Parse an expression into parts
string $expression Expression to parse:
array Returns an associative array of parts
private function parseExpression($expression) {
// Check for URI operators
$operator = '';
if (isset(self::$operatorHash[$expression[0]])) {
$operator = $expression[0];
$expression = substr($expression, 1);
}
$values = explode(',', $expression);
foreach ($values as &$value) {
$value = trim($value);
$varspec = array();
$substrPos = strpos($value, ':');
if ($substrPos) {
$varspec['value'] = substr($value, 0, $substrPos);
$varspec['modifier'] = ':';
$varspec['position'] = (int) substr($value, $substrPos + 1);
}
elseif (substr($value, -1) == '*') {
$varspec['modifier'] = '*';
$varspec['value'] = substr($value, 0, -1);
}
else {
$varspec['value'] = (string) $value;
$varspec['modifier'] = '';
}
$value = $varspec;
}
return array(
'operator' => $operator,
'values' => $values,
);
}