一个explode()函数忽略引号内的字符？

function customExplode($delimiter, $string) {
    $result = array();
    $quote = false;
    $buffer = '';
    
    for ($i = 0; $i < strlen($string); $i++) {
        $char = $string[$i];
        
        if ($char == '"') {
            $quote = !$quote;
        } elseif ($char == $delimiter && !$quote) {
            $result[] = $buffer;
            $buffer = '';
        } else {
            $buffer .= $char;
        }
    }
    
    $result[] = $buffer;
    
    return $result;
}

$string = 'apple, "banana, cherry", grape';
$result = customExplode(',', $string);
print_r($result);

Array
(
    [0] => apple
    [1] => "banana, cherry"
    [2] => grape
)