Hi!

Avi Bryant <avi at beta4.com> wrote:
[SNIP]
> >> You should not have to answer questions about
> >> different versions of stuff, unless you have explicitly asked to get
> >> into the nitty gritty.  Every package version you see in the tool,
> >> should be consistent with whatever universe you are operating in.
> >
> > Fine, again filtering and preferences.
> 
> I think you're missing a key point here, or at least dismissing it as 
> less important than I think it is.  When you say "just filtering", it 

No, I don't think I am. :)

> sounds like you're talking purely about UI: which packages (and package 
> releases) are displayed to the user in the package loader.

No, I was talking about filtering the model, in a general sense.

> But what 
> Lex is saying is deeper than that: first, that these "filters" will 
> affect which versions of required packages are used to fulfill 
> dependencies by default (so it doesn't just filter what the user sees, 
> but in some sense what the dependency engine sees as well), and second, 

Of course.

> that because of this behavior you can get away with a much simpler 
> dependency system - because it's the filters that are doing most of the 
> narrowing down to a particular release, and so the dependency engine 
> doesn't have to.

And you will be limited to that "universe", which I find to be a BIG
negative.

I simply think having a "full" model which you (or the depency engine)
can just view a subset of is much more powerful than having multiple
separate models and have all kinds of trouble trying to combine them and
still maintain "data integrity" etc.

Note though that in this case I am talking about "universes" meant to
represent different subsets - like "stable" vs "unstable" etc. Lex still
has a good point in the ability of having multiple maps but for
*visibility*, like a private map for a company etc. And I still fear the
consequences of enabling that without thinking hard about it. :)
 
> That's not a trivial thing, and it's not just a UI layer on top of the 
> SM mode: it's a very different way to think about the dependency model, 
> and I think you should take it into account.

I am taking it into account.

> FWIW, it also aligns 
> pretty well with the direction I've been meaning to take 
> Monticello-level dependencies/tags...
> 
> Avi

regards, Göran