[Xesam] Details of tag handling

[Mikkel Kamstrup Erlandsen]

Hi all,

I am starting this thread because I believe we need clarification on
how tags are employed and handling in Xesam.

Currently we have a field xesam:userKeywords on xesam:Source being a
list of strings. We also have a child of the content category
xesam:Annotation called xesam:Tag. The latter is to allow us handle
tags as first class objects.

The question is: "What do I store in xesam:userKeyword? the tag name
or a uri to the Tag object?". Here's what I propose:

 * Store the tag names in userKeyword, each tag name must be unique
and in fact constitutes an identifier

 * The Tag objects keep this tag name in their xesam:id field

Why this is good:
 - We can easily query objects on their tags
 - We can easily get a list of all tags (query all Tag content with id!="")
 - It handles all use cases found in
http://lists.freedesktop.org/archives/xesam/2007-December/000002.html

Cheers,
Mikkel