Re: Identifying Multi-valued items

On Sat, 1 Feb 2003, Sam Roberts wrote:

> I'm not a vCard expert, but since this list seems to be dead except for
> us...

Thanks Sam. :-)
 
> Quoteing [email protected], on Fri, Jan 31, 2003 at 06:59:04PM -0500:
> > Rfc2425 has this to say about multi-valued items:
> > 
> >    Each attribute defined in the text/directory body MAY have multiple
> >    values, if allowed in the definition of the profile in which the
> >    attribute is used. The general rule for encoding multi-valued items
> >    is to simply create a new content line for each value (including the
> >    type name).
> > 
> > Can someone please tell me how I can figure out which items are single 
> > valued and which are multi-valued? 
> 
> Do you mean from reading the RFCs?

Yes. Rfc2425 which I quoted above describes the directory mime content 
type and rfc2426 describes the vcard profile for the directory mime 
content type -- and I'm trying to understand both documents.

Rfc2425 says attributes may have multiple values if the profile allows.

The profile rfc2426 appears to provide no restrictions on multiple
values. (Every attribute is allowed multiple values.)

 
> Despite that quote, I guess you noticed RFC 2425 doesn't seem to really
> say much about multiplicity of values.
> 
> Some seem to obviously allow multiples (TEL), and SOURCE even says that
> you can have it multiple times. But NOTE, for example, doesn't say that
> it can be specified multiple times, but surely can. As, I would think,
> would PHOTO (a gif and a png in a vcard would seem reasonable).
> 
> Some things, like VERSION, would seem to only be allowed to be specified
> once, though I don't see that stated.

If an attribute like SORT-STRING occured more than once an application 
would need to make a decision on which SORT-STRING value to use in order 
to perform the sort.

> On the decoding side, if you see multiple values, I guess its
> multi-valued....

Is it true then that any parser that doesn't allow all attributes to 
contain multiple values is in error? 


--
Tony