Boost C++ Libraries

boost/xpressive/proto/literal.hpp

///////////////////////////////////////////////////////////////////////////////
/// \file literal.hpp
/// The literal\<\> terminal wrapper, and the proto::lit() function for
/// creating literal\<\> wrappers.
//
//  Copyright 2007 Eric Niebler. Distributed under 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)

#ifndef BOOST_PROTO_LITERAL_HPP_EAN_01_03_2007
#define BOOST_PROTO_LITERAL_HPP_EAN_01_03_2007

#include <boost/xpressive/proto/detail/prefix.hpp>
#include <boost/xpressive/proto/proto_fwd.hpp>
#include <boost/xpressive/proto/expr.hpp>
#include <boost/xpressive/proto/traits.hpp>
#include <boost/xpressive/proto/extends.hpp>
#include <boost/xpressive/proto/detail/suffix.hpp>

namespace boost { namespace proto
{
    namespace utility
    {
        template<typename T, typename Domain>
        struct literal
          : extends<typename terminal<T>::type, literal<T, Domain>, Domain>
        {
            typedef typename terminal<T>::type terminal_type;
            typedef extends<terminal_type, literal<T, Domain>, Domain> base_type;

            template<typename U>
            literal(U &u)
              : base_type(terminal_type::make(u))
            {}

            template<typename U>
            literal(U const &u)
              : base_type(terminal_type::make(u))
            {}

            template<typename U>
            literal(literal<U, Domain> const &u)
              : base_type(terminal_type::make(proto::arg(u)))
            {}

            using base_type::operator =;
        };
    }

    /// lit
    ///
    template<typename T>
    inline literal<T &> lit(T &t)
    {
        return literal<T &>(t);
    }

    /// \overload
    ///
    template<typename T>
    inline literal<T const &> lit(T const &t)
    {
        #ifdef _MSC_VER
        #pragma warning(push)
        #pragma warning(disable: 4180) // warning C4180: qualifier applied to function type has no meaning; ignored
        #endif

        return literal<T const &>(t);

        #ifdef _MSC_VER
        #pragma warning(pop)
        #endif
    }

}}

#endif