Ok, like this 
print join ' ', UniqueWalkers( $struct );

sub UniqueWalkers {
    my %found;
    
    Data::Walk::walk(
        sub {
            if (/^values$/) {
                foreach ( keys %{ $Data::Walk::container->{$_} } ) {
                    $found{$_}++;
                }
            }
            return;
        },
        @_
    );
    return sort keys %found;
}

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In reply to Re^5: How to find all occurrences of a key in a deeply nested structure? by Anonymous Monk
in thread How to find all occurrences of a key in a deeply nested structure? by deMize

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