Re: [Boost-bugs] [Boost C++ Libraries] #4704: Support for multicapture and balancing groups

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #4704: Support for multicapture and balancing groups
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2010-10-08 00:37:52

#4704: Support for multicapture and balancing groups
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  Reporter:  erik@…             |       Owner:  eric_niebler  
      Type:  Feature Requests   |      Status:  assigned      
 Milestone:  To Be Determined   |   Component:  xpressive     
   Version:  Boost 1.44.0       |    Severity:  Not Applicable
Resolution:                     |    Keywords:  xpressive     
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Comment (by Erik Rydgren <erik@…>):

 Replying to [comment:4 eric_niebler]:
 > There's probably a simple answer, but why did you change the handling of
 {{{token_named_mark}}} to allow the same capture name to be reused?
 Previously it was an error.

 I thought it to be nice to have the same capabilities in a dynamic
 expression as in static one. A static expression (s1 = whatever) << (s1 =
 whatever) is perfectly legal but the dynamic compiler frowned upon
 (?P<name> whatever) (?P<name> whatever). Now they behave the same. It
 makes it hard to figure out the resulting group numbers though, so these
 constructs are really only useful when using named multi captures. You can
 capture on several places in the expression to the same named stack of
 captures. Can be useful at times.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/4704#comment:6>
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