+# blackbox for %filtered
+{
+ my %filtered;
+
+ sub alreadyfiltered($$) { #{{{
+ my $page=shift;
+ my $destpage=shift;
+
+ return ( exists $filtered{$page}{$destpage}
+ && $filtered{$page}{$destpage} eq 1 );
+ } #}}}
+
+ sub setalreadyfiltered($$) { #{{{
+ my $page=shift;
+ my $destpage=shift;
+
+ $filtered{$page}{$destpage}=1;
+ } #}}}
+
+ sub unsetalreadyfiltered($$) { #{{{
+ my $page=shift;
+ my $destpage=shift;
+
+ if (exists $filtered{$page}{$destpage}) {
+ delete $filtered{$page}{$destpage};
+ }
+ } #}}}
+
+ sub resetalreadyfiltered() { #{{{
+ undef %filtered;
+ } #}}}
+}
+