TWiki::AggregateIterator
my $it = new TWiki::ListIterator(\@list); while ($it->hasNext()) { ...
{filter}
can be defined to be a sub that filters each entry. The entry will be ignored (next() will not return it) if the filter returns false.
{process}
can be defined to be a sub to process each entry before it is returned by next. The value returned from next is the value returned by the process function.