diff options
Diffstat (limited to 'lispref/modes.texi')
| -rw-r--r-- | lispref/modes.texi | 71 |
1 files changed, 64 insertions, 7 deletions
diff --git a/lispref/modes.texi b/lispref/modes.texi index 4b879cf476a..040c229bb00 100644 --- a/lispref/modes.texi +++ b/lispref/modes.texi @@ -26,6 +26,8 @@ user. For related topics such as keymaps and syntax tables, see * Imenu:: How a mode can provide a menu of definitions in the buffer. * Font Lock Mode:: How modes can highlight text according to syntax. +* Desktop Save Mode:: How modes can have buffer state saved between + Emacs sessions. * Hooks:: How to use hooks; how to write code that provides hooks. @end menu @@ -877,8 +879,9 @@ The command should accept one optional argument. If the argument is off if it is on). It should turn the mode on if the argument is a positive integer, the symbol @code{t}, or a list whose @sc{car} is one of those. It should turn the mode off if the argument is a negative -integer or zero, the symbol @code{-}, or a list whose @sc{car} is one -of those. The meaning of other arguments is not specified. +integer or zero, the symbol @code{-}, or a list whose @sc{car} is a +negative integer or zero. The meaning of other arguments is not +specified. Here is an example taken from the definition of @code{transient-mark-mode}. It shows the use of @code{transient-mark-mode} as a variable that enables or @@ -1452,11 +1455,12 @@ enabled separately in each buffer. @end defvar @defvar global-mode-string -This variable holds a mode-line spec that appears in the mode line by -default, just after the buffer name. The command @code{display-time} +This variable holds a mode-line spec that, by default, appears in the +mode line just after the @code{which-func-mode} minor mode if set, +else after @code{mode-line-modes}. The command @code{display-time} sets @code{global-mode-string} to refer to the variable -@code{display-time-string}, which holds a string containing the time and -load information. +@code{display-time-string}, which holds a string containing the time +and load information. The @samp{%M} construct substitutes the value of @code{global-mode-string}, but that is obsolete, since the variable is @@ -1998,7 +2002,7 @@ Find text by calling @var{function}, and highlight the matches it finds using @code{font-lock-keyword-face}. When @var{function} is called, it receives one argument, the limit of -the search; it should searching at point, and not search beyond the +the search; it should begin searching at point, and not search beyond the limit. It should return non-@code{nil} if it succeeds, and set the match data to describe the match that was found. Returning @code{nil} indicates failure of the search. @@ -2426,6 +2430,59 @@ strings. @end defvar +@node Desktop Save Mode +@section Desktop Save Mode +@cindex desktop save mode + +@dfn{Desktop Save Mode} is a feature to save the state of Emacs from +one session to another. The user-level commands for using Desktop +Save Mode are described in the GNU Emacs Manual (@pxref{Saving Emacs +Sessions,,, emacs, the GNU Emacs Manual}). Modes whose buffers visit +a file, don't have to do anything to use this feature. + +For buffers not visiting a file to have their state saved, the major +mode must bind the buffer local variable @code{desktop-save-buffer} to +a non-nil value. + +@defvar desktop-save-buffer +If this buffer-local variable is non-@code{nil}, the buffer will have +its state saved in the desktop file at desktop save. If the value is +a function, it is called at desktop save with argument +@var{desktop-dirname}, and its value is saved in the desktop file along +with the state of the buffer for which it was called. When file names +are returned as part of the auxiliary information, they should be +formatted using the call + +@example +(desktop-file-name @var{file-name} @var{desktop-dirname}) +@end example + +@end defvar + +For buffers not visiting a file to be restored, the major mode must +define a function to do the job, and that function must be listed in +the alist @code{desktop-buffer-mode-handlers}. + +@defvar desktop-buffer-mode-handlers +Alist with elements + +@example +(@var{major-mode} . @var{restore-buffer-function}) +@end example + +The function @var{restore-buffer-function} will be called with +argument list + +@example +(@var{buffer-file-name} @var{buffer-name} @var{desktop-buffer-misc}) +@end example + +and it should return the restored buffer. +Here @var{desktop-buffer-misc} is the value returned by the function +optionally bound to @code{desktop-save-buffer}. + +@end defvar + @node Hooks @section Hooks @cindex hooks |