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DTLL and Regular Expression Named Capture Groups

• From: "Pete Cordell" <petexmldev@codalogic.com>
• To: "XML Developers List" <xml-dev@lists.xml.org>
• Date: Sat, 5 Mar 2011 18:30:15 -0000

Most likely this has already been considered, but I note that DTLL as 
described at:

http://www.jenitennison.com/datatypes/DTLL.html

uses regular expression named capture groups of the form:

(?[year][0-9]{4})

etc.

Perl 5.10 and later does support named capture groups, as described at:

http://perldoc.perl.org/perlretut.html#Named-backreferences

The two forms supported are:

(?<name>...) and (?'name'...).

I note Jeni's comments about the former, but I believe the latter would work 
OK.

Thus instead of:

(?[year]-?[0-9]{4})-(?[month][0-9]{2})-(?[day][0-9]{2})

you'd have:

(?'year'-?[0-9]{4})-(?'month'[0-9]{2})-(?'day'[0-9]{2})

while in some ways I think the current DTLL option is better, I think 
consistency is more important than aesthetics in this case.

HTH,

Pete Cordell
Codalogic Ltd
Interface XML to C++ the easy way using C++ XML
data binding to convert XSD schemas to C++ classes.
Visit http://codalogic.com/lmx/ or http://www.xml2cpp.com
for more info

• Follow-Ups:
  • Re: DTLL and Regular Expression Named Capture Groups
    • From: David Carlisle <davidc@nag.co.uk>