Nextstep applications receive a number of special events which have no X equivalent. These are sent as specially defined key events, which do not correspond to any sequence of keystrokes. Under Emacs, these key events can be bound to functions just like ordinary keystrokes. Here is a list of these events.
This event occurs when another Nextstep application requests that
Emacs open a file. A typical reason for this would be a user
double-clicking a file in the Finder application. By default, Emacs
responds to this event by opening a new frame and visiting the file in
that frame (
ns-find-file). As an exception, if the selected
buffer is the *scratch* buffer, Emacs visits the file in the
You can change how Emacs responds to a
ns-open-file event by
changing the variable ns-pop-up-frames. Its default value,
‘fresh’, is what we have just described. A value of t
means to always visit the file in a new frame. A value of
means to always visit the file in an existing frame.
This event occurs when another application requests that Emacs open a
temporary file. By default, this is handled by just generating a
ns-open-file event, the results of which are described above.
Some applications, such as ProjectBuilder and gdb, request not only a
particular file, but also a particular line or sequence of lines in
the file. Emacs handles this by visiting that file and highlighting
the requested line (
This event occurs when a user drags files from another application
into an Emacs frame. The default behavior is to insert the contents
of all the dragged files into the current buffer
ns-insert-files). The list of dragged files is stored in the
This event occurs when a user drags a color from the color well (or
some other source) into an Emacs frame. The default behavior is to
alter the foreground color of the area the color was dragged onto
ns-set-foreground-at-mouse). If this event is issued with a
Shift modifier, Emacs changes the background color instead
ns-set-background-at-mouse). The name of the dragged color is
stored in the variable ns-input-color.
This event occurs when the user selects a font in a Nextstep font
panel (which can be opened with Cmd-t). The default behavior is
to adjust the font of the selected frame
ns-respond-to-changefont). The name and size of the selected
font are stored in the variables
This event occurs when the user logs out and Emacs is still running, or when “Quit Emacs” is chosen from the application menu. The default behavior is to save all file-visiting buffers.
Emacs also allows users to make use of Nextstep services, via a set
of commands whose names begin with ‘ns-service-’ and end with the
name of the service. Type M-x ns-service-TAB to
see a list of these commands. These functions either operate on
marked text (replacing it with the result) or take a string argument
and return the result as a string. You can also use the Lisp function
ns-perform-service to pass arbitrary strings to arbitrary
services and receive the results back. Note that you may need to
restart Emacs to access newly-available services.