Mobile Web Device Match

function mobile_web_device_match($class_capabilities, $user_capabilities) {
    $group_pass   = FALSE;
    // Default operator is AND
    $operator     = $class_capabilities['operator'] ? $class_capabilities['operator'] : 'AND';
    foreach ($class_capabilities['support'] as $logic) {
      if (array_key_exists('support', $logic)) {
        $match = mobile_web_device_match($logic, $user_capabilities); // Recurse, yo
        if (!$match) {
          return FALSE;
        }
      }
      else {
        // Default comparison operator is ==
        $comparison = $logic['comparison'] ? $logic['comparison'] : '==';
        $user_value = '';
        $cap        = $logic['capability'];
        $user_value = $user_capabilities[$cap];
        $test_value = $logic['value'];
        $pass       = FALSE;

        switch ($comparison) {  // Trying to avoid using eval()
          case '==':
            if ($user_value == $test_value) {
              $pass = TRUE;
            }
            break;
          case '!=':
            if ($user_value != $test_value) {
              $pass = TRUE;
            }
            break;
          case '>':
            if ($user_value > $test_value) {
              $pass = TRUE;
            }
            break;
          case '<':
            if ($user_value < $test_value) {
              $pass = TRUE;
            }
            break;
          case '>=':
            if ($user_value >= $test_value) {
              $pass = TRUE;
            }
            break;
          case '<=':
            if ($user_value <= $test_value) {
              $pass = TRUE;
            }
            break;
          case 'LIKE':
            if (strpos($user_value, $test_value) !== FALSE) {
              $pass = TRUE;
            }
            break;
          case 'NOT LIKE':
            if (strpos($user_value, $test_value) === FALSE) {
              $pass = TRUE;
            }
            break;
          default:
            if ($user_value == $test_value) {
              $pass = TRUE;
            }
            break;
        }
        // Test: $user_value $comparison $test_value
        // If fail AND operator == AND, return false
        $result = ($pass) ? "PASS" : "FAIL";
        if ($pass) {
          $group_pass = TRUE;
        }
        else if (!$pass && $operator == 'AND') {
          $group_pass = FALSE;
          break;
        }
      }
    }
    return $group_pass;
  }