TP04 3.1

get_cell.ml

(* --- 3.1 Cellule --- *)

let get_cell (x, y) board =
  let rec row list n = match (list, n) with (* this function reads the y value of the row sent by column *)
    |[], _ -> invalid_arg "y coordinate doesn't exist !"
    |e::l, 1 -> e (* return the cell value *)
    |e::l, n -> row l (n-1)
  in let rec column board n = match (board, n) with (* this function sends the correct row (our 'int list' inside our 'list') to the 'row' function *)
     |[], _ -> invalid_arg "x coordinate doesn't exist !"
     |e::l, 1 -> row e y (* when column reaches the correct n, it sends the selected row to the 'row' function along with the y parameter *)
     |e::l, n -> column l (n-1)
     in column board x ;;