define / const /static と種類は豊富
<?php
define('MESSAGE', 100); // OK
define('MESSAGE1', 100 + 10); // OK
define('MESSAGE2', time()); // OK
const MESSAGE1 = 100; // OK
const MESSAGE3 = 100 + 10; // NG
const MESSAGE2 = time(); // NG
static $MESSAGE = 'Hello World';ネタ元
