SEL has a now known issue with certain configurations of brackets (parenthesis).  This is a very limited situation and shouldn’t in most cases affect your code.  At the moment it has been identified:

$x=&ceil(($var)/2);  ## will not evaluate ceil

$x=&ceil($var/2); ## will evaluate ceil

… which seems to indicate a more general problem of parenthesis handling in my code somewhere.  Or maybe it’s simply parameter handling. as the expression within the parens actually evaluates fine.  I’m not sure yet.