Re: [Ocaml-lib-devel] Array interface

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

On Fri, 20 Jun 2003, Eric C. Cooper wrote:

> On Fri, Jun 20, 2003 at 03:58:38PM -0500, Brian Hurt wrote:
> > Unless I'm missing something (which is possible), there are three possible
> > implementations of Dynarray that I can see working:
> > 
> > 1) Have the internal array be a 'a option array, and not a 'a array as it 
> > is currently. [...]
> > 2) Use the null value kludge. [...]
> > 3) Write in C, leaving floats unboxed. [...]
> 
> I'm probably missing some essential context, but what is wrong with
> the simple approach of using a mutable 'a array that gets replaced
> with a bigger one when you try to set an element beyond its current
> length?

Because then you are allocating a new array- and copying all the elements 
of the old array- every time you add a new element to the end of the 
array.  So if you add n elements to an empty array, you end up allocating 
n arrays, and copying n*(n-1)/2 elements.  At which point you might as 
well be using lists and @.

Brian