[Bug 2732] Non-capturing subexpressions


           Summary: Non-capturing subexpressions
           Product: XPath / XQuery / XSLT
           Version: Candidate Recommendation
          Platform: PC
        OS/Version: Windows XP
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Functions and Operators
        AssignedTo: ashok.malhotra@oracle.com
        ReportedBy: ashok.malhotra@oracle.com
         QAContact: public-qt-comments@w3.org

Opened: 2006-01-15 19:30

http://www.w3.org/TR/2005/CR-xpath-functions-20051103/ extends the semantics
of the regular expressions defined in XML Schema 1.0 to allow for capture
buffers; I would like to re-use regular expressions as de- fined in the
candidate recommendation in a DTLL-like format, but an imporant requirement is
automatic assignment of names for the captured substrings based on the index
number of the parenthesized sub-expression as defined in the technical report.

This is not feasible however with the current syntax as it does not allow
non-capturing sub-expressions, so I would have to further extend the format
which makes sharing of regular expressions and regex engines difficult. In fact,
in order to re-use regular expressions as found on many web sites and programs,
and as produced by many tools, one would first have to re-write them to fit into
this model.

I thus think the regular expression syntax should further be extended to allow
for non-capturing sub-expressions using a syntax like (?:...) as is available in
most other regular expression formats.

Björn Höhrmann · mailto:bjoern@hoehrmann.de · http://bjoern.hoehrmann.de Weinh.
Str. 22 · Telefon: +49(0)621/4309674 · http://www.bjoernsworld.de
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Received on Friday, 20 January 2006 16:22:30 UTC