Re: [docbook-apps] Base URI for result of transformation?

[Stefan Seefeld <seefeld@sympatico.ca>]

Bob Stayton wrote:

>> (Some digging in the xsl-fo stylesheet parameter documentation reveals
>> that <xsl:param name="keep.relative.image.uris" select="0"/>
>> (http://docbook.sourceforge.net/release/xsl/current/doc/fo/keep.relative.image.uris.html)
>>
>> may do exactly that: replace relative-to-input-xml image URIs by absolute
>> URIs so the fo processor can find them by their absolute location. In
>> fact,
>> that was what my original question was all about, admittedly poorly
>> formulated. :-)
> 
> Not quite.  The effect of that parameter is for the stylesheet to
> resolve the fileref relative to any xml:base attributes on ancestor
> elements.  Most xml:base attributes are added by an XInclude processor
> (only if needed, though).  You won't get an absolute path unless one of
> the xml:base attributes is absolute.  You could manually add one on your
> root element to do that.

It seems I'm misunderstanding the semantics of xml:base, but the statement

"The attribute xml:base  may be inserted in XML documents to specify a base URI other than the base
URI of the document or external entity."

(from http://www.w3.org/TR/xmlbase/#syntax) seems to imply that all documents
have an implied 'base' that may be overwritten by an explicit xml:base attribute.
If that is indeed the case, why can't URLs always simply be interpreted as
relative to that (possibly implicit) base ? What am I missing ?


Thanks,
		Stefan

-- 

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