Re: extension-element-available()

Kay Michael wrote:
 
> What should the extension-element-available() function return if an
> implementation of the named extension element exists, but cannot be used in
> the current context because the namespace prefix is not declared in the
> [xsl:]extension-element-prefixes attribute of any enclosing element?
> 
> The current spec suggests "true",

Right.

> but usability considerations suggest
> "false", since if the extension-element is actually used in that context it
> will be interpreted as a literal result element rather than reverting to the
> xsl:fallback behaviour.

It depends.  I might do:

<!ATTLIST xt:document
  xsl:extension-element-prefixes NMTOKEN #FIXED "xt"
>

James