Re: Reminder, blatant ad

From: dawn <dawnwolthuis_at_gmail.com>
Date: 5 Feb 2006 16:08:04 -0800
Message-ID: <1139184484.058944.24350_at_g44g2000cwa.googlegroups.com>


David Cressey wrote:
> "JOG" <jog_at_cs.nott.ac.uk> wrote in message
> news:1139107816.478812.62630_at_g43g2000cwa.googlegroups.com...
>
> > Two possibilities that I can think of - it might be possible to say
> > that merging an unordered set and a totally-ordered set (list) might
> > reasonably create a partially ordered set. (hence you have a general
> > system that handles all types of ordered sets underneath the hood). Or
> > you might just want to make everything a list as in the case of lisp
> > (and who knows, there might be something to be said for that). I think
> > the former probably has more potential.
> >
>
> When we built Muddle (aka MDL) we implemented arrays and lists for almost
> precisely the reason you and Marshall have outlined here. If you have
> lists, you need arays for direct access, when things get big. If you have
> arrays, you need lists when
> splicing in a new item is cheaper than shuffling everything to one side.
>
> So we built both.

Just so I understand precisely, what is the user interface in working with arrays compared to lists? With these lists are you unable to directly access the n'th entry in the list (list[n], for example)?

>
> "arrays" doesn't really address the same issue as "sets", but there's some
> overlap.
> I'm talking physical, here.
>
> At the logical level, there isn't that much difference between a list and a
> set, is there?

At the logical level, I don't know the difference between a list and array, but a set does not have the ordering that a list has. If you ask for all e-mail addresses when they are in a list, you get them in the order of the list. If you ask for them when logically in a set, the ordering in the response has no logical meaning.

--dawn Received on Mon Feb 06 2006 - 01:08:04 CET

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