On Apr 16, 5:01 pm, "Edward K. Ream" <[EMAIL PROTECTED]> wrote:
> On Wed, Apr 16, 2008 at 9:08 AM, Terry Brown <[EMAIL PROTECTED]>
> wrote:
> > Ah, now I understand the "two clones can share the same parent" bit, I
> > didn't get it until now. But is there anything, in the most general of
> > generalized graphs, that says you can't have two links between nodes?
>
> Not to my knowledge: general means general :-)
Sure there are generalisations that allow multiple edges between the
same node, but you lose some properties, for instance to have the
graph represented by an adjacency matrix.
On the other hand, Leo's structure is more complex than graphs, for
instance children of nodes maintain the information of their order.
Note that I am not looking at the actual code, but the children of a
parent in a graph could be represented by a dictionary or an unordered
collection, not an ordered list.
> However, afaik clones are
> not a part of traditional graph "lore". That is, we could say that clones
> simply are not an issue: any node could have multiple links into that node.
> But if we wanted to represent clones directly in a graph, we would need a
> notation that indicates that two apparently separate nodes are clones.
> Something like A == A.
My view of clones is that they are the same entity, only referenced
from different position. The distinction between tnode uA's and vnode
uA's would be the distinction between annotating vertices and
annotating edges, both of which are a frequent generalisation of
classic graphs.
>
> So this means that clones are something pretty special to Leo.
>
No.
> > It seems unified node world could just have B appear in A's children
> > list twice. Obviously there a limited reasons for doing this,
> > basically to support the usually transient state created by the Clone
> > Node function, and maybe to make an entry visible at two places in a
> > long list. But I don't see how it's a problem - it's working now,
> > basically.
>
> Correct.
As long as the notion of order is preserved, there is a clear
distinction. If the list of parents contained tuples of (parent, order
number), you could mark identical twins as distinct according to those
tuples and you'd have a list of length > 1 and to come back to the
original question, a reason to set the clone mark.
>
> > I think it's a shame unified node world isn't happening, because I
> > don't think the v/tnode system has any advantages and I think the
> > v/tnode system is much less intuitive.
>
> I am more sanguine. The recent "little" aha says that tnodes should be
> considered subsidiary. In other words, most users should be able to pretend
> they don't exist. That's not quite the case now. To make that a reality we
> could a) retire or deprecate the tnode iters, b) ensure that all tnode
> getters/setters have analogs in the position and/or vnode classes. With
> these changes in place, tnodes would be relegated to "hidden helper" status.
>
This sounds to me as if you'll eventually drop tnode uA's. I am
assuming an alert position again.
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