Subject: Re: [xsl] Re: Re: What do we have in variable? From: "Roma Yankin" <polfin@xxxxxxxx> Date: Fri, 10 May 2002 14:38:20 +0400 |
----- Original Message ----- From: "Dimitre Novatchev" <dnovatchev@xxxxxxxxx> To: <xsl-list@xxxxxxxxxxxxxxxxxxxxxx> Sent: Thursday, May 09, 2002 11:48 PM Subject: [xsl] Re: Re: What do we have in variable? > > >I'm just trying to understand, whenever we initialize some variable > > > for example in that way <xsl:variable name="somevar" > > > select="ancestor::*"/> what do we have stored inside it? Is it an > > > array or some root node? > > > > It's not an array: there is no such thing in the data model. Nor is > > it a root node: it's a node set. > > More precisely, in this concrete case this will evaluate to a node-set > consisting only of element nodes, or the empty node-set. > > > > > What node set it is, exactly, depends on the context node, which is > > to say the node from which the ancestory axis, in this case, is > > traversed; this will depend on where the variable declaration occurs > > (inside which template or instruction, etc.). The dependence of the > > node set returned by an XPath location path on the context in which > > that location path is invoked is one of the important subtleties of > > XPath commonly missed by newcomers to the language. > > I think that the question "what an xsl:variable contains?" is a little > bit incorrect. The right question should be: "what an xsl:variable > evaluates to?". > > For me "contains" is synonymous with "it is a store, that has contents > at any moment". > > On the other side, an xsl:variable may be evaluated only when it's been > referenced (e.g. lazy evaluation), or it may not be created at all > until it's necessary, or it may be destroyed between two moments when > it's referenced (e.g. space optimisation). > > I think, it's important to distinguish an xsl:variable from "store". In > fact it is a "definition", which may or may not be evaluated. > > Cheers, > Dimitre Novatchev. > > > > Thanks everyone for your input!!! I guess the problem is resolved Roman. XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list
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