Calling function from PCF contraint

HI,
In Baan V I am trying to call a Baan V constraint. If the function has function declaration within body then I cannot compile constraint. e.g.

In constaint I have
! #include <itisfcc001>

In functiion itisfc001 if I have say

function tisfc001 () {
}

This will result in compilation error indicating function within function not supported.
I can though use function to define variable that can be used across the constraint without any issue.