Re: [xsl] // expanding to descendant-or-self::node()

[Evan Lenz <evan@xxxxxxxxxxxx>]

Evan Lenz wrote:
> Andrew Welch wrote:
> > > currently // expands to /descendant-or-self::node()/ which is not owhat
> > > one would first think of, but it works consistently without 
> > > depending on
> > > the following step. And that expansion is at the level of expression
> > > terms not syntax fragments.
> > >
> > > one might expect // to expand to descendant::  but descendant:: itself
> > > isn't really an expression, just part of the syntax for an axis step 
> > > and
> > > that causes problems..
> > >
> > > //foo could have been defined to be /descendant::foo
> > > but you can not define
> > > //@foo to be descendant::@foo as that's a syntax error, wheras
> > >  /descendant-or-self::node()/@foo is all foo attributes in the 
> > > document,
> > > which is the desired meaning.
> > >
> > > similarly any other axis, including child::
> > > //child::foo can't expand to /descendant::child::foo
> > >     
> >
> > //@foo and //child:: would both be errors -  //@* would need to be
> > //*/@foo and //child:: doesn't make sense anyway
> >   
> Not quite. If // was short for /descendant::, then //*/@foo would 
> still not be equivalent. That's because, in XPath as actually 
> designed, /descendant::*/@foo isn't the same as //@*. The former 
> excepts attributes of the context node, whereas //@* also includes 
> attributes of the context node.
>
> So, instead, you'd have to write (@* | ./descendant::*/@*). In that 
> case, the actual definition of // is handy.
>
> Evan
Oops, quick correction. When starting at the document node, there 
wouldn't be any attributes. So what I meant to say was that 
.//descendant::*/@* is not the same as .//@*.

Evan