fcn middle(ns){
   ns.apply("toString").apply('-("-"))
   .apply(fcn(n){nl:=n.len();
      if(nl<3 or nl.isEven) return(False);
      n[(nl-3)/2,3] : "%03d".fmt(_)
   })
}
middle(T(123,12345,1234567,987654321,10001,-10001,-123,-100,100,-12345)).println()
middle(T(1, 2, -1, -10, 2002, -2002, 0)).println();