Re: [xsl] variable in xpath?

Subject: Re: [xsl] variable in xpath?
From: "David N Bertoni/Cambridge/IBM" <david_n_bertoni@xxxxxxxxxx>
Date: Thu, 11 Apr 2002 16:58:29 -0700
Hi Steve,

'.' _always_ refers to the context node.  You're using the context node
implicitly when you call the name() function without an argument. That is:

   *[name()=$child]

is the same as

   *[name(.)=$child]

because of how the name() function is defined:

   http://www.w3.org/TR/xpath#function-name

   "...If the argument it omitted, it defaults to a node-set with the
   context node as its only member."

Many functions in XPath have the same default argument.

More info on the context node and predicate evaluation can be found in the
recommendation:

   http://www.w3.org/TR/xpath#predicates

In particular:

   "A predicate filters a node-set with respect to an axis to produce a new
   node-set. For each node in the node-set to be filtered, the
   PredicateExpr is evaluated with that node as the context node, with the
   number of nodes in the node-set as the context size, and with the
   proximity position of the node in the node-set with respect to the axis
   as the context position; if PredicateExpr evaluates to true for that
   node, the node is included in the new node-set; otherwise, it is not
   included."

If you're looking for an articulate description of the context node I'd
suggest Mike Kay's XSLT book.

Hope that helps...

Dave



|---------+------------------------------------->
|         |           "Steve Renshaw"           |
|         |           <renshaw_steve@xxxxxxxxxxx|
|         |           >                         |
|         |           Sent by:                  |
|         |           owner-xsl-list@xxxxxxxxxxx|
|         |           rrytech.com               |
|         |                                     |
|         |                                     |
|         |           04/11/2002 04:21 PM       |
|         |           Please respond to xsl-list|
|         |                                     |
|---------+------------------------------------->
  >---------------------------------------------------------------------------------------------------------------------------|
  |                                                                                                                           |
  |        To:      xsl-list@xxxxxxxxxxxxxxxxxxxxxx                                                                           |
  |        cc:      (bcc: David N Bertoni/Cambridge/IBM)                                                                      |
  |        Subject: Re: [xsl] variable in xpath?                                                                              |
  >---------------------------------------------------------------------------------------------------------------------------|



>select all <element> [which have a child element [whose name() is the same
>as stored in $child and whose concatenation of all descendant text nodes
is
>the same as stored in $value]]


Thanks. But for the second construct (I haven't tested it) it isn't 100%
clear what the context of "." is:

select="*[*[name()=$child and . = $value]]"

In what context is a dot used within nested predicates evaluated in?
I think I know what the answer is, but I am searching for an articulate
wording of it. Thansk agian



_________________________________________________________________
Join the world's largest e-mail service with MSN Hotmail.
http://www.hotmail.com


 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list







 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list


Current Thread