59 lines
1.4 KiB
C++
59 lines
1.4 KiB
C++
// Copyright (c) 2014-2021 Dr. Colin Hirsch and Daniel Frey
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
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#ifndef TAO_PEGTL_INTERNAL_OPT_HPP
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#define TAO_PEGTL_INTERNAL_OPT_HPP
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#include <type_traits>
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#include "../config.hpp"
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#include "enable_control.hpp"
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#include "seq.hpp"
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#include "success.hpp"
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#include "../apply_mode.hpp"
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#include "../rewind_mode.hpp"
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#include "../type_list.hpp"
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namespace TAO_PEGTL_NAMESPACE::internal
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{
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template< typename... Rules >
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struct opt
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: opt< seq< Rules... > >
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{};
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template<>
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struct opt<>
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: success
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{};
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template< typename Rule >
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struct opt< Rule >
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{
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using rule_t = opt;
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using subs_t = type_list< Rule >;
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template< apply_mode A,
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rewind_mode,
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template< typename... >
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class Action,
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template< typename... >
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class Control,
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typename ParseInput,
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typename... States >
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[[nodiscard]] static bool match( ParseInput& in, States&&... st )
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{
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(void)Control< Rule >::template match< A, rewind_mode::required, Action, Control >( in, st... );
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return true;
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}
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};
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template< typename... Rules >
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inline constexpr bool enable_control< opt< Rules... > > = false;
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} // namespace TAO_PEGTL_NAMESPACE::internal
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#endif
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