access.hpp

来自「Boost provides free peer-reviewed portab」· HPP 代码 · 共 42 行

/*=============================================================================
    Copyright (c) 2006-2007 Tobias Schwinger
  
    Use modification and distribution are subject to the Boost Software 
    License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
    http://www.boost.org/LICENSE_1_0.txt).
==============================================================================*/

#if !defined(BOOST_FUSION_FUNCTIONAL_ADAPTER_DETAIL_ACCESS_HPP_INCLUDED)
#define BOOST_FUSION_FUNCTIONAL_ADAPTER_DETAIL_ACCESS_HPP_INCLUDED

namespace boost { namespace fusion { namespace detail
{
    // const reference deduction for function templates that accept T const &
    template <typename T> struct cref               { typedef T const& type; };
    template <typename T> struct cref<T&>           { typedef T const& type; };
    template <typename T> struct cref<T const>      { typedef T const& type; };

    // mutable reference deduction for function templates that accept T &
    template <typename T> struct mref               { typedef T      & type; };
    template <typename T> struct mref<T&>           { typedef T      & type; };

    // generic reference deduction for function templates that are overloaded
    // to accept both T const & and T &
    template <typename T> struct gref               { typedef T const& type; };
    template <typename T> struct gref<T&>           { typedef T      & type; };
    template <typename T> struct gref<T const>      { typedef T const& type; };

    // appropriately qualified target function in const context
    template <typename T> struct qf_c          { typedef T const  type; };
    template <typename T> struct qf_c<T const> { typedef T const  type; };
    template <typename T> struct qf_c<T &>     { typedef T        type; };

    // appropriately qualified target function in non-const context
    template <typename T> struct qf            { typedef T        type; };
    template <typename T> struct qf<T const>   { typedef T const  type; };
    template <typename T> struct qf<T &>       { typedef T        type; };
}}}

#endif