not quite Olliegod :P $1 // 2 checks $1 is a factor of 2. you want the reverse, 2 // $1

there\'s lots of ways to accomplish this, FLCL\'s methods are probably amongst the worst i\'ve seen (sorry, just seems like you\'ve copied techniques without understanding them at all :P), here\'s quite possibly the shortest method:

alias iseven return $isodd($calc($1 -1))
alias isodd return $istok(1,$and($1,1),0)

there\'s a lot of other conditions you can use to check $1 is odd/even :P

if ($1 & 1) ; odd
if ($1 !& 1) ; even

if (1 \\\\ $calc($1 / 2)) ; odd
if (1 // $calc($1 / 2)) ; even

if ($calc($1 % 2)) ; odd
if (!$calc($1 % 2)) ; even

if ($1 == $or($1,1)) ; odd
if ($1 != $or($1,1)) ; even

and the list goes on :P