Chris@102: /*=============================================================================
Chris@102:     Copyright (c) 2001-2014 Joel de Guzman
Chris@102: 
Chris@102:     Distributed under the Boost Software License, Version 1.0. (See accompanying
Chris@102:     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@102: =============================================================================*/
Chris@102: #if !defined(BOOST_SPIRIT_X3_GUARD_FERBRUARY_02_2013_0649PM)
Chris@102: #define BOOST_SPIRIT_X3_GUARD_FERBRUARY_02_2013_0649PM
Chris@102: 
Chris@102: #if defined(_MSC_VER)
Chris@102: #pragma once
Chris@102: #endif
Chris@102: 
Chris@102: #include <boost/spirit/home/x3/support/context.hpp>
Chris@102: #include <boost/spirit/home/x3/directive/expect.hpp>
Chris@102: 
Chris@102: namespace boost { namespace spirit { namespace x3
Chris@102: {
Chris@102:     enum class error_handler_result
Chris@102:     {
Chris@102:         fail
Chris@102:       , retry
Chris@102:       , accept
Chris@102:       , rethrow
Chris@102:     };
Chris@102: 
Chris@102:     template <typename Subject, typename Handler>
Chris@102:     struct guard : unary_parser<Subject, guard<Subject, Handler>>
Chris@102:     {
Chris@102:         typedef unary_parser<Subject, guard<Subject, Handler>> base_type;
Chris@102:         static bool const is_pass_through_unary = true;
Chris@102: 
Chris@102:         guard(Subject const& subject, Handler handler)
Chris@102:           : base_type(subject), handler(handler) {}
Chris@102: 
Chris@102:         template <typename Iterator, typename Context
Chris@102:           , typename RuleContext, typename Attribute>
Chris@102:         bool parse(Iterator& first, Iterator const& last
Chris@102:           , Context const& context, RuleContext& rcontext, Attribute& attr) const
Chris@102:         {
Chris@102:             for (;;)
Chris@102:             {
Chris@102:                 try
Chris@102:                 {
Chris@102:                     Iterator i = first;
Chris@102:                     bool r = this->subject.parse(i, last, context, rcontext, attr);
Chris@102:                     if (r)
Chris@102:                         first = i;
Chris@102:                     return r;
Chris@102:                 }
Chris@102:                 catch (expectation_failure<Iterator> const& x)
Chris@102:                 {
Chris@102:                     switch (handler(first, last, x, context))
Chris@102:                     {
Chris@102:                         case error_handler_result::fail:
Chris@102:                             return false;
Chris@102:                         case error_handler_result::retry:
Chris@102:                             continue;
Chris@102:                         case error_handler_result::accept:
Chris@102:                             return true;
Chris@102:                         case error_handler_result::rethrow:
Chris@102:                             throw;
Chris@102:                     }
Chris@102:                 }
Chris@102:             }
Chris@102:             return false;
Chris@102:         }
Chris@102: 
Chris@102:         Handler handler;
Chris@102:     };
Chris@102: }}}
Chris@102: 
Chris@102: #endif