ext-boost/boost/url/grammar/not_empty_rule.hpp
2023-05-22 18:45:02 +10:00

109 lines
2.2 KiB
C++

//
// Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com)
//
// 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)
//
// Official repository: https://github.com/boostorg/url
//
#ifndef BOOST_URL_GRAMMAR_NOT_EMPTY_RULE_HPP
#define BOOST_URL_GRAMMAR_NOT_EMPTY_RULE_HPP
#include <boost/url/detail/config.hpp>
#include <boost/url/error_types.hpp>
#include <boost/url/grammar/type_traits.hpp>
namespace boost {
namespace urls {
namespace grammar {
/** Match another rule, if the result is not empty
This adapts another rule such that
when an empty string is successfully
parsed, the result is an error.
@par Value Type
@code
using value_type = typename Rule::value_type;
@endcode
@par Example
Rules are used with the function @ref parse.
@code
result< decode_view > rv = parse( "Program%20Files",
not_empty_rule( pct_encoded_rule( unreserved_chars ) ) );
@endcode
@param r The rule to match
@see
@ref parse,
@ref pct_encoded_rule,
@ref unreserved_chars.
*/
#ifdef BOOST_URL_DOCS
template<class Rule>
constexpr
__implementation_defined__
not_empty_rule( Rule r );
#else
template<class R>
struct not_empty_rule_t
{
using value_type =
typename R::value_type;
auto
parse(
char const*& it,
char const* end) const ->
result<value_type>;
template<class R_>
friend
constexpr
auto
not_empty_rule(
R_ const& r) ->
not_empty_rule_t<R_>;
private:
constexpr
not_empty_rule_t(
R const& r) noexcept
: r_(r)
{
}
R r_;
};
template<class Rule>
auto
constexpr
not_empty_rule(
Rule const& r) ->
not_empty_rule_t<Rule>
{
// If you get a compile error here it
// means that your rule does not meet
// the type requirements. Please check
// the documentation.
static_assert(
is_rule<Rule>::value,
"Rule requirements not met");
return { r };
}
#endif
} // grammar
} // urls
} // boost
#include <boost/url/grammar/impl/not_empty_rule.hpp>
#endif