Thanks, I suspected something from the distant SGML land as it seems entrenched in the DTD history ..
But obviously any sane person would assume
xml:id="D000001" == xml:id="D1"
:) 1/2
From: Michael Kay [mailto:mike@saxonica.com]
Sent: Friday, April 29, 2011 10:42 AM
To: xml-dev@lists.xml.org
Subject: Re: [xml-dev] Why cant xml:id be numeric only ?
On 29/04/2011 15:22, David Lee wrote:
First off I know asking "Why" for anything standards related is silly.
But given that, could anyone give me a rationale or history for restricting xml:id (or the ID type from DTD) to be NCName which then has to start with non-numeric ?
I seem to recall asking this once, and being told that the history lay in the SGML rules for abbreviated syntax. Something like allowing <e id="xyz"/> to be abbreviated as <e xyz>. Not that this in itself would make a numeric identifier ambiguous, but it would account for requiring an ID value to have the same syntax as an attribute name.
I guess another justification is that it prevents any debate about whether xml:id="01234" is a duplicate of xml:id="1234".
Michael Kay
Saxonica
