123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131 |
- ///////////////////////////////////////////////////////////////////////////////
- // as_alternate.hpp
- //
- // Copyright 2008 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_XPRESSIVE_DETAIL_STATIC_TRANSFORMS_AS_ALTERNATE_HPP_EAN_04_01_2007
- #define BOOST_XPRESSIVE_DETAIL_STATIC_TRANSFORMS_AS_ALTERNATE_HPP_EAN_04_01_2007
- // MS compatible compilers support #pragma once
- #if defined(_MSC_VER)
- # pragma once
- #endif
- #include <boost/config.hpp>
- #include <boost/mpl/assert.hpp>
- #include <boost/type_traits/is_same.hpp>
- #include <boost/proto/core.hpp>
- #include <boost/xpressive/detail/detail_fwd.hpp>
- #include <boost/xpressive/detail/static/static.hpp>
- #include <boost/xpressive/detail/core/matcher/alternate_matcher.hpp>
- #include <boost/xpressive/detail/utility/cons.hpp>
- namespace boost { namespace xpressive
- {
- namespace detail
- {
- ///////////////////////////////////////////////////////////////////////////////
- // alternates_list
- // a fusion-compatible sequence of alternate expressions, that also keeps
- // track of the list's width and purity.
- template<typename Head, typename Tail>
- struct alternates_list
- : fusion::cons<Head, Tail>
- {
- BOOST_STATIC_CONSTANT(std::size_t, width = Head::width == Tail::width ? Head::width : detail::unknown_width::value);
- BOOST_STATIC_CONSTANT(bool, pure = Head::pure && Tail::pure);
- alternates_list(Head const &head, Tail const &tail)
- : fusion::cons<Head, Tail>(head, tail)
- {
- }
- };
- template<typename Head>
- struct alternates_list<Head, fusion::nil>
- : fusion::cons<Head, fusion::nil>
- {
- BOOST_STATIC_CONSTANT(std::size_t, width = Head::width);
- BOOST_STATIC_CONSTANT(bool, pure = Head::pure);
- alternates_list(Head const &head, fusion::nil const &tail)
- : fusion::cons<Head, fusion::nil>(head, tail)
- {
- }
- };
- }
- namespace grammar_detail
- {
- ///////////////////////////////////////////////////////////////////////////////
- // in_alternate_list
- template<typename Grammar, typename Callable = proto::callable>
- struct in_alternate_list : proto::transform<in_alternate_list<Grammar, Callable> >
- {
- template<typename Expr, typename State, typename Data>
- struct impl : proto::transform_impl<Expr, State, Data>
- {
- typedef
- detail::alternates_list<
- typename Grammar::template impl<
- Expr
- , detail::alternate_end_xpression
- , Data
- >::result_type
- , State
- >
- result_type;
- result_type operator ()(
- typename impl::expr_param expr
- , typename impl::state_param state
- , typename impl::data_param data
- ) const
- {
- return result_type(
- typename Grammar::template impl<Expr, detail::alternate_end_xpression, Data>()(
- expr
- , detail::alternate_end_xpression()
- , data
- )
- , state
- );
- }
- };
- };
- ///////////////////////////////////////////////////////////////////////////////
- // as_alternate_matcher
- template<typename Grammar, typename Callable = proto::callable>
- struct as_alternate_matcher : proto::transform<as_alternate_matcher<Grammar, Callable> >
- {
- template<typename Expr, typename State, typename Data>
- struct impl : proto::transform_impl<Expr, State, Data>
- {
- typedef typename impl::data data_type;
- typedef
- detail::alternate_matcher<
- typename Grammar::template impl<Expr, State, Data>::result_type
- , typename data_type::traits_type
- >
- result_type;
- result_type operator ()(
- typename impl::expr_param expr
- , typename impl::state_param state
- , typename impl::data_param data
- ) const
- {
- return result_type(
- typename Grammar::template impl<Expr, State, Data>()(expr, state, data)
- );
- }
- };
- };
- }
- }}
- #endif
|