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The editor command loop sets several Lisp variables to keep status records for itself and for commands that are run.
This variable records the name of the previous command executed by the command loop (the one before the current command). Normally the value is a symbol with a function definition, but this is not guaranteed.
The value is copied from
this-command
when a command returns to the command loop, except when the command has specified a prefix argument for the following command.This variable is always local to the current terminal and cannot be buffer-local. See Multiple Displays.
This variable is set up by Emacs just like
last-command
, but never altered by Lisp programs.
This variable records the name of the command now being executed by the editor command loop. Like
last-command
, it is normally a symbol with a function definition.The command loop sets this variable just before running a command, and copies its value into
last-command
when the command finishes (unless the command specified a prefix argument for the following command).Some commands set this variable during their execution, as a flag for whatever command runs next. In particular, the functions for killing text set
this-command
tokill-region
so that any kill commands immediately following will know to append the killed text to the previous kill.
If you do not want a particular command to be recognized as the previous
command in the case where it got an error, you must code that command to
prevent this. One way is to set this-command
to t
at the
beginning of the command, and set this-command
back to its proper
value at the end, like this:
(defun foo (args...)
(interactive ...)
(let ((old-this-command this-command))
(setq this-command t)
...do the work...
(setq this-command old-this-command)))
We do not bind this-command
with let
because that would
restore the old value in case of error—a feature of let
which
in this case does precisely what we want to avoid.
This function returns a string or vector containing the key sequence that invoked the present command, plus any previous commands that generated the prefix argument for this command. The value is a string if all those events were characters. See Input Events.
(this-command-keys) ;; Now use C-u C-x C-e to evaluate that. => "^U^X^E"
Like
this-command-keys
, except that it always returns the events in a vector, so you don't need to deal with the complexities of storing input events in a string (see Strings of Events).
This function empties out the table of events for
this-command-keys
to return, and also empties the records that the functionrecent-keys
(see Recording Input) will subsequently return. This is useful after reading a password, to prevent the password from echoing inadvertently as part of the next command in certain cases.
This variable holds the last input event read as part of a key sequence, not counting events resulting from mouse menus.
One use of this variable is for telling
x-popup-menu
where to pop up a menu. It is also used internally byy-or-n-p
(see Yes-or-No Queries).
This variable is set to the last input event that was read by the command loop as part of a command. The principal use of this variable is in
self-insert-command
, which uses it to decide which character to insert.last-command-event ;; Now use C-u C-x C-e to evaluate that. => 5The value is 5 because that is the ascii code for C-e.
The alias
last-command-char
exists for compatibility with Emacs version 18.
This variable records which frame the last input event was directed to. Usually this is the frame that was selected when the event was generated, but if that frame has redirected input focus to another frame, the value is the frame to which the event was redirected. See Input Focus.