| /*============================================================================= |
| 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_HOLD_FEBRUARY_6_2010_0917AM) |
| #define SPIRIT_HOLD_FEBRUARY_6_2010_0917AM |
| |
| #if defined(_MSC_VER) |
| #pragma once |
| #endif |
| |
| #include <boost/spirit/home/qi/meta_compiler.hpp> |
| #include <boost/spirit/home/qi/skip_over.hpp> |
| #include <boost/spirit/home/qi/parser.hpp> |
| #include <boost/spirit/home/support/attributes.hpp> |
| #include <boost/spirit/home/support/info.hpp> |
| #include <boost/spirit/home/support/common_terminals.hpp> |
| #include <boost/spirit/home/support/unused.hpp> |
| #include <boost/spirit/home/support/has_semantic_action.hpp> |
| |
| namespace boost { namespace spirit |
| { |
| /////////////////////////////////////////////////////////////////////////// |
| // Enablers |
| /////////////////////////////////////////////////////////////////////////// |
| template <> |
| struct use_directive<qi::domain, tag::hold> // enables hold |
| : mpl::true_ {}; |
| }} |
| |
| namespace boost { namespace spirit { namespace qi |
| { |
| using spirit::hold; |
| using spirit::hold_type; |
| |
| template <typename Subject> |
| struct hold_directive : unary_parser<hold_directive<Subject> > |
| { |
| typedef Subject subject_type; |
| hold_directive(Subject const& subject) |
| : subject(subject) {} |
| |
| template <typename Context, typename Iterator> |
| struct attribute |
| { |
| typedef typename |
| traits::attribute_of<subject_type, Context, Iterator>::type |
| type; |
| }; |
| |
| template <typename Iterator, typename Context |
| , typename Skipper, typename Attribute> |
| bool parse(Iterator& first, Iterator const& last |
| , Context& context, Skipper const& skipper, Attribute& attr) const |
| { |
| Attribute copy(attr); |
| if (subject.parse(first, last, context, skipper, copy)) |
| { |
| traits::swap_impl(copy, attr); |
| return true; |
| } |
| return false; |
| } |
| |
| template <typename Context> |
| info what(Context& context) const |
| { |
| return info("hold", subject.what(context)); |
| |
| } |
| |
| Subject subject; |
| }; |
| |
| /////////////////////////////////////////////////////////////////////////// |
| // Parser generators: make_xxx function (objects) |
| /////////////////////////////////////////////////////////////////////////// |
| template <typename Subject, typename Modifiers> |
| struct make_directive<tag::hold, Subject, Modifiers> |
| { |
| typedef hold_directive<Subject> result_type; |
| result_type operator()(unused_type, Subject const& subject, unused_type) const |
| { |
| return result_type(subject); |
| } |
| }; |
| }}} |
| |
| namespace boost { namespace spirit { namespace traits |
| { |
| template <typename Subject> |
| struct has_semantic_action<qi::hold_directive<Subject> > |
| : unary_has_semantic_action<Subject> {}; |
| }}} |
| |
| #endif |