Forum OpenACS Q&A: Re: Templating System : Designer Guide : Tag Reference : Property

And, just as another example, some properties are aggregated up the hierarchy:

ADP:
<property name="header_stuff">
@header_stuff;noquote@
... some more ...
</property>

TCL:
if { ![info exists header_stuff] } {
set header_stuff {}
}

(Theres possibly a more beautyful way...)