[Seaside] Action Message propagation

[Avi Bryant]

On Sat, 14 Jun 2003, Keith P. Hodges wrote:

> Avi,
>
> if am finding a need to have some kind of semantic messaging
> framework. Whereby and inner component can signal an action and the
> message propagates out through the containership heirarchy. The
> ability to register dependants would also be useful. I have used this
> successfully in the past.

Yes, some people may remember that there was briefly such a facility in
Seaside 0.9x, inspired by NewtonScript - you could send "self container
someMessage" and it would get picked up by the first enclosing component
that could handle the message.

One goal I've had in Seaside 2.3 is to eliminate explicit parent links
in components, to allow the component hierarchy to be as dynamic as
possible.  This has been a positive move, in my opinion, and I don't want
to go back to enforcing a static hierarchy.  This makes it hard to build
in anything that traverses the containership tree.

However, you can certainly add and manage a 'parent' ivar in your
own component subclasses...

And yes, some kind of standard dependents/event system for components
might well be useful.  What kind of thing were you thinking of using this
for?