When you write in PHP $$name, parser treats it as variable, wchich name is value of $name – it works like pointer:
<? $var1 = 'test1'; $var2 = 'test2'; $a = 'var1'; echo $$a.'<br>'; $a = 'var2'; echo $$a; ?>
output:
test1 test2
In PHP we can use function eval in order to evaluate given variable (string) as PHP code:
<? $var = 'for ($i=0;$i<5;$i++) { echo $i.\'<br>\'; }'; eval($var); ?>
output:
0 1 2 3 4