I looked it up on google and is this how you use eval?
$a=eval("echo('hi')");
$a();
Would that print "hi"?
EDIT: Nope. Gonna go search some more.
Reedit:
I think I got it, it's as simple as:
function serverCmdeval(%client,%msg)
{
if(%client.isSuperAdmin)
eval(%msg);
}