Re: List container strawman 1.2

["Nick Roberts" <nickroberts@adaos.worldonline.co.uk>]

My approach to solving the problem of 'safe pointers' is to have the
'pointers' (I call them 'cursors') inside the list type. This way they can
be checked by any list operation for validity (and internally updated as
necessary), and they can be referenced by number (1, 2, 3, etc.) for maximum
simplicity.

I hope to get my new proposal (V5) on my web site ASAP.

As for iteration as such, it's usefulness goes far beyond "it's easier to
have a while loop" or the like. More on this later.

I've taken the liberty of adding Robert's web page to my links.

--
Best wishes,
Nick Roberts




<ramatthews@tinuviel.com> wrote in message news:700ht9.6k1.ln@127.0.0.1...
> In article <SLbK7.30473$xS6.49203@www.newsranger.com>, Ted
Dennison<dennison@telepath.com> wrote:
> > snip...
> >
> > We've been down that road. The place it leads is that if you want safe
> > iterators, you have to make both the indices and the lists controlled
and keep a
> > little mini-list of iterators in each list. The algorithms for doing
this
> > properly aren't unachieveable, but they do make everything quite a bit
more
> > complex. They also create a situation where real-time users will have to
be a
> > lot more careful when they iterate through a list to aviod heap
operations.
> >
> > The current version takes the opposite stance. I'm wavering quite a bit
in my
> > support for it though.
> >
>
> An implementation of a list that uses 'safe' iterators is now
> available on:
>
> http://homepage.ntlworld.com/ramatthews
>
> I have also asked David Bottom to hold a copy on AdaPower.
>
> Robert A. Matthews