[PATCH] Window-groups

[joakim]

Heres a patch to implement Window-groups in Emacs, which I submit for
review.  Theres comments in the patch to explain what Window-groups are
in practice. In brief, the aim is to create Emacs primitives useful to ECB
like frameworks. 

The code builds on top of the already comitted window-properties code.
The patch has C level changes and an elisp interface.

To understand the design rationale, please read previous rather
long-winded window group threads. The patch is a joint effort between
me, Stefan Monnier, Chong Yidong, and Martin Rudalics.



=== modified file 'lisp/window.el'
--- lisp/window.el      2008-06-17 22:33:06 +0000
+++ lisp/window.el      2008-06-22 12:25:44 +0000
@@ -1625,5 +1625,77 @@
 (define-key ctl-x-map "+" 'balance-windows)
 (define-key ctl-x-4-map "0" 'kill-buffer-and-window)
 
+
+;; Below are functions for managing window-groups.  Window
+;; groups allow windows in a frame a degree of separation from other
+;; windows in the same frame, similar to the way windows in different
+;; frames are separated from each other.
+
+;; Here's some examples.
+
+;; Make a new frame and split it vertically:
+;;    (split-window-horizontally)
+;; Call the left side the  "Context Area" and the left one the "Edit Area".
+;; Now make the "Context Area" into a group:
+;;    (window-group-create (selected-window))
+;; Theres actually two groups now, the "Context Area" and the default "Edit 
Area".
+;; Now try "c-x o". Notice that you dont go to the "Edit Area".
+;; Now try splitting the "Context Area" with "c-x 2", and switch buffers a bit 
+;; Now try removing windows with "c-x 0". Notice that only windows in the
+;; current group are affected.
+;; To return the state as it was:
+;;    (window-group-dissolve (window-group (selected-window)))
+
+
+(defun window-group (window)
+  "Return the window group object that WINDOW belongs to.
+Return nil if WINDOW is not in a window group."
+  (window-parameter window 'group))
+
+(defun window-group-member-p (window group)
+  "Non nil if WINDOW is a member of GROUP."
+  (eq group (window-group window)))
+
+(defun window-group-members (group)
+  "Return all windows in GROUP.
+Must be in selected frame."
+  (let ((group-windows ()))
+    (walk-windows
+     (lambda (w)
+       (when (window-group-member-p w group )
+         (push w group-windows))))
+    group-windows))
+
+(defvar window-group--counter 0
+  "An internal variable to keep track of window groups.")
+
+(defun window-group-create (window)
+  "Return a window group object with WINDOW as its only member.
+An error is signalled if WINDOW is not visible or already part of
+a group."
+  (if (window-group window)
+      (error "Window %s is already part of group %s"
+             ;;TODO check that the resulting error is not nonsensical
+             window (window-group window)))
+  ;;TODO we should now test for window visibility
+  (setq window-group--counter (1+ window-group--counter))
+  (let* ((name (concat "group-" (number-to-string window-group--counter)))
+         (group (make-symbol name)))
+    (set-window-parameter window 'group group)
+    group))
+
+(defun window-group-dissolve (group)
+  "Dissolve the window group object GROUP.
+The windows in the group are not deleted."
+  (let ((group-windows (window-group-members group)))
+    (if (null group-windows)
+        (error "No group %s on current frame" group)
+      ;;TODO I think the group id is not suitable for printing!
+      (dolist (win group-windows)
+        (set-window-parameter win 'group nil)))))
+
+(provide 'window-group)
+
+
 ;; arch-tag: b508dfcc-c353-4c37-89fa-e773fe10cea9
 ;;; window.el ends here

=== modified file 'src/window.c'
--- src/window.c        2008-06-10 22:08:42 +0000
+++ src/window.c        2008-06-19 13:25:41 +0000
@@ -54,6 +54,7 @@
 Lisp_Object Qwindowp, Qwindow_live_p, Qwindow_configuration_p;
 Lisp_Object Qdisplay_buffer;
 Lisp_Object Qscroll_up, Qscroll_down;
+Lisp_Object Qgroup;
 Lisp_Object Qwindow_size_fixed;
 
 extern Lisp_Object Qleft_margin, Qright_margin;
@@ -82,7 +83,8 @@
                                         Lisp_Object *));
 static int foreach_window_1 P_ ((struct window *,
                                 int (* fn) (struct window *, void *),
-                                void *));
+                                void *,
+                                 int));
 static Lisp_Object window_list_1 P_ ((Lisp_Object, Lisp_Object, Lisp_Object));
 
 /* This is the window in which the terminal's cursor should
@@ -1041,7 +1043,7 @@
 
   window = Qnil;
   cw.window = &window, cw.x = &x, cw.y = &y; cw.part = part;
-  foreach_window (f, check_window_containing, &cw);
+  foreach_window (f, check_window_containing, &cw, 1);
 
   /* If not found above, see if it's in the tool bar window, if a tool
      bar exists.  */
@@ -1733,7 +1735,8 @@
 static Lisp_Object
 window_list ()
 {
-  if (!CONSP (Vwindow_list))
+  //if(!CONSP (Vwindow_list))
+  if (1) //never cache the window list for now FIXME
     {
       Lisp_Object tail;
 
