Way to give emacs the KDE look and feel

Controlling KDE activities via dbus

KDE can be controlled from the command line with qdbus. The general syntax is qdbus COMPONENT PATH METHOD ARGUMENT1... where COMPONENT is typically something like org.freedesktop.Foo or org.kde.Bar, PATH denotes a class exposed by the component, METHOD is the name of a particular action in that class, and there may be further arguments depending on the method.

Here are commands for KDE ≥4.7 to list activities, to get the current activity, and to set the current activity.

qdbus org.kde.kactivitymanagerd /ActivityManager org.kde.ActivityManager.ListActivities
qdbus org.kde.kactivitymanagerd /ActivityManager org.kde.ActivityManager.CurrentActivity
qdbus org.kde.kactivitymanagerd /ActivityManager org.kde.ActivityManager.SetCurrentActivity "activity identifier "

Finding out what dbus can do

KDE's dbus documentation is very poor. Each class is minimally documented, e.g. Activity, DesktopCorona). But you'll probably have to experiment and perhaps read the source (there are links in the API documentation pages) to find out what is available.

If you type qdbus with up to two arguments, it will list the possibilities for the next argument. The following shell snippet lists all available Qt-dbus methods:

for x in $(qdbus | sed '/^:/d'); do
  for y in $(qdbus $x); do
    qdbus $x $y | sed "s~^~$x $y ~"
  done
done 2>/dev/null >qdbus.list

Another way to explore the dbus tree is qdbusviewer in the Qt development tools. There is also a Python qt-dbus interface as part of PyQt.

Getting the shell to react

To make a shell react to external events, the best you can reasonably do is make it check something before displaying a prompt. Bash runs $PROMPT_COMMAND before displaying a prompt, and zsh executes the precmd function. So you can look up the current KDE activity and do something if it's changed from the last time you looked.

Type C-u before either M-: or M-! to get the result inserted instead of sent to the echo area.

To get things directly into the kill ring, you need to dabble in Elisp. Something like this (untested):

;;; kill ring version of M-!
(defun shell-command-to-kill-ring (command)
    (interactive
      (list
        (read-shell-command "Shell command: " nil nil
                (let ((filename
                       (cond
                    (buffer-file-name)
                    ((eq major-mode 'dired-mode)
                     (dired-get-filename nil t)))))
                  (and filename (file-relative-name filename))))
        current-prefix-arg
        shell-command-default-error-buffer))
    (kill-new (shell-command-to-string command)))

;;; kill-ring version of M-:
(defun eval-expression-to-kill-ring ()
    (interactive)
    (call-interactively 'eval-expression)
    (kill-new (car values)))