projects / ceph.git / blame
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1 | /*============================================================================= |
| 2 | Copyright (c) 2001-2014 Joel de Guzman | |
| 3 | Copyright (c) 2001-2011 Hartmut Kaiser | |
| 4 | ||
| 5 | Distributed under the Boost Software License, Version 1.0. (See accompanying | |
| 6 | file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
| 7 | =============================================================================*/ | |
| 11fdf7f2 TL |
8 | #if !defined(BOOST_SPIRIT_X3_OPTIONAL_MARCH_23_2007_1117PM) |
| 9 | #define BOOST_SPIRIT_X3_OPTIONAL_MARCH_23_2007_1117PM | |
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10 | |
| 11 | #include <boost/spirit/home/x3/core/proxy.hpp> | |
| 12 | #include <boost/spirit/home/x3/core/detail/parse_into_container.hpp> | |
| 13 | #include <boost/spirit/home/x3/support/traits/attribute_of.hpp> | |
| 14 | #include <boost/spirit/home/x3/support/traits/move_to.hpp> | |
| 15 | #include <boost/spirit/home/x3/support/traits/optional_traits.hpp> | |
| 16 | #include <boost/spirit/home/x3/support/traits/attribute_category.hpp> | |
| 17 | ||
| 18 | namespace boost { namespace spirit { namespace x3 | |
| 19 | { | |
| 20 | template <typename Subject> | |
| 21 | struct optional : proxy<Subject, optional<Subject>> | |
| 22 | { | |
| 23 | typedef proxy<Subject, optional<Subject>> base_type; | |
| 24 | static bool const handles_container = true; | |
| 25 | ||
| f67539c2 | 26 | constexpr optional(Subject const& subject) |
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27 | : base_type(subject) {} |
| 28 | ||
| 29 | using base_type::parse_subject; | |
| 30 | ||
| 31 | // Attribute is a container | |
| 32 | template <typename Iterator, typename Context | |
| 33 | , typename RContext, typename Attribute> | |
| 34 | bool parse_subject(Iterator& first, Iterator const& last | |
| 35 | , Context const& context, RContext& rcontext, Attribute& attr | |
| 36 | , traits::container_attribute) const | |
| 37 | { | |
| 38 | detail::parse_into_container( | |
| 39 | this->subject, first, last, context, rcontext, attr); | |
| 40 | return true; | |
| 41 | } | |
| 42 | ||
| 43 | // Attribute is an optional | |
| 44 | template <typename Iterator, typename Context | |
| 45 | , typename RContext, typename Attribute> | |
| 46 | bool parse_subject(Iterator& first, Iterator const& last | |
| 47 | , Context const& context, RContext& rcontext, Attribute& attr | |
| 48 | , traits::optional_attribute) const | |
| 49 | { | |
| 50 | typedef typename | |
| 51 | x3::traits::optional_value<Attribute>::type | |
| 52 | value_type; | |
| 53 | ||
| 54 | // create a local value | |
| 92f5a8d4 | 55 | value_type val{}; |
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56 | |
| 57 | if (this->subject.parse(first, last, context, rcontext, val)) | |
| 58 | { | |
| 59 | // assign the parsed value into our attribute | |
| 60 | x3::traits::move_to(val, attr); | |
| 61 | } | |
| 62 | return true; | |
| 63 | } | |
| 64 | }; | |
| 65 | ||
| 66 | template <typename Subject> | |
| f67539c2 | 67 | constexpr optional<typename extension::as_parser<Subject>::value_type> |
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68 | operator-(Subject const& subject) |
| 69 | { | |
| 70 | return { as_parser(subject) }; | |
| 71 | } | |
| 72 | }}} | |
| 73 | ||
| 74 | namespace boost { namespace spirit { namespace x3 { namespace traits | |
| 75 | { | |
| 76 | template <typename Subject, typename Context> | |
| 77 | struct attribute_of<x3::optional<Subject>, Context> | |
| 78 | : build_optional< | |
| 79 | typename attribute_of<Subject, Context>::type> {}; | |
| 80 | }}}} | |
| 81 | ||
| 82 | #endif |