- From: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>
- Date: Mon, 16 Nov 2009 02:25:43 +0100
- To: ietf-http-wg@w3.org
- CC: RDFa mailing list <public-rdf-in-xhtml-tf@w3.org>, HTMLWG <public-html@w3.org>
This is input on the http-link-header draft. CC to public-html@ and public-rdf-in-xhtml@. Please see the following 2 links to some comments by Alexandre Alapetite on the HTML 5 draft's understanding of link relations. The latter text (the table) seeks to document the most important compound document link relations as defined/understood by implementations and specs [note that the table is still a work in progress - it is still being expanded and updated/corrected/discussed - e.g. at the moment it doesn't mention whether the Nottingham draft or RDFa-in-XHTML.]: [Message] http://lists.w3.org/Archives/Public/public-html/2009Nov/0373.html [ Table] http://alexandre.alapetite.fr/divers/vrac/20091115_HTML_link_rel.html I note that the latest http-link-header draft defines "first" and "last", and that it defines them as opposites. (Quite naturally to see them as opposites, I must say.) http://www.mnot.net/drafts/draft-nottingham-http-link-header-07.txt The http-link-header draft says that it is the first to define "first" and "last". However, "last" is already defined in the XHTML Vocabulary document, which sees "last" as the opposite of "start": http://www.w3.org/1999/xhtml/vocab/#last http://www.w3.org/1999/xhtml/vocab/#start The XHTML Vocabulary builds on RDFa in XHTML: http://www.w3.org/TR/rdfa-syntax/#relValues However, when we look at RDFa in XHTML, then it also defines "first" - without there being any corresponding definition of "first" in the Vocabulary document ... That is: "first" is lacking from the Vocabulary document ... RDFa also operates with "start" and "top". I don't understand this discrepancy between the Vocabulary and RDFa-in-XHTML ... There may also be other values that are in RDFa but which are not in the Vocabulary ... The RDFa spec claims to be older than the Vocabulary ... HTML 4 did not define "last" but it defined "start". It's definition of "start" includes the word "first". However, when W3C in a "W3C QA Tips" explains what "start" means, then it shows an example that has to do with file/folder/directory hierarchy: <link rel="Start" href="/solar-system/" /> <link rel="Prev" href="/solar-system/venus/" /> <link rel="Next" href="/solar-system/mars/" /> http://www.w3.org/QA/Tips/use-links Thus it seems like "start" as defined in HTML 4 (at least as understood by the QA Tips page) is more similar to "top" and "home". Or in plain English: "homepage". As one can see in Alexandre's table, almost all the implementations (all web browsers and browser extensions) that support link relations have "top", "home" and "start" as synonyms. None of them see "start" and "first" as synonyms. (And they all support "first"!) So in a summary: 1. The nottingham draft is not correct in saying that it is the first to define "first" and "last". 2. Secondly, in my view, the best thing would be to follow the implementations and RDFa-in-XHTML with regard to he meaning of "start" versus "first". 3. Thus we should separate "start" and "first" - as the nottingham draft does. 4. I hope the XHTML Vocabulary document gets updated so that it actually documents what it claims to document, namely the RDFa-in-XHTML syntax specifications. -- Leif Halvard Silli
Received on Monday, 16 November 2009 01:26:27 UTC