[help-texinfo] Re: xml id characters

[Per Bothner]

Karl Berry wrote:
> However, I had thought that XML, being based on Unicode,

But SGML predates Unicode.  The original DocBook was SGML-based,
the current version can be SGML or XML, and Docbook 5.0 is XML-only.

I use the xslt stylesheets to process DocBook.  They require XML.
I see little point in emitting DocBook-SGML.

> allowed more or less anything in its id's.  E.g.,
> http://www.w3.org/TR/2000/WD-xml-2e-20000814#sec-common-syn
> http://www.w3.org/TR/2000/WD-xml-2e-20000814#NT-Letter
>
> Can you shed any light on this?  Can we just allow anything (except ")
> in the Docbook/XML and Texinfo/XML id values?

http://www.w3.org/TR/2000/WD-xml-2e-20000814#id
"Values of type ID must match the Name production."

http://www.w3.org/TR/xml-id/ says an "xml:id processor must assure that 
the following constraints hold for all xml:id attributes: ...
      The normalized value of the attribute is an NCName."
I.e. colons are not allowed for "xml:id" attributes and that is probably
a good idea for DocBook "id" attributes too.

If you pick XML 1.1 the rules are slightly more liberal, and
easier to implement:
http://www.w3.org/TR/2006/REC-xml11-20060816/#NT-Name

How well does texinfo handle Unicode characters?
--
        --Per Bothner
address@hidden   http://per.bothner.com/