f3 100644
--- a/doc/lispref/ChangeLog
+++ b/doc/lispref/ChangeLog
@@ -1,3 +1,11 @@
+2012-11-16  Martin Rudalics  <rudalics@gmx.at>
+
+        * windows.texi (Choosing Window): Rewrite description of
+        display-buffer-alist (Bug#12167).
+        (Display Action Functions): Mention inhibit-switch-frame.  Fix
+        description of display-buffer-below-selected.  Reorder actions.
+        Add example (Bug#12848).
+
 2012-11-15  Stefan Monnier  <monnier@iro.umontreal.ca>
 
         * keymaps.texi (Translation Keymaps): Add a subsection "Interaction
diff --git a/doc/lispref/windows.texi b/doc/lispref/windows.texi
index bb02b1d54fd..77f1ff9a179 100644
--- a/doc/lispref/windows.texi
+++ b/doc/lispref/windows.texi
@@ -1766,6 +1766,7 @@ Like @code{switch-to-buffer}, this function updates the buffer list
 unless @var{norecord} is non-@code{nil}.
 @end deffn
 
+
 @node Choosing Window
 @section Choosing a Window for Display
 
@@ -1851,10 +1852,14 @@ default value is empty, i.e. @code{(nil . nil)}.
 @end defvar
 
 @defopt display-buffer-alist
-The value of this option is an alist mapping regular expressions to
-display actions.  If the name of the buffer passed to
-@code{display-buffer} matches a regular expression in this alist, then
-@code{display-buffer} uses the corresponding display action.
+The value of this option is an alist mapping conditions to display
+actions.  Each condition may be either a regular expression matching a
+buffer name or a function that takes two arguments - a buffer name and
+the @var{action} argument passed to @code{display-buffer}.  If the name
+of the buffer passed to @code{display-buffer} either matches a regular
+expression in this alist or the function specified by a condition
+returns non-@code{nil}, then @code{display-buffer} uses the
+corresponding display action to display the buffer.
 @end defopt
 
 @defopt display-buffer-base-action
@@ -1868,6 +1873,7 @@ This display action specifies the fallback behavior for
 @code{display-buffer} if no other display actions are given.
 @end defvr
 
+
 @node Display Action Functions
 @section Action Functions for @code{display-buffer}
 
@@ -1911,8 +1917,9 @@ normally searches just the selected frame; however, if the variable
 @code{pop-up-frames} is non-@code{nil}, it searches all frames on the
 current terminal.  @xref{Choosing Window Options}.
 
-If this function chooses a window on another frame, it makes that
-frame visible and raises it if necessary.
+If this function chooses a window on another frame, it makes that frame
+visible and, unless @var{alist} contains an @code{inhibit-switch-frame}
+entry (@pxref{Choosing Window Options}), raises that frame if necessary.
 @end defun
 
 @defun display-buffer-pop-up-frame buffer alist
@@ -1976,16 +1983,12 @@ reason (e.g. if there is just one frame and it has an
 @code{unsplittable} frame parameter; @pxref{Buffer Parameters}).
 @end defun
 
-@defun display-buffer-use-some-window buffer alist
-This function tries to display @var{buffer} by choosing an existing
-window and displaying the buffer in that window.  It can fail if all
-windows are dedicated to another buffer (@pxref{Dedicated Windows}).
-@end defun
-
 @defun display-buffer-below-selected buffer alist
 This function tries to display @var{buffer} in a window below the
-selected window.  This means to either split the selected window or
-reuse the window below the selected one.
+selected window.  This means to either split the selected window or use
+the window below the selected one.  If it does create a new window, it
+will also adjust its size provided @var{alist} contains a suitable
+@code{window-height} or @code{window-width} entry, see above.
 @end defun
 
 @defun display-buffer-in-previous-window buffer alist
@@ -2001,6 +2004,83 @@ specified by that entry will override any other window found by the
 methods above, even if that window never showed @var{buffer} before.
 @end defun
 
