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Diffstat (limited to 'boost/spirit/home/x3/auxiliary/guard.hpp')
-rw-r--r-- | boost/spirit/home/x3/auxiliary/guard.hpp | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/boost/spirit/home/x3/auxiliary/guard.hpp b/boost/spirit/home/x3/auxiliary/guard.hpp new file mode 100644 index 0000000000..6fd63c822c --- /dev/null +++ b/boost/spirit/home/x3/auxiliary/guard.hpp @@ -0,0 +1,73 @@ +/*============================================================================= + 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 |