RE: Variable references in path expressions

"Michael Rys" <[email protected]> Fri, 29 Apr 2005 19:48:41 -0700
Newsgroups gmane.comp.web.query-languages
Message-ID <BAE415CEAA831548800F68C44E905AF501FA6B54@RED-MSG-60.redmond.corp.microsoft.com>
I doubt that expressions of the form $a/$b will be used often.

Best regards
Michael

> -----Original Message-----
> From: [email protected] [mailto:[email protected]] On Behalf
Of
> TAN Kuan Hui
> Sent: Friday, April 29, 2005 7:43 PM
> To: Michael Dyck; [email protected]
> Subject: Re: Variable references in path expressions
> 
> 
> >
> > > I am concern about evaluating only the rhs. The following
> > > production shows that we can do something to the rhs of "/"
> > > prior to evaluating the expression.
> > >
> > > [67]    PathExpr    ::=    ("/" RelativePathExpr?)
> > >                                     | ("//" RelativePathExpr)
> > >                                     | RelativePathExpr /* gn:
leading-
> lone-slash */
> > > [68]    RelativePathExpr    ::=    StepExpr (("/" | "//")
StepExpr)*
> >
> > Why do you think these productions show that? It's the normalization
> > and evaluation rules, not the grammar productions, that dictate
> > whether we can "do something" to a StepExpr prior to evaluating the
> > expression.
> >
> This is where I think our interpretation differs. I take it that you
> are inferring from the normalization and evaluation rules as layout
> in formal semantics. Now, I see those rules being manifested
> depending on how the semantics of the expression is to be fullfilled.
> If there is agreement on how $a/$b should be processed, then
> those evaluation rules has to fine tuned accordingly.
> If there is a will there is a way.
> 
> I suspect $a/$b is going to be a very common construct
> the result however is going to catch a lot of people by surprise.
> Its just going to take some explaining and whether it will be
> convincing is entirely another matter.
> 
> 
>