XOM API for Processing XML with Java

[John Cowan <cowan AT mercury.ccil.org>]

Johan Strandberg scripsit:

> Good point. It is not like this is easy to disambiguate. There is also a
> passage in Appendix-F (although that is non-normative -- thanks a lot,
> you get some info that you can work with and the you realize that
> anything it says may have to be ignored [sigh])

The reason Appendix F is non-normative is that no parser has to make
use of it.   It's perfectly conformant to recognize only UTF-8 and
UTF-16, just verify that the correct encoding declaration is present
in each case, and tell all other encoding declarations to go to Hell.

> The magic word here is "must" because according to the standard:

Magic words are not effective in non-normative sections.  In any case,
the XML 3rd Edition is switching to RFC 2119 definitions of
MUST, MAY, SHOULD, etc.

> The more I look at the difference between error and fatal error, I get
> the feeling that the standards use of "error" corresponds to what I
> think most people think of as a really stern warning.

Actually, the point of "error" is as a constraint on document authors.
A document that contains an error should not be created, because parsers
may or may not catch the error -- it is a quality-of-implementation issue,
not a conformance issue.  A document with a fatal error will always be
caught by a conformant parser.

Warnings are essentially free: a parser may warn about anything it likes,
even "This document begins with an html element, but does not appear
to be XHTML".  Again, a quality-of-implementation issue.

-- 
John Cowan          http://www.ccil.org/~cowan        jcowan AT reutershealth.com
To say that Bilbo's breath was taken away is no description at all.  There are
no words left to express his staggerment, since Men changed the language that
they learned of elves in the days when all the world was wonderful. --The 
Hobbit