[XSL-LIST Mailing List Archive Home] [By Thread] [By Date]

Re: [xsl] Comparing nodes in XPath

Subject: Re: [xsl] Comparing nodes in XPath
From: Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>
Date: Fri, 21 Jan 2005 15:57:56 -0500

At 03:13 PM 1/21/2005, you wrote:
Ok, but that's not the case when using variable. And i change that to


but it still doen4t work the way i expected...


What you're missing is the concept of the "context node" for evaluating the

The expression "Conn" is short for "child::Conn".

The expression "./Conn" is short for "self::node()/child::Conn".

In the example provided, the context node for the expression "@id=Conn" or
"@id=./Conn" is the same -- as Mike said, the connection. (The context node
for a predicate is each of the nodes being predicated.) Both of these
expressions return the same thing when the context is the same.

When you use a variable, you have already bound your Conn child to the
variable when the expression is evaluated, so the context node is not a
concern. Note that where you bind your variable does matter.

If you did extra work to do the same thing, and said

<xsl:for-each select="document('connections.xml')/connections/connection">
  <xsl:variable name="conn" select="Conn"/>
  <xsl:if test="@id = $conn">
    <xsl:value-of select="."/>

it wouldn't work. (Nor would you, an XSLT expert, expect it to.) But this

<xsl:variable name="conn" select="Conn"/>
<xsl:for-each select="document('connections.xml')/connections/connection">
  <xsl:if test="@id = $conn">
    <xsl:value-of select="."/>

Right? (And this is the better analogue to what you're doing when your
predicate has "@id=$conn")

The short answer: you probably want your predicate to read
"@id=current()/Conn", though without seeing the rest of the logic it's
impossible to be certain. Or just use the variable: we do this all the time.


====================================================================== Wendell Piez mailto:wapiez@xxxxxxxxxxxxxxxx Mulberry Technologies, Inc. http://www.mulberrytech.com 17 West Jefferson Street Direct Phone: 301/315-9635 Suite 207 Phone: 301/315-9631 Rockville, MD 20850 Fax: 301/315-8285 ---------------------------------------------------------------------- Mulberry Technologies: A Consultancy Specializing in SGML and XML ======================================================================

Current Thread