org-colview: Allow simultaneous columns views

* lisp/org-colview.el (org-columns-overlays):
(org-columns-begin-marker):
(org-columns-top-level-marker): Make variables buffer local.

(org-columns-remove-overlays): Assume columns view are to be removed
in current buffer.

(org-columns-edit-allowed): Small refactoring.  Raise an error when
called although no columns view is active in current buffer.

(org-columns-goto-top-level):
(org-columns):
(org-agenda-columns): Do not assume `org-columns-begin-marker' and
`org-columns-top-level-marker' are markers.

(org-columns-store-format):
(org-columns-redo): Skip if no columns view is current active.

(org-agenda-colview-compute): Do not let-bind
`org-columns-begin-marker' and `org-columns-top-level-marker'.

etc/ORG-NEWS

@@ -370,6 +370,10 @@ Call ~org-agenda-set-restriction-lock~ from the agenda.
 
 ** Miscellaneous
 
+*** Allow multiple columns view
+
+Columns view is not limited to a single buffer anymore.
+
 *** Org Attach obeys ~dired-dwim-target~
 
 When a Dired buffer is opened next to the Org document being edited,

lisp/org-colview.el

@@ -94,12 +94,9 @@ in `org-columns-summary-types-default', which see."
 
 ;;; Column View
 
-(defvar org-columns-overlays nil
+(defvar-local org-columns-overlays nil
   "Holds the list of current column overlays.")
 
-(defvar org-columns--time 0.0
-  "Number of seconds since the epoch, as a floating point number.")
-
 (defvar-local org-columns-current-fmt nil
   "Local variable, holds the currently active column format.")
 
@@ -110,12 +107,15 @@ This is the compiled version of the format.")
 (defvar-local org-columns-current-maxwidths nil
   "Currently active maximum column widths, as a vector.")
 
-(defvar org-columns-begin-marker (make-marker)
+(defvar-local org-columns-begin-marker nil
   "Points to the position where last a column creation command was called.")
 
-(defvar org-columns-top-level-marker (make-marker)
+(defvar-local org-columns-top-level-marker nil
   "Points to the position where current columns region starts.")
 
+(defvar org-columns--time 0.0
+  "Number of seconds since the epoch, as a floating point number.")
+
 (defvar org-columns-map (make-sparse-keymap)
   "The keymap valid in column display.")
 
@@ -458,23 +458,22 @@ for the duration of the command.")
 (defun org-columns-remove-overlays ()
   "Remove all currently active column overlays."
   (interactive)
-  (when (marker-buffer org-columns-begin-marker)
+  (when org-columns-overlays
-    (with-current-buffer (marker-buffer org-columns-begin-marker)
     (when (local-variable-p 'org-previous-header-line-format)
       (setq header-line-format org-previous-header-line-format)
       (kill-local-variable 'org-previous-header-line-format)
       (remove-hook 'post-command-hook 'org-columns-hscroll-title 'local))
-      (move-marker org-columns-begin-marker nil)
+    (set-marker org-columns-begin-marker nil)
-      (move-marker org-columns-top-level-marker nil)
+    (set-marker org-columns-top-level-marker nil)
     (org-with-silent-modifications
-       (mapc 'delete-overlay org-columns-overlays)
+     (mapc #'delete-overlay org-columns-overlays)
      (setq org-columns-overlays nil)
      (let ((inhibit-read-only t))
        (remove-text-properties (point-min) (point-max) '(read-only t))))
     (when org-columns-flyspell-was-active
       (flyspell-mode 1))
     (when (local-variable-p 'org-colview-initial-truncate-line-value)
-	(setq truncate-lines org-colview-initial-truncate-line-value)))))
+      (setq truncate-lines org-colview-initial-truncate-line-value))))
 
 (defun org-columns-compact-links (s)
   "Replace [[link][desc]] with [desc] or [link]."
@@ -613,20 +612,20 @@ Where possible, use the standard interface for changing this line."
   (let* ((pom (or (org-get-at-bol 'org-marker)
 		  (org-get-at-bol 'org-hd-marker)
 		  (point)))
-	 (key (get-char-property (point) 'org-columns-key))
+	 (key (concat (or (get-char-property (point) 'org-columns-key)
-	 (key1 (concat key "_ALL"))
+			  (user-error "No column to edit at point"))
-	 (allowed (org-entry-get pom key1 t))
+		      "_ALL"))
-	 nval)
+	 (allowed (org-entry-get pom key t))
+	 (new-value (read-string "Allowed: " allowed)))
     ;; FIXME: Cover editing TODO, TAGS etc in-buffer settings.????
     ;; FIXME: Write back to #+PROPERTY setting if that is needed.
-    (setq nval (read-string "Allowed: " allowed))
     (org-entry-put
      (cond ((marker-position org-entry-property-inherited-from)
 	    org-entry-property-inherited-from)
 	   ((marker-position org-columns-top-level-marker)
 	    org-columns-top-level-marker)
 	   (t pom))
-     key1 nval)))
+     key new-value)))
 
