rem - return true (-1) if even, otherwise false (0)
function even(i = integer) = integer
var one = integer    rem - both operands must be variables
one = 1
end = ((i and one) = 0)

rem - exercise the function
var i = integer
for i = 1 to 10 step 3
   print i; " is ";
   if even(i) then
     print "even"
   else
     print "odd"
next

end