Demonstrating how to assign to private class members in PHP (not recommended)

SomeClass.php

<?php

class SomeClass {
    private $priv;
    public $pub;
}

// This function demonstrates how to access and assign to private
// or undeclared class members using Closure::bindTo
function assignPrivate($obj, $key, $value) {
    $fn = function($k, $v) {
        $this->$k = $v;
    };
    $boundFn = $fn->bindTo($obj, $obj);
    $boundFn($key, $value);
    return $obj;
}

$o = new SomeClass;
$o->pub = 'a';
assignPrivate($o, 'priv', 'b');
assignPrivate($o, 'undeclared', 'c');

$expected = 'SomeClass Object
(
    [priv:SomeClass:private] => b
    [pub] => a
    [undeclared] => c
)
';

assert(print_r($o, true) == $expected);
print_r($o);