ceph/src/boost/libs/spirit/include/boost/spirit/home/x3/support/traits/transform_attribute.hpp

   1 /*=============================================================================
   2     Copyright (c) 2001-2014 Joel de Guzman
   3     Copyright (c) 2001-2012 Hartmut Kaiser
   4     http://spirit.sourceforge.net/
   5
   6     Distributed under the Boost Software License, Version 1.0. (See accompanying
   7     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   8 =============================================================================*/
   9 #if !defined(BOOST_SPIRIT_X3_ATTRIBUTE_TRANSFORM_JAN_8_2012_0721PM)
  10 #define BOOST_SPIRIT_X3_ATTRIBUTE_TRANSFORM_JAN_8_2012_0721PM
  11
  12 #include <boost/mpl/identity.hpp>
  13
  14 namespace boost { namespace spirit { namespace x3 { namespace traits
  15 {
  16     ///////////////////////////////////////////////////////////////////////////
  17     //  transform_attribute
  18     //
  19     //  Sometimes the user needs to transform the attribute types for certain
  20     //  attributes. This template can be used as a customization point, where
  21     //  the user is able specify specific transformation rules for any attribute
  22     //  type.
  23     ///////////////////////////////////////////////////////////////////////////
  24     template <typename Exposed, typename Transformed, typename Tag
  25       , typename Enable = void>
  26     struct transform_attribute;
  27
  28     ///////////////////////////////////////////////////////////////////////////
  29     template <typename Tag, typename Transformed, typename Exposed>
  30     typename transform_attribute<Exposed, Transformed, Tag>::type
  31     pre_transform(Exposed& attr)
  32     {
  33         return transform_attribute<Exposed, Transformed, Tag>::pre(attr);
  34     }
  35
  36     template <typename Tag, typename Transformed, typename Exposed>
  37     typename transform_attribute<Exposed, Transformed, Tag>::type
  38     pre_transform(Exposed const& attr)
  39     {
  40         return transform_attribute<Exposed const, Transformed, Tag>::pre(attr);
  41     }
  42 }}}}
  43
  44 #endif