Flickr uses namespaces. or 'machine tags'. or NOT.

Hello all

Flickr have an article on what they call 'machine tags'. Or in other
words, sort of using namespaces, while coining a new term to avoid the
gag reflex from the HTMLorati. (But see below)

http://www.flickr.com/groups/api/discuss/72157594497877875/

> We are rolling out a new feature called "machine tags" that allows
> users to be more precise in how they tag, and how they search, their
> photos.
> 
> Many of you may already be familiar with machine tags by another
> name (triple tags) or because you are already using them,
> informally, in your code (for example, "geo:long=123.456").
> 
> "Machine tags" is the technical term for the extra hamsters we've
> added to the Flickr servers to formalize how these sorts of tags are
> treated. I've included a "Ceci n'est pas un FAQ" below with all the
> details.
> 
> For the moment, machine tags are principally an API "thing". The
> photo pages have been updated to display tags a little differently
> but otherwise all the magic you can perform with machine tags
> happens here at the API layer. (This includes the special wildcard
> syntax for searching photos with machine tags.)

and the FAQ kicks off by saying they use 'namespaces'.

But then goes on to explain a syntax that does not use namespaces at
all, but does use hardcoded magic prefixes:

> 1) A "namespace" :
> 
> Namespaces MUST begin with any character between a - z; remaining
> characters MAY be a - z, 0 - 9 and underbars. Namespaces are
> case-insensitive.
> 
> 2) A "predicate" :
> 
> Predicates MUST begin with any character between a - z; remaining
> characters MAY be a - z, 0 - 9 and underbars. Namespaces are
> case-insensitive.
> 
> 3) A "value" :
> 
> Values MAY contain any characters that a "plain vanilla" tags
> use. Values may also contain spaces but, like regular tags, they
> need to wrapped in quote

Note the lack of a URI anywhere in this description.

So in conclusion - they don't use namespaces at all. But they have a
registry of colon-separated prefixes, which may or may not conflict
with other peoples usage.


-- 
 w3c:Chris_Lilley                    mailto:chris@w3.org
 Interaction Domain Leader
 Co-Chair, W3C SVG Working Group
 W3C Graphics Activity Lead
 Co-Chair, W3C Hypertext CG

Received on Friday, 16 February 2007 13:59:35 UTC