Slightly tweaked and committed, thanks. Also merged to FRAMEWORK_3 to 
line up Nag 2.1 with Kronolith 2.1.

I at least thought about doing the check for the return value but I 
guess I never added it.  Here's an updated version and it handles 
editing and deleting too.

Looks good. The only nit I found is that you probably want to check if 
the return value of _add() is an error and don't proceed in this case.

Are you going to update the patch to hook into editing and deleting, 
or should I commit it for now?

Also, I left $priority in as a parameter for notification.  I was 
thinking that it could be used to set the X-Priority header in the 
email that is generated.

Here is a patch that implements notifications as suggested.  It 
currently only handles notifications when tasks are added but could be 
extended in the same manner for modifications or deletions.  I added a 
$uid parameter to the kolab driver, only because it existed in the SQL 
driver, but it looks like they are autogenerated anyway, so it might 
not be necessary.  The notification could be changed to work with a 
user's 'date_format' and 'time_format' preferences, but I think that 
would only make sense if time_format was in the horde preference scope 
and not imp.

Not quite, the backend specific code goes into Driver_foo::_add(), 
because you will call these methods from the parent class, not the 
parent class' method from the inherited class.
It makes a lot of sense, because you would make notifications work 
with *all* driver at once.

If I understand you right, that would mean leaving the backend 
specific code in Driver_foo::add() and drawing the common code into 
Driver::add()?



I really only wanted to get notifications working, but if it makes 
sense to make those changes, I can certainly try :)

How about splitting up add() to Driver::add() and Driver_foo::_add()? 
History logging and notificiation would be done in add() and the 
actual adding in _add().

Here's an attempt to add email notifications for tasks.  I found it 
simpler to model the Kronolith code for this, so this also implements 
a (largely unused) Nag_Task object, based on the Kronolith_Event 
object.  Notifications are currently only supported in the SQL driver, 
although it should be easily adapted to the Kolab driver, but I have 
no way of testing that.

This feature would be similar to the option available in Kronolith, 
where you can choose the types of actions for an event on your 
calendar that generate a notification for you.  Example, if someone 
adds a task to your tasklist, you could choose to be notified by email 
that a new task has been addded.