Re: [xml-dev] nextml

[Norman Gray <norman@astro.gla.ac.uk>]

Greetings,

On 2010 Dec 9, at 05:59, James Clark wrote:

> I much prefer requiring only UTF-8. UTF-8 is enormously more common and a
> single encoding is a significant simplification; the gains from UTF-16 are
> much reduced by the fact that markup almost always uses ASCII characters.
> If an implementation wants to support UTF-16, it should be free to do so,
> but as a requirement it is on the wrong side of the 80/20 line by a long
> way.


...and later, Liam Quinn wrote:

> The most frequent change request I hear is to remove the strict syntax
> requirements and make every XML implementation include some sort of
> HTML-like expert system to do the parsing, automatically "correcting"
> errors like missing quotes off attribute values.  That's not a change
> you're likely to hear from the XML community, where the "draconian"
> error handling, widely misunderstood though it be, is generally
> taken as a given.

I'm puzzled by these remarks, since they appear to be mixing layers, in the sense that both of these concerns seem to be about lexing, rather than the grammar of XML.

If 'XML-bis' were defined using lexer events, with strings defined as sequences of unicode code points, then a JIS-encoded document with missing quotes could be (required to be) handled by the lexer, entirely transparently.  In other words, why is file/wire encoding anything to do with XML?

The current XML spec says that " All XML processors must accept the UTF-8 and UTF-16 encodings of Unicode", but I really don't know why it matters, since the rest of the spec appears to define the XML grammar purely in terms of codepoints, rather than byte sequences (obviously).

All the best,

Norman


-- 
Norman Gray  :  http://nxg.me.uk