Re: [Ocaml-lib-devel] Proposed addition to DynArray

[Brian H. <bri...@ql...>]

On Thu, 29 May 2003, William D. Neumann wrote:

> I have a situation  where I need to expand the
> size of the array to fit the data I will be adding, but I might be adding
> the elements out of order, so I can't just call DynArray.add

I don't have a problem with a pre-expand, but adding elements out of order 
doesn't work (at least the way I think they work).  If the dynarray has n 
elements, the elements are numbers 0..n-1 inclusive.

The solution is to use a 'a option Dynarray.t.  You're null element then
becomes None.  I dislike exposing the null elements as "valid entries"- to
my mind, they're just filler.  This is especially important if you
consider an int Dynarray.t - is that 0 a real, important 0, or a null
element?  So I would would fake up a enum that returns n Nones and append
it to the dynarray to increase the size.  Dynarray.set can then change the
Nones to Some x.

We might want to consider adding a function in Enum to create an enum that 
returns so many of a given value, to make this easier.

Brian