qi/directive/lexeme.hpp

0001 /*=============================================================================
0002     Copyright (c) 2001-2011 Joel de Guzman
0003
0004     Distributed under the Boost Software License, Version 1.0. (See accompanying
0005     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 =============================================================================*/
0007 #ifndef BOOST_SPIRIT_QI_DIRECTIVE_LEXEME_HPP
0008 #define BOOST_SPIRIT_QI_DIRECTIVE_LEXEME_HPP
0009
0010 #if defined(_MSC_VER)
0011 #pragma once
0012 #endif
0013
0014 #include <boost/spirit/home/qi/meta_compiler.hpp>
0015 #include <boost/spirit/home/qi/skip_over.hpp>
0016 #include <boost/spirit/home/qi/parser.hpp>
0017 #include <boost/spirit/home/qi/detail/unused_skipper.hpp>
0018 #include <boost/spirit/home/support/unused.hpp>
0019 #include <boost/spirit/home/support/common_terminals.hpp>
0020 #include <boost/spirit/home/qi/detail/attributes.hpp>
0021 #include <boost/spirit/home/support/info.hpp>
0022 #include <boost/spirit/home/support/handles_container.hpp>
0023 #include <boost/utility/enable_if.hpp>
0024
0025 namespace boost { namespace spirit
0026 {
0027     ///////////////////////////////////////////////////////////////////////////
0028     // Enablers
0029     ///////////////////////////////////////////////////////////////////////////
0030     template <>
0031     struct use_directive<qi::domain, tag::lexeme> // enables lexeme
0032       : mpl::true_ {};
0033 }}
0034
0035 namespace boost { namespace spirit { namespace qi
0036 {
0037 #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
0038     using spirit::lexeme;
0039 #endif
0040     using spirit::lexeme_type;
0041
0042     template <typename Subject>
0043     struct lexeme_directive : unary_parser<lexeme_directive<Subject> >
0044     {
0045         typedef Subject subject_type;
0046         lexeme_directive(Subject const& subject_)
0047           : subject(subject_) {}
0048
0049         template <typename Context, typename Iterator>
0050         struct attribute
0051         {
0052             typedef typename
0053                 traits::attribute_of<subject_type, Context, Iterator>::type
0054             type;
0055         };
0056
0057         template <typename Iterator, typename Context
0058           , typename Skipper, typename Attribute>
0059         typename disable_if<detail::is_unused_skipper<Skipper>, bool>::type
0060         parse(Iterator& first, Iterator const& last
0061           , Context& context, Skipper const& skipper
0062           , Attribute& attr_) const
0063         {
0064             qi::skip_over(first, last, skipper);
0065             return subject.parse(first, last, context
0066               , detail::unused_skipper<Skipper>(skipper), attr_);
0067         }
0068         template <typename Iterator, typename Context
0069           , typename Skipper, typename Attribute>
0070         typename enable_if<detail::is_unused_skipper<Skipper>, bool>::type
0071         parse(Iterator& first, Iterator const& last
0072           , Context& context, Skipper const& skipper
0073           , Attribute& attr_) const
0074         {
0075             //  no need to pre-skip if skipper is unused
0076             //- qi::skip_over(first, last, skipper);
0077             return subject.parse(first, last, context
0078               , skipper, attr_);
0079         }
0080
0081         template <typename Context>
0082         info what(Context& context) const
0083         {
0084             return info("lexeme", subject.what(context));
0085
0086         }
0087
0088         Subject subject;
0089     };
0090
0091     ///////////////////////////////////////////////////////////////////////////
0092     // Parser generators: make_xxx function (objects)
0093     ///////////////////////////////////////////////////////////////////////////
0094     template <typename Subject, typename Modifiers>
0095     struct make_directive<tag::lexeme, Subject, Modifiers>
0096     {
0097         typedef lexeme_directive<Subject> result_type;
0098         result_type operator()(unused_type, Subject const& subject, unused_type) const
0099         {
0100             return result_type(subject);
0101         }
0102     };
0103 }}}
0104
0105 namespace boost { namespace spirit { namespace traits
0106 {
0107     ///////////////////////////////////////////////////////////////////////////
0108     template <typename Subject>
0109     struct has_semantic_action<qi::lexeme_directive<Subject> >
0110       : unary_has_semantic_action<Subject> {};
0111
0112     ///////////////////////////////////////////////////////////////////////////
0113     template <typename Subject, typename Attribute, typename Context
0114         , typename Iterator>
0115     struct handles_container<qi::lexeme_directive<Subject>, Attribute
0116         , Context, Iterator>
0117       : unary_handles_container<Subject, Attribute, Context, Iterator> {};
0118 }}}
0119
0120 #endif