Re: again on numbering..

[Giovanni Bartolomeo <giovanni.bartolomeo@uniroma2.it>]

Hello again!

I see this could be a solution as well, however, I would like share with
you some thoughts:

1)  The use of "!" (bang) was originally designed to be
similar to the use of "ip addesses" (maybe I'm getting wrong
here, in case please correct me :-), so thinks like !203.173.1276.1663
were permitted. This is obviously a misleading semantics as "
!203.173.1276.1663" is more an identifier than a number. What do you
think?

2) Actually, I see a slightly different meaning for the two
statements:
=markus/+email!1/"
markus.sabadello@gmail.com"
and
=markus+email/$num$1/"
markus.sabadello@gmail.com"

Try to explain my concern (that's a bit hard!).
In the first statement, it's like as the concept +email in itself has
subspaces for !1, !2, etc. As far as I've understood, by concatenating
two subsegments the second one assumes a meaning related to the first
one, so it's like to have the email, taken as concept (+email), having
some multiplicity in its own.
In the second statement, instead, we just use $num an integer in order to
index one of the +email attributes kept by =markus, which exist because
they've been explicitly declared as such (Markus' attributes). They
wouldn't exist otherwise.
It's somehow like the java statements:

Person markus;
markus.email=new Email[]
{"
markus.sabadello@gmail.com
","
markus.sabadello@xdi.org"};
Email selectedMail=markus.email[1];

But maybe I'm getting wrong here as well, so you comments will be more
than welcome! (and sorry if maybe it sounds a bit too
"philosophic"!)

Bests,
Giovanni

At 18.41 29/01/2008, Markus Sabadello wrote:

Heya Giovanni,
 
I think the idea of having a way to express ordered collections in XDI would be very useful...
 
We came across a similar problem a few days ago.. How do we express multiple values for a predicate? For example, =markus could have multiple e-mail addresses. We came up with the following idea:
 
=markus/+email!1/" markus.sabadello@gmail.com"
=markus/+email!2/" markus.sabadello@xdi.org"
 
But your pattern would work too:
 
=markus+email/$num$1/" markus.sabadello@gmail.com"
=markus+email/$num$2/" markus.sabadello@xdi.org"
 
A third idea Drummond had was to use inner graphs, like this:
 
=markus
    +email
        /
            $
                $1
                    " markus.sabadello@gmail.com"
                $2
                    " markus.sabadello@xdi.org"
 
I like all three methods.. But we should probably decide on one of them.. Or just experiment for a while and see what works best...
 
Markus
 
On 1/29/08, Giovanni Bartolomeo < giovanni.bartolomeo@uniroma2.it> wrote:

Hello,

some new inputs about this issue:

>* Markus asked if $num is always used in conjuntion with $has predicate, or

>if there would be other uses? Giovanni said it would also be useful

>standalone.

I think that $num could be useful also in accessing arrays, vectors

and similar structures what we could call "ordered collections".

Let's consider again this use case:

=football.team/$has$num$11/+player

@as.roma.calcio/$is$a/+football.team

we could index each player using $num${x} as follow:

@as.roma.calcio+player/$num$0/=curci

...

@as.roma.calcio+player/$num$7/=derossi

...

@as.roma.calcio+player/$num$10/=totti

etc.

Do you think this capability could be of help for XDI?

BTW maybe we can avoid the prefix $num and leave only ${num}, e.g.

$0, $5, $7 are valid XRIs which represent the number 0, 5, 7.

What do you think?

Bests,

Giovanni

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