PHP:格式化JSON为PHP语法格式

1. 原生函数

$arr = [1,2,3,4];
$str = var_export($a,true);
var_dump($str);

2. 自定义方法

class Export{
  private static $space;
  private static function do($a, string $prev){
    $res = '';
    $next = $prev . self::$space;
    if (is_array($a)) {
      $res .= '[';
      foreach ($a as $k => $v)  if (is_int($k)) {
        $res .= $next . self::do($v, $next) . ',';
      } else {
        $res .= $next . self::do($k, $next) . ' => ' . self::do($v, $next) . ',';
      }
      return $res . $prev . ']';
    } else if (is_scalar($a)) {
      return is_string($a) ? '\'' . str_replace('\'', '\\\'', $a) . '\'' : json_encode($a);
    } else return 'NULL';
  }
  public static function to($a, int $space_len = 2){
    self::$space = str_repeat(' ', max($space_len, 2));
    return self::do($a, PHP_EOL);
  }
}

// $str = Export::to(转化的数据);
// var_dump($str);