[uf-discuss] Re: rel-license: what does the license apply to? (open issue revisited)

Toby A Inkster mail at tobyinkster.co.uk
Wed Mar 19 15:21:56 PST 2008

Angus McIntyre wrote:

> I seem to remember one of the microformats has a poorly-understood
> algorithm for determining the scope of a declaration; could this be
> reapplied here?

The problem lies deeper than rel-license. The rel attribute in (X) 
HTML is able to specify a specific element within a page as its  
"target" (using a fragment identifier), but doesn't offer the same  
granularity to specify its "source".

XHTML2 (and RDFa, which is basically a "backport" of XHTML2's  
metadata features to earlier versions of XHTML) solves this through  
its "about" attribute.

One routes for rel-license to achieve the same trick might be to  
adopt eRDF, a formulation of competing RDF-in-HTML, which doesn't  
require adding any additional attributes or elements to the page. It  
co-opts the "id" attribute to indicate a "container" for metadata. So:

	<div id="foo">
		<p>Some content.</p>
		<div id="bar">
			<p>Some more content.</p>
			<a rel="license" href="licence.html">licence</a>

Here "some more content" is licensed under the terms of licence.html.

Unfortunately, my experience with implementing eRDF has been that is  
requires a great amount of thought from the very beginning of  
designing a page. "id" attributes are too commonly used in the wild  
to tack on this functionality -- you get unintentional narrowing of  
the scope of metadata. If a page is written with eRDF in mind from  
the start, it's just about usable. RDFa is much more pleasant to use.

I added an example to the licensing-brainstorming a few days ago  
which goes some way to solving the problem and allowing authors to  
specify exactly what is under the licence.


A key feature is that it uses rev=license to link from a licence  
summary to the licensed work, thus allowing the work to be targeted  
in more detail (e.g. fragment identifiers can be used), and  
deliberately flying under the radar of existing rel-license tools.

Toby A Inkster
<mailto:mail at tobyinkster.co.uk>

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