| // Copyright Daniel Wallin 2006. Use, modification and distribution is |
| // 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) |
| |
| #ifndef BOOST_PARAMETER_CAST_060902_HPP |
| # define BOOST_PARAMETER_CAST_060902_HPP |
| |
| # include <boost/detail/workaround.hpp> |
| |
| # if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) \ |
| && !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564)) |
| # include <boost/type_traits/add_reference.hpp> |
| # include <boost/type_traits/remove_const.hpp> |
| # endif |
| |
| namespace boost { namespace parameter { namespace aux { |
| |
| struct use_default_tag {}; |
| |
| # if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) \ |
| || BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564)) |
| |
| # define BOOST_PARAMETER_FUNCTION_CAST(value, predicate) value |
| |
| # else |
| |
| // Handles possible implicit casts. Used by preprocessor.hpp to |
| // normalize user input. |
| // |
| // cast<void*>::execute() is identity |
| // cast<void*(X)>::execute() is identity |
| // cast<void(X)>::execute() casts to X |
| // |
| // preprocessor.hpp uses this like this: |
| // |
| // #define X(value, predicate) |
| // cast<void predicate>::execute(value) |
| // |
| // X(something, *) |
| // X(something, *(predicate)) |
| // X(something, (int)) |
| |
| template <class T, class Args> |
| struct cast; |
| |
| template <class Args> |
| struct cast<void*, Args> |
| { |
| static use_default_tag execute(use_default_tag) |
| { |
| return use_default_tag(); |
| } |
| |
| static use_default_tag remove_const(use_default_tag) |
| { |
| return use_default_tag(); |
| } |
| |
| template <class U> |
| static U& execute(U& value) |
| { |
| return value; |
| } |
| |
| template <class U> |
| static U& remove_const(U& x) |
| { |
| return x; |
| } |
| }; |
| |
| #if BOOST_WORKAROUND(__SUNPRO_CC, BOOST_TESTED_AT(0x580)) |
| |
| typedef void* voidstar; |
| |
| template <class T, class Args> |
| struct cast<voidstar(T), Args> |
| : cast<void*, Args> |
| { |
| }; |
| |
| #else |
| |
| template <class T, class Args> |
| struct cast<void*(T), Args> |
| : cast<void*, Args> |
| { |
| }; |
| |
| #endif |
| |
| // This is a hack used in cast<> to turn the user supplied type, |
| // which may or may not be a placeholder expression into one, so |
| // that it will be properly evaluated by mpl::apply. |
| template <class T, class Dummy = mpl::_1> |
| struct as_placeholder_expr |
| { |
| typedef T type; |
| }; |
| |
| template <class T, class Args> |
| struct cast<void(T), Args> |
| { |
| typedef typename mpl::apply2< |
| as_placeholder_expr<T>, Args, Args>::type type0; |
| |
| typedef typename boost::add_reference< |
| typename boost::remove_const<type0>::type |
| >::type reference; |
| |
| static use_default_tag execute(use_default_tag) |
| { |
| return use_default_tag(); |
| } |
| |
| static use_default_tag remove_const(use_default_tag) |
| { |
| return use_default_tag(); |
| } |
| |
| static type0 execute(type0 value) |
| { |
| return value; |
| } |
| |
| template <class U> |
| static reference remove_const(U const& x) |
| { |
| return const_cast<reference>(x); |
| } |
| }; |
| |
| # define BOOST_PARAMETER_FUNCTION_CAST(value, predicate, args) \ |
| boost::parameter::aux::cast<void predicate, args>::remove_const( \ |
| boost::parameter::aux::cast<void predicate, args>::execute(value) \ |
| ) |
| |
| # endif |
| |
| }}} // namespace boost::parameter::aux |
| |
| #endif // BOOST_PARAMETER_CAST_060902_HPP |
| |