| /*============================================================================= |
| Copyright (c) 2001-2010 Joel de Guzman |
| |
| 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(SPIRIT_ACTION_JANUARY_07_2007_1128AM) |
| #define SPIRIT_ACTION_JANUARY_07_2007_1128AM |
| |
| #if defined(_MSC_VER) |
| #pragma once |
| #endif |
| |
| #include <boost/spirit/home/qi/meta_compiler.hpp> |
| #include <boost/spirit/home/qi/parser.hpp> |
| #include <boost/spirit/home/qi/detail/attributes.hpp> |
| #include <boost/spirit/home/support/argument.hpp> |
| #include <boost/spirit/home/support/context.hpp> |
| #include <boost/spirit/home/support/unused.hpp> |
| #include <boost/spirit/home/support/info.hpp> |
| #include <boost/spirit/home/support/action_dispatch.hpp> |
| |
| #include <boost/mpl/bool.hpp> |
| #include <boost/mpl/if.hpp> |
| #include <boost/type_traits/remove_const.hpp> |
| #include <boost/type_traits/is_same.hpp> |
| |
| namespace boost { namespace spirit { namespace qi |
| { |
| BOOST_PP_REPEAT(SPIRIT_ARGUMENTS_LIMIT, SPIRIT_USING_ARGUMENT, _) |
| |
| template <typename Subject, typename Action> |
| struct action : unary_parser<action<Subject, Action> > |
| { |
| typedef Subject subject_type; |
| typedef Action action_type; |
| |
| template <typename Context, typename Iterator> |
| struct attribute |
| : traits::attribute_of<Subject, Context, Iterator> |
| {}; |
| |
| action(Subject const& subject, Action f) |
| : subject(subject), f(f) {} |
| |
| template <typename Iterator, typename Context |
| , typename Skipper, typename Attribute> |
| bool parse(Iterator& first, Iterator const& last |
| , Context& context, Skipper const& skipper |
| , Attribute& attr_) const |
| { |
| typedef typename attribute<Context, Iterator>::type attr_type; |
| typedef traits::make_attribute<attr_type, Attribute> make_attribute; |
| |
| // create an attribute if one is not supplied |
| typedef traits::transform_attribute< |
| typename make_attribute::type, attr_type, domain> transform; |
| |
| typename make_attribute::type made_attr = make_attribute::call(attr_); |
| typename transform::type attr = transform::pre(made_attr); |
| |
| Iterator save = first; |
| if (subject.parse(first, last, context, skipper, attr)) |
| { |
| // call the function, passing the attribute, the context. |
| // The client can return false to fail parsing. |
| if (traits::action_dispatch<Subject>()(f, attr, context)) |
| return true; |
| |
| // reset iterators if semantic action failed the match |
| // retrospectively |
| first = save; |
| } |
| return false; |
| } |
| |
| template <typename Context> |
| info what(Context& context) const |
| { |
| // the action is transparent (does not add any info) |
| return subject.what(context); |
| } |
| |
| Subject subject; |
| Action f; |
| |
| private: |
| // silence MSVC warning C4512: assignment operator could not be generated |
| action& operator= (action const&); |
| }; |
| }}} |
| |
| namespace boost { namespace spirit |
| { |
| // Qi action meta-compiler |
| template <> |
| struct make_component<qi::domain, tag::action> |
| { |
| template <typename Sig> |
| struct result; |
| |
| template <typename This, typename Elements, typename Modifiers> |
| struct result<This(Elements, Modifiers)> |
| { |
| typedef typename |
| remove_const<typename Elements::car_type>::type |
| subject_type; |
| |
| typedef typename |
| remove_const<typename Elements::cdr_type::car_type>::type |
| action_type; |
| |
| typedef qi::action<subject_type, action_type> type; |
| }; |
| |
| template <typename Elements> |
| typename result<make_component(Elements, unused_type)>::type |
| operator()(Elements const& elements, unused_type) const |
| { |
| typename result<make_component(Elements, unused_type)>::type |
| result(elements.car, elements.cdr.car); |
| return result; |
| } |
| }; |
| }} |
| |
| namespace boost { namespace spirit { namespace traits |
| { |
| template <typename Subject, typename Action> |
| struct has_semantic_action<qi::action<Subject, Action> > |
| : mpl::true_ {}; |
| |
| }}} |
| |
| #endif |