is there a way to explode this reliably even if there is commas inside the desired chunks?
PHP by default does not provide such a function. However you have a compact subset of PHP inside your string and PHP offers some tools here: A PHP tokenizer and a PHP parser.
Therefore it's possible for your string specification to create a helper function that validates the input against allowed tokens and then parse it:
$str = "array(1,3,4),array(array(4,5,6)),'this is a comma , inside a string', array('asdf' => 'lalal')";
function explode_string($str)
{
$result = NULL;
// validate string
$isValid = FALSE;
$tokens = token_get_all(sprintf('
The tokens used are:
T_LNUMBER (305)
T_CONSTANT_ENCAPSED_STRING (315)
T_DOUBLE_ARROW (358)
T_ARRAY (360)
T_WHITESPACE (371)
The token index number can be given a token name by using token_name.
Which gives you (Demo):
Array
(
[0] => Array
(
[0] => 1
[1] => 3
[2] => 4
)
[1] => Array
(
[0] => Array
(
[0] => 4
[1] => 5
[2] => 6
)
)
[2] => this is a comma , inside a string
[3] => Array
(
[asdf] => lalal
)
)
