diff options
Diffstat (limited to 'boost/parameter/aux_/pack/deduce_tag.hpp')
| -rw-r--r-- | boost/parameter/aux_/pack/deduce_tag.hpp | 217 |
1 files changed, 217 insertions, 0 deletions
diff --git a/boost/parameter/aux_/pack/deduce_tag.hpp b/boost/parameter/aux_/pack/deduce_tag.hpp new file mode 100644 index 0000000000..12ad563f53 --- /dev/null +++ b/boost/parameter/aux_/pack/deduce_tag.hpp @@ -0,0 +1,217 @@ +// Copyright David Abrahams, Daniel Wallin 2003. +// 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_PARAMETER_AUX_PACK_DEDUCE_TAG_HPP +#define BOOST_PARAMETER_AUX_PACK_DEDUCE_TAG_HPP + +namespace boost { namespace parameter { namespace aux { + + template < + typename Argument + , typename ArgumentPack + , typename DeducedArgs + , typename UsedArgs + , typename TagFn + , typename EmitsErrors + > + struct deduce_tag; +}}} // namespace boost::parameter::aux + +#include <boost/parameter/aux_/lambda_tag.hpp> +#include <boost/parameter/config.hpp> +#include <boost/mpl/apply_wrap.hpp> +#include <boost/mpl/lambda.hpp> + +#if defined(BOOST_PARAMETER_CAN_USE_MP11) + +namespace boost { namespace parameter { namespace aux { + + template <typename Predicate, typename Argument, typename ArgumentPack> + struct deduce_tag_condition_mpl + : ::boost::mpl::apply_wrap2< + typename ::boost::mpl::lambda< + Predicate + , ::boost::parameter::aux::lambda_tag + >::type + , Argument + , ArgumentPack + > + { + }; +}}} // namespace boost::parameter::aux + +#include <boost/parameter/aux_/has_nested_template_fn.hpp> +#include <boost/mp11/list.hpp> +#include <boost/mp11/utility.hpp> + +namespace boost { namespace parameter { namespace aux { + + template <typename Predicate, typename Argument, typename ArgumentPack> + struct deduce_tag_condition_mp11 + { + using type = ::boost::mp11::mp_apply_q< + Predicate + , ::boost::mp11::mp_list<Argument,ArgumentPack> + >; + }; + + template <typename Predicate, typename Argument, typename ArgumentPack> + using deduce_tag_condition = ::boost::mp11::mp_if< + ::boost::parameter::aux::has_nested_template_fn<Predicate> + , ::boost::parameter::aux + ::deduce_tag_condition_mp11<Predicate,Argument,ArgumentPack> + , ::boost::parameter::aux + ::deduce_tag_condition_mpl<Predicate,Argument,ArgumentPack> + >; +}}} // namespace boost::parameter::aux + +#else +#include <boost/mpl/bool.hpp> +#include <boost/mpl/if.hpp> +#include <boost/mpl/eval_if.hpp> +#include <boost/mpl/assert.hpp> +#endif // BOOST_PARAMETER_CAN_USE_MP11 + +#include <boost/parameter/aux_/set.hpp> +#include <boost/parameter/aux_/pack/tag_type.hpp> +#include <boost/parameter/aux_/pack/tag_deduced.hpp> + +namespace boost { namespace parameter { namespace aux { + + // Helper for deduce_tag<...>, below. + template < + typename Argument + , typename ArgumentPack + , typename DeducedArgs + , typename UsedArgs + , typename TagFn + , typename EmitsErrors + > + class deduce_tag0 + { + typedef typename DeducedArgs::spec _spec; + +#if defined(BOOST_PARAMETER_CAN_USE_MP11) + typedef typename ::boost::parameter::aux::deduce_tag_condition< + typename _spec::predicate +#else + typedef typename ::boost::mpl::apply_wrap2< + typename ::boost::mpl::lambda< + typename _spec::predicate + , ::boost::parameter::aux::lambda_tag + >::type +#endif + , Argument + , ArgumentPack + >::type _condition; + +#if !defined(BOOST_PARAMETER_CAN_USE_MP11) + // Deduced parameter matches several arguments. + BOOST_MPL_ASSERT(( + typename ::boost::mpl::eval_if< + typename ::boost::parameter::aux::has_key_< + UsedArgs + , typename ::boost::parameter::aux::tag_type<_spec>::type + >::type + , ::boost::mpl::eval_if< + _condition + , ::boost::mpl::if_< + EmitsErrors + , ::boost::mpl::false_ + , ::boost::mpl::true_ + > + , ::boost::mpl::true_ + > + , ::boost::mpl::true_ + >::type + )); +#endif // BOOST_PARAMETER_CAN_USE_MP11 + + public: +#if defined(BOOST_PARAMETER_CAN_USE_MP11) + using type = typename ::boost::mp11::mp_if< +#else + typedef typename ::boost::mpl::eval_if< +#endif + _condition + , ::boost::parameter::aux + ::tag_deduced<UsedArgs,_spec,Argument,TagFn> + , ::boost::parameter::aux::deduce_tag< + Argument + , ArgumentPack + , typename DeducedArgs::tail + , UsedArgs + , TagFn + , EmitsErrors + > +#if defined(BOOST_PARAMETER_CAN_USE_MP11) + >::type; +#else + >::type type; +#endif + }; +}}} // namespace boost::parameter::aux + +#include <boost/parameter/aux_/void.hpp> + +#if defined(BOOST_PARAMETER_CAN_USE_MP11) +#include <type_traits> +#else +#include <boost/mpl/pair.hpp> +#include <boost/type_traits/is_same.hpp> +#endif + +namespace boost { namespace parameter { namespace aux { + + // Tries to deduced a keyword tag for a given Argument. + // Returns an mpl::pair<> consisting of the tagged_argument<>, + // and an mpl::set<> where the new tag has been inserted. + // + // Argument: The argument type to be tagged. + // + // ArgumentPack: The ArgumentPack built so far. + // + // DeducedArgs: A specialization of deduced_item<> (see below). + // A list containing only the deduced ParameterSpecs. + // + // UsedArgs: An mpl::set<> containing the keyword tags used so far. + // + // TagFn: A metafunction class used to tag positional or deduced + // arguments with a keyword tag. + template < + typename Argument + , typename ArgumentPack + , typename DeducedArgs + , typename UsedArgs + , typename TagFn + , typename EmitsErrors + > + struct deduce_tag +#if defined(BOOST_PARAMETER_CAN_USE_MP11) + : ::boost::mp11::mp_if< + ::std::is_same<DeducedArgs,::boost::parameter::void_> + , ::boost::mp11::mp_identity< + ::boost::mp11::mp_list< ::boost::parameter::void_,UsedArgs> + > +#else + : ::boost::mpl::eval_if< + ::boost::is_same<DeducedArgs,::boost::parameter::void_> + , ::boost::mpl::pair< ::boost::parameter::void_,UsedArgs> +#endif + , ::boost::parameter::aux::deduce_tag0< + Argument + , ArgumentPack + , DeducedArgs + , UsedArgs + , TagFn + , EmitsErrors + > + > + { + }; +}}} // namespace boost::parameter::aux + +#endif // include guard + |