I think the point is, the steps specified
by the path do not have to be the steps followed by XPath to arrive at the
node. So you can’t say that XPath exposes the internal logic externally
since the steps may not be the internal logic it uses at all, and it’s
fair to say that one interpretation of the path from users can’t be used
to determine whether the language is procedural or declarative.
However, if you are saying that given a
requirement to address the very node C that appears in a certain context such
as /A/B/C, there is an alternative to specify the requested C that is better
than the way to specify the steps navigating to the C, then I would suggest you
might argue more about it rather than declaring that XPath as a programming language
is procedural.
Lisa
From: mike@adatinc.com
[mailto:mike@adatinc.com]
Sent: Thursday, February 07, 2008
6:38 PM
To: Xia Li; mike@adatinc.com;
noah_mendelsohn@us.ibm.com
Cc: xml-dev@lists.xml.org
Subject: Re: [xml-dev] The
limitations of XPath and navigation for XML database processing
-----Original Message-----
From: Xia Li [mailto:xli@galdosinc.com]
Sent: Thursday, February 7, 2008
08:14 PM
To: mike@adatinc.com,
noah_mendelsohn@us.ibm.com
Cc: xml-dev@lists.xml.org
Subject: RE: [xml-dev] The
limitations of XPath and navigation for XML database processing
|
Hi Mike,
You wrote, ?What it boils down to with me is that
XPath is logically specifying the logic (externally) that is needed to be
performed (internally). The external navigation instructions must be
specified procedurally to correctly define any of the possible choices for
internal operations.?
But it is not XPath requires you to define
the detailed step from A to C with /A/B/C. It is the requirement of your
application that requires you to give such a detailed step so that you can
get the C that appears within B which is under A. If your application, for
example, just want to retrieve C no matter where it appears, then even with
XPath, you can just say ?//C? without giving every step from A to C. So I
think the path is actually says what you want instead of instructing the
processor how to get it.
Lisa
Hi Lisa,
What about ?//C//G?. To me as an external
user, it says go to C, then go to G (from C). How it is processed internally
is not important as long as it gets the right result. "//C"
could be argued either way I think, but generally navigation has to be
externally specified as a series of steps.
/Mike
|
