[XML Base] Comments on new XML Base draft

1. The rules on returning xml:base unescaped seem to have changed too
radically for an erratum: this needs the spec to be versioned.

2. There are several deficiencies in the existing spec that aren't
addressed:

2a. When the spec says that the xml:base attribute "may be used", it should
make it clear that the attribute has no special status as far as DTD or XML
Schema validity checking is concerned: it may be used only if permitted by
the DTD or schema.

2b. The spec doesn't say which relative URIs in a document are affected by
xml:base. Possible positions on this are

(i) no relative URI is affected by xml:base unless the relevant
specification says it is affected

(ii) relative URIs should be assumed to be affected unless the relevant
specification says otherwise

(iii) relative URIs are affected if and only if they are dereferenced.

(This is a real issue, there have been disagreements for example over
whether xml:base should affect the interpretation of schemaLocation in XML
Schema 1.0).

2c. The spec says nothing about leading and trailing spaces in the xml:base
attribute value.

2d. The spec says nothing useful about the situation where the base URI of
the document entity is unknown. (should be OK if xml:base is absolute)

3 (Comment on XLink v1.1 5.4.1) the spec says that to convert an XML
resource identifier to an IRI Reference, the character #0 must be escaped.
This implies that the character #0 can exist in unescaped form; but it
can't.

4. It would be useful if we could all converge on the term
"percent-encoding" as used in the RFCs, rather than "escaping" which is a
much less specific term.

Michael Kay
http://www.saxonica.com/

Received on Monday, 13 November 2006 20:01:43 UTC