ceph/src/boost/libs/metaparse/doc/metaprogramming_value.qbk

   1 [#metaprogramming_value]
   2 [section Template metaprogramming value]
   3
   4 A ['template metaprogramming value] is a
   5 [link nullary_metafunction nullary template metafunction] returning itself.
   6 For example:
   7
   8   struct void_
   9   {
  10     using type = void_;
  11   };
  12
  13 This template metaprogramming value is called `void_`. It is a nullary
  14 metafunction returning itself as its result. Because of this, it can be treated
  15 as a nullary metafunction and evaluated any number of times. For example
  16 `void_::type::type::type` is still `void_`.
  17
  18 [endsect]
  19