Just spent about a half hour debugging this. It's such a shame that if you try to do anything neat in PHP, stupid behaviour foils your plan:
php > $n = NULL;
php > var_dump($n['something']);
NULL
php > var_dump($n[0]);
NULL
How this makes any sense is beyond me. It even happens if $n is FALSE...
Python, for comparison, throws an exception sanely:
In [1]: n = None
In [2]: n['something']
TypeError: 'NoneType' object is unsubscriptable
