iterators: traversing arbitrary data structure

[dimar]

Given a data structure like this ...

$oWkBook    = {
    students =>[
        {fname=>'joe',lname=>'bloe',age=>'18'},
        {fname=>'jill',lname=>'bill',age=>'16'},
    ],
    teachers => [
        {fname=>'joe',lname=>'sloe',age=>'38'},
        {fname=>'jill',lname=>'sill',age=>'36'},
    ],
    admins  =>[
        {fname=>'koe',lname=>'moe',age=>'58'},
        {fname=>'dill',lname=>'mill',age=>'56'},
    ],
};

How can I change this ...

### iterate (current)
for my $oWkSheet (keys %{$oWkBook}){
    for my $oRec (@{$oWkBook->{$oWkSheet}}){
        for my $oFld (keys %{$oRec}){
            $oRec->{$oFld} =~ s/^\s+\n$//;
        };
    };
};

into this ...

### iterate (wanted)
for my $item ($oWkBook->iterate_fields()){
    $item   =~ s/^\s+\n$//;
};

I've given SuperSearch a say, but it seems the examples assume a simple sequence of items (e.g. array), when what I want to do is iterate over an arbitrarily-nested data structure. (e.g. HoAoH)

My long term goal is to be able to reproduce this pattern regardless of the structure of the data variable. The request here is for a link or an example of handling HoAoH with iterators that I can use as a starting point for understanding this design pattern a little better.