+@defun display-buffer-use-some-window buffer alist
+This function tries to display @var{buffer} by choosing an existing
+window and displaying the buffer in that window.  It can fail if all
+windows are dedicated to another buffer (@pxref{Dedicated Windows}).
+@end defun
+
+To illustrate the use of action functions, consider the following
+example.
+
+@example
+@group
+(display-buffer
+ (get-buffer-create "*foo*")
+ '((display-buffer-reuse-window
+    display-buffer-pop-up-window
+    display-buffer-pop-up-frame)
+   (reusable-frames . 0)
+   (window-height . 10) (window-width . 40)))
+@end group
+@end example
+
+@noindent
+Evaluating the form above will cause @code{display-buffer} to proceed as
+follows: If `*foo*' already appears on a visible or iconified frame, it
+will reuse its window.  Otherwise, it will try to pop up a new window
+or, if that is impossible, a new frame.  If all these steps fail, it
+will try to use some existing window.
+
+   Furthermore, @code{display-buffer} will try to adjust a reused window
+(provided `*foo*' was put by @code{display-buffer} there before) or a
+popped-up window as follows: If the window is part of a vertical
+combination, it will set its height to ten lines.  Note that if, instead
+of the number ``10'', we specified the function
+@code{fit-window-to-buffer}, @code{display-buffer} would come up with a
+one-line window to fit the empty buffer.  If the window is part of a
+horizontal combination, it sets its width to 40 columns.  Whether a new
+window is vertically or horizontally combined depends on the shape of
+the window split and the values of
+@code{split-window-preferred-function}, @code{split-height-threshold}
+and @code{split-width-threshold} (@pxref{Choosing Window Options}).
+
+   Now suppose we combine this call with a preexisting setup for
+`display-buffer-alist' as follows.
+
+@example
+@group
+(let ((display-buffer-alist
+       (cons
+        '("\\*foo\\*"
+          (display-buffer-reuse-window display-buffer-below-selected)
+          (reusable-frames)
+          (window-height . 5))
+        display-buffer-alist)))
+  (display-buffer
+   (get-buffer-create "*foo*")
+   '((display-buffer-reuse-window
+      display-buffer-pop-up-window
+      display-buffer-pop-up-frame)
+     (reusable-frames . 0)
+     (window-height . 10) (window-width . 40))))
+@end group
+@end example
+
+@noindent
+Evaluating this form will cause @code{display-buffer} to first try
+reusing a window showing @code{*foo*} on the selected frame.
+If no such window exists, it will try to split the selected window or,
+if that is impossible, use the window below the selected window.
+
+   If there's no window below the selected one, or the window below the
+selected one is dedicated to its buffer, @code{display-buffer} will
+proceed as described in the previous example.  Note, however, that when
+it tries to adjust the height of any reused or popped-up window, it will
+in any case try to set its number of lines to ``5'' since that value
+overrides the corresponding specification in the @var{action} argument
+of @code{display-buffer}.
+
 
 @node Choosing Window Options
 @section Additional Options for Displaying Buffers
diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 74d66809d55..a267c726986 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,16 @@
+2012-11-16  Martin Rudalics  <rudalics@gmx.at>
+
+        * window.el (enlarge-window, shrink-window): Don't mention return
+        value in doc-string (Bug#12896).
+        (window--display-buffer): Don't resize frames - it won't work
+        with all window managers and defeat pop-up-frame-alist.
+        (display-buffer-alist): In doc-string explain that CONDITION can
+        be a function and which arguments are passed to it (Bug#12854).
+        (display-buffer-assq-regexp): New argument ACTION.  Handle lambda
+        expressions (Bug#12854).
+        (display-buffer): Pass ACTION argument to
+        display-buffer-assq-regexp.
+
 2012-11-16  Glenn Morris  <rgm@gnu.org>
 
         * window.el (fit-frame-to-buffer-bottom-margin)
diff --git a/lisp/window.el b/lisp/window.el
index c9ea8351e8c..9ac3a4ecda0 100644
--- a/lisp/window.el
+++ b/lisp/window.el
@@ -2571,8 +2571,7 @@ move it as far as possible in the desired direction."
 Interactively, if no argument is given, make the selected window
 one line taller.  If optional argument HORIZONTAL is non-nil,
 make selected window wider by DELTA columns.  If DELTA is
-negative, shrink selected window by -DELTA lines or columns.
-Return nil."
+negative, shrink selected window by -DELTA lines or columns."
   (interactive "p")
   (let ((minibuffer-window (minibuffer-window)))
     (cond
@@ -2605,8 +2604,7 @@ Interactively, if no argument is given, make the selected window
 one line smaller.  If optional argument HORIZONTAL is non-nil,
 make selected window narrower by DELTA columns.  If DELTA is
 negative, enlarge selected window by -DELTA lines or columns.
-Also see the `window-min-height' variable.
-Return nil."
+Also see the `window-min-height' variable."
   (interactive "p")
   (let ((minibuffer-window (minibuffer-window)))
     (cond
@@ -5176,11 +5174,12 @@ is higher than WINDOW."
       (error nil))))
 
