Here is a pretty simple example
in first.tcl:
set x [list a b c d]
in first.adp:
<master>
<form action="next">
<list name="x">
<input type="text" name="var.@x:rownum@" value="@x:item@">
</list>
<input type="submit">
</form>
in next.tcl :
ad_page_contract {
next page
} {
var:array
}
doc_return 200 text/plain [array get var]