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Re: Question about XPath expressions

From: Jonathan Robie <jonathan.robie@datadirect.com>
Date: Mon, 08 Nov 2004 07:21:20 -0500
Message-ID: <418F64C0.2080506@datadirect.com>
To: Arjan Huijzer <huijzer@gmail.com>
CC: www-ql@w3.org

Hi Arjan,

The change log in I.2 is pretty informal in the way it discusses this
change. Take a look at 3.2 to see the actual change. Look for the text
starting with "Each operation E1/E2 is evaluated as follows:". The
change is that it is no longer an error if E2 evaluates to a sequence of
atomic values. We provide specifically for that case:

> If every evaluation of E2 returns a (possibly empty) sequence of
> atomic values, these sequences are concatenated, in order, and
> returned.

Although the change log is informal, I think this reference is precise 
and clear. Do you agree?


Arjan Huijzer wrote:
> Hello,
> I have a question about the usage of XPath expressions.
> In the latest XQuery specifications it says that the last step of a 
> XPath expression can now return a sequence of nodes (I.2 29 Oct
> 2004). Looking at the grammar rules (A.1 EBNF), it seems that
> PathExpr (rule 61) is a special form of an OrExpr (43), which can
> only return a "true" or "false" value.
> Are the specifications not clear on this point or am I missing
> something?
> Thanks in advance for any help!
> Arjan Huijzer The Netherlands
Received on Monday, 8 November 2004 12:21:59 UTC

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