 (defun org-columns--call (fun)
   "Call function FUN while preserving heading visibility.
@@ -760,6 +759,8 @@ current specifications.  This function also sets
 (defun org-columns-goto-top-level ()
   "Move to the beginning of the column view area.
 Also sets `org-columns-top-level-marker' to the new position."
+  (unless (markerp org-columns-top-level-marker)
+    (setq org-columns-top-level-marker (make-marker)))
   (goto-char
    (move-marker
     org-columns-top-level-marker
@@ -782,7 +783,9 @@ When COLUMNS-FMT-STRING is non-nil, use it as the column format."
   (interactive "P")
   (org-columns-remove-overlays)
   (when global (goto-char (point-min)))
+  (if (markerp org-columns-begin-marker)
       (move-marker org-columns-begin-marker (point))
+    (setq org-columns-begin-marker (point-marker)))
   (org-columns-goto-top-level)
   ;; Initialize `org-columns-current-fmt' and
   ;; `org-columns-current-fmt-compiled'.
@@ -940,9 +943,8 @@ starting the current column display, or in a #+COLUMNS line of
 the current buffer."
   (let ((fmt (org-columns-uncompile-format org-columns-current-fmt-compiled)))
     (setq-local org-columns-current-fmt fmt)
-    (when (marker-position org-columns-top-level-marker)
+    (when org-columns-overlays
-      (org-with-wide-buffer
+      (org-with-point-at org-columns-top-level-marker
-       (goto-char org-columns-top-level-marker)
 	(if (and (org-at-heading-p) (org-entry-get nil "COLUMNS"))
 	    (org-entry-put nil "COLUMNS" fmt)
 	  (goto-char (point-min))
@@ -994,18 +996,17 @@ the current buffer."
 (defun org-columns-redo ()
   "Construct the column display again."
   (interactive)
+  (when org-columns-overlays
     (message "Recomputing columns...")
-  (org-with-wide-buffer
+    (org-with-point-at org-columns-begin-marker
-   (when (marker-position org-columns-begin-marker)
-     (goto-char org-columns-begin-marker))
       (org-columns-remove-overlays)
       (if (derived-mode-p 'org-mode)
-       ;; Since we already know the columns format, provide it instead
+	  ;; Since we already know the columns format, provide it
-       ;; of computing again.
+	  ;; instead of computing again.
 	  (call-interactively #'org-columns org-columns-current-fmt)
 	(org-agenda-redo)
 	(call-interactively #'org-agenda-columns)))
-  (message "Recomputing columns...done"))
+    (message "Recomputing columns...done")))
 
 (defun org-columns-uncompile-format (compiled)
   "Turn the compiled columns format back into a string representation.
@@ -1489,7 +1490,9 @@ PARAMS is a property list of parameters:
   "Turn on or update column view in the agenda."
   (interactive)
   (org-columns-remove-overlays)
+  (if (markerp org-columns-begin-marker)
       (move-marker org-columns-begin-marker (point))
+    (setq org-columns-begin-marker (point-marker)))
   (let* ((org-columns--time (float-time (current-time)))
 	 (fmt
 	  (cond
@@ -1608,11 +1611,8 @@ This will add overlays to the date lines, to show the summary for each day."
 
 (defun org-agenda-colview-compute (fmt)
   "Compute the relevant columns in the contributing source buffers."
-  (let ((files org-agenda-contributing-files)
+  (dolist (file org-agenda-contributing-files)
-	(org-columns-begin-marker (make-marker))
+    (let ((b (find-buffer-visiting file)))
-	(org-columns-top-level-marker (make-marker)))
-    (dolist (f files)
-      (let ((b (find-buffer-visiting f)))
       (with-current-buffer (or (buffer-base-buffer b) b)
 	(org-with-wide-buffer
 	 (org-with-silent-modifications
@@ -1627,7 +1627,7 @@ This will add overlays to the date lines, to show the summary for each day."
 	      ((and (nth 3 spec)
 		    (let ((a (assoc prop org-columns-current-fmt-compiled)))
 		      (equal (nth 3 a) (nth 3 spec))))
-		 (org-columns-compute prop)))))))))))
+	       (org-columns-compute prop))))))))))
 
 
 (provide 'org-colview)