| Line | Branch | Exec | Source |
|---|---|---|---|
| 1 | // | ||
| 2 | // Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com) | ||
| 3 | // | ||
| 4 | // Distributed under the Boost Software License, Version 1.0. (See accompanying | ||
| 5 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | ||
| 6 | // | ||
| 7 | // Official repository: https://github.com/boostorg/url | ||
| 8 | // | ||
| 9 | |||
| 10 | #ifndef BOOST_URL_GRAMMAR_OPTIONAL_RULE_HPP | ||
| 11 | #define BOOST_URL_GRAMMAR_OPTIONAL_RULE_HPP | ||
| 12 | |||
| 13 | #include <boost/url/detail/config.hpp> | ||
| 14 | #include <boost/url/optional.hpp> | ||
| 15 | #include <boost/url/error_types.hpp> | ||
| 16 | #include <boost/core/empty_value.hpp> | ||
| 17 | #include <boost/assert.hpp> | ||
| 18 | |||
| 19 | namespace boost { | ||
| 20 | namespace urls { | ||
| 21 | namespace grammar { | ||
| 22 | |||
| 23 | /** Match a rule, or the empty string | ||
| 24 | |||
| 25 | Optional BNF elements are denoted with | ||
| 26 | square brackets. If the specified rule | ||
| 27 | returns any error it is treated as if | ||
| 28 | the rule did not match. | ||
| 29 | |||
| 30 | @par Value Type | ||
| 31 | @code | ||
| 32 | using value_type = optional< typename Rule::value_type >; | ||
| 33 | @endcode | ||
| 34 | |||
| 35 | @par Example | ||
| 36 | Rules are used with the function @ref grammar::parse. | ||
| 37 | @code | ||
| 38 | system::result< optional< core::string_view > > rv = parse( "", optional_rule( token_rule( alpha_chars ) ) ); | ||
| 39 | @endcode | ||
| 40 | |||
| 41 | @par BNF | ||
| 42 | @code | ||
| 43 | optional = [ rule ] | ||
| 44 | @endcode | ||
| 45 | |||
| 46 | @par Specification | ||
| 47 | @li <a href="https://datatracker.ietf.org/doc/html/rfc5234#section-3.8" | ||
| 48 | >3.8. Optional Sequence (rfc5234)</a> | ||
| 49 | |||
| 50 | @param r The rule to match | ||
| 51 | |||
| 52 | @see | ||
| 53 | @ref alpha_chars, | ||
| 54 | @ref parse, | ||
| 55 | @ref optional, | ||
| 56 | @ref token_rule. | ||
| 57 | */ | ||
| 58 | #ifdef BOOST_URL_DOCS | ||
| 59 | template<class Rule> | ||
| 60 | constexpr | ||
| 61 | __implementation_defined__ | ||
| 62 | optional_rule( Rule r ) noexcept; | ||
| 63 | #else | ||
| 64 | namespace implementation_defined { | ||
| 65 | template<class Rule> | ||
| 66 | struct optional_rule_t | ||
| 67 | : private empty_value<Rule> | ||
| 68 | { | ||
| 69 | using value_type = boost::optional< | ||
| 70 | typename Rule::value_type>; | ||
| 71 | |||
| 72 | system::result<value_type> | ||
| 73 | parse( | ||
| 74 | char const*& it, | ||
| 75 | char const* end) const; | ||
| 76 | |||
| 77 | constexpr | ||
| 78 | 2030 | optional_rule_t( | |
| 79 | Rule const& r) noexcept | ||
| 80 | : empty_value<Rule>( | ||
| 81 | empty_init, | ||
| 82 | 2030 | r) | |
| 83 | { | ||
| 84 | 2030 | } | |
| 85 | }; | ||
| 86 | } // implementation_defined | ||
| 87 | |||
| 88 | /** Match a rule, or the empty string | ||
| 89 | |||
| 90 | Optional BNF elements are denoted with | ||
| 91 | square brackets. If the specified rule | ||
| 92 | returns any error it is treated as if | ||
| 93 | the rule did not match. | ||
| 94 | |||
| 95 | @par Value Type | ||
| 96 | @code | ||
| 97 | using value_type = optional< typename Rule::value_type >; | ||
| 98 | @endcode | ||
| 99 | |||
| 100 | @par Example | ||
| 101 | Rules are used with the function @ref grammar::parse. | ||
| 102 | @code | ||
| 103 | system::result< optional< core::string_view > > rv = parse( "", optional_rule( token_rule( alpha_chars ) ) ); | ||
| 104 | @endcode | ||
| 105 | |||
| 106 | @par BNF | ||
| 107 | @code | ||
| 108 | optional = [ rule ] | ||
| 109 | @endcode | ||
| 110 | |||
| 111 | @par Specification | ||
| 112 | @li <a href="https://datatracker.ietf.org/doc/html/rfc5234#section-3.8" | ||
| 113 | >3.8. Optional Sequence (rfc5234)</a> | ||
| 114 | |||
| 115 | @param r The rule to match | ||
| 116 | |||
| 117 | @see | ||
| 118 | @ref alpha_chars, | ||
| 119 | @ref parse, | ||
| 120 | @ref optional, | ||
| 121 | @ref token_rule. | ||
| 122 | */ | ||
| 123 | template<class Rule> | ||
| 124 | auto | ||
| 125 | constexpr | ||
| 126 | 1966 | optional_rule( | |
| 127 | Rule const& r) -> | ||
| 128 | implementation_defined::optional_rule_t<Rule> | ||
| 129 | { | ||
| 130 | 1966 | return { r }; | |
| 131 | } | ||
| 132 | #endif | ||
| 133 | |||
| 134 | } // grammar | ||
| 135 | } // urls | ||
| 136 | } // boost | ||
| 137 | |||
| 138 | #include <boost/url/grammar/impl/optional_rule.hpp> | ||
| 139 | |||
| 140 | #endif | ||
| 141 |