xojoc

#lang typed/racket

(require math/array)

(: possible-moves ((Array Fixnum) Indexes -> (Listof Indexes)))
(define (possible-moves arr idx)
  (let ((shape (array-shape arr)))
    (cast
     (filter (λ ([i : (Vector Integer Integer)]) (and (< -1 (vector-ref i 0) (vector-ref shape 0))
                                                      (< -1 (vector-ref i 1) (vector-ref shape 1))