 (defun window--display-buffer (buffer window type &optional alist dedicated)
-  "Display BUFFER in WINDOW and make its frame visible.
+  "Display BUFFER in WINDOW.
 TYPE must be one of the symbols `reuse', `window' or `frame' and
-is passed unaltered to `display-buffer-record-window'. Set
-`window-dedicated-p' to DEDICATED if non-nil.  Return WINDOW if
-BUFFER and WINDOW are live."
+is passed unaltered to `display-buffer-record-window'.  ALIST is
+the alist argument of `display-buffer'.  Set `window-dedicated-p'
+to DEDICATED if non-nil.  Return WINDOW if BUFFER and WINDOW are
+live."
   (when (and (buffer-live-p buffer) (window-live-p window))
     (display-buffer-record-window type window buffer)
     (unless (eq buffer (window-buffer window))
@@ -5193,10 +5192,10 @@ BUFFER and WINDOW are live."
     (let ((parameter (window-parameter window 'quit-restore))
           (height (cdr (assq 'window-height alist)))
           (width (cdr (assq 'window-width alist))))
-      (when (or (memq type '(window frame))
+      (when (or (eq type 'window)
                 (and (eq (car parameter) 'same)
-                     (memq (nth 1 parameter) '(window frame))))
-        ;; Adjust height of new window or frame.
+                     (eq (nth 1 parameter) 'window)))
+        ;; Adjust height of window if asked for.
         (cond
          ((not height))
          ((numberp height)
@@ -5207,19 +5206,12 @@ BUFFER and WINDOW are live."
                      (* (window-total-size (frame-root-window window))
                         height))))
                  (delta (- new-height (window-total-size window))))
-            (cond
-             ((and (window--resizable-p window delta nil 'safe)
-                   (window-combined-p window))
-              (window-resize window delta nil 'safe))
-             ((or (eq type 'frame)
-                  (and (eq (car parameter) 'same)
-                       (eq (nth 1 parameter) 'frame)))
-              (set-frame-height
-               (window-frame window)
-               (+ (frame-height (window-frame window)) delta))))))
+            (when (and (window--resizable-p window delta nil 'safe)
+                       (window-combined-p window))
+              (window-resize window delta nil 'safe))))
          ((functionp height)
           (ignore-errors (funcall height window))))
-        ;; Adjust width of a window or frame.
+        ;; Adjust width of window if asked for.
         (cond
          ((not width))
          ((numberp width)
@@ -5230,18 +5222,12 @@ BUFFER and WINDOW are live."
                      (* (window-total-size (frame-root-window window) t)
                         width))))
                  (delta (- new-width (window-total-size window t))))
-            (cond
-             ((and (window--resizable-p window delta t 'safe)
-                   (window-combined-p window t))
-              (window-resize window delta t 'safe))
-             ((or (eq type 'frame)
-                  (and (eq (car parameter) 'same)
-                       (eq (nth 1 parameter) 'frame)))
-              (set-frame-width
-               (window-frame window)
-               (+ (frame-width (window-frame window)) delta))))))
+            (when (and (window--resizable-p window delta t 'safe)
+                       (window-combined-p window t))
+              (window-resize window delta t 'safe))))
          ((functionp width)
           (ignore-errors (funcall width window))))))
+
     window))
 
 (defun window--maybe-raise-frame (frame)
@@ -5301,13 +5287,19 @@ See `display-buffer' for details.")
   "Alist of conditional actions for `display-buffer'.
 This is a list of elements (CONDITION . ACTION), where:
 
- CONDITION is either a regexp matching buffer names, or a function
-  that takes a buffer and returns a boolean.
+ CONDITION is either a regexp matching buffer names, or a
+  function that takes two arguments - a buffer name and the
+  ACTION argument of `display-buffer' - and returns a boolean.
 
  ACTION is a cons cell (FUNCTION . ALIST), where FUNCTION is a
   function or a list of functions.  Each such function should
   accept two arguments: a buffer to display and an alist of the
-  same form as ALIST.  See `display-buffer' for details."
+  same form as ALIST.  See `display-buffer' for details.
+
+`display-buffer' scans this alist until it either finds a
+matching regular expression or the function specified by a
+condition returns non-nil.  In any of these cases, it adds the
+associated action to the list of actions it will try."
   :type `(alist :key-type
                 (choice :tag "Condition"
                         regexp
@@ -5341,15 +5333,16 @@ specified, e.g. by the user options `display-buffer-alist' or
 `display-buffer-base-action'.  See `display-buffer'.")
 (put 'display-buffer-fallback-action 'risky-local-variable t)
 
-(defun display-buffer-assq-regexp (buffer-name alist)
-  "Retrieve ALIST entry corresponding to BUFFER-NAME."
+(defun display-buffer-assq-regexp (buffer-name alist action)
+  "Retrieve ALIST entry corresponding to BUFFER-NAME.
+ACTION is the action argument passed to `display-buffer'."
   (catch 'match
     (dolist (entry alist)
       (let ((key (car entry)))
         (when (or (and (stringp key)
                        (string-match-p key buffer-name))
-                  (and (symbolp key) (functionp key)
-                       (funcall key buffer-name alist)))
+                  (and (functionp key)
+                       (funcall key buffer-name action)))
           (throw 'match (cdr entry)))))))
 
 (defvar display-buffer--same-window-action
@@ -5459,8 +5452,8 @@ argument, ACTION is t."
         (funcall display-buffer-function buffer inhibit-same-window)
       ;; Otherwise, use the defined actions.
       (let* ((user-action
-              (display-buffer-assq-regexp (buffer-name buffer)
-                                          display-buffer-alist))
+              (display-buffer-assq-regexp
+               (buffer-name buffer) display-buffer-alist action))
              (special-action (display-buffer--special-action buffer))
              ;; Extra actions from the arguments to this function:
              (extra-action