Re: Re: why is "(chapter//footnote)" illegal?
On Sat, 23 Aug 2003, Dimitre Novatchev wrote: > > "Robert P. J. Day" <rpjday@xxxxxxxxxxxxxx> wrote in message > news:Pine.LNX.4.44.0308230904470.1866-100000@xxxxxxxxxxxxxxxxxxxxxxxx > > > > boning up on my predicates and patterns, i'm reading > > kay, p. 443, which states: > > > > "(chapter//footnote) is not a valid pattern. (Why not? > > No good reason, it's just that the spec doesn't allow it." > > It cannot be derived from the syntax of "Patterns" as specified in > > http://www.w3.org/TR/xslt#patterns > > If you remove the brackets you'll get a valid match pattern. > > > > > but on p. 408, there is an explanation of the (apparently > > acceptable) path expression "(chapter/para)". > > > > so is it just the difference between using the child axis > > and the descendant-or-self axis? it's not obvious to me > > why the first should be illegal while the second is legal. > > Because the first is illegal *pattern* (it is a legal XPath expression). > > Patterns are a strict subset of XPath expressions. > > Patterns were introduced (in my opinion) to allow for some optimization > opportunities as well as for sanity in the template matching and > instantiation process. i can see why, *technically*, the above holds. i guess my confusion is more that it's just non-intuitive, particularly since (according to kay, p. 355), the expression "($chapters//diagram)" is legal. so, we have (chapter/para) legal (chapter//footnote) illegal ($chapters//diagram) legal while i'm sure all of this holds according to the acceptable rules of patterns, it sure doesn't do any favors for those looking for obviously intuitive rules for what's legal and what isn't. rday XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list
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