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. > > >