Re: Updated: issue qnameAsId-18

/ Bill de hÓra <dehora@eircom.net> was heard to say:
| Again, that's making assumptions about implementations. If an XML
| parser can do it for elements and attributes, what's distinct about
| attribute values?

Attribute values can contain arbitrary strings. XML element and attribute
names occur at precisely defined and unambiguous locations in the grammar.
Given:

  <a:foo b:bar="some text: what about this:is it valid?"/>

the parse knows that a:foo is an element name, b:bar is an attribute
name, and "some text: what about this:is it valid?" is an attribute
value. What it can't reasonably be expected to know (IMHO) is whether
or not this:is is a QName or not.

| Note that XML Schema uses qnames in attribute
| values, so the W3C has already sanctioned this.

Yes, and the finding sanctions it as well, provided that the attribute
in question contains only an xs:QName.

|> there is
|> also the extensibility of URI schemes that must be 
|> considered.  
|
| If a namespace prefix happens to be http it will get expanded.

Only if it's recognized in a context where a QName is allowed.

| XML
| Schema might have issues if someone ever registers the xsd: URI
| scheme, and indeed weird things might happen in the processing
| chain soon enough if people use urn: et al as a namespace prefix.

No, I don't think either of those situations will cause any problems.
<urn:foo xmlns:urn="http://example.com/" href="urn:publicid:foo:bar:en"/>
is entirely unambiguous.

|> Therefore, a qname must not be allowed anywhere 
|> that a normal URI is expected.
|
| It probably is a bad idea (Dan Connolly's suggestion seems far
| saner), but respectfully, this does not follow from the grounds you
| cite.

Uhm, I though it followed quite logically from the argument that given
<foo bar="http:somename"/>, you can't tell if http:somename is a relative
URI reference or a QName. If you can't tell, then you shouldn't do that.

                                        Be seeing you,
                                          norm

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Received on Thursday, 6 June 2002 10:01:49 UTC