/**
* Parses a character separated list of instructions or null if the
* sequence is not valid
*
* @param callable $fn Parsing instruction function
* @param array $args Arguments that will be passed to the function
* @param string $char Separator
*
* @return array
*
* @throws Exception
*/
protected function charSeparatedListOf($fn, $args = array(), $char = ",")
{
$list = array();
$valid = true;
while ($param = call_user_func_array(array($this, $fn), $args)) {
$list[] = $param;
$valid = true;
if (!$this->scanner->consume($char)) {
break;
} else {
$valid = false;
}
}
if (!$valid) {
return $this->error();
}
return $list;
}
