{
    my $cmpval;
    BEGIN {
        $cmpval= sub {
            my ($val1, $val2) = @_;
            if (ref($val1) eq 'Node') { $val1 = $$val1{node_id}; };
            if (ref($val2) eq 'Node') { $val2 = $$val2{node_id}; }
            $val1 eq $val2;
        };
    }

    sub getWorkspace {
    # ...
             $match = 0 unless &$cmpval($$N{$_}, $$WHERE{$_});
    # ...
    }
}