[Seaside] Updating sub-components: where?

[Michael Neumann]

Avi Bryant wrote:
> On Sat, 19 Feb 2005 12:17:17 +0100, Martin J. Laubach <mjl at laubach.at> wrote:
> 
>>   Is there a method that is called before a page is being built? I want
>>to update the visual state of my component depending on some global
>>session
>>state, possibly changing/adding some subcomponents.
>>
>>   I'm currently doing that in #children, but (a) that is called twice (I
>>guess once for the redirect, once for the real page), and (b) it
>>probably
>>(most certainly?) is not what was intended for #children.
>>
>>   Where to do that?
> 

Hi Avi,

> As a general piece of advice, I've found that Seaside apps work much
> better when built with a pull model instead of push: for example,
> determine your current subcomponents on the fly based on the state of
> the world, rather than trying to keep a list constantly up to date. 
> Polling is almost always simpler and more robust than notifying, and
> in a web application the refresh rate is low enough that there are
> usually no performance concerns.

I currently have a similar problem. So you suggest to rebuild the 
children array on each render, right?
Do you favor an extra children-build step or doing that in-place, too?
Something like this (in Ruby):

   def render
     @children.clear

     for obj in domain_objects
       r.render add_child(editor_for(obj))
     end
   end

In this case, wouldn't it be nice if "r.render" automatically adds each 
rendered child to the children array? Maybe:

   def render
     for obj in domain_objects
       r.render_child editor_for(obj)
     end
     @children = r.rendered_children
   end

Or another idea is to leave @children for static childs and have an 
@dynamic_children array, which would be reset before each render-phase 
and include the rendered children.

Regards,

   Michael