Re: [xml] Question regarding XPath

["James Dennett" <jdennett technocom-wireless com>]

Daniel Veillard [mailto:veillard redhat com] wrote:
>
> On Fri, Mar 16, 2007 at 09:39:33AM -0700, James Dennett wrote:
> > Daniel Veillard wrote:
> >
> > > On Fri, Mar 16, 2007 at 09:03:01AM -0500, Ethan Metsger wrote:
> >
> > [snip]
> >
> > > > shed some light on how xmlXPathEval differs from
> > xmlXPathEvalExpression,
> > > > and whether the issue is related to the context passed?
> >
> > This seems to be something of an FAQ around here.  It would be
useful
> > for the documentation of these functions to document how they
differ,
> > possibly with a reference to the XPath spec.  Maybe some kind soul
> > reading this thread can find the time to prepare a patch.  I don't
have
> > time right now.
> >
> > >   Use xmlXPathEval(), see XPath spec to see the real difference:
> > >   http://www.w3.org/TR/xpath#NT-LocationPath
> > >   [1]   	LocationPath
> > >
> > >   http://www.w3.org/TR/xpath#NT-Expr
> > >   [14]   	Expr
> >
> > So the difference is that xmlXPathEvalExpression handles an XPath
> > "Expr", whereas xmlXPathEval handles an XPath "Location Path", which
is
> > a particular kind of Expr.  In other words: xmlXPathEvalExpression
> > should be able to handle any expression that xmlXPathEval can, and a
> > number more.
> 
>   Actually no, they both call xmlXPathEvalExpr() and hence both
evaluate
> based on production 14. As I said there should be no perceived
differences
> between both call.

OK; that matches your message in the older thread, but in this thread I
was confused by you writing "see XPath spec to see the real difference",
if the answer is that there is no difference.  Would you agree that a
patch to the documentation would be helpful, were someone to prepare
one?

-- James