Lambda dan Clousure serta callback

<?php

//contoh lambda

$call = function($say){

    return "HAllo + ".$say;

};

echo $call('rifki');

?>

<hr>

<?php

//contoh clousur

$name = " rifki";

$hello = function() use ($name) {

    echo "HAllo + ".$name;

};

$hello();

?>

<hr>

<?php

//clousue dengan callback

$user = array("muhammad","rifki");

array_walk($user, function($name){

    echo "HAllo + ".$name ."<br>";

});

?>