RE: Determining the context node
Hi Evan & everyone, Thanks very much for your help--the context node has often confused me and this message from Evan is the most helpful information on it I've ever gotten (especially the part about for-each and apply-templates being the only things that change it). <xsl:value-of select="name()"/> is exactly what I was looking for. Re: xsl:copy, since I didn't know how to get the name of the node, I was trying to print out the content of the node using either xsl:copy or xsl:copy-of. I would think the only real way you could do this is to use xsl:copy...with xsl:copy-of if the current node had no text content (and perhaps contained other elements), you would get the text content of all the element(s) below it so you couldn't really tell what node you were on if you were in a deep tree structure. The problem with xsl:copy, however, was that if you were on a node with no text content itself (e.g. the node only contained other elements) you would get nothing. Thanks again! Allison -----Original Message----- From: Evan Lenz [mailto:evan@xxxxxxxxxxxx] Sent: Wednesday, April 12, 2006 10:59 PM To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx Subject: Re: Determining the context node Hi Allison, <xsl:value-of select="name()"/> will print the name of the current node (if it has a name) to the output. Also, the local-name() function returns just the local part, and namespace-uri() returns the namespace URI part. Each of these functions take a node-set as an argument (and operate on just the first node in the set if there's more than one), but the default argument is the context node, so that writing name(.) is equivalent to name(), for example. For debugging, you may also want to look at <xsl:message>, the content of which most processors print to stderr output. As far as keeping track of the context node goes, I try to write my code in such a way as to make this as transparent as possible. Bite-sized template rules, for example, let you look up just a few lines to see what the match attribute says, which often gives you a good hint as to the context, as long as the pattern is not completely generic like *. But even then you at least know it's an element. This is also one of the reasons why I try to avoid using xsl:call-template when context will be relevant. Instead, I use xsl:apply-templates with a particular mode name. Named templates don't give you any hints about the context. All you know is that the context is the same as the context of the corresponding xsl:call-template. But if you use a template rule instead (i.e. with a "match" attribute and invoked with xsl:apply-templates), then you can build in some documentation about your context without having to write any comments (which have the potential of getting out of sync). The key things to remember about the current node: 1. Only two instructions change it: <xsl:for-each> and <xsl:apply-templates> 2. <xsl:call-template> does *not* change the context I hope this helps. Once you've fully grasped context in XSLT, you'll be well on your way to mastery :-) I'm afraid I can't address your question about xsl:copy, because I can't make sense of it, given the way you've stated it. Maybe an example would help. Evan Allison Bloodworth wrote: > Hi, > > I sometimes get confused about what the context node is when I'm writing a > complicated XSL stylesheet. I'm wondering if someone can suggest an easy way > to determine what node I'm on (e.g. by using some code to print this info > out to my output)? > > I've tried xsl:copy, xsl:copy-of, and xsl:value-of, but I don't want to know > the value of the element, I want to know the name of the element (e.g. for > <EventWebsite>www.berkeley.edu</EventWebsite> I want to know that I'm on > EventWebsite, not that the value is www.berkeley.edu). Also, because most of > my elements contain other elements instead of text, often doing xsl:copy > (which is more rational than using copy-of) doesn't get me anything. I > assume there's probably an easy XPath expression for this, but even after > doing quite a bit of research I can't find it. > > Thanks for any suggestions on this! > > Allison Bloodworth > Principal Administrative Analyst > Technology Program Office > University of California, Berkeley > (415) 377-8243 > abloodworth@xxxxxxxxxxxx
PURCHASE STYLUS STUDIO ONLINE TODAY!
Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced!
Download The World's Best XML IDE!
Accelerate XML development with our award-winning XML IDE - Download a free trial today!
Subscribe in XML format