Mikhail Osher

>>> date('d.m.Y H:i:s', strtotime('this week monday', 1454944515));
=> "08.02.2016 00:00:00"
>>> date('d.m.Y H:i:s', strtotime('this week monday', time()));
=> "08.02.2016 00:00:00"

switch (true):
    case ($_SESSION['user_group'] ?? null) === 1:
        // admin
        break;
    case ($_SESSION['user_group'] ?? null) === 5:
        // user
        break;
    default:
        // guest
        break;
endswitch;

<?php

$foo = function () {
    return 1;
};

$bar = function () {
    return 2;
};

var_dump(
    spl_object_hash($foo),
    spl_object_hash($bar)
);