Tips that can come as question in PHP certification

Tips.md

🚫 Functions names are case-insensitive !

<?php

define('CONSTANT', 1);
define('_CONSTANT', 0);
define('EMPTY', '');

if (!empty(EMPTY)) {
    # ...
} elseif (constant('CONSTANT')) {
    # ...
}

// user function
function my_func()
{
    echo 'Je suis une mouche';
}

MY_FUNC();

# This code will produce Parse error because empty() === EMPTY()

BUT 🚫 variables names are case-insensitive !

<?php
$var = 'my var';
echo $VAR, PHP_EOL; // Notice: Undefined variable: VAR