text: /*!
  @file
  Forward declares `boost::hana::default_` and `boost::hana::is_default`.
  
  @copyright Louis Dionne 2013-2016
  Distributed under the Boost Software License, Version 1.0.
  (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
   */
  
  #ifndef BOOST_HANA_FWD_CORE_DEFAULT_HPP
  #define BOOST_HANA_FWD_CORE_DEFAULT_HPP
  
  #include <boost/hana/config.hpp>
  
  
  BOOST_HANA_NAMESPACE_BEGIN
      //! @ingroup group-core
      //! Mark a tag-dispatched method implementation as a default implementation.
      //!
      //! When defining a new concept with tag-dispatched methods, it is
      //! sometimes possible to provide a default implementation for some
      //! method(s). Making `default_` a base class of such a default
      //! implementation makes it possible to detect whether the method
      //! was dispatched to the default implementation afterwards.
      //!
      //!
      //! Example
      //! -------
      //! @include example/core/default.cpp
      struct default_ { };
  
      //! @ingroup group-core
      //! Returns whether a tag-dispatched method implementation is a default
      //! implementation.
      //!
      //! Given a tag-dispatched method implementation `method_impl<T...>`,
      //! `is_default<method_impl<T...>>` returns whether `method_impl<T...>`
      //! is a default implementation. Note that if there is no default
      //! implementation for the method, then `is_default` should not be
      //! used unless a static assertion saying that "the method is not
      //! implemented" is acceptable.
      //!
      //!
      //! Example
      //! -------
      //! @include example/core/default.cpp
  #ifdef BOOST_HANA_DOXYGEN_INVOKED
      template <typename Method>
      struct is_default { see documentation };
  #else
      template <typename T, typename = void>
      struct is_default;
  #endif
  BOOST_HANA_NAMESPACE_END
  
  #endif // !BOOST_HANA_FWD_CORE_DEFAULT_HPP
  