RosettaCodeData/Task/Anonymous-recursion/Zkl/anonymous-recursion.zkl

fcn fib(n){
   if (n<0) throw(Exception.ValueError);
   fcn(n){
      if (n < 2) return(1);
      else       return(self.fcn(n-1) + self.fcn(n-2));
   }(n);
}
fib(8) .println();
fib(-8).println();