gistfile1.php

<?php

$context = 'foobar';

$closure = function($value, $index) use($context) {
    var_dump($context);
    var_dump($value * 2);
};

unset($context);

foreach(array(23, 42) as $index => $value) {
    $closure($value, $index);
}


string(6) "foobar"
int(46)
string(6) "foobar"
int(84)