Variable: bookmark-file-format-version

bookmark-file-format-version is a variable defined in bookmark.el.gz.

Value

1

Documentation

The current version of the format used by bookmark files.

You should never need to change this.

Source Code

;; Defined in /usr/src/emacs/lisp/bookmark.el.gz
;;; File format stuff

;; *IMPORTANT NOTICE* If you are thinking about modifying (redefining)
;; the bookmark file format -- please don't.  The current format
;; should be extensible enough.  If you feel the need to change it,
;; please discuss it with other Emacs developers first.
;;
;; The format of `bookmark-alist' has changed twice in its lifetime.
;; This comment describes the three formats, FIRST, SECOND, and
;; CURRENT.
;;
;; The FIRST format was used prior to Emacs 20:
;;
;;       ((BOOKMARK-NAME (FILENAME
;;                          STRING-IN-FRONT
;;                          STRING-BEHIND
;;                          POINT))
;;        ...)
;;
;; The SECOND format was introduced in Emacs 20:
;;
;;       ((BOOKMARK-NAME ((filename   . FILENAME)
;;                        (position   . POS)
;;                        (front-context-string . STR-AFTER-POS)
;;                        (rear-context-string  . STR-BEFORE-POS)
;;                        (annotation . ANNOTATION)
;;                        (whatever   . VALUE)
;;                        ...
;;                       ))
;;        ...)
;;
;; The CURRENT format was introduced in Emacs 22:
;;
;;       ((BOOKMARK-NAME (filename   . FILENAME)
;;                       (position   . POS)
;;                       (front-context-string . STR-AFTER-POS)
;;                       (rear-context-string  . STR-BEFORE-POS)
;;                       (annotation . ANNOTATION)
;;                       (whatever   . VALUE)
;;                       ...
;;                       )
;;        ...)
;;
;; Both FIRST and SECOND have the same level of nesting: the cadr of a
;; bookmark record is a list of entry information.  FIRST and SECOND
;; differ in the form of the record information: FIRST uses a list of
;; atoms, and SECOND uses an alist.  In the FIRST format, the order of
;; the list elements matters.  In the SECOND format, the order of the
;; alist elements is unimportant.  The SECOND format facilitates the
;; addition of new kinds of elements, to support new kinds of
;; bookmarks or code evolution.
;;
;; The CURRENT format removes a level of nesting wrt FIRST and SECOND,
;; saving one cons cell per bookmark: the cadr of a bookmark record is
;; no longer a cons.  Why that change was made remains a mystery --
;; just be aware of it.  (Be aware too that this explanatory comment
;; was incorrect in Emacs 22 and Emacs 23.1.)
;;
;; To deal with the change from FIRST format to SECOND, conversion
;; code was added, which is no longer used and has been declared
;; obsolete.  See `bookmark-maybe-upgrade-file-format'.
;;
;; No conversion from SECOND to CURRENT is done.  Instead, the code
;; handles both formats OK.  It must continue to do so.
;;
;; See the doc string of `bookmark-alist' for information about the
;; elements that define a bookmark (e.g. `filename').


(defconst bookmark-file-format-version 1
  "The current version of the format used by bookmark files.
You should never need to change this.")