Re: again on numbering..

Hello Markus,

2) Hmm yes I think I understand
the difference.. But I think concatenating the subject and predicate the
way you do it
(=markus+email/$num$1/"
") could cause trouble, because how
are you supposed to know later that +email is an attribute of =markus. I
think the "list" situation, in which you have multiple values
for an attribute, should look as similar as possible to the
"normal" situation, in which you have just one value for the
attribute.

I think I guessed what you mean, but I'm not sure... could you make an
example? In any case,  what about to use this alternative form:

=markus+email$1/$type$xsd$string/"
 "

which sounds solid, as it keeps the advantage of avoid to
semantically overload "!", is compliant with my original idea
about the usage of $num notation, and should not cause the troubles you
mentioned (if my guess was corrent), as $ is a subcontext refereing to
=markus+email... What do you think?

Looking forward!

Giovanni

Markus

 

On 1/31/08, Giovanni Bartolomeo
<
> wrote: 

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/"
"

and

=markus+email/$num$1/"
"

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[]
{"


","
"};

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/+email!2/"
"

 

But your pattern would work too:

 

=markus+email/$num$1/"
"

=markus+email/$num$2/"
"

 

A third idea Drummond had was to use inner graphs, like this:

 

=markus

    +email

        /

           
$

               
$1

                   
"
"

               
$2

                   
"
"

 

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
<
> 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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