qi/directive/expect.hpp

0001 /*=============================================================================
0002 Copyright (c) 2016 Frank Hein, maxence business consulting gmbh
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_EXPECT_HPP
0008 #define BOOST_SPIRIT_QI_DIRECTIVE_EXPECT_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/support/has_semantic_action.hpp>
0016 #include <boost/spirit/home/qi/detail/attributes.hpp>
0017 #include <boost/spirit/home/qi/detail/expectation_failure.hpp>
0018 #include <boost/spirit/home/support/common_terminals.hpp>
0019 #include <boost/spirit/home/support/handles_container.hpp>
0020 #include <boost/spirit/home/support/unused.hpp>
0021 #include <boost/spirit/home/support/info.hpp>
0022
0023 namespace boost { namespace spirit {
0024     ///////////////////////////////////////////////////////////////////////////
0025     // Enablers
0026     ///////////////////////////////////////////////////////////////////////////
0027     template <>
0028     struct use_directive<qi::domain, tag::expect> // enables expect[p]
0029         : mpl::true_ {};
0030 }}
0031
0032 namespace boost { namespace spirit { namespace qi {
0033
0034 #ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
0035     using spirit::expect;
0036 #endif
0037     using spirit::expect_type;
0038
0039     template <typename Subject>
0040     struct expect_directive : unary_parser<expect_directive<Subject> >
0041     {
0042         typedef result_of::compile<domain, Subject> subject_type;
0043
0044         template <typename Context, typename Iterator>
0045         struct attribute
0046         {
0047             typedef traits::attribute_of<subject_type, Context, Iterator>
0048                 type;
0049         };
0050
0051         expect_directive(Subject const& subject_) : subject(subject_) {}
0052
0053         template <typename Iterator, typename Context
0054             , typename Skipper, typename Attribute>
0055         bool parse(Iterator& first, Iterator const& last
0056             , Context& context, Skipper const& skipper
0057             , Attribute& attr_) const
0058         {
0059             typedef expectation_failure<Iterator> exception;
0060
0061             if (!subject.parse(first, last, context, skipper, attr_))
0062             {
0063                 boost::throw_exception(
0064                     exception(first, last, subject.what(context)));
0065 #if defined(BOOST_NO_EXCEPTIONS)
0066                 return false;            // for systems not supporting exceptions
0067 #endif
0068             }
0069             return true;
0070         }
0071
0072         template <typename Context>
0073         info what(Context& context) const
0074         {
0075             return info("expect", subject.what(context));
0076         }
0077
0078         Subject subject;
0079     };
0080
0081     ///////////////////////////////////////////////////////////////////////////
0082     // Parser generators: make_xxx function (objects)
0083     ///////////////////////////////////////////////////////////////////////////
0084     template <typename Subject, typename Modifiers>
0085     struct make_directive<tag::expect, Subject, Modifiers>
0086     {
0087         typedef expect_directive<Subject> result_type;
0088
0089         result_type operator()
0090             (unused_type, Subject const& subject, unused_type) const
0091         {
0092             return result_type(subject);
0093         }
0094     };
0095
0096 }}}
0097
0098 namespace boost { namespace spirit { namespace traits {
0099     ///////////////////////////////////////////////////////////////////////////
0100     template <typename Subject>
0101     struct has_semantic_action<qi::expect_directive<Subject> >
0102         : unary_has_semantic_action<Subject> {};
0103
0104     ///////////////////////////////////////////////////////////////////////////
0105     template <typename Subject, typename Attribute
0106         , typename Context, typename Iterator>
0107     struct handles_container<
0108         qi::expect_directive<Subject>, Attribute, Context, Iterator
0109     >
0110         : unary_handles_container<Subject, Attribute, Context, Iterator> {};
0111 }}}
0112
0113 #endif