[Boost-bugs] [Boost C++ Libraries] #6216: Add an unwrap adaptor to Range

Subject: [Boost-bugs] [Boost C++ Libraries] #6216: Add an unwrap adaptor to Range
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2011-12-05 16:28:51

#6216: Add an unwrap adaptor to Range
---------------------------------+------------------------------------------
 Reporter:  ne01026@…            |       Owner:  neilgroves
     Type:  Feature Requests     |      Status:  new       
Milestone:  To Be Determined     |   Component:  range     
  Version:  Boost 1.48.0         |    Severity:  Problem   
 Keywords:                       |  
---------------------------------+------------------------------------------
 Iterator adaptors can be easily unwrapped by calling `iterator .base ()`;
 range adaptors should provide a similar functionality.

 My implementation:

 {{{
 #!cpp
 namespace boost
 {
   namespace adaptors
   {
     namespace detail
 { struct unwrap_forwarder {};
 template < class P_R >
 inline
 ::boost:: iterator_range
     < typename ::boost:: range_iterator < P_R >:: type:: base_type >
 operator | (P_R const &p_r, detail:: unwrap_forwarder const &)
     {
 return
 ::boost:: make_iterator_range
   (::boost:: begin (p_r). base (), ::boost:: end (p_r). base ()); }
       /* !boost.adaptors.|unwrapped X */ } /* &boost.adaptors.detail X */
     namespace
 {
 detail:: unwrap_forwarder const
 (&unwrapped) ((detail:: unwrap_forwarder ())); }
  } /* &boost.adaptors X */ } /* &boost X */
 }}}

 My test:

 {{{
 #!cpp
 int main ()
 { ::boost:: iterator_range < ::std:: string:: const_iterator >
       ((::boost:: equal_range
         (::std:: string ()
 | ::boost:: adaptors:: transformed (::std:: negate < int > ()), 0)
         | ::boost:: adaptors:: unwrapped)); }
 }}}

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/6216>
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