PHP匿名函数在某些安装上导致语法错误

Question

I have the following code:

    $file_check_method_func = function($n) {
        $n = absint($n);
        if(1 !== $n) { $n = 0; }
        return $n;
    };
    $valid['file_check_method'] = array_map($file_check_method_func, $input['file_check_method']);

This works on my PHP 5.3.5 installation but when I run this code on a PHP 5.2.15 installation I get:

Parse error: syntax error, unexpected T_FUNCTION in /home/xxxx/public_html/xxxx/xxxxxxx/wp-content/plugins/wordpress-file-monitor-plus/classes/wpfmp.settings.class.php on line 220

Line 220 being the first line of the above code.

So my question(s), is there something wrongly written in my code that would give this error? If not is it because of a bug or not supported feature in PHP 5.2.15? If yes then how can I write the above code so not to generate the error?

The above code is in a function in a class.

Answer 1

Anonymous functions is a feature added in 5.3

For earlier versions, create a named function and refer it by name. Eg.:

function file_check_method_func($n) {
    $n = absint($n);
    if(1 !== $n) { $n = 0; }
    return $n;
}
$valid['file_check_method'] = array_map('file_check_method_func', $input['file_check_method']);

or inside a class:

class Foo {
  protected function file_check_method_func($n) {
    $n = absint($n);
    if(1 !== $n) { $n = 0; }
    return $n;
  }
  function validate($input) {
    $valid = array();
    $valid['file_check_method'] = array_map(array($this, 'file_check_method_func'), $input['file_check_method']);
    return $valid;
  }
}

I would strongly suggest not to rely on create_function.