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F&O: Non-capturing sub-expressions

From: Bjoern Hoehrmann <derhoermi@gmx.net>
Date: Sat, 14 Jan 2006 16:11:34 +0100
To: public-qt-comments@w3.org
Message-ID: <lc4is1te6aidlij6ml68oet6vf5seha2bq@hive.bjoern.hoehrmann.de>

Dear XML Query Working Group,
Dear XSL Working Group,

  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.

regards,
-- 
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 Saturday, 14 January 2006 15:10:57 UTC

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