- From: Chris Lilley <chris@w3.org>
- Date: Thu, 19 Apr 2007 13:19:45 +0200
- To: Sandro Hawke <sandro@w3.org>
- Cc: John Cowan <cowan@ccil.org>, Jeremy Carroll <jjc@hpl.hp.com>, <semantic-web@w3.org>, <www-international@w3.org>
On Wednesday, April 18, 2007, 9:03:19 PM, Sandro wrote: >> The value of an xml:base attribute is not so limited: it can contain >> (almost) arbitrary Unicode, which is %-escaped before being used >> to alter the base URI property of the element on which it appears >> and the element's children. SH> Percent-escaping has got to be among the 10 most confusing and confused SH> subjects in the history of computing. :-) This is why its better if computers do it, and humans see the real characters. SH> My sense is that the 2001 XML Base Recommendation [1] is very confused SH> about how to handle percent-escaping. Of course, it long predated IRIs, SH> so this isn't so surprising. I agree that the newer PER is clearer. SH> There is a Proposed Edited Recommendation [2] which, to my mind, is much SH> clearer about this. It says, essentially, don't do percent-escaping. SH> XML is safe for Unicode, so just use Unicode. Which is pretty much what The set of characters allowed in xml:base attributes is the same as for XML, namely [Unicode]. However, some Unicode characters are disallowed from URI references, and thus processors must encode and escape these characters to obtain a valid URI reference from the attribute value. says. The improvement in the PER is to clarify that the 'processor' is the software which reads the XML attribute value and constructs a URI to fetch; not, as it could be read, the software which creates the XML document. -- 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 Thursday, 19 April 2007 11:20:57 UTC