| /*============================================================================= |
| Copyright (c) 2001-2014 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(BOOST_SPIRIT_X3_GUARD_FERBRUARY_02_2013_0649PM) |
| #define BOOST_SPIRIT_X3_GUARD_FERBRUARY_02_2013_0649PM |
| |
| #if defined(_MSC_VER) |
| #pragma once |
| #endif |
| |
| #include <boost/spirit/home/x3/support/context.hpp> |
| #include <boost/spirit/home/x3/directive/expect.hpp> |
| |
| namespace boost { namespace spirit { namespace x3 |
| { |
| enum class error_handler_result |
| { |
| fail |
| , retry |
| , accept |
| , rethrow |
| }; |
| |
| template <typename Subject, typename Handler> |
| struct guard : unary_parser<Subject, guard<Subject, Handler>> |
| { |
| typedef unary_parser<Subject, guard<Subject, Handler>> base_type; |
| static bool const is_pass_through_unary = true; |
| |
| guard(Subject const& subject, Handler handler) |
| : base_type(subject), handler(handler) {} |
| |
| template <typename Iterator, typename Context |
| , typename RuleContext, typename Attribute> |
| bool parse(Iterator& first, Iterator const& last |
| , Context const& context, RuleContext& rcontext, Attribute& attr) const |
| { |
| for (;;) |
| { |
| try |
| { |
| Iterator i = first; |
| bool r = this->subject.parse(i, last, context, rcontext, attr); |
| if (r) |
| first = i; |
| return r; |
| } |
| catch (expectation_failure<Iterator> const& x) |
| { |
| switch (handler(first, last, x, context)) |
| { |
| case error_handler_result::fail: |
| return false; |
| case error_handler_result::retry: |
| continue; |
| case error_handler_result::accept: |
| return true; |
| case error_handler_result::rethrow: |
| throw; |
| } |
| } |
| } |
| return false; |
| } |
| |
| Handler handler; |
| }; |
| }}} |
| |
| #endif |