qi/directive/seek.hpp

0001 /*=============================================================================
0002     Copyright (c) 2011 Jamboree
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_REPOSITORY_QI_SEEK
0008 #define BOOST_SPIRIT_REPOSITORY_QI_SEEK
0009
0010
0011 #if defined(_MSC_VER)
0012 #pragma once
0013 #endif
0014
0015
0016 #include <boost/spirit/home/qi/meta_compiler.hpp>
0017 #include <boost/spirit/home/qi/parser.hpp>
0018 #include <boost/spirit/home/qi/detail/attributes.hpp>
0019 #include <boost/spirit/home/support/info.hpp>
0020 #include <boost/spirit/home/support/unused.hpp>
0021 #include <boost/spirit/home/support/has_semantic_action.hpp>
0022 #include <boost/spirit/home/support/handles_container.hpp>
0023 #include <boost/spirit/repository/home/support/seek.hpp>
0024
0025
0026 namespace boost { namespace spirit
0027 {
0028     ///////////////////////////////////////////////////////////////////////////
0029     // Enablers
0030     ///////////////////////////////////////////////////////////////////////////
0031
0032     // enables seek[...]
0033     template <>
0034     struct use_directive<qi::domain, repository::tag::seek>
0035       : mpl::true_ {};
0036 }} // namespace boost::spirit
0037
0038
0039 namespace boost { namespace spirit { namespace repository {namespace qi
0040 {
0041 #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
0042     using repository::seek;
0043 #endif
0044     using repository::seek_type;
0045
0046     template <typename Subject>
0047     struct seek_directive
0048       : spirit::qi::unary_parser<seek_directive<Subject> >
0049     {
0050         typedef Subject subject_type;
0051
0052         template <typename Context, typename Iterator>
0053         struct attribute
0054         {
0055             typedef typename
0056                 traits::attribute_of<subject_type, Context, Iterator>::type
0057             type;
0058         };
0059
0060         seek_directive(Subject const& subject)
0061           : subject(subject)
0062         {}
0063
0064         template
0065         <
0066             typename Iterator, typename Context
0067           , typename Skipper, typename Attribute
0068         >
0069         bool parse
0070         (
0071             Iterator& first, Iterator const& last
0072           , Context& context, Skipper const& skipper
0073           , Attribute& attr
0074         ) const
0075         {
0076             for (Iterator it(first); ; ++it)
0077             {
0078                 if (subject.parse(it, last, context, skipper, attr))
0079                 {
0080                     first = it;
0081                     return true;
0082                 }
0083                 // fail only after subject fails & no input
0084                 if (it == last)
0085                     return false;
0086             }
0087         }
0088
0089         template <typename Context>
0090         info what(Context& context) const
0091         {
0092             return info("seek", subject.what(context));
0093         }
0094
0095         Subject subject;
0096     };
0097 }}}} // namespace boost::spirit::repository::qi
0098
0099
0100 namespace boost { namespace spirit { namespace qi
0101 {
0102     ///////////////////////////////////////////////////////////////////////////
0103     // Parser generators: make_xxx function (objects)
0104     ///////////////////////////////////////////////////////////////////////////
0105     template <typename Subject, typename Modifiers>
0106     struct make_directive<repository::tag::seek, Subject, Modifiers>
0107     {
0108         typedef repository::qi::seek_directive<Subject> result_type;
0109
0110         result_type operator()(unused_type, Subject const& subject, unused_type) const
0111         {
0112             return result_type(subject);
0113         }
0114     };
0115 }}} // namespace boost::spirit::qi
0116
0117
0118 namespace boost { namespace spirit { namespace traits
0119 {
0120     ///////////////////////////////////////////////////////////////////////////
0121     template <typename Subject>
0122     struct has_semantic_action<repository::qi::seek_directive<Subject> >
0123       : unary_has_semantic_action<Subject> {};
0124
0125     ///////////////////////////////////////////////////////////////////////////
0126     template <typename Subject, typename Attribute, typename Context
0127         , typename Iterator>
0128     struct handles_container<repository::qi::seek_directive<Subject>, Attribute
0129         , Context, Iterator>
0130       : unary_handles_container<Subject, Attribute, Context, Iterator> {};
0131 }}} // namespace boost::spirit::traits
0132
0133
0134 #endif