Re: Patch for "virtual buffers" in iswitchb

[John Wiegley]

After receiving an e-mail from the author of recentf -- which is
already part of the Emacs distribution and handles maintenance of a
list of "recently opened files" -- I've altered the virtual buffers
patch to iswitchb.el to use that package instead of doing the work
itself:

--- iswitchb.el 18 Apr 2004 03:28:12 -0700      1.48
+++ iswitchb.el 20 Apr 2004 14:30:00 -0700      
@@ -305,6 +305,20 @@
   :type 'integer
   :group 'iswitchb)
 
+(defcustom iswitchb-use-virtual-buffers nil
+  "*If non-nil, refer to past buffers when none match.
+This feature relies upon the `recentf' package, which will be
+enabled if this variable is configured to a non-nil value."
+  :type 'boolean
+  :require 'recentf
+  :set (function
+       (lambda (sym value)
+         (recentf-mode value)
+         (set sym value)))
+  :group 'iswitchb)
+
+(defvar iswitchb-virtual-buffers nil)
+
 (defcustom iswitchb-cannot-complete-hook 'iswitchb-completion-help
   "*Hook run when `iswitchb-complete' can't complete any more.
 The most useful values are `iswitchb-completion-help', which pops up a
@@ -613,7 +627,16 @@
     (if (and (not (eq iswitchb-exit 'usefirst))
             (get-buffer iswitchb-final-text))
        ;; This happens for example if the buffer was chosen with the mouse.
-       (setq iswitchb-matches (list iswitchb-final-text)))
+       (setq iswitchb-matches (list iswitchb-final-text)
+             iswitchb-virtual-buffers nil))
+
+    (if (and iswitchb-use-virtual-buffers
+            iswitchb-virtual-buffers
+            (not (iswitchb-existing-buffer-p)))
+       (let ((virt (car iswitchb-virtual-buffers)))
+         (find-file-noselect virt)
+         (setq iswitchb-matches (list (file-name-nondirectory virt))
+               iswitchb-virtual-buffers nil)))
 
     ;; Handling the require-match must be done in a better way.
     (if (and require-match (not (iswitchb-existing-buffer-p)))
@@ -833,7 +856,8 @@
       (setq iswitchb-matches
            (let* ((buflist iswitchb-buflist))
              (iswitchb-get-matched-buffers iswitchb-text iswitchb-regexp
-                                           buflist)))))
+                                           buflist))
+           iswitchb-virtual-buffers nil)))
 
 (defun iswitchb-get-matched-buffers (regexp
                                     &optional string-format buffer-list)
@@ -1225,6 +1253,33 @@
                             first)
          (setq comps  (cons first (cdr comps)))))
 
+    ;; If no buffers matched, and virtual buffers are being used, then
+    ;; consult the list of past visited files, to see if we can find
+    ;; the file which the user might thought was still open.
+    (when (and iswitchb-use-virtual-buffers (null comps)
+              recentf-list)
+      (setq iswitchb-virtual-buffers nil)
+      (let ((head recentf-list) name)
+       (while head
+         (if (and (null (find-buffer-visiting (car head)))
+                  (setq name (file-name-nondirectory (car head)))
+                  (or (if iswitchb-regexp
+                          (string-match iswitchb-text name))
+                      (string-match (regexp-quote iswitchb-text) name))
+                  (not (iswitchb-ignore-buffername-p name))
+                  (file-exists-p (car head)))
+             (setq iswitchb-virtual-buffers
+                   (cons (car head) iswitchb-virtual-buffers)))
+         (setq head (cdr head)))
+       (setq comps (mapcar 'file-name-nondirectory
+                           (nreverse iswitchb-virtual-buffers)))
+       (let ((comp comps))
+         (while comp
+           (put-text-property 0 (length (car comp))
+                              'face 'font-lock-builtin-face
+                              (car comp))
+           (setq comp (cdr comp))))))
+
     (cond ((null comps) (format " %sNo match%s"
                                open-bracket-determined
                                close-bracket-determined))