lookup into different dataset

lookup into different dataset

using syntax like:

lookup($row->{from}, 'on_path' => 'on_col', sub {
	# $on is record from on_path dataset
	# where $on_col matches $row->{$from}

	map {
		push @{$update->{on_id}} => $_;
	} @{$on->{id2}}
});