| // Copyright (c) 2001-2009 Hartmut Kaiser |
| // |
| // 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) |
| |
| #if !defined(BOOST_SPIRIT_KARMA_META_GRAMMAR_MAY_01_2007_0313PM) |
| #define BOOST_SPIRIT_KARMA_META_GRAMMAR_MAY_01_2007_0313PM |
| |
| #if defined(_MSC_VER) && (_MSC_VER >= 1020) |
| #pragma once // MS compatible compilers support #pragma once |
| #endif |
| |
| #include <boost/spirit/home/karma/domain.hpp> |
| #include <boost/spirit/home/support/meta_grammar.hpp> |
| #include <boost/utility/enable_if.hpp> |
| |
| namespace boost { namespace spirit { namespace karma |
| { |
| /////////////////////////////////////////////////////////////////////////// |
| // forwards |
| /////////////////////////////////////////////////////////////////////////// |
| template <typename Char> |
| struct any_stream; |
| |
| template <typename Char> |
| struct stream_director; |
| |
| struct main_meta_grammar; |
| |
| template <typename Expr, typename Enable> |
| struct is_valid_expr; |
| |
| template <typename Expr, typename Enable> |
| struct expr_transform; |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // get the director for a stream |
| /////////////////////////////////////////////////////////////////////////// |
| template <typename Tag> |
| struct extract_any_stream_director; |
| |
| template <> |
| struct extract_any_stream_director<tag::stream> |
| { |
| typedef any_stream<char> type; |
| }; |
| |
| template <> |
| struct extract_any_stream_director<tag::wstream> |
| { |
| typedef any_stream<wchar_t> type; |
| }; |
| |
| /////////////////////////////////////////////////////////////////////////// |
| template <typename Tag, typename T> |
| struct extract_stream_director; |
| |
| template <typename T> |
| struct extract_stream_director<tag::stream, T> |
| { |
| typedef stream_director<char> type; |
| }; |
| |
| template <typename T> |
| struct extract_stream_director<tag::wstream, T> |
| { |
| typedef stream_director<wchar_t> type; |
| }; |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // utility meta-grammar |
| /////////////////////////////////////////////////////////////////////////// |
| struct utility_meta_grammar |
| : proto::or_< |
| // stream, wstream |
| meta_grammar::compose_empty< |
| proto::if_< |
| is_stream_tag<proto::_child, karma::domain>() |
| >, |
| karma::domain, |
| mpl::identity<extract_any_stream_director<mpl::_> > |
| >, |
| // stream(T), wstream(T) |
| meta_grammar::compose_function1_eval< |
| proto::function< |
| proto::if_< |
| is_stream_tag<proto::_child, karma::domain>() |
| >, |
| proto::_ |
| >, |
| karma::domain, |
| mpl::identity<extract_stream_director<mpl::_, mpl::_> > |
| > |
| > |
| { |
| }; |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // These specializations non-intrusively hook into the Karma meta-grammar. |
| // (see karma/meta_grammar.hpp) |
| /////////////////////////////////////////////////////////////////////////// |
| template <typename Expr> |
| struct is_valid_expr< |
| Expr, |
| typename enable_if< |
| proto::matches<Expr, utility_meta_grammar> |
| >::type |
| > |
| : mpl::true_ |
| { |
| }; |
| |
| template <typename Expr> |
| struct expr_transform< |
| Expr, |
| typename enable_if< |
| proto::matches<Expr, utility_meta_grammar> |
| >::type |
| > |
| : mpl::identity<utility_meta_grammar> |
| { |
| }; |
| |
| }}} |
| |
| #endif |