@@ -1746,7 +1749,7 @@
             new windows at the front of args[1], which means we
             have to reverse this list at the end.  */
          args[1] = Qnil;
-         foreach_window (XFRAME (XCAR (tail)), add_window_to_list, &args[1]);
+         foreach_window (XFRAME (XCAR (tail)), add_window_to_list, &args[1], 
0);
          args[0] = Vwindow_list;
          args[1] = Fnreverse (args[1]);
          Vwindow_list = Fnconc (2, args);
@@ -2213,7 +2216,7 @@
            break;
 
          case DELETE_OTHER_WINDOWS:
-           if (!EQ (window, obj))
+            if (!EQ (window, obj) )
              Fdelete_window (window);
            break;
 
@@ -3882,6 +3885,12 @@
   adjust_glyphs (fo);
 
   Fset_window_buffer (new, o->buffer, Qt);
+  /* make the new window inherit group properties.  We
+     inherit only those atm, because its not obvious that all
+     properties should be inherited
+   */
+  if(!NILP(Fwindow_parameter(window, Qgroup)))
+    Fset_window_parameter(new, Qgroup, Fwindow_parameter(window, Qgroup));
   return new;
 }
 
@@ -6826,17 +6835,20 @@
 
 /* Call FN for all leaf windows on frame F.  FN is called with the
    first argument being a pointer to the leaf window, and with
-   additional argument USER_DATA.  Stops when FN returns 0.  */
+   additional argument USER_DATA.  Stops when FN returns 0.
+   ALLWINDOWS 1 means iterate every window, else only the group of the 
selected window
+*/
 
 void
-foreach_window (f, fn, user_data)
+foreach_window (f, fn, user_data, allwindows)
      struct frame *f;
      int (* fn) P_ ((struct window *, void *));
      void *user_data;
+     int allwindows;
 {
   /* Fdelete_frame may set FRAME_ROOT_WINDOW (f) to Qnil.  */
   if (WINDOWP (FRAME_ROOT_WINDOW (f)))
-    foreach_window_1 (XWINDOW (FRAME_ROOT_WINDOW (f)), fn, user_data);
+    foreach_window_1 (XWINDOW (FRAME_ROOT_WINDOW (f)), fn, 
user_data,allwindows);
 }
 
 
@@ -6846,22 +6858,31 @@
    Stop when FN returns 0.  Value is 0 if stopped by FN.  */
 
 static int
-foreach_window_1 (w, fn, user_data)
+foreach_window_1 (w, fn, user_data, allwindows)
      struct window *w;
      int (* fn) P_ ((struct window *, void *));
      void *user_data;
+     int allwindows;
 {
   int cont;
-
+  struct window *current_window=XWINDOW(selected_window);
+  register Lisp_Object group = Fcdr(Fassq(Qgroup, 
current_window->window_parameters));
+  Lisp_Object group2;
   for (cont = 1; w && cont;)
     {
       if (!NILP (w->hchild))
-       cont = foreach_window_1 (XWINDOW (w->hchild), fn, user_data);
+       cont = foreach_window_1 (XWINDOW (w->hchild), fn, user_data,allwindows);
       else if (!NILP (w->vchild))
-       cont = foreach_window_1 (XWINDOW (w->vchild), fn, user_data);
-      else
-       cont = fn (w, user_data);
-
+       cont = foreach_window_1 (XWINDOW (w->vchild), fn, user_data,allwindows);
+      else{
+        //only call fn if the group of the frames selected window 
+        //is the same as the group of the current window in the loop.
+        group2=Fcdr(Fassq(Qgroup,w->window_parameters));
+        debug_print(group);
+        debug_print(group2);
+        if (allwindows || EQ(group ,  group2  ))
+          cont = fn (w, user_data);
+      }
       w = NILP (w->next) ? 0 : XWINDOW (w->next);
     }
 
@@ -6900,7 +6921,7 @@
      struct frame *f;
      int freeze_p;
 {
-  foreach_window (f, freeze_window_start, (void *) (freeze_p ? f : 0));
+  foreach_window (f, freeze_window_start, (void *) (freeze_p ? f : 0),1);
 }
 
 
@@ -7061,6 +7082,10 @@
 void
 syms_of_window ()
 {
+
+  Qgroup = intern ("group");
+  staticpro (&Qgroup);
+
   Qscroll_up = intern ("scroll-up");
   staticpro (&Qscroll_up);
 

=== modified file 'src/window.h'
--- src/window.h        2008-06-06 00:00:29 +0000
+++ src/window.h        2008-06-07 22:28:47 +0000
@@ -784,7 +784,8 @@
 extern void freeze_window_starts P_ ((struct frame *, int));
 extern void foreach_window P_ ((struct frame *,
                                int (* fn) (struct window *, void *),
-                               void *));
+                               void *,
+                                int allwindows));
 extern void grow_mini_window P_ ((struct window *, int));
 extern void shrink_mini_window P_ ((struct window *));
 


-- 
Joakim Verona