I'm using XML::Simple to get chatterbox lines from the XML ticker. Calling XMLin($url) puts the data into a nested list. If there's only one line in the CB the data looks like this (simplified): 
$data = {
 'foo' => {
           'one' => '1',
           'two' => '2'
          }
};

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But if there's more, say two lines, we get this: 
$data = {
 'foo' => [{
            'one' => '1',
            'two' => '2'
           },
           {
            'one' => '1',
            'two' => '2'
           }]
};

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Thanks to a lesson from dkubb on references i know how to extract the data from either one, and setup some conditions to check if we have one or the other, but one still fails if the other succeeds.

If there's multiple cb lines the condition checking for one line: 

if(exists $data->{'foo'}->{'one'}){
..code..
}

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fails with "Bad index while coercing array into hash"

And if there's one line the condition checking for multiple lines: 

if(defined @{$data->{'foo'}}){
..code..
}

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fails with "Not an ARRAY reference".

I can see why this is happening, and pretty much understand the errors, but don't know how to properly test these conditions and escape the catch-22. Thanks in advance to whoever saves me from endless hours of "hack, hack, hack, did that work?" debugging.

In reply to Testing Complex Data Structures by epoptai

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