Brian Hurt wrote:
> let get arr idx =
>     if (idx < 0) || (idx > arr.len) then
>        invalid_arg "get_arr"
>     else
>        arr.data.(idx)
> ;;

Maybe:

let get arr idx =
    if (idx < 0) || (idx > arr.len) then
       invalid_arg "get_arr"
    else
       match arr.data.(idx) with None -> assert false | Some a -> a
;;

would be better...

> let append arr x = (* add x to the end of arr *)
>     if (arr.len == (Array.length arr.data)) then
>         begin
>             let newarr = Array.make (2*arr.len) None in
>             Array.blit arr.data 0 newarr 0 arr.len;
>             arr.data <- newarr;
>         end;
>     arr.data.(arr.len) <- Some(x);
>     arr.len <- arr.len + 1;
>     ()
> ;;

Maybe storing the arr.data's length in the record would be better...

Of course, all this would be wrapped in a module so that 'a t is an
abstract type.

But skaller already argued that he didn't like this approach.


-- 

Stephane Glondu.