x3/directive/expect.hpp

0001 /*=============================================================================
0002     Copyright (c) 2001-2014 Joel de Guzman
0003     Copyright (c) 2017 wanghan02
0004     Copyright (c) 2024 Nana Sakisaka
0005
0006     Distributed under the Boost Software License, Version 1.0. (See accompanying
0007     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0008 =============================================================================*/
0009 #if !defined(BOOST_SPIRIT_X3_EXPECT_MARCH_16_2012_1024PM)
0010 #define BOOST_SPIRIT_X3_EXPECT_MARCH_16_2012_1024PM
0011
0012 #include <boost/spirit/home/x3/support/context.hpp>
0013 #include <boost/spirit/home/x3/support/expectation.hpp>
0014 #include <boost/spirit/home/x3/core/parser.hpp>
0015 #include <boost/spirit/home/x3/core/detail/parse_into_container.hpp>
0016
0017 namespace boost { namespace spirit { namespace x3
0018 {
0019     template <typename Subject>
0020     struct expect_directive : unary_parser<Subject, expect_directive<Subject>>
0021     {
0022         typedef unary_parser<Subject, expect_directive<Subject> > base_type;
0023         static bool const is_pass_through_unary = true;
0024
0025         constexpr expect_directive(Subject const& subject)
0026           : base_type(subject) {}
0027
0028         template <typename Iterator, typename Context
0029           , typename RContext, typename Attribute>
0030         bool parse(Iterator& first, Iterator const& last
0031           , Context const& context, RContext& rcontext, Attribute& attr) const
0032         {
0033             bool const r = this->subject.parse(first, last, context, rcontext, attr);
0034
0035             if (!r)
0036             {
0037             #if BOOST_SPIRIT_X3_THROW_EXPECTATION_FAILURE
0038                 boost::throw_exception(
0039                     expectation_failure<Iterator>(
0040                         first, what(this->subject)));
0041             #else
0042                 if (!has_expectation_failure(context))
0043                 {
0044                     set_expectation_failure(first, this->subject, context);
0045                 }
0046             #endif
0047             }
0048             return r;
0049         }
0050     };
0051
0052     struct expect_gen
0053     {
0054         template <typename Subject>
0055         constexpr expect_directive<typename extension::as_parser<Subject>::value_type>
0056         operator[](Subject const& subject) const
0057         {
0058             return { as_parser(subject) };
0059         }
0060     };
0061
0062     constexpr auto expect = expect_gen{};
0063 }}}
0064
0065 namespace boost { namespace spirit { namespace x3 { namespace detail
0066 {
0067     // Special case handling for expect expressions.
0068     template <typename Subject, typename Context, typename RContext>
0069     struct parse_into_container_impl<expect_directive<Subject>, Context, RContext>
0070     {
0071         template <typename Iterator, typename Attribute>
0072         static bool call(
0073             expect_directive<Subject> const& parser
0074           , Iterator& first, Iterator const& last
0075           , Context const& context, RContext& rcontext, Attribute& attr)
0076         {
0077             bool const r = parse_into_container(
0078                 parser.subject, first, last, context, rcontext, attr);
0079
0080             if (!r)
0081             {
0082             #if BOOST_SPIRIT_X3_THROW_EXPECTATION_FAILURE
0083                 boost::throw_exception(
0084                     expectation_failure<Iterator>(
0085                         first, what(parser.subject)));
0086             #else
0087                 if (!has_expectation_failure(context))
0088                 {
0089                     set_expectation_failure(first, parser.subject, context);
0090                 }
0091             #endif
0092             }
0093             return r;
0094         }
0095     };
0096 }}}}
0097
0098 #endif