fib=lambda -> {
       fib1=lambda (x)->If(x>1->lambda(x-1)+lambda(x-2), x)
      =lambda fib1 (x) -> {
            If x<0 then Error "argument outside of range"
            If x<2 then =x : exit
            =fib1(x)
      }
}()  ' using () execute this lambda so fib get the returned lambda
Module  CheckIt (&k()) {
      Print k(12)
}
CheckIt &Fib()
Try {
      Print fib(-2)
}
Print Error$
Z=Fib
Print Z(12)
Dim a(10)
a(3)=Z
Print a(3)(12)=144
Inventory Alfa = "key1":=Z
Print Alfa("key1")(12)=144