Reading “this” and “use” arguments from a PHP closure

Question

When you create a method that returns a closure in PHP:

class ExampleClass {
  public function test() {
    $example = 10;

    return function() use ($examp         


        

Answer 1

It seems you may have overlooked some of the ReflectionFunction methods.

Take a look at the ReflectionFunction::getClosureThis() method. I tracked it down by looking through the PHP 7 source code by doing a search for the zend_get_closure_this_ptr() which is defined in zend_closures.c.

The manual currently doesn't have a lot of documentation for this function. I'm using 7.0.9; try running this code based on your example:

class ExampleClass {
  private $testProperty = 33;

  public function test() {
    $example = 10;

    return function() use ($example) {
      return $example;
    };
  }
}

$instance = new ExampleClass();
$closure = $instance->test();

print_r($closure);

$func = new ReflectionFunction($closure);
print_r($func->getClosureThis());

You should get output similar to

Closure Object
(
    [static] => Array
        (
            [example] => 10
        )

    [this] => ExampleClass Object
        (
            [testProperty:ExampleClass:private] => 33
        )

)

ExampleClass Object
(
    [testProperty:ExampleClass:private] => 33
)

Regarding the closure static variables, these are returned with ReflectionFunction::getStaticVariables():

php > var_dump($func->getStaticVariables());
array(1) {
  ["example"]=>
  int(10)
}