(import std.Math)
(import std.String)

(let middle_three_digits (fun (i) {
  (let s (toString (math:abs i)))
  (if (and (math:odd (len s)) (>= (len s) 3))
    (string:slice s (- (/ (len s) 2) 1) 3)
    "Need odd and at least 3 digits") }))

(import std.List :forEach)

(forEach [123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345]
  (fun (x) (print (middle_three_digits x))))
(forEach [1 2 -1 -10 2002 -2002 0]
  (fun (x) (print (middle_three_digits x))))