(: enemy-adj-pawns : Board Player Loc -> (Listof Loc))
(define (enemy-adj-pawns b p l)
  (local
    {(define opp-player (switch-player p))
     (: with-bounds :  (Listof Integer) -> (Listof Loc))
     (define (with-bounds c-dirs)
       (match* (c-dirs l p)
         [('() _ _) '()]
         [((cons hd tl) (Loc row col) 'Black)
          (match (board-ref b (Loc row (+ col hd)))
            [(Some (Piece 'Pawn 'White))
             (cons (Loc row (+ col hd)) (with-bounds tl))]
            [_ (with-bounds tl)])]
         [((cons hd tl) (Loc row col) 'White)
          (match (board-ref b (Loc row (+ col hd)))
            [(Some (Piece 'Pawn 'Black))
             (cons (Loc row (+ col hd)) (with-bounds tl))]
            [_ (with-bounds tl)])]))}
    (cond
      [(zero? (Loc-col l)) (with-bounds (list 1))]
      [(= (sub1 (length (list-ref b 0))) (Loc-col l)) (with-bounds (list -1))]
      [else (with-bounds (list -1 1))])))