Cycling through favored buffers

[Rami A]

Hi,

I have some code in my dotemacs file that would allow me to switch between 
opened files and ignoring specific buffers, like "TAGS" "Messages" and some 
folder names "headers" "source". I am binding this behavior to both C-Tab and 
C-M-Tab.

I have two questions"
1. How do I ignore "all directory type buffers" and limit the switching to be 
between files only.

2. How do I create another list of buffers that only includes directories 
"headers" and "source" and when press a combination of keys lets say C-M-S-Tab 
to cycle through only these?

This is the snippet of code that I have:


;; Control TABbuffer Cycling
; necessary support function for buffer burial
(defun crs-delete-these (delete-these from-this-list)
  "Delete DELETE-THESE FROM-THIS-LIST."
  (cond
   ((car delete-these)
    (if (member (car delete-these) from-this-list)
        (crs-delete-these (cdr delete-these) (delete (car delete-these)
                                                     from-this-list))
      (crs-delete-these (cdr delete-these) from-this-list)))
   (t from-this-list)))

; this is the list of buffers I never want to see
(defvar crs-hated-buffers
  '("KILL" "*Compile-Log*" "*Buffer List*" "*Messages*"
    "*compilation*" "TAGS" "*scratch*" "source" "headers"))
; might as well use this for both
(setq iswitchb-buffer-ignore (append '("^ " "*Buffer") crs-hated-buffers))

(defun crs-hated-buffers ()
  "List of buffers I never want to see, converted from names to buffers."
  (delete nil
          (append
           (mapcar 'get-buffer crs-hated-buffers)
           (mapcar (lambda (this-buffer)
                     (if (string-match "^ " (buffer-name this-buffer))
                         this-buffer))
                   (buffer-list)))))
; I'm sick of switching buffers only to find KILL right in front of me
(defun crs-bury-buffer (&optional n)
  (interactive)
  (unless n
    (setq n 1))
  (let ((my-buffer-list (crs-delete-these (crs-hated-buffers)
                                          (buffer-list (selected-frame)))))
    (switch-to-buffer
     (if (< n 0)
         (nth (+ (length my-buffer-list) n)
              my-buffer-list)
       (bury-buffer)
       (nth n my-buffer-list)))))
; Key Bindings
(global-set-key [(control tab)] 'crs-bury-buffer)
(global-set-key [(control meta tab)] (lambda ()
                                       (interactive)
                                       (crs-bury-buffer -1)))