from xpath to surrounding context?

["Evan Owens" <Evan.Owens@portico.org>]

Given an xpath expression that points into a document, can anyone suggest a clever way to extract an arbitrary chunk of the document immediately before and after that point?  Say, 40 characters before and after?

 

Here's the use case: we have an error report that is generated as part of an XSLT batch transformation process.  The error message include the xpath that describes the element that caused the problem; e.g.,   /ART[1]/BM[1]/BIBL[1]/BIB[5]/NOTE[1]/P[1].  The users of the report have requested that we add a bit of context to help them assess the errors without having to open every single file...a preview snippet as it were. 

 

It doesn't have to be a pure XML solution nor does it have to be extremely efficient in processor time.  These are not large documents and it would be okay to reread the files as part of the error report generation.  

 

Thanks in advance for any suggestions as to ways to tackle this problem.

 

Evan Owens