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Match pattern vs XPath
Added by Anonymous about 16 years ago
Legacy ID: #5766209
Legacy Poster: David Lee (daldei)
Is there any API in Saxon that makes a Match Pattern into an XPath ? I'm using the
XPath classes from s9API and find I need to handle "Match Patterns"
instead. Is there some kind of regex or api that I can take a match pattern and convert
it into an xpath to use with the saxon API ? Example: (trivial case) Match Pattern =
"foo" Xpath expression = "//foo" but its not as
simple as adding "//" to the pattern because the match pattern CAN
start with "/" and look like an xpath expression. The other thought I
had was to iterate the nodes one by one cand call the XPath evaluator on each node in
turn as the context ... but I think that may be exponentially more inefficient then
trying to convert a match pattern to an xpath expression and calling the evaluator once.
Legacy ID: #5776709
Legacy Poster: Michael Kay (mhkay)
The s9api XPathCompiler class in 9.1 introduced a method compilerPattern() which
takes an XSLT pattern as input and returns an equivalent XPath expression. The
equivalence isn't quite as you had it in mind however - rather than returning an
expression that selects all the nodes that match, it returns an expression that
evaluates to true() if the context node matches, false() it it doesn't. So you can use
this by iterating over all the nodes in the document (use
XdmNode.axisIterator(Axis.DESCENDANT_OR_SELF)) and testing each one in turn against the
pattern.
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